1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/mm/page_alloc.c |
4 | * |
5 | * Manages the free list, the system allocates free pages here. |
6 | * Note that kmalloc() lives in slab.c |
7 | * |
8 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
9 | * Swap reorganised 29.12.95, Stephen Tweedie |
10 | * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 |
11 | * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999 |
12 | * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 |
13 | * Zone balancing, Kanoj Sarcar, SGI, Jan 2000 |
14 | * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002 |
15 | * (lots of bits borrowed from Ingo Molnar & Andrew Morton) |
16 | */ |
17 | |
18 | #include <linux/stddef.h> |
19 | #include <linux/mm.h> |
20 | #include <linux/highmem.h> |
21 | #include <linux/interrupt.h> |
22 | #include <linux/jiffies.h> |
23 | #include <linux/compiler.h> |
24 | #include <linux/kernel.h> |
25 | #include <linux/kasan.h> |
26 | #include <linux/kmsan.h> |
27 | #include <linux/module.h> |
28 | #include <linux/suspend.h> |
29 | #include <linux/ratelimit.h> |
30 | #include <linux/oom.h> |
31 | #include <linux/topology.h> |
32 | #include <linux/sysctl.h> |
33 | #include <linux/cpu.h> |
34 | #include <linux/cpuset.h> |
35 | #include <linux/memory_hotplug.h> |
36 | #include <linux/nodemask.h> |
37 | #include <linux/vmstat.h> |
38 | #include <linux/fault-inject.h> |
39 | #include <linux/compaction.h> |
40 | #include <trace/events/kmem.h> |
41 | #include <trace/events/oom.h> |
42 | #include <linux/prefetch.h> |
43 | #include <linux/mm_inline.h> |
44 | #include <linux/mmu_notifier.h> |
45 | #include <linux/migrate.h> |
46 | #include <linux/sched/mm.h> |
47 | #include <linux/page_owner.h> |
48 | #include <linux/page_table_check.h> |
49 | #include <linux/memcontrol.h> |
50 | #include <linux/ftrace.h> |
51 | #include <linux/lockdep.h> |
52 | #include <linux/psi.h> |
53 | #include <linux/khugepaged.h> |
54 | #include <linux/delayacct.h> |
55 | #include <linux/cacheinfo.h> |
56 | #include <asm/div64.h> |
57 | #include "internal.h" |
58 | #include "shuffle.h" |
59 | #include "page_reporting.h" |
60 | |
61 | /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */ |
62 | typedef int __bitwise fpi_t; |
63 | |
64 | /* No special request */ |
65 | #define FPI_NONE ((__force fpi_t)0) |
66 | |
67 | /* |
68 | * Skip free page reporting notification for the (possibly merged) page. |
69 | * This does not hinder free page reporting from grabbing the page, |
70 | * reporting it and marking it "reported" - it only skips notifying |
71 | * the free page reporting infrastructure about a newly freed page. For |
72 | * example, used when temporarily pulling a page from a freelist and |
73 | * putting it back unmodified. |
74 | */ |
75 | #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0)) |
76 | |
77 | /* |
78 | * Place the (possibly merged) page to the tail of the freelist. Will ignore |
79 | * page shuffling (relevant code - e.g., memory onlining - is expected to |
80 | * shuffle the whole zone). |
81 | * |
82 | * Note: No code should rely on this flag for correctness - it's purely |
83 | * to allow for optimizations when handing back either fresh pages |
84 | * (memory onlining) or untouched pages (page isolation, free page |
85 | * reporting). |
86 | */ |
87 | #define FPI_TO_TAIL ((__force fpi_t)BIT(1)) |
88 | |
89 | /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */ |
90 | static DEFINE_MUTEX(pcp_batch_high_lock); |
91 | #define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8) |
92 | |
93 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) |
94 | /* |
95 | * On SMP, spin_trylock is sufficient protection. |
96 | * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP. |
97 | */ |
98 | #define pcp_trylock_prepare(flags) do { } while (0) |
99 | #define pcp_trylock_finish(flag) do { } while (0) |
100 | #else |
101 | |
102 | /* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */ |
103 | #define pcp_trylock_prepare(flags) local_irq_save(flags) |
104 | #define pcp_trylock_finish(flags) local_irq_restore(flags) |
105 | #endif |
106 | |
107 | /* |
108 | * Locking a pcp requires a PCP lookup followed by a spinlock. To avoid |
109 | * a migration causing the wrong PCP to be locked and remote memory being |
110 | * potentially allocated, pin the task to the CPU for the lookup+lock. |
111 | * preempt_disable is used on !RT because it is faster than migrate_disable. |
112 | * migrate_disable is used on RT because otherwise RT spinlock usage is |
113 | * interfered with and a high priority task cannot preempt the allocator. |
114 | */ |
115 | #ifndef CONFIG_PREEMPT_RT |
116 | #define pcpu_task_pin() preempt_disable() |
117 | #define pcpu_task_unpin() preempt_enable() |
118 | #else |
119 | #define pcpu_task_pin() migrate_disable() |
120 | #define pcpu_task_unpin() migrate_enable() |
121 | #endif |
122 | |
123 | /* |
124 | * Generic helper to lookup and a per-cpu variable with an embedded spinlock. |
125 | * Return value should be used with equivalent unlock helper. |
126 | */ |
127 | #define pcpu_spin_lock(type, member, ptr) \ |
128 | ({ \ |
129 | type *_ret; \ |
130 | pcpu_task_pin(); \ |
131 | _ret = this_cpu_ptr(ptr); \ |
132 | spin_lock(&_ret->member); \ |
133 | _ret; \ |
134 | }) |
135 | |
136 | #define pcpu_spin_trylock(type, member, ptr) \ |
137 | ({ \ |
138 | type *_ret; \ |
139 | pcpu_task_pin(); \ |
140 | _ret = this_cpu_ptr(ptr); \ |
141 | if (!spin_trylock(&_ret->member)) { \ |
142 | pcpu_task_unpin(); \ |
143 | _ret = NULL; \ |
144 | } \ |
145 | _ret; \ |
146 | }) |
147 | |
148 | #define pcpu_spin_unlock(member, ptr) \ |
149 | ({ \ |
150 | spin_unlock(&ptr->member); \ |
151 | pcpu_task_unpin(); \ |
152 | }) |
153 | |
154 | /* struct per_cpu_pages specific helpers. */ |
155 | #define pcp_spin_lock(ptr) \ |
156 | pcpu_spin_lock(struct per_cpu_pages, lock, ptr) |
157 | |
158 | #define pcp_spin_trylock(ptr) \ |
159 | pcpu_spin_trylock(struct per_cpu_pages, lock, ptr) |
160 | |
161 | #define pcp_spin_unlock(ptr) \ |
162 | pcpu_spin_unlock(lock, ptr) |
163 | |
164 | #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID |
165 | DEFINE_PER_CPU(int, numa_node); |
166 | EXPORT_PER_CPU_SYMBOL(numa_node); |
167 | #endif |
168 | |
169 | DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key); |
170 | |
171 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES |
172 | /* |
173 | * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly. |
174 | * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined. |
175 | * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem() |
176 | * defined in <linux/topology.h>. |
177 | */ |
178 | DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */ |
179 | EXPORT_PER_CPU_SYMBOL(_numa_mem_); |
180 | #endif |
181 | |
182 | static DEFINE_MUTEX(pcpu_drain_mutex); |
183 | |
184 | #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY |
185 | volatile unsigned long latent_entropy __latent_entropy; |
186 | EXPORT_SYMBOL(latent_entropy); |
187 | #endif |
188 | |
189 | /* |
190 | * Array of node states. |
191 | */ |
192 | nodemask_t node_states[NR_NODE_STATES] __read_mostly = { |
193 | [N_POSSIBLE] = NODE_MASK_ALL, |
194 | [N_ONLINE] = { .bits: { [0] = 1UL } }, |
195 | #ifndef CONFIG_NUMA |
196 | [N_NORMAL_MEMORY] = { { [0] = 1UL } }, |
197 | #ifdef CONFIG_HIGHMEM |
198 | [N_HIGH_MEMORY] = { { [0] = 1UL } }, |
199 | #endif |
200 | [N_MEMORY] = { { [0] = 1UL } }, |
201 | [N_CPU] = { { [0] = 1UL } }, |
202 | #endif /* NUMA */ |
203 | }; |
204 | EXPORT_SYMBOL(node_states); |
205 | |
206 | gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; |
207 | |
208 | /* |
209 | * A cached value of the page's pageblock's migratetype, used when the page is |
210 | * put on a pcplist. Used to avoid the pageblock migratetype lookup when |
211 | * freeing from pcplists in most cases, at the cost of possibly becoming stale. |
212 | * Also the migratetype set in the page does not necessarily match the pcplist |
213 | * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any |
214 | * other index - this ensures that it will be put on the correct CMA freelist. |
215 | */ |
216 | static inline int get_pcppage_migratetype(struct page *page) |
217 | { |
218 | return page->index; |
219 | } |
220 | |
221 | static inline void set_pcppage_migratetype(struct page *page, int migratetype) |
222 | { |
223 | page->index = migratetype; |
224 | } |
225 | |
226 | #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE |
227 | unsigned int pageblock_order __read_mostly; |
228 | #endif |
229 | |
230 | static void __free_pages_ok(struct page *page, unsigned int order, |
231 | fpi_t fpi_flags); |
232 | |
233 | /* |
234 | * results with 256, 32 in the lowmem_reserve sysctl: |
235 | * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high) |
236 | * 1G machine -> (16M dma, 784M normal, 224M high) |
237 | * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA |
238 | * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL |
239 | * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA |
240 | * |
241 | * TBD: should special case ZONE_DMA32 machines here - in those we normally |
242 | * don't need any ZONE_NORMAL reservation |
243 | */ |
244 | static int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { |
245 | #ifdef CONFIG_ZONE_DMA |
246 | [ZONE_DMA] = 256, |
247 | #endif |
248 | #ifdef CONFIG_ZONE_DMA32 |
249 | [ZONE_DMA32] = 256, |
250 | #endif |
251 | [ZONE_NORMAL] = 32, |
252 | #ifdef CONFIG_HIGHMEM |
253 | [ZONE_HIGHMEM] = 0, |
254 | #endif |
255 | [ZONE_MOVABLE] = 0, |
256 | }; |
257 | |
258 | char * const zone_names[MAX_NR_ZONES] = { |
259 | #ifdef CONFIG_ZONE_DMA |
260 | "DMA" , |
261 | #endif |
262 | #ifdef CONFIG_ZONE_DMA32 |
263 | "DMA32" , |
264 | #endif |
265 | "Normal" , |
266 | #ifdef CONFIG_HIGHMEM |
267 | "HighMem" , |
268 | #endif |
269 | "Movable" , |
270 | #ifdef CONFIG_ZONE_DEVICE |
271 | "Device" , |
272 | #endif |
273 | }; |
274 | |
275 | const char * const migratetype_names[MIGRATE_TYPES] = { |
276 | "Unmovable" , |
277 | "Movable" , |
278 | "Reclaimable" , |
279 | "HighAtomic" , |
280 | #ifdef CONFIG_CMA |
281 | "CMA" , |
282 | #endif |
283 | #ifdef CONFIG_MEMORY_ISOLATION |
284 | "Isolate" , |
285 | #endif |
286 | }; |
287 | |
288 | int min_free_kbytes = 1024; |
289 | int user_min_free_kbytes = -1; |
290 | static int watermark_boost_factor __read_mostly = 15000; |
291 | static int watermark_scale_factor = 10; |
292 | |
293 | /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */ |
294 | int movable_zone; |
295 | EXPORT_SYMBOL(movable_zone); |
296 | |
297 | #if MAX_NUMNODES > 1 |
298 | unsigned int nr_node_ids __read_mostly = MAX_NUMNODES; |
299 | unsigned int nr_online_nodes __read_mostly = 1; |
300 | EXPORT_SYMBOL(nr_node_ids); |
301 | EXPORT_SYMBOL(nr_online_nodes); |
302 | #endif |
303 | |
304 | static bool page_contains_unaccepted(struct page *page, unsigned int order); |
305 | static void accept_page(struct page *page, unsigned int order); |
306 | static bool try_to_accept_memory(struct zone *zone, unsigned int order); |
307 | static inline bool has_unaccepted_memory(void); |
308 | static bool __free_unaccepted(struct page *page); |
309 | |
310 | int page_group_by_mobility_disabled __read_mostly; |
311 | |
312 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT |
313 | /* |
314 | * During boot we initialize deferred pages on-demand, as needed, but once |
315 | * page_alloc_init_late() has finished, the deferred pages are all initialized, |
316 | * and we can permanently disable that path. |
317 | */ |
318 | DEFINE_STATIC_KEY_TRUE(deferred_pages); |
319 | |
320 | static inline bool deferred_pages_enabled(void) |
321 | { |
322 | return static_branch_unlikely(&deferred_pages); |
323 | } |
324 | |
325 | /* |
326 | * deferred_grow_zone() is __init, but it is called from |
327 | * get_page_from_freelist() during early boot until deferred_pages permanently |
328 | * disables this call. This is why we have refdata wrapper to avoid warning, |
329 | * and to ensure that the function body gets unloaded. |
330 | */ |
331 | static bool __ref |
332 | _deferred_grow_zone(struct zone *zone, unsigned int order) |
333 | { |
334 | return deferred_grow_zone(zone, order); |
335 | } |
336 | #else |
337 | static inline bool deferred_pages_enabled(void) |
338 | { |
339 | return false; |
340 | } |
341 | #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ |
342 | |
343 | /* Return a pointer to the bitmap storing bits affecting a block of pages */ |
344 | static inline unsigned long *get_pageblock_bitmap(const struct page *page, |
345 | unsigned long pfn) |
346 | { |
347 | #ifdef CONFIG_SPARSEMEM |
348 | return section_to_usemap(ms: __pfn_to_section(pfn)); |
349 | #else |
350 | return page_zone(page)->pageblock_flags; |
351 | #endif /* CONFIG_SPARSEMEM */ |
352 | } |
353 | |
354 | static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn) |
355 | { |
356 | #ifdef CONFIG_SPARSEMEM |
357 | pfn &= (PAGES_PER_SECTION-1); |
358 | #else |
359 | pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn); |
360 | #endif /* CONFIG_SPARSEMEM */ |
361 | return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; |
362 | } |
363 | |
364 | /** |
365 | * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages |
366 | * @page: The page within the block of interest |
367 | * @pfn: The target page frame number |
368 | * @mask: mask of bits that the caller is interested in |
369 | * |
370 | * Return: pageblock_bits flags |
371 | */ |
372 | unsigned long get_pfnblock_flags_mask(const struct page *page, |
373 | unsigned long pfn, unsigned long mask) |
374 | { |
375 | unsigned long *bitmap; |
376 | unsigned long bitidx, word_bitidx; |
377 | unsigned long word; |
378 | |
379 | bitmap = get_pageblock_bitmap(page, pfn); |
380 | bitidx = pfn_to_bitidx(page, pfn); |
381 | word_bitidx = bitidx / BITS_PER_LONG; |
382 | bitidx &= (BITS_PER_LONG-1); |
383 | /* |
384 | * This races, without locks, with set_pfnblock_flags_mask(). Ensure |
385 | * a consistent read of the memory array, so that results, even though |
386 | * racy, are not corrupted. |
387 | */ |
388 | word = READ_ONCE(bitmap[word_bitidx]); |
389 | return (word >> bitidx) & mask; |
390 | } |
391 | |
392 | static __always_inline int get_pfnblock_migratetype(const struct page *page, |
393 | unsigned long pfn) |
394 | { |
395 | return get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK); |
396 | } |
397 | |
398 | /** |
399 | * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages |
400 | * @page: The page within the block of interest |
401 | * @flags: The flags to set |
402 | * @pfn: The target page frame number |
403 | * @mask: mask of bits that the caller is interested in |
404 | */ |
405 | void set_pfnblock_flags_mask(struct page *page, unsigned long flags, |
406 | unsigned long pfn, |
407 | unsigned long mask) |
408 | { |
409 | unsigned long *bitmap; |
410 | unsigned long bitidx, word_bitidx; |
411 | unsigned long word; |
412 | |
413 | BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4); |
414 | BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits)); |
415 | |
416 | bitmap = get_pageblock_bitmap(page, pfn); |
417 | bitidx = pfn_to_bitidx(page, pfn); |
418 | word_bitidx = bitidx / BITS_PER_LONG; |
419 | bitidx &= (BITS_PER_LONG-1); |
420 | |
421 | VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); |
422 | |
423 | mask <<= bitidx; |
424 | flags <<= bitidx; |
425 | |
426 | word = READ_ONCE(bitmap[word_bitidx]); |
427 | do { |
428 | } while (!try_cmpxchg(&bitmap[word_bitidx], &word, (word & ~mask) | flags)); |
429 | } |
430 | |
431 | void set_pageblock_migratetype(struct page *page, int migratetype) |
432 | { |
433 | if (unlikely(page_group_by_mobility_disabled && |
434 | migratetype < MIGRATE_PCPTYPES)) |
435 | migratetype = MIGRATE_UNMOVABLE; |
436 | |
437 | set_pfnblock_flags_mask(page, flags: (unsigned long)migratetype, |
438 | page_to_pfn(page), MIGRATETYPE_MASK); |
439 | } |
440 | |
441 | #ifdef CONFIG_DEBUG_VM |
442 | static int page_outside_zone_boundaries(struct zone *zone, struct page *page) |
443 | { |
444 | int ret; |
445 | unsigned seq; |
446 | unsigned long pfn = page_to_pfn(page); |
447 | unsigned long sp, start_pfn; |
448 | |
449 | do { |
450 | seq = zone_span_seqbegin(zone); |
451 | start_pfn = zone->zone_start_pfn; |
452 | sp = zone->spanned_pages; |
453 | ret = !zone_spans_pfn(zone, pfn); |
454 | } while (zone_span_seqretry(zone, iv: seq)); |
455 | |
456 | if (ret) |
457 | pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n" , |
458 | pfn, zone_to_nid(zone), zone->name, |
459 | start_pfn, start_pfn + sp); |
460 | |
461 | return ret; |
462 | } |
463 | |
464 | /* |
465 | * Temporary debugging check for pages not lying within a given zone. |
466 | */ |
467 | static int __maybe_unused bad_range(struct zone *zone, struct page *page) |
468 | { |
469 | if (page_outside_zone_boundaries(zone, page)) |
470 | return 1; |
471 | if (zone != page_zone(page)) |
472 | return 1; |
473 | |
474 | return 0; |
475 | } |
476 | #else |
477 | static inline int __maybe_unused bad_range(struct zone *zone, struct page *page) |
478 | { |
479 | return 0; |
480 | } |
481 | #endif |
482 | |
483 | static void bad_page(struct page *page, const char *reason) |
484 | { |
485 | static unsigned long resume; |
486 | static unsigned long nr_shown; |
487 | static unsigned long nr_unshown; |
488 | |
489 | /* |
490 | * Allow a burst of 60 reports, then keep quiet for that minute; |
491 | * or allow a steady drip of one report per second. |
492 | */ |
493 | if (nr_shown == 60) { |
494 | if (time_before(jiffies, resume)) { |
495 | nr_unshown++; |
496 | goto out; |
497 | } |
498 | if (nr_unshown) { |
499 | pr_alert( |
500 | "BUG: Bad page state: %lu messages suppressed\n" , |
501 | nr_unshown); |
502 | nr_unshown = 0; |
503 | } |
504 | nr_shown = 0; |
505 | } |
506 | if (nr_shown++ == 0) |
507 | resume = jiffies + 60 * HZ; |
508 | |
509 | pr_alert("BUG: Bad page state in process %s pfn:%05lx\n" , |
510 | current->comm, page_to_pfn(page)); |
511 | dump_page(page, reason); |
512 | |
513 | print_modules(); |
514 | dump_stack(); |
515 | out: |
516 | /* Leave bad fields for debug, except PageBuddy could make trouble */ |
517 | page_mapcount_reset(page); /* remove PageBuddy */ |
518 | add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
519 | } |
520 | |
521 | static inline unsigned int order_to_pindex(int migratetype, int order) |
522 | { |
523 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
524 | if (order > PAGE_ALLOC_COSTLY_ORDER) { |
525 | VM_BUG_ON(order != pageblock_order); |
526 | return NR_LOWORDER_PCP_LISTS; |
527 | } |
528 | #else |
529 | VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); |
530 | #endif |
531 | |
532 | return (MIGRATE_PCPTYPES * order) + migratetype; |
533 | } |
534 | |
535 | static inline int pindex_to_order(unsigned int pindex) |
536 | { |
537 | int order = pindex / MIGRATE_PCPTYPES; |
538 | |
539 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
540 | if (pindex == NR_LOWORDER_PCP_LISTS) |
541 | order = pageblock_order; |
542 | #else |
543 | VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); |
544 | #endif |
545 | |
546 | return order; |
547 | } |
548 | |
549 | static inline bool pcp_allowed_order(unsigned int order) |
550 | { |
551 | if (order <= PAGE_ALLOC_COSTLY_ORDER) |
552 | return true; |
553 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
554 | if (order == pageblock_order) |
555 | return true; |
556 | #endif |
557 | return false; |
558 | } |
559 | |
560 | static inline void free_the_page(struct page *page, unsigned int order) |
561 | { |
562 | if (pcp_allowed_order(order)) /* Via pcp? */ |
563 | free_unref_page(page, order); |
564 | else |
565 | __free_pages_ok(page, order, FPI_NONE); |
566 | } |
567 | |
568 | /* |
569 | * Higher-order pages are called "compound pages". They are structured thusly: |
570 | * |
571 | * The first PAGE_SIZE page is called the "head page" and have PG_head set. |
572 | * |
573 | * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded |
574 | * in bit 0 of page->compound_head. The rest of bits is pointer to head page. |
575 | * |
576 | * The first tail page's ->compound_order holds the order of allocation. |
577 | * This usage means that zero-order pages may not be compound. |
578 | */ |
579 | |
580 | void prep_compound_page(struct page *page, unsigned int order) |
581 | { |
582 | int i; |
583 | int nr_pages = 1 << order; |
584 | |
585 | __SetPageHead(page); |
586 | for (i = 1; i < nr_pages; i++) |
587 | prep_compound_tail(head: page, tail_idx: i); |
588 | |
589 | prep_compound_head(page, order); |
590 | } |
591 | |
592 | void destroy_large_folio(struct folio *folio) |
593 | { |
594 | if (folio_test_hugetlb(folio)) { |
595 | free_huge_folio(folio); |
596 | return; |
597 | } |
598 | |
599 | if (folio_test_large_rmappable(folio)) |
600 | folio_undo_large_rmappable(folio); |
601 | |
602 | mem_cgroup_uncharge(folio); |
603 | free_the_page(page: &folio->page, order: folio_order(folio)); |
604 | } |
605 | |
606 | static inline void set_buddy_order(struct page *page, unsigned int order) |
607 | { |
608 | set_page_private(page, private: order); |
609 | __SetPageBuddy(page); |
610 | } |
611 | |
612 | #ifdef CONFIG_COMPACTION |
613 | static inline struct capture_control *task_capc(struct zone *zone) |
614 | { |
615 | struct capture_control *capc = current->capture_control; |
616 | |
617 | return unlikely(capc) && |
618 | !(current->flags & PF_KTHREAD) && |
619 | !capc->page && |
620 | capc->cc->zone == zone ? capc : NULL; |
621 | } |
622 | |
623 | static inline bool |
624 | compaction_capture(struct capture_control *capc, struct page *page, |
625 | int order, int migratetype) |
626 | { |
627 | if (!capc || order != capc->cc->order) |
628 | return false; |
629 | |
630 | /* Do not accidentally pollute CMA or isolated regions*/ |
631 | if (is_migrate_cma(migratetype) || |
632 | is_migrate_isolate(migratetype)) |
633 | return false; |
634 | |
635 | /* |
636 | * Do not let lower order allocations pollute a movable pageblock. |
637 | * This might let an unmovable request use a reclaimable pageblock |
638 | * and vice-versa but no more than normal fallback logic which can |
639 | * have trouble finding a high-order free page. |
640 | */ |
641 | if (order < pageblock_order && migratetype == MIGRATE_MOVABLE) |
642 | return false; |
643 | |
644 | capc->page = page; |
645 | return true; |
646 | } |
647 | |
648 | #else |
649 | static inline struct capture_control *task_capc(struct zone *zone) |
650 | { |
651 | return NULL; |
652 | } |
653 | |
654 | static inline bool |
655 | compaction_capture(struct capture_control *capc, struct page *page, |
656 | int order, int migratetype) |
657 | { |
658 | return false; |
659 | } |
660 | #endif /* CONFIG_COMPACTION */ |
661 | |
662 | /* Used for pages not on another list */ |
663 | static inline void add_to_free_list(struct page *page, struct zone *zone, |
664 | unsigned int order, int migratetype) |
665 | { |
666 | struct free_area *area = &zone->free_area[order]; |
667 | |
668 | list_add(new: &page->buddy_list, head: &area->free_list[migratetype]); |
669 | area->nr_free++; |
670 | } |
671 | |
672 | /* Used for pages not on another list */ |
673 | static inline void add_to_free_list_tail(struct page *page, struct zone *zone, |
674 | unsigned int order, int migratetype) |
675 | { |
676 | struct free_area *area = &zone->free_area[order]; |
677 | |
678 | list_add_tail(new: &page->buddy_list, head: &area->free_list[migratetype]); |
679 | area->nr_free++; |
680 | } |
681 | |
682 | /* |
683 | * Used for pages which are on another list. Move the pages to the tail |
684 | * of the list - so the moved pages won't immediately be considered for |
685 | * allocation again (e.g., optimization for memory onlining). |
686 | */ |
687 | static inline void move_to_free_list(struct page *page, struct zone *zone, |
688 | unsigned int order, int migratetype) |
689 | { |
690 | struct free_area *area = &zone->free_area[order]; |
691 | |
692 | list_move_tail(list: &page->buddy_list, head: &area->free_list[migratetype]); |
693 | } |
694 | |
695 | static inline void del_page_from_free_list(struct page *page, struct zone *zone, |
696 | unsigned int order) |
697 | { |
698 | /* clear reported state and update reported page count */ |
699 | if (page_reported(page)) |
700 | __ClearPageReported(page); |
701 | |
702 | list_del(entry: &page->buddy_list); |
703 | __ClearPageBuddy(page); |
704 | set_page_private(page, private: 0); |
705 | zone->free_area[order].nr_free--; |
706 | } |
707 | |
708 | static inline struct page *get_page_from_free_area(struct free_area *area, |
709 | int migratetype) |
710 | { |
711 | return list_first_entry_or_null(&area->free_list[migratetype], |
712 | struct page, buddy_list); |
713 | } |
714 | |
715 | /* |
716 | * If this is not the largest possible page, check if the buddy |
717 | * of the next-highest order is free. If it is, it's possible |
718 | * that pages are being freed that will coalesce soon. In case, |
719 | * that is happening, add the free page to the tail of the list |
720 | * so it's less likely to be used soon and more likely to be merged |
721 | * as a higher order page |
722 | */ |
723 | static inline bool |
724 | buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, |
725 | struct page *page, unsigned int order) |
726 | { |
727 | unsigned long higher_page_pfn; |
728 | struct page *higher_page; |
729 | |
730 | if (order >= MAX_ORDER - 1) |
731 | return false; |
732 | |
733 | higher_page_pfn = buddy_pfn & pfn; |
734 | higher_page = page + (higher_page_pfn - pfn); |
735 | |
736 | return find_buddy_page_pfn(page: higher_page, pfn: higher_page_pfn, order: order + 1, |
737 | NULL) != NULL; |
738 | } |
739 | |
740 | /* |
741 | * Freeing function for a buddy system allocator. |
742 | * |
743 | * The concept of a buddy system is to maintain direct-mapped table |
744 | * (containing bit values) for memory blocks of various "orders". |
745 | * The bottom level table contains the map for the smallest allocatable |
746 | * units of memory (here, pages), and each level above it describes |
747 | * pairs of units from the levels below, hence, "buddies". |
748 | * At a high level, all that happens here is marking the table entry |
749 | * at the bottom level available, and propagating the changes upward |
750 | * as necessary, plus some accounting needed to play nicely with other |
751 | * parts of the VM system. |
752 | * At each level, we keep a list of pages, which are heads of continuous |
753 | * free pages of length of (1 << order) and marked with PageBuddy. |
754 | * Page's order is recorded in page_private(page) field. |
755 | * So when we are allocating or freeing one, we can derive the state of the |
756 | * other. That is, if we allocate a small block, and both were |
757 | * free, the remainder of the region must be split into blocks. |
758 | * If a block is freed, and its buddy is also free, then this |
759 | * triggers coalescing into a block of larger size. |
760 | * |
761 | * -- nyc |
762 | */ |
763 | |
764 | static inline void __free_one_page(struct page *page, |
765 | unsigned long pfn, |
766 | struct zone *zone, unsigned int order, |
767 | int migratetype, fpi_t fpi_flags) |
768 | { |
769 | struct capture_control *capc = task_capc(zone); |
770 | unsigned long buddy_pfn = 0; |
771 | unsigned long combined_pfn; |
772 | struct page *buddy; |
773 | bool to_tail; |
774 | |
775 | VM_BUG_ON(!zone_is_initialized(zone)); |
776 | VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); |
777 | |
778 | VM_BUG_ON(migratetype == -1); |
779 | if (likely(!is_migrate_isolate(migratetype))) |
780 | __mod_zone_freepage_state(zone, nr_pages: 1 << order, migratetype); |
781 | |
782 | VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page); |
783 | VM_BUG_ON_PAGE(bad_range(zone, page), page); |
784 | |
785 | while (order < MAX_ORDER) { |
786 | if (compaction_capture(capc, page, order, migratetype)) { |
787 | __mod_zone_freepage_state(zone, nr_pages: -(1 << order), |
788 | migratetype); |
789 | return; |
790 | } |
791 | |
792 | buddy = find_buddy_page_pfn(page, pfn, order, buddy_pfn: &buddy_pfn); |
793 | if (!buddy) |
794 | goto done_merging; |
795 | |
796 | if (unlikely(order >= pageblock_order)) { |
797 | /* |
798 | * We want to prevent merge between freepages on pageblock |
799 | * without fallbacks and normal pageblock. Without this, |
800 | * pageblock isolation could cause incorrect freepage or CMA |
801 | * accounting or HIGHATOMIC accounting. |
802 | */ |
803 | int buddy_mt = get_pfnblock_migratetype(page: buddy, pfn: buddy_pfn); |
804 | |
805 | if (migratetype != buddy_mt |
806 | && (!migratetype_is_mergeable(mt: migratetype) || |
807 | !migratetype_is_mergeable(mt: buddy_mt))) |
808 | goto done_merging; |
809 | } |
810 | |
811 | /* |
812 | * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, |
813 | * merge with it and move up one order. |
814 | */ |
815 | if (page_is_guard(page: buddy)) |
816 | clear_page_guard(zone, page: buddy, order, migratetype); |
817 | else |
818 | del_page_from_free_list(page: buddy, zone, order); |
819 | combined_pfn = buddy_pfn & pfn; |
820 | page = page + (combined_pfn - pfn); |
821 | pfn = combined_pfn; |
822 | order++; |
823 | } |
824 | |
825 | done_merging: |
826 | set_buddy_order(page, order); |
827 | |
828 | if (fpi_flags & FPI_TO_TAIL) |
829 | to_tail = true; |
830 | else if (is_shuffle_order(order)) |
831 | to_tail = shuffle_pick_tail(); |
832 | else |
833 | to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order); |
834 | |
835 | if (to_tail) |
836 | add_to_free_list_tail(page, zone, order, migratetype); |
837 | else |
838 | add_to_free_list(page, zone, order, migratetype); |
839 | |
840 | /* Notify page reporting subsystem of freed page */ |
841 | if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY)) |
842 | page_reporting_notify_free(order); |
843 | } |
844 | |
845 | /** |
846 | * split_free_page() -- split a free page at split_pfn_offset |
847 | * @free_page: the original free page |
848 | * @order: the order of the page |
849 | * @split_pfn_offset: split offset within the page |
850 | * |
851 | * Return -ENOENT if the free page is changed, otherwise 0 |
852 | * |
853 | * It is used when the free page crosses two pageblocks with different migratetypes |
854 | * at split_pfn_offset within the page. The split free page will be put into |
855 | * separate migratetype lists afterwards. Otherwise, the function achieves |
856 | * nothing. |
857 | */ |
858 | int split_free_page(struct page *free_page, |
859 | unsigned int order, unsigned long split_pfn_offset) |
860 | { |
861 | struct zone *zone = page_zone(page: free_page); |
862 | unsigned long free_page_pfn = page_to_pfn(free_page); |
863 | unsigned long pfn; |
864 | unsigned long flags; |
865 | int free_page_order; |
866 | int mt; |
867 | int ret = 0; |
868 | |
869 | if (split_pfn_offset == 0) |
870 | return ret; |
871 | |
872 | spin_lock_irqsave(&zone->lock, flags); |
873 | |
874 | if (!PageBuddy(page: free_page) || buddy_order(page: free_page) != order) { |
875 | ret = -ENOENT; |
876 | goto out; |
877 | } |
878 | |
879 | mt = get_pfnblock_migratetype(page: free_page, pfn: free_page_pfn); |
880 | if (likely(!is_migrate_isolate(mt))) |
881 | __mod_zone_freepage_state(zone, nr_pages: -(1UL << order), migratetype: mt); |
882 | |
883 | del_page_from_free_list(page: free_page, zone, order); |
884 | for (pfn = free_page_pfn; |
885 | pfn < free_page_pfn + (1UL << order);) { |
886 | int mt = get_pfnblock_migratetype(pfn_to_page(pfn), pfn); |
887 | |
888 | free_page_order = min_t(unsigned int, |
889 | pfn ? __ffs(pfn) : order, |
890 | __fls(split_pfn_offset)); |
891 | __free_one_page(pfn_to_page(pfn), pfn, zone, order: free_page_order, |
892 | migratetype: mt, FPI_NONE); |
893 | pfn += 1UL << free_page_order; |
894 | split_pfn_offset -= (1UL << free_page_order); |
895 | /* we have done the first part, now switch to second part */ |
896 | if (split_pfn_offset == 0) |
897 | split_pfn_offset = (1UL << order) - (pfn - free_page_pfn); |
898 | } |
899 | out: |
900 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
901 | return ret; |
902 | } |
903 | /* |
904 | * A bad page could be due to a number of fields. Instead of multiple branches, |
905 | * try and check multiple fields with one check. The caller must do a detailed |
906 | * check if necessary. |
907 | */ |
908 | static inline bool page_expected_state(struct page *page, |
909 | unsigned long check_flags) |
910 | { |
911 | if (unlikely(atomic_read(&page->_mapcount) != -1)) |
912 | return false; |
913 | |
914 | if (unlikely((unsigned long)page->mapping | |
915 | page_ref_count(page) | |
916 | #ifdef CONFIG_MEMCG |
917 | page->memcg_data | |
918 | #endif |
919 | (page->flags & check_flags))) |
920 | return false; |
921 | |
922 | return true; |
923 | } |
924 | |
925 | static const char *page_bad_reason(struct page *page, unsigned long flags) |
926 | { |
927 | const char *bad_reason = NULL; |
928 | |
929 | if (unlikely(atomic_read(&page->_mapcount) != -1)) |
930 | bad_reason = "nonzero mapcount" ; |
931 | if (unlikely(page->mapping != NULL)) |
932 | bad_reason = "non-NULL mapping" ; |
933 | if (unlikely(page_ref_count(page) != 0)) |
934 | bad_reason = "nonzero _refcount" ; |
935 | if (unlikely(page->flags & flags)) { |
936 | if (flags == PAGE_FLAGS_CHECK_AT_PREP) |
937 | bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set" ; |
938 | else |
939 | bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set" ; |
940 | } |
941 | #ifdef CONFIG_MEMCG |
942 | if (unlikely(page->memcg_data)) |
943 | bad_reason = "page still charged to cgroup" ; |
944 | #endif |
945 | return bad_reason; |
946 | } |
947 | |
948 | static void free_page_is_bad_report(struct page *page) |
949 | { |
950 | bad_page(page, |
951 | page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE)); |
952 | } |
953 | |
954 | static inline bool free_page_is_bad(struct page *page) |
955 | { |
956 | if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) |
957 | return false; |
958 | |
959 | /* Something has gone sideways, find it */ |
960 | free_page_is_bad_report(page); |
961 | return true; |
962 | } |
963 | |
964 | static inline bool is_check_pages_enabled(void) |
965 | { |
966 | return static_branch_unlikely(&check_pages_enabled); |
967 | } |
968 | |
969 | static int free_tail_page_prepare(struct page *head_page, struct page *page) |
970 | { |
971 | struct folio *folio = (struct folio *)head_page; |
972 | int ret = 1; |
973 | |
974 | /* |
975 | * We rely page->lru.next never has bit 0 set, unless the page |
976 | * is PageTail(). Let's make sure that's true even for poisoned ->lru. |
977 | */ |
978 | BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1); |
979 | |
980 | if (!is_check_pages_enabled()) { |
981 | ret = 0; |
982 | goto out; |
983 | } |
984 | switch (page - head_page) { |
985 | case 1: |
986 | /* the first tail page: these may be in place of ->mapping */ |
987 | if (unlikely(folio_entire_mapcount(folio))) { |
988 | bad_page(page, reason: "nonzero entire_mapcount" ); |
989 | goto out; |
990 | } |
991 | if (unlikely(atomic_read(&folio->_nr_pages_mapped))) { |
992 | bad_page(page, reason: "nonzero nr_pages_mapped" ); |
993 | goto out; |
994 | } |
995 | if (unlikely(atomic_read(&folio->_pincount))) { |
996 | bad_page(page, reason: "nonzero pincount" ); |
997 | goto out; |
998 | } |
999 | break; |
1000 | case 2: |
1001 | /* |
1002 | * the second tail page: ->mapping is |
1003 | * deferred_list.next -- ignore value. |
1004 | */ |
1005 | break; |
1006 | default: |
1007 | if (page->mapping != TAIL_MAPPING) { |
1008 | bad_page(page, reason: "corrupted mapping in tail page" ); |
1009 | goto out; |
1010 | } |
1011 | break; |
1012 | } |
1013 | if (unlikely(!PageTail(page))) { |
1014 | bad_page(page, reason: "PageTail not set" ); |
1015 | goto out; |
1016 | } |
1017 | if (unlikely(compound_head(page) != head_page)) { |
1018 | bad_page(page, reason: "compound_head not consistent" ); |
1019 | goto out; |
1020 | } |
1021 | ret = 0; |
1022 | out: |
1023 | page->mapping = NULL; |
1024 | clear_compound_head(page); |
1025 | return ret; |
1026 | } |
1027 | |
1028 | /* |
1029 | * Skip KASAN memory poisoning when either: |
1030 | * |
1031 | * 1. For generic KASAN: deferred memory initialization has not yet completed. |
1032 | * Tag-based KASAN modes skip pages freed via deferred memory initialization |
1033 | * using page tags instead (see below). |
1034 | * 2. For tag-based KASAN modes: the page has a match-all KASAN tag, indicating |
1035 | * that error detection is disabled for accesses via the page address. |
1036 | * |
1037 | * Pages will have match-all tags in the following circumstances: |
1038 | * |
1039 | * 1. Pages are being initialized for the first time, including during deferred |
1040 | * memory init; see the call to page_kasan_tag_reset in __init_single_page. |
1041 | * 2. The allocation was not unpoisoned due to __GFP_SKIP_KASAN, with the |
1042 | * exception of pages unpoisoned by kasan_unpoison_vmalloc. |
1043 | * 3. The allocation was excluded from being checked due to sampling, |
1044 | * see the call to kasan_unpoison_pages. |
1045 | * |
1046 | * Poisoning pages during deferred memory init will greatly lengthen the |
1047 | * process and cause problem in large memory systems as the deferred pages |
1048 | * initialization is done with interrupt disabled. |
1049 | * |
1050 | * Assuming that there will be no reference to those newly initialized |
1051 | * pages before they are ever allocated, this should have no effect on |
1052 | * KASAN memory tracking as the poison will be properly inserted at page |
1053 | * allocation time. The only corner case is when pages are allocated by |
1054 | * on-demand allocation and then freed again before the deferred pages |
1055 | * initialization is done, but this is not likely to happen. |
1056 | */ |
1057 | static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) |
1058 | { |
1059 | if (IS_ENABLED(CONFIG_KASAN_GENERIC)) |
1060 | return deferred_pages_enabled(); |
1061 | |
1062 | return page_kasan_tag(page) == 0xff; |
1063 | } |
1064 | |
1065 | static void kernel_init_pages(struct page *page, int numpages) |
1066 | { |
1067 | int i; |
1068 | |
1069 | /* s390's use of memset() could override KASAN redzones. */ |
1070 | kasan_disable_current(); |
1071 | for (i = 0; i < numpages; i++) |
1072 | clear_highpage_kasan_tagged(page: page + i); |
1073 | kasan_enable_current(); |
1074 | } |
1075 | |
1076 | static __always_inline bool free_pages_prepare(struct page *page, |
1077 | unsigned int order, fpi_t fpi_flags) |
1078 | { |
1079 | int bad = 0; |
1080 | bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags); |
1081 | bool init = want_init_on_free(); |
1082 | bool compound = PageCompound(page); |
1083 | |
1084 | VM_BUG_ON_PAGE(PageTail(page), page); |
1085 | |
1086 | trace_mm_page_free(page, order); |
1087 | kmsan_free_page(page, order); |
1088 | |
1089 | if (unlikely(PageHWPoison(page)) && !order) { |
1090 | /* |
1091 | * Do not let hwpoison pages hit pcplists/buddy |
1092 | * Untie memcg state and reset page's owner |
1093 | */ |
1094 | if (memcg_kmem_online() && PageMemcgKmem(page)) |
1095 | __memcg_kmem_uncharge_page(page, order); |
1096 | reset_page_owner(page, order); |
1097 | page_table_check_free(page, order); |
1098 | return false; |
1099 | } |
1100 | |
1101 | VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); |
1102 | |
1103 | /* |
1104 | * Check tail pages before head page information is cleared to |
1105 | * avoid checking PageCompound for order-0 pages. |
1106 | */ |
1107 | if (unlikely(order)) { |
1108 | int i; |
1109 | |
1110 | if (compound) |
1111 | page[1].flags &= ~PAGE_FLAGS_SECOND; |
1112 | for (i = 1; i < (1 << order); i++) { |
1113 | if (compound) |
1114 | bad += free_tail_page_prepare(head_page: page, page: page + i); |
1115 | if (is_check_pages_enabled()) { |
1116 | if (free_page_is_bad(page: page + i)) { |
1117 | bad++; |
1118 | continue; |
1119 | } |
1120 | } |
1121 | (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
1122 | } |
1123 | } |
1124 | if (PageMappingFlags(page)) |
1125 | page->mapping = NULL; |
1126 | if (memcg_kmem_online() && PageMemcgKmem(page)) |
1127 | __memcg_kmem_uncharge_page(page, order); |
1128 | if (is_check_pages_enabled()) { |
1129 | if (free_page_is_bad(page)) |
1130 | bad++; |
1131 | if (bad) |
1132 | return false; |
1133 | } |
1134 | |
1135 | page_cpupid_reset_last(page); |
1136 | page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; |
1137 | reset_page_owner(page, order); |
1138 | page_table_check_free(page, order); |
1139 | |
1140 | if (!PageHighMem(page)) { |
1141 | debug_check_no_locks_freed(page_address(page), |
1142 | PAGE_SIZE << order); |
1143 | debug_check_no_obj_freed(page_address(page), |
1144 | PAGE_SIZE << order); |
1145 | } |
1146 | |
1147 | kernel_poison_pages(page, numpages: 1 << order); |
1148 | |
1149 | /* |
1150 | * As memory initialization might be integrated into KASAN, |
1151 | * KASAN poisoning and memory initialization code must be |
1152 | * kept together to avoid discrepancies in behavior. |
1153 | * |
1154 | * With hardware tag-based KASAN, memory tags must be set before the |
1155 | * page becomes unavailable via debug_pagealloc or arch_free_page. |
1156 | */ |
1157 | if (!skip_kasan_poison) { |
1158 | kasan_poison_pages(page, order, init); |
1159 | |
1160 | /* Memory is already initialized if KASAN did it internally. */ |
1161 | if (kasan_has_integrated_init()) |
1162 | init = false; |
1163 | } |
1164 | if (init) |
1165 | kernel_init_pages(page, numpages: 1 << order); |
1166 | |
1167 | /* |
1168 | * arch_free_page() can make the page's contents inaccessible. s390 |
1169 | * does this. So nothing which can access the page's contents should |
1170 | * happen after this. |
1171 | */ |
1172 | arch_free_page(page, order); |
1173 | |
1174 | debug_pagealloc_unmap_pages(page, numpages: 1 << order); |
1175 | |
1176 | return true; |
1177 | } |
1178 | |
1179 | /* |
1180 | * Frees a number of pages from the PCP lists |
1181 | * Assumes all pages on list are in same zone. |
1182 | * count is the number of pages to free. |
1183 | */ |
1184 | static void free_pcppages_bulk(struct zone *zone, int count, |
1185 | struct per_cpu_pages *pcp, |
1186 | int pindex) |
1187 | { |
1188 | unsigned long flags; |
1189 | unsigned int order; |
1190 | bool isolated_pageblocks; |
1191 | struct page *page; |
1192 | |
1193 | /* |
1194 | * Ensure proper count is passed which otherwise would stuck in the |
1195 | * below while (list_empty(list)) loop. |
1196 | */ |
1197 | count = min(pcp->count, count); |
1198 | |
1199 | /* Ensure requested pindex is drained first. */ |
1200 | pindex = pindex - 1; |
1201 | |
1202 | spin_lock_irqsave(&zone->lock, flags); |
1203 | isolated_pageblocks = has_isolate_pageblock(zone); |
1204 | |
1205 | while (count > 0) { |
1206 | struct list_head *list; |
1207 | int nr_pages; |
1208 | |
1209 | /* Remove pages from lists in a round-robin fashion. */ |
1210 | do { |
1211 | if (++pindex > NR_PCP_LISTS - 1) |
1212 | pindex = 0; |
1213 | list = &pcp->lists[pindex]; |
1214 | } while (list_empty(head: list)); |
1215 | |
1216 | order = pindex_to_order(pindex); |
1217 | nr_pages = 1 << order; |
1218 | do { |
1219 | int mt; |
1220 | |
1221 | page = list_last_entry(list, struct page, pcp_list); |
1222 | mt = get_pcppage_migratetype(page); |
1223 | |
1224 | /* must delete to avoid corrupting pcp list */ |
1225 | list_del(entry: &page->pcp_list); |
1226 | count -= nr_pages; |
1227 | pcp->count -= nr_pages; |
1228 | |
1229 | /* MIGRATE_ISOLATE page should not go to pcplists */ |
1230 | VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); |
1231 | /* Pageblock could have been isolated meanwhile */ |
1232 | if (unlikely(isolated_pageblocks)) |
1233 | mt = get_pageblock_migratetype(page); |
1234 | |
1235 | __free_one_page(page, page_to_pfn(page), zone, order, migratetype: mt, FPI_NONE); |
1236 | trace_mm_page_pcpu_drain(page, order, migratetype: mt); |
1237 | } while (count > 0 && !list_empty(head: list)); |
1238 | } |
1239 | |
1240 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1241 | } |
1242 | |
1243 | static void free_one_page(struct zone *zone, |
1244 | struct page *page, unsigned long pfn, |
1245 | unsigned int order, |
1246 | int migratetype, fpi_t fpi_flags) |
1247 | { |
1248 | unsigned long flags; |
1249 | |
1250 | spin_lock_irqsave(&zone->lock, flags); |
1251 | if (unlikely(has_isolate_pageblock(zone) || |
1252 | is_migrate_isolate(migratetype))) { |
1253 | migratetype = get_pfnblock_migratetype(page, pfn); |
1254 | } |
1255 | __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); |
1256 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1257 | } |
1258 | |
1259 | static void __free_pages_ok(struct page *page, unsigned int order, |
1260 | fpi_t fpi_flags) |
1261 | { |
1262 | unsigned long flags; |
1263 | int migratetype; |
1264 | unsigned long pfn = page_to_pfn(page); |
1265 | struct zone *zone = page_zone(page); |
1266 | |
1267 | if (!free_pages_prepare(page, order, fpi_flags)) |
1268 | return; |
1269 | |
1270 | /* |
1271 | * Calling get_pfnblock_migratetype() without spin_lock_irqsave() here |
1272 | * is used to avoid calling get_pfnblock_migratetype() under the lock. |
1273 | * This will reduce the lock holding time. |
1274 | */ |
1275 | migratetype = get_pfnblock_migratetype(page, pfn); |
1276 | |
1277 | spin_lock_irqsave(&zone->lock, flags); |
1278 | if (unlikely(has_isolate_pageblock(zone) || |
1279 | is_migrate_isolate(migratetype))) { |
1280 | migratetype = get_pfnblock_migratetype(page, pfn); |
1281 | } |
1282 | __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); |
1283 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1284 | |
1285 | __count_vm_events(item: PGFREE, delta: 1 << order); |
1286 | } |
1287 | |
1288 | void __free_pages_core(struct page *page, unsigned int order) |
1289 | { |
1290 | unsigned int nr_pages = 1 << order; |
1291 | struct page *p = page; |
1292 | unsigned int loop; |
1293 | |
1294 | /* |
1295 | * When initializing the memmap, __init_single_page() sets the refcount |
1296 | * of all pages to 1 ("allocated"/"not free"). We have to set the |
1297 | * refcount of all involved pages to 0. |
1298 | */ |
1299 | prefetchw(x: p); |
1300 | for (loop = 0; loop < (nr_pages - 1); loop++, p++) { |
1301 | prefetchw(x: p + 1); |
1302 | __ClearPageReserved(page: p); |
1303 | set_page_count(page: p, v: 0); |
1304 | } |
1305 | __ClearPageReserved(page: p); |
1306 | set_page_count(page: p, v: 0); |
1307 | |
1308 | atomic_long_add(i: nr_pages, v: &page_zone(page)->managed_pages); |
1309 | |
1310 | if (page_contains_unaccepted(page, order)) { |
1311 | if (order == MAX_ORDER && __free_unaccepted(page)) |
1312 | return; |
1313 | |
1314 | accept_page(page, order); |
1315 | } |
1316 | |
1317 | /* |
1318 | * Bypass PCP and place fresh pages right to the tail, primarily |
1319 | * relevant for memory onlining. |
1320 | */ |
1321 | __free_pages_ok(page, order, FPI_TO_TAIL); |
1322 | } |
1323 | |
1324 | /* |
1325 | * Check that the whole (or subset of) a pageblock given by the interval of |
1326 | * [start_pfn, end_pfn) is valid and within the same zone, before scanning it |
1327 | * with the migration of free compaction scanner. |
1328 | * |
1329 | * Return struct page pointer of start_pfn, or NULL if checks were not passed. |
1330 | * |
1331 | * It's possible on some configurations to have a setup like node0 node1 node0 |
1332 | * i.e. it's possible that all pages within a zones range of pages do not |
1333 | * belong to a single zone. We assume that a border between node0 and node1 |
1334 | * can occur within a single pageblock, but not a node0 node1 node0 |
1335 | * interleaving within a single pageblock. It is therefore sufficient to check |
1336 | * the first and last page of a pageblock and avoid checking each individual |
1337 | * page in a pageblock. |
1338 | * |
1339 | * Note: the function may return non-NULL struct page even for a page block |
1340 | * which contains a memory hole (i.e. there is no physical memory for a subset |
1341 | * of the pfn range). For example, if the pageblock order is MAX_ORDER, which |
1342 | * will fall into 2 sub-sections, and the end pfn of the pageblock may be hole |
1343 | * even though the start pfn is online and valid. This should be safe most of |
1344 | * the time because struct pages are still initialized via init_unavailable_range() |
1345 | * and pfn walkers shouldn't touch any physical memory range for which they do |
1346 | * not recognize any specific metadata in struct pages. |
1347 | */ |
1348 | struct page *__pageblock_pfn_to_page(unsigned long start_pfn, |
1349 | unsigned long end_pfn, struct zone *zone) |
1350 | { |
1351 | struct page *start_page; |
1352 | struct page *end_page; |
1353 | |
1354 | /* end_pfn is one past the range we are checking */ |
1355 | end_pfn--; |
1356 | |
1357 | if (!pfn_valid(pfn: end_pfn)) |
1358 | return NULL; |
1359 | |
1360 | start_page = pfn_to_online_page(pfn: start_pfn); |
1361 | if (!start_page) |
1362 | return NULL; |
1363 | |
1364 | if (page_zone(page: start_page) != zone) |
1365 | return NULL; |
1366 | |
1367 | end_page = pfn_to_page(end_pfn); |
1368 | |
1369 | /* This gives a shorter code than deriving page_zone(end_page) */ |
1370 | if (page_zone_id(page: start_page) != page_zone_id(page: end_page)) |
1371 | return NULL; |
1372 | |
1373 | return start_page; |
1374 | } |
1375 | |
1376 | /* |
1377 | * The order of subdivision here is critical for the IO subsystem. |
1378 | * Please do not alter this order without good reasons and regression |
1379 | * testing. Specifically, as large blocks of memory are subdivided, |
1380 | * the order in which smaller blocks are delivered depends on the order |
1381 | * they're subdivided in this function. This is the primary factor |
1382 | * influencing the order in which pages are delivered to the IO |
1383 | * subsystem according to empirical testing, and this is also justified |
1384 | * by considering the behavior of a buddy system containing a single |
1385 | * large block of memory acted on by a series of small allocations. |
1386 | * This behavior is a critical factor in sglist merging's success. |
1387 | * |
1388 | * -- nyc |
1389 | */ |
1390 | static inline void expand(struct zone *zone, struct page *page, |
1391 | int low, int high, int migratetype) |
1392 | { |
1393 | unsigned long size = 1 << high; |
1394 | |
1395 | while (high > low) { |
1396 | high--; |
1397 | size >>= 1; |
1398 | VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]); |
1399 | |
1400 | /* |
1401 | * Mark as guard pages (or page), that will allow to |
1402 | * merge back to allocator when buddy will be freed. |
1403 | * Corresponding page table entries will not be touched, |
1404 | * pages will stay not present in virtual address space |
1405 | */ |
1406 | if (set_page_guard(zone, page: &page[size], order: high, migratetype)) |
1407 | continue; |
1408 | |
1409 | add_to_free_list(page: &page[size], zone, order: high, migratetype); |
1410 | set_buddy_order(page: &page[size], order: high); |
1411 | } |
1412 | } |
1413 | |
1414 | static void check_new_page_bad(struct page *page) |
1415 | { |
1416 | if (unlikely(page->flags & __PG_HWPOISON)) { |
1417 | /* Don't complain about hwpoisoned pages */ |
1418 | page_mapcount_reset(page); /* remove PageBuddy */ |
1419 | return; |
1420 | } |
1421 | |
1422 | bad_page(page, |
1423 | page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP)); |
1424 | } |
1425 | |
1426 | /* |
1427 | * This page is about to be returned from the page allocator |
1428 | */ |
1429 | static int check_new_page(struct page *page) |
1430 | { |
1431 | if (likely(page_expected_state(page, |
1432 | PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON))) |
1433 | return 0; |
1434 | |
1435 | check_new_page_bad(page); |
1436 | return 1; |
1437 | } |
1438 | |
1439 | static inline bool check_new_pages(struct page *page, unsigned int order) |
1440 | { |
1441 | if (is_check_pages_enabled()) { |
1442 | for (int i = 0; i < (1 << order); i++) { |
1443 | struct page *p = page + i; |
1444 | |
1445 | if (check_new_page(page: p)) |
1446 | return true; |
1447 | } |
1448 | } |
1449 | |
1450 | return false; |
1451 | } |
1452 | |
1453 | static inline bool should_skip_kasan_unpoison(gfp_t flags) |
1454 | { |
1455 | /* Don't skip if a software KASAN mode is enabled. */ |
1456 | if (IS_ENABLED(CONFIG_KASAN_GENERIC) || |
1457 | IS_ENABLED(CONFIG_KASAN_SW_TAGS)) |
1458 | return false; |
1459 | |
1460 | /* Skip, if hardware tag-based KASAN is not enabled. */ |
1461 | if (!kasan_hw_tags_enabled()) |
1462 | return true; |
1463 | |
1464 | /* |
1465 | * With hardware tag-based KASAN enabled, skip if this has been |
1466 | * requested via __GFP_SKIP_KASAN. |
1467 | */ |
1468 | return flags & __GFP_SKIP_KASAN; |
1469 | } |
1470 | |
1471 | static inline bool should_skip_init(gfp_t flags) |
1472 | { |
1473 | /* Don't skip, if hardware tag-based KASAN is not enabled. */ |
1474 | if (!kasan_hw_tags_enabled()) |
1475 | return false; |
1476 | |
1477 | /* For hardware tag-based KASAN, skip if requested. */ |
1478 | return (flags & __GFP_SKIP_ZERO); |
1479 | } |
1480 | |
1481 | inline void post_alloc_hook(struct page *page, unsigned int order, |
1482 | gfp_t gfp_flags) |
1483 | { |
1484 | bool init = !want_init_on_free() && want_init_on_alloc(flags: gfp_flags) && |
1485 | !should_skip_init(flags: gfp_flags); |
1486 | bool zero_tags = init && (gfp_flags & __GFP_ZEROTAGS); |
1487 | int i; |
1488 | |
1489 | set_page_private(page, private: 0); |
1490 | set_page_refcounted(page); |
1491 | |
1492 | arch_alloc_page(page, order); |
1493 | debug_pagealloc_map_pages(page, numpages: 1 << order); |
1494 | |
1495 | /* |
1496 | * Page unpoisoning must happen before memory initialization. |
1497 | * Otherwise, the poison pattern will be overwritten for __GFP_ZERO |
1498 | * allocations and the page unpoisoning code will complain. |
1499 | */ |
1500 | kernel_unpoison_pages(page, numpages: 1 << order); |
1501 | |
1502 | /* |
1503 | * As memory initialization might be integrated into KASAN, |
1504 | * KASAN unpoisoning and memory initializion code must be |
1505 | * kept together to avoid discrepancies in behavior. |
1506 | */ |
1507 | |
1508 | /* |
1509 | * If memory tags should be zeroed |
1510 | * (which happens only when memory should be initialized as well). |
1511 | */ |
1512 | if (zero_tags) { |
1513 | /* Initialize both memory and memory tags. */ |
1514 | for (i = 0; i != 1 << order; ++i) |
1515 | tag_clear_highpage(page: page + i); |
1516 | |
1517 | /* Take note that memory was initialized by the loop above. */ |
1518 | init = false; |
1519 | } |
1520 | if (!should_skip_kasan_unpoison(flags: gfp_flags) && |
1521 | kasan_unpoison_pages(page, order, init)) { |
1522 | /* Take note that memory was initialized by KASAN. */ |
1523 | if (kasan_has_integrated_init()) |
1524 | init = false; |
1525 | } else { |
1526 | /* |
1527 | * If memory tags have not been set by KASAN, reset the page |
1528 | * tags to ensure page_address() dereferencing does not fault. |
1529 | */ |
1530 | for (i = 0; i != 1 << order; ++i) |
1531 | page_kasan_tag_reset(page: page + i); |
1532 | } |
1533 | /* If memory is still not initialized, initialize it now. */ |
1534 | if (init) |
1535 | kernel_init_pages(page, numpages: 1 << order); |
1536 | |
1537 | set_page_owner(page, order, gfp_mask: gfp_flags); |
1538 | page_table_check_alloc(page, order); |
1539 | } |
1540 | |
1541 | static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, |
1542 | unsigned int alloc_flags) |
1543 | { |
1544 | post_alloc_hook(page, order, gfp_flags); |
1545 | |
1546 | if (order && (gfp_flags & __GFP_COMP)) |
1547 | prep_compound_page(page, order); |
1548 | |
1549 | /* |
1550 | * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to |
1551 | * allocate the page. The expectation is that the caller is taking |
1552 | * steps that will free more memory. The caller should avoid the page |
1553 | * being used for !PFMEMALLOC purposes. |
1554 | */ |
1555 | if (alloc_flags & ALLOC_NO_WATERMARKS) |
1556 | set_page_pfmemalloc(page); |
1557 | else |
1558 | clear_page_pfmemalloc(page); |
1559 | } |
1560 | |
1561 | /* |
1562 | * Go through the free lists for the given migratetype and remove |
1563 | * the smallest available page from the freelists |
1564 | */ |
1565 | static __always_inline |
1566 | struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, |
1567 | int migratetype) |
1568 | { |
1569 | unsigned int current_order; |
1570 | struct free_area *area; |
1571 | struct page *page; |
1572 | |
1573 | /* Find a page of the appropriate size in the preferred list */ |
1574 | for (current_order = order; current_order <= MAX_ORDER; ++current_order) { |
1575 | area = &(zone->free_area[current_order]); |
1576 | page = get_page_from_free_area(area, migratetype); |
1577 | if (!page) |
1578 | continue; |
1579 | del_page_from_free_list(page, zone, order: current_order); |
1580 | expand(zone, page, low: order, high: current_order, migratetype); |
1581 | set_pcppage_migratetype(page, migratetype); |
1582 | trace_mm_page_alloc_zone_locked(page, order, migratetype, |
1583 | percpu_refill: pcp_allowed_order(order) && |
1584 | migratetype < MIGRATE_PCPTYPES); |
1585 | return page; |
1586 | } |
1587 | |
1588 | return NULL; |
1589 | } |
1590 | |
1591 | |
1592 | /* |
1593 | * This array describes the order lists are fallen back to when |
1594 | * the free lists for the desirable migrate type are depleted |
1595 | * |
1596 | * The other migratetypes do not have fallbacks. |
1597 | */ |
1598 | static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = { |
1599 | [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE }, |
1600 | [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE }, |
1601 | [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE }, |
1602 | }; |
1603 | |
1604 | #ifdef CONFIG_CMA |
1605 | static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone, |
1606 | unsigned int order) |
1607 | { |
1608 | return __rmqueue_smallest(zone, order, migratetype: MIGRATE_CMA); |
1609 | } |
1610 | #else |
1611 | static inline struct page *__rmqueue_cma_fallback(struct zone *zone, |
1612 | unsigned int order) { return NULL; } |
1613 | #endif |
1614 | |
1615 | /* |
1616 | * Move the free pages in a range to the freelist tail of the requested type. |
1617 | * Note that start_page and end_pages are not aligned on a pageblock |
1618 | * boundary. If alignment is required, use move_freepages_block() |
1619 | */ |
1620 | static int move_freepages(struct zone *zone, |
1621 | unsigned long start_pfn, unsigned long end_pfn, |
1622 | int migratetype, int *num_movable) |
1623 | { |
1624 | struct page *page; |
1625 | unsigned long pfn; |
1626 | unsigned int order; |
1627 | int pages_moved = 0; |
1628 | |
1629 | for (pfn = start_pfn; pfn <= end_pfn;) { |
1630 | page = pfn_to_page(pfn); |
1631 | if (!PageBuddy(page)) { |
1632 | /* |
1633 | * We assume that pages that could be isolated for |
1634 | * migration are movable. But we don't actually try |
1635 | * isolating, as that would be expensive. |
1636 | */ |
1637 | if (num_movable && |
1638 | (PageLRU(page) || __PageMovable(page))) |
1639 | (*num_movable)++; |
1640 | pfn++; |
1641 | continue; |
1642 | } |
1643 | |
1644 | /* Make sure we are not inadvertently changing nodes */ |
1645 | VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); |
1646 | VM_BUG_ON_PAGE(page_zone(page) != zone, page); |
1647 | |
1648 | order = buddy_order(page); |
1649 | move_to_free_list(page, zone, order, migratetype); |
1650 | pfn += 1 << order; |
1651 | pages_moved += 1 << order; |
1652 | } |
1653 | |
1654 | return pages_moved; |
1655 | } |
1656 | |
1657 | int move_freepages_block(struct zone *zone, struct page *page, |
1658 | int migratetype, int *num_movable) |
1659 | { |
1660 | unsigned long start_pfn, end_pfn, pfn; |
1661 | |
1662 | if (num_movable) |
1663 | *num_movable = 0; |
1664 | |
1665 | pfn = page_to_pfn(page); |
1666 | start_pfn = pageblock_start_pfn(pfn); |
1667 | end_pfn = pageblock_end_pfn(pfn) - 1; |
1668 | |
1669 | /* Do not cross zone boundaries */ |
1670 | if (!zone_spans_pfn(zone, pfn: start_pfn)) |
1671 | start_pfn = pfn; |
1672 | if (!zone_spans_pfn(zone, pfn: end_pfn)) |
1673 | return 0; |
1674 | |
1675 | return move_freepages(zone, start_pfn, end_pfn, migratetype, |
1676 | num_movable); |
1677 | } |
1678 | |
1679 | static void change_pageblock_range(struct page *pageblock_page, |
1680 | int start_order, int migratetype) |
1681 | { |
1682 | int nr_pageblocks = 1 << (start_order - pageblock_order); |
1683 | |
1684 | while (nr_pageblocks--) { |
1685 | set_pageblock_migratetype(page: pageblock_page, migratetype); |
1686 | pageblock_page += pageblock_nr_pages; |
1687 | } |
1688 | } |
1689 | |
1690 | /* |
1691 | * When we are falling back to another migratetype during allocation, try to |
1692 | * steal extra free pages from the same pageblocks to satisfy further |
1693 | * allocations, instead of polluting multiple pageblocks. |
1694 | * |
1695 | * If we are stealing a relatively large buddy page, it is likely there will |
1696 | * be more free pages in the pageblock, so try to steal them all. For |
1697 | * reclaimable and unmovable allocations, we steal regardless of page size, |
1698 | * as fragmentation caused by those allocations polluting movable pageblocks |
1699 | * is worse than movable allocations stealing from unmovable and reclaimable |
1700 | * pageblocks. |
1701 | */ |
1702 | static bool can_steal_fallback(unsigned int order, int start_mt) |
1703 | { |
1704 | /* |
1705 | * Leaving this order check is intended, although there is |
1706 | * relaxed order check in next check. The reason is that |
1707 | * we can actually steal whole pageblock if this condition met, |
1708 | * but, below check doesn't guarantee it and that is just heuristic |
1709 | * so could be changed anytime. |
1710 | */ |
1711 | if (order >= pageblock_order) |
1712 | return true; |
1713 | |
1714 | if (order >= pageblock_order / 2 || |
1715 | start_mt == MIGRATE_RECLAIMABLE || |
1716 | start_mt == MIGRATE_UNMOVABLE || |
1717 | page_group_by_mobility_disabled) |
1718 | return true; |
1719 | |
1720 | return false; |
1721 | } |
1722 | |
1723 | static inline bool boost_watermark(struct zone *zone) |
1724 | { |
1725 | unsigned long max_boost; |
1726 | |
1727 | if (!watermark_boost_factor) |
1728 | return false; |
1729 | /* |
1730 | * Don't bother in zones that are unlikely to produce results. |
1731 | * On small machines, including kdump capture kernels running |
1732 | * in a small area, boosting the watermark can cause an out of |
1733 | * memory situation immediately. |
1734 | */ |
1735 | if ((pageblock_nr_pages * 4) > zone_managed_pages(zone)) |
1736 | return false; |
1737 | |
1738 | max_boost = mult_frac(zone->_watermark[WMARK_HIGH], |
1739 | watermark_boost_factor, 10000); |
1740 | |
1741 | /* |
1742 | * high watermark may be uninitialised if fragmentation occurs |
1743 | * very early in boot so do not boost. We do not fall |
1744 | * through and boost by pageblock_nr_pages as failing |
1745 | * allocations that early means that reclaim is not going |
1746 | * to help and it may even be impossible to reclaim the |
1747 | * boosted watermark resulting in a hang. |
1748 | */ |
1749 | if (!max_boost) |
1750 | return false; |
1751 | |
1752 | max_boost = max(pageblock_nr_pages, max_boost); |
1753 | |
1754 | zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages, |
1755 | max_boost); |
1756 | |
1757 | return true; |
1758 | } |
1759 | |
1760 | /* |
1761 | * This function implements actual steal behaviour. If order is large enough, |
1762 | * we can steal whole pageblock. If not, we first move freepages in this |
1763 | * pageblock to our migratetype and determine how many already-allocated pages |
1764 | * are there in the pageblock with a compatible migratetype. If at least half |
1765 | * of pages are free or compatible, we can change migratetype of the pageblock |
1766 | * itself, so pages freed in the future will be put on the correct free list. |
1767 | */ |
1768 | static void steal_suitable_fallback(struct zone *zone, struct page *page, |
1769 | unsigned int alloc_flags, int start_type, bool whole_block) |
1770 | { |
1771 | unsigned int current_order = buddy_order(page); |
1772 | int free_pages, movable_pages, alike_pages; |
1773 | int old_block_type; |
1774 | |
1775 | old_block_type = get_pageblock_migratetype(page); |
1776 | |
1777 | /* |
1778 | * This can happen due to races and we want to prevent broken |
1779 | * highatomic accounting. |
1780 | */ |
1781 | if (is_migrate_highatomic(migratetype: old_block_type)) |
1782 | goto single_page; |
1783 | |
1784 | /* Take ownership for orders >= pageblock_order */ |
1785 | if (current_order >= pageblock_order) { |
1786 | change_pageblock_range(pageblock_page: page, start_order: current_order, migratetype: start_type); |
1787 | goto single_page; |
1788 | } |
1789 | |
1790 | /* |
1791 | * Boost watermarks to increase reclaim pressure to reduce the |
1792 | * likelihood of future fallbacks. Wake kswapd now as the node |
1793 | * may be balanced overall and kswapd will not wake naturally. |
1794 | */ |
1795 | if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD)) |
1796 | set_bit(nr: ZONE_BOOSTED_WATERMARK, addr: &zone->flags); |
1797 | |
1798 | /* We are not allowed to try stealing from the whole block */ |
1799 | if (!whole_block) |
1800 | goto single_page; |
1801 | |
1802 | free_pages = move_freepages_block(zone, page, migratetype: start_type, |
1803 | num_movable: &movable_pages); |
1804 | /* moving whole block can fail due to zone boundary conditions */ |
1805 | if (!free_pages) |
1806 | goto single_page; |
1807 | |
1808 | /* |
1809 | * Determine how many pages are compatible with our allocation. |
1810 | * For movable allocation, it's the number of movable pages which |
1811 | * we just obtained. For other types it's a bit more tricky. |
1812 | */ |
1813 | if (start_type == MIGRATE_MOVABLE) { |
1814 | alike_pages = movable_pages; |
1815 | } else { |
1816 | /* |
1817 | * If we are falling back a RECLAIMABLE or UNMOVABLE allocation |
1818 | * to MOVABLE pageblock, consider all non-movable pages as |
1819 | * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or |
1820 | * vice versa, be conservative since we can't distinguish the |
1821 | * exact migratetype of non-movable pages. |
1822 | */ |
1823 | if (old_block_type == MIGRATE_MOVABLE) |
1824 | alike_pages = pageblock_nr_pages |
1825 | - (free_pages + movable_pages); |
1826 | else |
1827 | alike_pages = 0; |
1828 | } |
1829 | /* |
1830 | * If a sufficient number of pages in the block are either free or of |
1831 | * compatible migratability as our allocation, claim the whole block. |
1832 | */ |
1833 | if (free_pages + alike_pages >= (1 << (pageblock_order-1)) || |
1834 | page_group_by_mobility_disabled) |
1835 | set_pageblock_migratetype(page, migratetype: start_type); |
1836 | |
1837 | return; |
1838 | |
1839 | single_page: |
1840 | move_to_free_list(page, zone, order: current_order, migratetype: start_type); |
1841 | } |
1842 | |
1843 | /* |
1844 | * Check whether there is a suitable fallback freepage with requested order. |
1845 | * If only_stealable is true, this function returns fallback_mt only if |
1846 | * we can steal other freepages all together. This would help to reduce |
1847 | * fragmentation due to mixed migratetype pages in one pageblock. |
1848 | */ |
1849 | int find_suitable_fallback(struct free_area *area, unsigned int order, |
1850 | int migratetype, bool only_stealable, bool *can_steal) |
1851 | { |
1852 | int i; |
1853 | int fallback_mt; |
1854 | |
1855 | if (area->nr_free == 0) |
1856 | return -1; |
1857 | |
1858 | *can_steal = false; |
1859 | for (i = 0; i < MIGRATE_PCPTYPES - 1 ; i++) { |
1860 | fallback_mt = fallbacks[migratetype][i]; |
1861 | if (free_area_empty(area, migratetype: fallback_mt)) |
1862 | continue; |
1863 | |
1864 | if (can_steal_fallback(order, start_mt: migratetype)) |
1865 | *can_steal = true; |
1866 | |
1867 | if (!only_stealable) |
1868 | return fallback_mt; |
1869 | |
1870 | if (*can_steal) |
1871 | return fallback_mt; |
1872 | } |
1873 | |
1874 | return -1; |
1875 | } |
1876 | |
1877 | /* |
1878 | * Reserve a pageblock for exclusive use of high-order atomic allocations if |
1879 | * there are no empty page blocks that contain a page with a suitable order |
1880 | */ |
1881 | static void reserve_highatomic_pageblock(struct page *page, struct zone *zone) |
1882 | { |
1883 | int mt; |
1884 | unsigned long max_managed, flags; |
1885 | |
1886 | /* |
1887 | * Limit the number reserved to 1 pageblock or roughly 1% of a zone. |
1888 | * Check is race-prone but harmless. |
1889 | */ |
1890 | max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages; |
1891 | if (zone->nr_reserved_highatomic >= max_managed) |
1892 | return; |
1893 | |
1894 | spin_lock_irqsave(&zone->lock, flags); |
1895 | |
1896 | /* Recheck the nr_reserved_highatomic limit under the lock */ |
1897 | if (zone->nr_reserved_highatomic >= max_managed) |
1898 | goto out_unlock; |
1899 | |
1900 | /* Yoink! */ |
1901 | mt = get_pageblock_migratetype(page); |
1902 | /* Only reserve normal pageblocks (i.e., they can merge with others) */ |
1903 | if (migratetype_is_mergeable(mt)) { |
1904 | zone->nr_reserved_highatomic += pageblock_nr_pages; |
1905 | set_pageblock_migratetype(page, migratetype: MIGRATE_HIGHATOMIC); |
1906 | move_freepages_block(zone, page, migratetype: MIGRATE_HIGHATOMIC, NULL); |
1907 | } |
1908 | |
1909 | out_unlock: |
1910 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1911 | } |
1912 | |
1913 | /* |
1914 | * Used when an allocation is about to fail under memory pressure. This |
1915 | * potentially hurts the reliability of high-order allocations when under |
1916 | * intense memory pressure but failed atomic allocations should be easier |
1917 | * to recover from than an OOM. |
1918 | * |
1919 | * If @force is true, try to unreserve a pageblock even though highatomic |
1920 | * pageblock is exhausted. |
1921 | */ |
1922 | static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, |
1923 | bool force) |
1924 | { |
1925 | struct zonelist *zonelist = ac->zonelist; |
1926 | unsigned long flags; |
1927 | struct zoneref *z; |
1928 | struct zone *zone; |
1929 | struct page *page; |
1930 | int order; |
1931 | bool ret; |
1932 | |
1933 | for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx, |
1934 | ac->nodemask) { |
1935 | /* |
1936 | * Preserve at least one pageblock unless memory pressure |
1937 | * is really high. |
1938 | */ |
1939 | if (!force && zone->nr_reserved_highatomic <= |
1940 | pageblock_nr_pages) |
1941 | continue; |
1942 | |
1943 | spin_lock_irqsave(&zone->lock, flags); |
1944 | for (order = 0; order <= MAX_ORDER; order++) { |
1945 | struct free_area *area = &(zone->free_area[order]); |
1946 | |
1947 | page = get_page_from_free_area(area, migratetype: MIGRATE_HIGHATOMIC); |
1948 | if (!page) |
1949 | continue; |
1950 | |
1951 | /* |
1952 | * In page freeing path, migratetype change is racy so |
1953 | * we can counter several free pages in a pageblock |
1954 | * in this loop although we changed the pageblock type |
1955 | * from highatomic to ac->migratetype. So we should |
1956 | * adjust the count once. |
1957 | */ |
1958 | if (is_migrate_highatomic_page(page)) { |
1959 | /* |
1960 | * It should never happen but changes to |
1961 | * locking could inadvertently allow a per-cpu |
1962 | * drain to add pages to MIGRATE_HIGHATOMIC |
1963 | * while unreserving so be safe and watch for |
1964 | * underflows. |
1965 | */ |
1966 | zone->nr_reserved_highatomic -= min( |
1967 | pageblock_nr_pages, |
1968 | zone->nr_reserved_highatomic); |
1969 | } |
1970 | |
1971 | /* |
1972 | * Convert to ac->migratetype and avoid the normal |
1973 | * pageblock stealing heuristics. Minimally, the caller |
1974 | * is doing the work and needs the pages. More |
1975 | * importantly, if the block was always converted to |
1976 | * MIGRATE_UNMOVABLE or another type then the number |
1977 | * of pageblocks that cannot be completely freed |
1978 | * may increase. |
1979 | */ |
1980 | set_pageblock_migratetype(page, migratetype: ac->migratetype); |
1981 | ret = move_freepages_block(zone, page, migratetype: ac->migratetype, |
1982 | NULL); |
1983 | if (ret) { |
1984 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1985 | return ret; |
1986 | } |
1987 | } |
1988 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
1989 | } |
1990 | |
1991 | return false; |
1992 | } |
1993 | |
1994 | /* |
1995 | * Try finding a free buddy page on the fallback list and put it on the free |
1996 | * list of requested migratetype, possibly along with other pages from the same |
1997 | * block, depending on fragmentation avoidance heuristics. Returns true if |
1998 | * fallback was found so that __rmqueue_smallest() can grab it. |
1999 | * |
2000 | * The use of signed ints for order and current_order is a deliberate |
2001 | * deviation from the rest of this file, to make the for loop |
2002 | * condition simpler. |
2003 | */ |
2004 | static __always_inline bool |
2005 | __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, |
2006 | unsigned int alloc_flags) |
2007 | { |
2008 | struct free_area *area; |
2009 | int current_order; |
2010 | int min_order = order; |
2011 | struct page *page; |
2012 | int fallback_mt; |
2013 | bool can_steal; |
2014 | |
2015 | /* |
2016 | * Do not steal pages from freelists belonging to other pageblocks |
2017 | * i.e. orders < pageblock_order. If there are no local zones free, |
2018 | * the zonelists will be reiterated without ALLOC_NOFRAGMENT. |
2019 | */ |
2020 | if (order < pageblock_order && alloc_flags & ALLOC_NOFRAGMENT) |
2021 | min_order = pageblock_order; |
2022 | |
2023 | /* |
2024 | * Find the largest available free page in the other list. This roughly |
2025 | * approximates finding the pageblock with the most free pages, which |
2026 | * would be too costly to do exactly. |
2027 | */ |
2028 | for (current_order = MAX_ORDER; current_order >= min_order; |
2029 | --current_order) { |
2030 | area = &(zone->free_area[current_order]); |
2031 | fallback_mt = find_suitable_fallback(area, order: current_order, |
2032 | migratetype: start_migratetype, only_stealable: false, can_steal: &can_steal); |
2033 | if (fallback_mt == -1) |
2034 | continue; |
2035 | |
2036 | /* |
2037 | * We cannot steal all free pages from the pageblock and the |
2038 | * requested migratetype is movable. In that case it's better to |
2039 | * steal and split the smallest available page instead of the |
2040 | * largest available page, because even if the next movable |
2041 | * allocation falls back into a different pageblock than this |
2042 | * one, it won't cause permanent fragmentation. |
2043 | */ |
2044 | if (!can_steal && start_migratetype == MIGRATE_MOVABLE |
2045 | && current_order > order) |
2046 | goto find_smallest; |
2047 | |
2048 | goto do_steal; |
2049 | } |
2050 | |
2051 | return false; |
2052 | |
2053 | find_smallest: |
2054 | for (current_order = order; current_order <= MAX_ORDER; |
2055 | current_order++) { |
2056 | area = &(zone->free_area[current_order]); |
2057 | fallback_mt = find_suitable_fallback(area, order: current_order, |
2058 | migratetype: start_migratetype, only_stealable: false, can_steal: &can_steal); |
2059 | if (fallback_mt != -1) |
2060 | break; |
2061 | } |
2062 | |
2063 | /* |
2064 | * This should not happen - we already found a suitable fallback |
2065 | * when looking for the largest page. |
2066 | */ |
2067 | VM_BUG_ON(current_order > MAX_ORDER); |
2068 | |
2069 | do_steal: |
2070 | page = get_page_from_free_area(area, migratetype: fallback_mt); |
2071 | |
2072 | steal_suitable_fallback(zone, page, alloc_flags, start_type: start_migratetype, |
2073 | whole_block: can_steal); |
2074 | |
2075 | trace_mm_page_alloc_extfrag(page, alloc_order: order, fallback_order: current_order, |
2076 | alloc_migratetype: start_migratetype, fallback_migratetype: fallback_mt); |
2077 | |
2078 | return true; |
2079 | |
2080 | } |
2081 | |
2082 | /* |
2083 | * Do the hard work of removing an element from the buddy allocator. |
2084 | * Call me with the zone->lock already held. |
2085 | */ |
2086 | static __always_inline struct page * |
2087 | __rmqueue(struct zone *zone, unsigned int order, int migratetype, |
2088 | unsigned int alloc_flags) |
2089 | { |
2090 | struct page *page; |
2091 | |
2092 | if (IS_ENABLED(CONFIG_CMA)) { |
2093 | /* |
2094 | * Balance movable allocations between regular and CMA areas by |
2095 | * allocating from CMA when over half of the zone's free memory |
2096 | * is in the CMA area. |
2097 | */ |
2098 | if (alloc_flags & ALLOC_CMA && |
2099 | zone_page_state(zone, item: NR_FREE_CMA_PAGES) > |
2100 | zone_page_state(zone, item: NR_FREE_PAGES) / 2) { |
2101 | page = __rmqueue_cma_fallback(zone, order); |
2102 | if (page) |
2103 | return page; |
2104 | } |
2105 | } |
2106 | retry: |
2107 | page = __rmqueue_smallest(zone, order, migratetype); |
2108 | if (unlikely(!page)) { |
2109 | if (alloc_flags & ALLOC_CMA) |
2110 | page = __rmqueue_cma_fallback(zone, order); |
2111 | |
2112 | if (!page && __rmqueue_fallback(zone, order, start_migratetype: migratetype, |
2113 | alloc_flags)) |
2114 | goto retry; |
2115 | } |
2116 | return page; |
2117 | } |
2118 | |
2119 | /* |
2120 | * Obtain a specified number of elements from the buddy allocator, all under |
2121 | * a single hold of the lock, for efficiency. Add them to the supplied list. |
2122 | * Returns the number of new pages which were placed at *list. |
2123 | */ |
2124 | static int rmqueue_bulk(struct zone *zone, unsigned int order, |
2125 | unsigned long count, struct list_head *list, |
2126 | int migratetype, unsigned int alloc_flags) |
2127 | { |
2128 | unsigned long flags; |
2129 | int i; |
2130 | |
2131 | spin_lock_irqsave(&zone->lock, flags); |
2132 | for (i = 0; i < count; ++i) { |
2133 | struct page *page = __rmqueue(zone, order, migratetype, |
2134 | alloc_flags); |
2135 | if (unlikely(page == NULL)) |
2136 | break; |
2137 | |
2138 | /* |
2139 | * Split buddy pages returned by expand() are received here in |
2140 | * physical page order. The page is added to the tail of |
2141 | * caller's list. From the callers perspective, the linked list |
2142 | * is ordered by page number under some conditions. This is |
2143 | * useful for IO devices that can forward direction from the |
2144 | * head, thus also in the physical page order. This is useful |
2145 | * for IO devices that can merge IO requests if the physical |
2146 | * pages are ordered properly. |
2147 | */ |
2148 | list_add_tail(new: &page->pcp_list, head: list); |
2149 | if (is_migrate_cma(get_pcppage_migratetype(page))) |
2150 | __mod_zone_page_state(zone, item: NR_FREE_CMA_PAGES, |
2151 | -(1 << order)); |
2152 | } |
2153 | |
2154 | __mod_zone_page_state(zone, item: NR_FREE_PAGES, -(i << order)); |
2155 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
2156 | |
2157 | return i; |
2158 | } |
2159 | |
2160 | /* |
2161 | * Called from the vmstat counter updater to decay the PCP high. |
2162 | * Return whether there are addition works to do. |
2163 | */ |
2164 | int decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp) |
2165 | { |
2166 | int high_min, to_drain, batch; |
2167 | int todo = 0; |
2168 | |
2169 | high_min = READ_ONCE(pcp->high_min); |
2170 | batch = READ_ONCE(pcp->batch); |
2171 | /* |
2172 | * Decrease pcp->high periodically to try to free possible |
2173 | * idle PCP pages. And, avoid to free too many pages to |
2174 | * control latency. This caps pcp->high decrement too. |
2175 | */ |
2176 | if (pcp->high > high_min) { |
2177 | pcp->high = max3(pcp->count - (batch << CONFIG_PCP_BATCH_SCALE_MAX), |
2178 | pcp->high - (pcp->high >> 3), high_min); |
2179 | if (pcp->high > high_min) |
2180 | todo++; |
2181 | } |
2182 | |
2183 | to_drain = pcp->count - pcp->high; |
2184 | if (to_drain > 0) { |
2185 | spin_lock(lock: &pcp->lock); |
2186 | free_pcppages_bulk(zone, count: to_drain, pcp, pindex: 0); |
2187 | spin_unlock(lock: &pcp->lock); |
2188 | todo++; |
2189 | } |
2190 | |
2191 | return todo; |
2192 | } |
2193 | |
2194 | #ifdef CONFIG_NUMA |
2195 | /* |
2196 | * Called from the vmstat counter updater to drain pagesets of this |
2197 | * currently executing processor on remote nodes after they have |
2198 | * expired. |
2199 | */ |
2200 | void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) |
2201 | { |
2202 | int to_drain, batch; |
2203 | |
2204 | batch = READ_ONCE(pcp->batch); |
2205 | to_drain = min(pcp->count, batch); |
2206 | if (to_drain > 0) { |
2207 | spin_lock(lock: &pcp->lock); |
2208 | free_pcppages_bulk(zone, count: to_drain, pcp, pindex: 0); |
2209 | spin_unlock(lock: &pcp->lock); |
2210 | } |
2211 | } |
2212 | #endif |
2213 | |
2214 | /* |
2215 | * Drain pcplists of the indicated processor and zone. |
2216 | */ |
2217 | static void drain_pages_zone(unsigned int cpu, struct zone *zone) |
2218 | { |
2219 | struct per_cpu_pages *pcp; |
2220 | |
2221 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); |
2222 | if (pcp->count) { |
2223 | spin_lock(lock: &pcp->lock); |
2224 | free_pcppages_bulk(zone, count: pcp->count, pcp, pindex: 0); |
2225 | spin_unlock(lock: &pcp->lock); |
2226 | } |
2227 | } |
2228 | |
2229 | /* |
2230 | * Drain pcplists of all zones on the indicated processor. |
2231 | */ |
2232 | static void drain_pages(unsigned int cpu) |
2233 | { |
2234 | struct zone *zone; |
2235 | |
2236 | for_each_populated_zone(zone) { |
2237 | drain_pages_zone(cpu, zone); |
2238 | } |
2239 | } |
2240 | |
2241 | /* |
2242 | * Spill all of this CPU's per-cpu pages back into the buddy allocator. |
2243 | */ |
2244 | void drain_local_pages(struct zone *zone) |
2245 | { |
2246 | int cpu = smp_processor_id(); |
2247 | |
2248 | if (zone) |
2249 | drain_pages_zone(cpu, zone); |
2250 | else |
2251 | drain_pages(cpu); |
2252 | } |
2253 | |
2254 | /* |
2255 | * The implementation of drain_all_pages(), exposing an extra parameter to |
2256 | * drain on all cpus. |
2257 | * |
2258 | * drain_all_pages() is optimized to only execute on cpus where pcplists are |
2259 | * not empty. The check for non-emptiness can however race with a free to |
2260 | * pcplist that has not yet increased the pcp->count from 0 to 1. Callers |
2261 | * that need the guarantee that every CPU has drained can disable the |
2262 | * optimizing racy check. |
2263 | */ |
2264 | static void __drain_all_pages(struct zone *zone, bool force_all_cpus) |
2265 | { |
2266 | int cpu; |
2267 | |
2268 | /* |
2269 | * Allocate in the BSS so we won't require allocation in |
2270 | * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y |
2271 | */ |
2272 | static cpumask_t cpus_with_pcps; |
2273 | |
2274 | /* |
2275 | * Do not drain if one is already in progress unless it's specific to |
2276 | * a zone. Such callers are primarily CMA and memory hotplug and need |
2277 | * the drain to be complete when the call returns. |
2278 | */ |
2279 | if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) { |
2280 | if (!zone) |
2281 | return; |
2282 | mutex_lock(&pcpu_drain_mutex); |
2283 | } |
2284 | |
2285 | /* |
2286 | * We don't care about racing with CPU hotplug event |
2287 | * as offline notification will cause the notified |
2288 | * cpu to drain that CPU pcps and on_each_cpu_mask |
2289 | * disables preemption as part of its processing |
2290 | */ |
2291 | for_each_online_cpu(cpu) { |
2292 | struct per_cpu_pages *pcp; |
2293 | struct zone *z; |
2294 | bool has_pcps = false; |
2295 | |
2296 | if (force_all_cpus) { |
2297 | /* |
2298 | * The pcp.count check is racy, some callers need a |
2299 | * guarantee that no cpu is missed. |
2300 | */ |
2301 | has_pcps = true; |
2302 | } else if (zone) { |
2303 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); |
2304 | if (pcp->count) |
2305 | has_pcps = true; |
2306 | } else { |
2307 | for_each_populated_zone(z) { |
2308 | pcp = per_cpu_ptr(z->per_cpu_pageset, cpu); |
2309 | if (pcp->count) { |
2310 | has_pcps = true; |
2311 | break; |
2312 | } |
2313 | } |
2314 | } |
2315 | |
2316 | if (has_pcps) |
2317 | cpumask_set_cpu(cpu, dstp: &cpus_with_pcps); |
2318 | else |
2319 | cpumask_clear_cpu(cpu, dstp: &cpus_with_pcps); |
2320 | } |
2321 | |
2322 | for_each_cpu(cpu, &cpus_with_pcps) { |
2323 | if (zone) |
2324 | drain_pages_zone(cpu, zone); |
2325 | else |
2326 | drain_pages(cpu); |
2327 | } |
2328 | |
2329 | mutex_unlock(lock: &pcpu_drain_mutex); |
2330 | } |
2331 | |
2332 | /* |
2333 | * Spill all the per-cpu pages from all CPUs back into the buddy allocator. |
2334 | * |
2335 | * When zone parameter is non-NULL, spill just the single zone's pages. |
2336 | */ |
2337 | void drain_all_pages(struct zone *zone) |
2338 | { |
2339 | __drain_all_pages(zone, force_all_cpus: false); |
2340 | } |
2341 | |
2342 | static bool free_unref_page_prepare(struct page *page, unsigned long pfn, |
2343 | unsigned int order) |
2344 | { |
2345 | int migratetype; |
2346 | |
2347 | if (!free_pages_prepare(page, order, FPI_NONE)) |
2348 | return false; |
2349 | |
2350 | migratetype = get_pfnblock_migratetype(page, pfn); |
2351 | set_pcppage_migratetype(page, migratetype); |
2352 | return true; |
2353 | } |
2354 | |
2355 | static int nr_pcp_free(struct per_cpu_pages *pcp, int batch, int high, bool free_high) |
2356 | { |
2357 | int min_nr_free, max_nr_free; |
2358 | |
2359 | /* Free as much as possible if batch freeing high-order pages. */ |
2360 | if (unlikely(free_high)) |
2361 | return min(pcp->count, batch << CONFIG_PCP_BATCH_SCALE_MAX); |
2362 | |
2363 | /* Check for PCP disabled or boot pageset */ |
2364 | if (unlikely(high < batch)) |
2365 | return 1; |
2366 | |
2367 | /* Leave at least pcp->batch pages on the list */ |
2368 | min_nr_free = batch; |
2369 | max_nr_free = high - batch; |
2370 | |
2371 | /* |
2372 | * Increase the batch number to the number of the consecutive |
2373 | * freed pages to reduce zone lock contention. |
2374 | */ |
2375 | batch = clamp_t(int, pcp->free_count, min_nr_free, max_nr_free); |
2376 | |
2377 | return batch; |
2378 | } |
2379 | |
2380 | static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, |
2381 | int batch, bool free_high) |
2382 | { |
2383 | int high, high_min, high_max; |
2384 | |
2385 | high_min = READ_ONCE(pcp->high_min); |
2386 | high_max = READ_ONCE(pcp->high_max); |
2387 | high = pcp->high = clamp(pcp->high, high_min, high_max); |
2388 | |
2389 | if (unlikely(!high)) |
2390 | return 0; |
2391 | |
2392 | if (unlikely(free_high)) { |
2393 | pcp->high = max(high - (batch << CONFIG_PCP_BATCH_SCALE_MAX), |
2394 | high_min); |
2395 | return 0; |
2396 | } |
2397 | |
2398 | /* |
2399 | * If reclaim is active, limit the number of pages that can be |
2400 | * stored on pcp lists |
2401 | */ |
2402 | if (test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) { |
2403 | int free_count = max_t(int, pcp->free_count, batch); |
2404 | |
2405 | pcp->high = max(high - free_count, high_min); |
2406 | return min(batch << 2, pcp->high); |
2407 | } |
2408 | |
2409 | if (high_min == high_max) |
2410 | return high; |
2411 | |
2412 | if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) { |
2413 | int free_count = max_t(int, pcp->free_count, batch); |
2414 | |
2415 | pcp->high = max(high - free_count, high_min); |
2416 | high = max(pcp->count, high_min); |
2417 | } else if (pcp->count >= high) { |
2418 | int need_high = pcp->free_count + batch; |
2419 | |
2420 | /* pcp->high should be large enough to hold batch freed pages */ |
2421 | if (pcp->high < need_high) |
2422 | pcp->high = clamp(need_high, high_min, high_max); |
2423 | } |
2424 | |
2425 | return high; |
2426 | } |
2427 | |
2428 | static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, |
2429 | struct page *page, int migratetype, |
2430 | unsigned int order) |
2431 | { |
2432 | int high, batch; |
2433 | int pindex; |
2434 | bool free_high = false; |
2435 | |
2436 | /* |
2437 | * On freeing, reduce the number of pages that are batch allocated. |
2438 | * See nr_pcp_alloc() where alloc_factor is increased for subsequent |
2439 | * allocations. |
2440 | */ |
2441 | pcp->alloc_factor >>= 1; |
2442 | __count_vm_events(item: PGFREE, delta: 1 << order); |
2443 | pindex = order_to_pindex(migratetype, order); |
2444 | list_add(new: &page->pcp_list, head: &pcp->lists[pindex]); |
2445 | pcp->count += 1 << order; |
2446 | |
2447 | batch = READ_ONCE(pcp->batch); |
2448 | /* |
2449 | * As high-order pages other than THP's stored on PCP can contribute |
2450 | * to fragmentation, limit the number stored when PCP is heavily |
2451 | * freeing without allocation. The remainder after bulk freeing |
2452 | * stops will be drained from vmstat refresh context. |
2453 | */ |
2454 | if (order && order <= PAGE_ALLOC_COSTLY_ORDER) { |
2455 | free_high = (pcp->free_count >= batch && |
2456 | (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && |
2457 | (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || |
2458 | pcp->count >= READ_ONCE(batch))); |
2459 | pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; |
2460 | } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { |
2461 | pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; |
2462 | } |
2463 | if (pcp->free_count < (batch << CONFIG_PCP_BATCH_SCALE_MAX)) |
2464 | pcp->free_count += (1 << order); |
2465 | high = nr_pcp_high(pcp, zone, batch, free_high); |
2466 | if (pcp->count >= high) { |
2467 | free_pcppages_bulk(zone, count: nr_pcp_free(pcp, batch, high, free_high), |
2468 | pcp, pindex); |
2469 | if (test_bit(ZONE_BELOW_HIGH, &zone->flags) && |
2470 | zone_watermark_ok(z: zone, order: 0, high_wmark_pages(zone), |
2471 | highest_zoneidx: ZONE_MOVABLE, alloc_flags: 0)) |
2472 | clear_bit(nr: ZONE_BELOW_HIGH, addr: &zone->flags); |
2473 | } |
2474 | } |
2475 | |
2476 | /* |
2477 | * Free a pcp page |
2478 | */ |
2479 | void free_unref_page(struct page *page, unsigned int order) |
2480 | { |
2481 | unsigned long __maybe_unused UP_flags; |
2482 | struct per_cpu_pages *pcp; |
2483 | struct zone *zone; |
2484 | unsigned long pfn = page_to_pfn(page); |
2485 | int migratetype, pcpmigratetype; |
2486 | |
2487 | if (!free_unref_page_prepare(page, pfn, order)) |
2488 | return; |
2489 | |
2490 | /* |
2491 | * We only track unmovable, reclaimable and movable on pcp lists. |
2492 | * Place ISOLATE pages on the isolated list because they are being |
2493 | * offlined but treat HIGHATOMIC and CMA as movable pages so we can |
2494 | * get those areas back if necessary. Otherwise, we may have to free |
2495 | * excessively into the page allocator |
2496 | */ |
2497 | migratetype = pcpmigratetype = get_pcppage_migratetype(page); |
2498 | if (unlikely(migratetype >= MIGRATE_PCPTYPES)) { |
2499 | if (unlikely(is_migrate_isolate(migratetype))) { |
2500 | free_one_page(zone: page_zone(page), page, pfn, order, migratetype, FPI_NONE); |
2501 | return; |
2502 | } |
2503 | pcpmigratetype = MIGRATE_MOVABLE; |
2504 | } |
2505 | |
2506 | zone = page_zone(page); |
2507 | pcp_trylock_prepare(UP_flags); |
2508 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); |
2509 | if (pcp) { |
2510 | free_unref_page_commit(zone, pcp, page, migratetype: pcpmigratetype, order); |
2511 | pcp_spin_unlock(pcp); |
2512 | } else { |
2513 | free_one_page(zone, page, pfn, order, migratetype, FPI_NONE); |
2514 | } |
2515 | pcp_trylock_finish(UP_flags); |
2516 | } |
2517 | |
2518 | /* |
2519 | * Free a list of 0-order pages |
2520 | */ |
2521 | void free_unref_page_list(struct list_head *list) |
2522 | { |
2523 | unsigned long __maybe_unused UP_flags; |
2524 | struct page *page, *next; |
2525 | struct per_cpu_pages *pcp = NULL; |
2526 | struct zone *locked_zone = NULL; |
2527 | int batch_count = 0; |
2528 | int migratetype; |
2529 | |
2530 | /* Prepare pages for freeing */ |
2531 | list_for_each_entry_safe(page, next, list, lru) { |
2532 | unsigned long pfn = page_to_pfn(page); |
2533 | if (!free_unref_page_prepare(page, pfn, order: 0)) { |
2534 | list_del(entry: &page->lru); |
2535 | continue; |
2536 | } |
2537 | |
2538 | /* |
2539 | * Free isolated pages directly to the allocator, see |
2540 | * comment in free_unref_page. |
2541 | */ |
2542 | migratetype = get_pcppage_migratetype(page); |
2543 | if (unlikely(is_migrate_isolate(migratetype))) { |
2544 | list_del(entry: &page->lru); |
2545 | free_one_page(zone: page_zone(page), page, pfn, order: 0, migratetype, FPI_NONE); |
2546 | continue; |
2547 | } |
2548 | } |
2549 | |
2550 | list_for_each_entry_safe(page, next, list, lru) { |
2551 | struct zone *zone = page_zone(page); |
2552 | |
2553 | list_del(entry: &page->lru); |
2554 | migratetype = get_pcppage_migratetype(page); |
2555 | |
2556 | /* |
2557 | * Either different zone requiring a different pcp lock or |
2558 | * excessive lock hold times when freeing a large list of |
2559 | * pages. |
2560 | */ |
2561 | if (zone != locked_zone || batch_count == SWAP_CLUSTER_MAX) { |
2562 | if (pcp) { |
2563 | pcp_spin_unlock(pcp); |
2564 | pcp_trylock_finish(UP_flags); |
2565 | } |
2566 | |
2567 | batch_count = 0; |
2568 | |
2569 | /* |
2570 | * trylock is necessary as pages may be getting freed |
2571 | * from IRQ or SoftIRQ context after an IO completion. |
2572 | */ |
2573 | pcp_trylock_prepare(UP_flags); |
2574 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); |
2575 | if (unlikely(!pcp)) { |
2576 | pcp_trylock_finish(UP_flags); |
2577 | free_one_page(zone, page, page_to_pfn(page), |
2578 | order: 0, migratetype, FPI_NONE); |
2579 | locked_zone = NULL; |
2580 | continue; |
2581 | } |
2582 | locked_zone = zone; |
2583 | } |
2584 | |
2585 | /* |
2586 | * Non-isolated types over MIGRATE_PCPTYPES get added |
2587 | * to the MIGRATE_MOVABLE pcp list. |
2588 | */ |
2589 | if (unlikely(migratetype >= MIGRATE_PCPTYPES)) |
2590 | migratetype = MIGRATE_MOVABLE; |
2591 | |
2592 | trace_mm_page_free_batched(page); |
2593 | free_unref_page_commit(zone, pcp, page, migratetype, order: 0); |
2594 | batch_count++; |
2595 | } |
2596 | |
2597 | if (pcp) { |
2598 | pcp_spin_unlock(pcp); |
2599 | pcp_trylock_finish(UP_flags); |
2600 | } |
2601 | } |
2602 | |
2603 | /* |
2604 | * split_page takes a non-compound higher-order page, and splits it into |
2605 | * n (1<<order) sub-pages: page[0..n] |
2606 | * Each sub-page must be freed individually. |
2607 | * |
2608 | * Note: this is probably too low level an operation for use in drivers. |
2609 | * Please consult with lkml before using this in your driver. |
2610 | */ |
2611 | void split_page(struct page *page, unsigned int order) |
2612 | { |
2613 | int i; |
2614 | |
2615 | VM_BUG_ON_PAGE(PageCompound(page), page); |
2616 | VM_BUG_ON_PAGE(!page_count(page), page); |
2617 | |
2618 | for (i = 1; i < (1 << order); i++) |
2619 | set_page_refcounted(page + i); |
2620 | split_page_owner(page, nr: 1 << order); |
2621 | split_page_memcg(head: page, nr: 1 << order); |
2622 | } |
2623 | EXPORT_SYMBOL_GPL(split_page); |
2624 | |
2625 | int __isolate_free_page(struct page *page, unsigned int order) |
2626 | { |
2627 | struct zone *zone = page_zone(page); |
2628 | int mt = get_pageblock_migratetype(page); |
2629 | |
2630 | if (!is_migrate_isolate(migratetype: mt)) { |
2631 | unsigned long watermark; |
2632 | /* |
2633 | * Obey watermarks as if the page was being allocated. We can |
2634 | * emulate a high-order watermark check with a raised order-0 |
2635 | * watermark, because we already know our high-order page |
2636 | * exists. |
2637 | */ |
2638 | watermark = zone->_watermark[WMARK_MIN] + (1UL << order); |
2639 | if (!zone_watermark_ok(z: zone, order: 0, mark: watermark, highest_zoneidx: 0, ALLOC_CMA)) |
2640 | return 0; |
2641 | |
2642 | __mod_zone_freepage_state(zone, nr_pages: -(1UL << order), migratetype: mt); |
2643 | } |
2644 | |
2645 | del_page_from_free_list(page, zone, order); |
2646 | |
2647 | /* |
2648 | * Set the pageblock if the isolated page is at least half of a |
2649 | * pageblock |
2650 | */ |
2651 | if (order >= pageblock_order - 1) { |
2652 | struct page *endpage = page + (1 << order) - 1; |
2653 | for (; page < endpage; page += pageblock_nr_pages) { |
2654 | int mt = get_pageblock_migratetype(page); |
2655 | /* |
2656 | * Only change normal pageblocks (i.e., they can merge |
2657 | * with others) |
2658 | */ |
2659 | if (migratetype_is_mergeable(mt)) |
2660 | set_pageblock_migratetype(page, |
2661 | migratetype: MIGRATE_MOVABLE); |
2662 | } |
2663 | } |
2664 | |
2665 | return 1UL << order; |
2666 | } |
2667 | |
2668 | /** |
2669 | * __putback_isolated_page - Return a now-isolated page back where we got it |
2670 | * @page: Page that was isolated |
2671 | * @order: Order of the isolated page |
2672 | * @mt: The page's pageblock's migratetype |
2673 | * |
2674 | * This function is meant to return a page pulled from the free lists via |
2675 | * __isolate_free_page back to the free lists they were pulled from. |
2676 | */ |
2677 | void __putback_isolated_page(struct page *page, unsigned int order, int mt) |
2678 | { |
2679 | struct zone *zone = page_zone(page); |
2680 | |
2681 | /* zone lock should be held when this function is called */ |
2682 | lockdep_assert_held(&zone->lock); |
2683 | |
2684 | /* Return isolated page to tail of freelist. */ |
2685 | __free_one_page(page, page_to_pfn(page), zone, order, migratetype: mt, |
2686 | FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL); |
2687 | } |
2688 | |
2689 | /* |
2690 | * Update NUMA hit/miss statistics |
2691 | */ |
2692 | static inline void zone_statistics(struct zone *preferred_zone, struct zone *z, |
2693 | long nr_account) |
2694 | { |
2695 | #ifdef CONFIG_NUMA |
2696 | enum numa_stat_item local_stat = NUMA_LOCAL; |
2697 | |
2698 | /* skip numa counters update if numa stats is disabled */ |
2699 | if (!static_branch_likely(&vm_numa_stat_key)) |
2700 | return; |
2701 | |
2702 | if (zone_to_nid(zone: z) != numa_node_id()) |
2703 | local_stat = NUMA_OTHER; |
2704 | |
2705 | if (zone_to_nid(zone: z) == zone_to_nid(zone: preferred_zone)) |
2706 | __count_numa_events(zone: z, item: NUMA_HIT, delta: nr_account); |
2707 | else { |
2708 | __count_numa_events(zone: z, item: NUMA_MISS, delta: nr_account); |
2709 | __count_numa_events(zone: preferred_zone, item: NUMA_FOREIGN, delta: nr_account); |
2710 | } |
2711 | __count_numa_events(zone: z, item: local_stat, delta: nr_account); |
2712 | #endif |
2713 | } |
2714 | |
2715 | static __always_inline |
2716 | struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, |
2717 | unsigned int order, unsigned int alloc_flags, |
2718 | int migratetype) |
2719 | { |
2720 | struct page *page; |
2721 | unsigned long flags; |
2722 | |
2723 | do { |
2724 | page = NULL; |
2725 | spin_lock_irqsave(&zone->lock, flags); |
2726 | if (alloc_flags & ALLOC_HIGHATOMIC) |
2727 | page = __rmqueue_smallest(zone, order, migratetype: MIGRATE_HIGHATOMIC); |
2728 | if (!page) { |
2729 | page = __rmqueue(zone, order, migratetype, alloc_flags); |
2730 | |
2731 | /* |
2732 | * If the allocation fails, allow OOM handling access |
2733 | * to HIGHATOMIC reserves as failing now is worse than |
2734 | * failing a high-order atomic allocation in the |
2735 | * future. |
2736 | */ |
2737 | if (!page && (alloc_flags & ALLOC_OOM)) |
2738 | page = __rmqueue_smallest(zone, order, migratetype: MIGRATE_HIGHATOMIC); |
2739 | |
2740 | if (!page) { |
2741 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
2742 | return NULL; |
2743 | } |
2744 | } |
2745 | __mod_zone_freepage_state(zone, nr_pages: -(1 << order), |
2746 | migratetype: get_pcppage_migratetype(page)); |
2747 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
2748 | } while (check_new_pages(page, order)); |
2749 | |
2750 | __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); |
2751 | zone_statistics(preferred_zone, z: zone, nr_account: 1); |
2752 | |
2753 | return page; |
2754 | } |
2755 | |
2756 | static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order) |
2757 | { |
2758 | int high, base_batch, batch, max_nr_alloc; |
2759 | int high_max, high_min; |
2760 | |
2761 | base_batch = READ_ONCE(pcp->batch); |
2762 | high_min = READ_ONCE(pcp->high_min); |
2763 | high_max = READ_ONCE(pcp->high_max); |
2764 | high = pcp->high = clamp(pcp->high, high_min, high_max); |
2765 | |
2766 | /* Check for PCP disabled or boot pageset */ |
2767 | if (unlikely(high < base_batch)) |
2768 | return 1; |
2769 | |
2770 | if (order) |
2771 | batch = base_batch; |
2772 | else |
2773 | batch = (base_batch << pcp->alloc_factor); |
2774 | |
2775 | /* |
2776 | * If we had larger pcp->high, we could avoid to allocate from |
2777 | * zone. |
2778 | */ |
2779 | if (high_min != high_max && !test_bit(ZONE_BELOW_HIGH, &zone->flags)) |
2780 | high = pcp->high = min(high + batch, high_max); |
2781 | |
2782 | if (!order) { |
2783 | max_nr_alloc = max(high - pcp->count - base_batch, base_batch); |
2784 | /* |
2785 | * Double the number of pages allocated each time there is |
2786 | * subsequent allocation of order-0 pages without any freeing. |
2787 | */ |
2788 | if (batch <= max_nr_alloc && |
2789 | pcp->alloc_factor < CONFIG_PCP_BATCH_SCALE_MAX) |
2790 | pcp->alloc_factor++; |
2791 | batch = min(batch, max_nr_alloc); |
2792 | } |
2793 | |
2794 | /* |
2795 | * Scale batch relative to order if batch implies free pages |
2796 | * can be stored on the PCP. Batch can be 1 for small zones or |
2797 | * for boot pagesets which should never store free pages as |
2798 | * the pages may belong to arbitrary zones. |
2799 | */ |
2800 | if (batch > 1) |
2801 | batch = max(batch >> order, 2); |
2802 | |
2803 | return batch; |
2804 | } |
2805 | |
2806 | /* Remove page from the per-cpu list, caller must protect the list */ |
2807 | static inline |
2808 | struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, |
2809 | int migratetype, |
2810 | unsigned int alloc_flags, |
2811 | struct per_cpu_pages *pcp, |
2812 | struct list_head *list) |
2813 | { |
2814 | struct page *page; |
2815 | |
2816 | do { |
2817 | if (list_empty(head: list)) { |
2818 | int batch = nr_pcp_alloc(pcp, zone, order); |
2819 | int alloced; |
2820 | |
2821 | alloced = rmqueue_bulk(zone, order, |
2822 | count: batch, list, |
2823 | migratetype, alloc_flags); |
2824 | |
2825 | pcp->count += alloced << order; |
2826 | if (unlikely(list_empty(list))) |
2827 | return NULL; |
2828 | } |
2829 | |
2830 | page = list_first_entry(list, struct page, pcp_list); |
2831 | list_del(entry: &page->pcp_list); |
2832 | pcp->count -= 1 << order; |
2833 | } while (check_new_pages(page, order)); |
2834 | |
2835 | return page; |
2836 | } |
2837 | |
2838 | /* Lock and remove page from the per-cpu list */ |
2839 | static struct page *rmqueue_pcplist(struct zone *preferred_zone, |
2840 | struct zone *zone, unsigned int order, |
2841 | int migratetype, unsigned int alloc_flags) |
2842 | { |
2843 | struct per_cpu_pages *pcp; |
2844 | struct list_head *list; |
2845 | struct page *page; |
2846 | unsigned long __maybe_unused UP_flags; |
2847 | |
2848 | /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ |
2849 | pcp_trylock_prepare(UP_flags); |
2850 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); |
2851 | if (!pcp) { |
2852 | pcp_trylock_finish(UP_flags); |
2853 | return NULL; |
2854 | } |
2855 | |
2856 | /* |
2857 | * On allocation, reduce the number of pages that are batch freed. |
2858 | * See nr_pcp_free() where free_factor is increased for subsequent |
2859 | * frees. |
2860 | */ |
2861 | pcp->free_count >>= 1; |
2862 | list = &pcp->lists[order_to_pindex(migratetype, order)]; |
2863 | page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list); |
2864 | pcp_spin_unlock(pcp); |
2865 | pcp_trylock_finish(UP_flags); |
2866 | if (page) { |
2867 | __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); |
2868 | zone_statistics(preferred_zone, z: zone, nr_account: 1); |
2869 | } |
2870 | return page; |
2871 | } |
2872 | |
2873 | /* |
2874 | * Allocate a page from the given zone. |
2875 | * Use pcplists for THP or "cheap" high-order allocations. |
2876 | */ |
2877 | |
2878 | /* |
2879 | * Do not instrument rmqueue() with KMSAN. This function may call |
2880 | * __msan_poison_alloca() through a call to set_pfnblock_flags_mask(). |
2881 | * If __msan_poison_alloca() attempts to allocate pages for the stack depot, it |
2882 | * may call rmqueue() again, which will result in a deadlock. |
2883 | */ |
2884 | __no_sanitize_memory |
2885 | static inline |
2886 | struct page *rmqueue(struct zone *preferred_zone, |
2887 | struct zone *zone, unsigned int order, |
2888 | gfp_t gfp_flags, unsigned int alloc_flags, |
2889 | int migratetype) |
2890 | { |
2891 | struct page *page; |
2892 | |
2893 | /* |
2894 | * We most definitely don't want callers attempting to |
2895 | * allocate greater than order-1 page units with __GFP_NOFAIL. |
2896 | */ |
2897 | WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); |
2898 | |
2899 | if (likely(pcp_allowed_order(order))) { |
2900 | page = rmqueue_pcplist(preferred_zone, zone, order, |
2901 | migratetype, alloc_flags); |
2902 | if (likely(page)) |
2903 | goto out; |
2904 | } |
2905 | |
2906 | page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags, |
2907 | migratetype); |
2908 | |
2909 | out: |
2910 | /* Separate test+clear to avoid unnecessary atomics */ |
2911 | if ((alloc_flags & ALLOC_KSWAPD) && |
2912 | unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { |
2913 | clear_bit(nr: ZONE_BOOSTED_WATERMARK, addr: &zone->flags); |
2914 | wakeup_kswapd(zone, gfp_mask: 0, order: 0, zone_idx(zone)); |
2915 | } |
2916 | |
2917 | VM_BUG_ON_PAGE(page && bad_range(zone, page), page); |
2918 | return page; |
2919 | } |
2920 | |
2921 | noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) |
2922 | { |
2923 | return __should_fail_alloc_page(gfp_mask, order); |
2924 | } |
2925 | ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE); |
2926 | |
2927 | static inline long __zone_watermark_unusable_free(struct zone *z, |
2928 | unsigned int order, unsigned int alloc_flags) |
2929 | { |
2930 | long unusable_free = (1 << order) - 1; |
2931 | |
2932 | /* |
2933 | * If the caller does not have rights to reserves below the min |
2934 | * watermark then subtract the high-atomic reserves. This will |
2935 | * over-estimate the size of the atomic reserve but it avoids a search. |
2936 | */ |
2937 | if (likely(!(alloc_flags & ALLOC_RESERVES))) |
2938 | unusable_free += z->nr_reserved_highatomic; |
2939 | |
2940 | #ifdef CONFIG_CMA |
2941 | /* If allocation can't use CMA areas don't use free CMA pages */ |
2942 | if (!(alloc_flags & ALLOC_CMA)) |
2943 | unusable_free += zone_page_state(zone: z, item: NR_FREE_CMA_PAGES); |
2944 | #endif |
2945 | #ifdef CONFIG_UNACCEPTED_MEMORY |
2946 | unusable_free += zone_page_state(zone: z, item: NR_UNACCEPTED); |
2947 | #endif |
2948 | |
2949 | return unusable_free; |
2950 | } |
2951 | |
2952 | /* |
2953 | * Return true if free base pages are above 'mark'. For high-order checks it |
2954 | * will return true of the order-0 watermark is reached and there is at least |
2955 | * one free page of a suitable size. Checking now avoids taking the zone lock |
2956 | * to check in the allocation paths if no pages are free. |
2957 | */ |
2958 | bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, |
2959 | int highest_zoneidx, unsigned int alloc_flags, |
2960 | long free_pages) |
2961 | { |
2962 | long min = mark; |
2963 | int o; |
2964 | |
2965 | /* free_pages may go negative - that's OK */ |
2966 | free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); |
2967 | |
2968 | if (unlikely(alloc_flags & ALLOC_RESERVES)) { |
2969 | /* |
2970 | * __GFP_HIGH allows access to 50% of the min reserve as well |
2971 | * as OOM. |
2972 | */ |
2973 | if (alloc_flags & ALLOC_MIN_RESERVE) { |
2974 | min -= min / 2; |
2975 | |
2976 | /* |
2977 | * Non-blocking allocations (e.g. GFP_ATOMIC) can |
2978 | * access more reserves than just __GFP_HIGH. Other |
2979 | * non-blocking allocations requests such as GFP_NOWAIT |
2980 | * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get |
2981 | * access to the min reserve. |
2982 | */ |
2983 | if (alloc_flags & ALLOC_NON_BLOCK) |
2984 | min -= min / 4; |
2985 | } |
2986 | |
2987 | /* |
2988 | * OOM victims can try even harder than the normal reserve |
2989 | * users on the grounds that it's definitely going to be in |
2990 | * the exit path shortly and free memory. Any allocation it |
2991 | * makes during the free path will be small and short-lived. |
2992 | */ |
2993 | if (alloc_flags & ALLOC_OOM) |
2994 | min -= min / 2; |
2995 | } |
2996 | |
2997 | /* |
2998 | * Check watermarks for an order-0 allocation request. If these |
2999 | * are not met, then a high-order request also cannot go ahead |
3000 | * even if a suitable page happened to be free. |
3001 | */ |
3002 | if (free_pages <= min + z->lowmem_reserve[highest_zoneidx]) |
3003 | return false; |
3004 | |
3005 | /* If this is an order-0 request then the watermark is fine */ |
3006 | if (!order) |
3007 | return true; |
3008 | |
3009 | /* For a high-order request, check at least one suitable page is free */ |
3010 | for (o = order; o <= MAX_ORDER; o++) { |
3011 | struct free_area *area = &z->free_area[o]; |
3012 | int mt; |
3013 | |
3014 | if (!area->nr_free) |
3015 | continue; |
3016 | |
3017 | for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) { |
3018 | if (!free_area_empty(area, migratetype: mt)) |
3019 | return true; |
3020 | } |
3021 | |
3022 | #ifdef CONFIG_CMA |
3023 | if ((alloc_flags & ALLOC_CMA) && |
3024 | !free_area_empty(area, migratetype: MIGRATE_CMA)) { |
3025 | return true; |
3026 | } |
3027 | #endif |
3028 | if ((alloc_flags & (ALLOC_HIGHATOMIC|ALLOC_OOM)) && |
3029 | !free_area_empty(area, migratetype: MIGRATE_HIGHATOMIC)) { |
3030 | return true; |
3031 | } |
3032 | } |
3033 | return false; |
3034 | } |
3035 | |
3036 | bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, |
3037 | int highest_zoneidx, unsigned int alloc_flags) |
3038 | { |
3039 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, |
3040 | free_pages: zone_page_state(zone: z, item: NR_FREE_PAGES)); |
3041 | } |
3042 | |
3043 | static inline bool zone_watermark_fast(struct zone *z, unsigned int order, |
3044 | unsigned long mark, int highest_zoneidx, |
3045 | unsigned int alloc_flags, gfp_t gfp_mask) |
3046 | { |
3047 | long free_pages; |
3048 | |
3049 | free_pages = zone_page_state(zone: z, item: NR_FREE_PAGES); |
3050 | |
3051 | /* |
3052 | * Fast check for order-0 only. If this fails then the reserves |
3053 | * need to be calculated. |
3054 | */ |
3055 | if (!order) { |
3056 | long usable_free; |
3057 | long reserved; |
3058 | |
3059 | usable_free = free_pages; |
3060 | reserved = __zone_watermark_unusable_free(z, order: 0, alloc_flags); |
3061 | |
3062 | /* reserved may over estimate high-atomic reserves. */ |
3063 | usable_free -= min(usable_free, reserved); |
3064 | if (usable_free > mark + z->lowmem_reserve[highest_zoneidx]) |
3065 | return true; |
3066 | } |
3067 | |
3068 | if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, |
3069 | free_pages)) |
3070 | return true; |
3071 | |
3072 | /* |
3073 | * Ignore watermark boosting for __GFP_HIGH order-0 allocations |
3074 | * when checking the min watermark. The min watermark is the |
3075 | * point where boosting is ignored so that kswapd is woken up |
3076 | * when below the low watermark. |
3077 | */ |
3078 | if (unlikely(!order && (alloc_flags & ALLOC_MIN_RESERVE) && z->watermark_boost |
3079 | && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) { |
3080 | mark = z->_watermark[WMARK_MIN]; |
3081 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, |
3082 | alloc_flags, free_pages); |
3083 | } |
3084 | |
3085 | return false; |
3086 | } |
3087 | |
3088 | bool zone_watermark_ok_safe(struct zone *z, unsigned int order, |
3089 | unsigned long mark, int highest_zoneidx) |
3090 | { |
3091 | long free_pages = zone_page_state(zone: z, item: NR_FREE_PAGES); |
3092 | |
3093 | if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) |
3094 | free_pages = zone_page_state_snapshot(zone: z, item: NR_FREE_PAGES); |
3095 | |
3096 | return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags: 0, |
3097 | free_pages); |
3098 | } |
3099 | |
3100 | #ifdef CONFIG_NUMA |
3101 | int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE; |
3102 | |
3103 | static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) |
3104 | { |
3105 | return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <= |
3106 | node_reclaim_distance; |
3107 | } |
3108 | #else /* CONFIG_NUMA */ |
3109 | static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) |
3110 | { |
3111 | return true; |
3112 | } |
3113 | #endif /* CONFIG_NUMA */ |
3114 | |
3115 | /* |
3116 | * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid |
3117 | * fragmentation is subtle. If the preferred zone was HIGHMEM then |
3118 | * premature use of a lower zone may cause lowmem pressure problems that |
3119 | * are worse than fragmentation. If the next zone is ZONE_DMA then it is |
3120 | * probably too small. It only makes sense to spread allocations to avoid |
3121 | * fragmentation between the Normal and DMA32 zones. |
3122 | */ |
3123 | static inline unsigned int |
3124 | alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) |
3125 | { |
3126 | unsigned int alloc_flags; |
3127 | |
3128 | /* |
3129 | * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD |
3130 | * to save a branch. |
3131 | */ |
3132 | alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM); |
3133 | |
3134 | #ifdef CONFIG_ZONE_DMA32 |
3135 | if (!zone) |
3136 | return alloc_flags; |
3137 | |
3138 | if (zone_idx(zone) != ZONE_NORMAL) |
3139 | return alloc_flags; |
3140 | |
3141 | /* |
3142 | * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and |
3143 | * the pointer is within zone->zone_pgdat->node_zones[]. Also assume |
3144 | * on UMA that if Normal is populated then so is DMA32. |
3145 | */ |
3146 | BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1); |
3147 | if (nr_online_nodes > 1 && !populated_zone(zone: --zone)) |
3148 | return alloc_flags; |
3149 | |
3150 | alloc_flags |= ALLOC_NOFRAGMENT; |
3151 | #endif /* CONFIG_ZONE_DMA32 */ |
3152 | return alloc_flags; |
3153 | } |
3154 | |
3155 | /* Must be called after current_gfp_context() which can change gfp_mask */ |
3156 | static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask, |
3157 | unsigned int alloc_flags) |
3158 | { |
3159 | #ifdef CONFIG_CMA |
3160 | if (gfp_migratetype(gfp_flags: gfp_mask) == MIGRATE_MOVABLE) |
3161 | alloc_flags |= ALLOC_CMA; |
3162 | #endif |
3163 | return alloc_flags; |
3164 | } |
3165 | |
3166 | /* |
3167 | * get_page_from_freelist goes through the zonelist trying to allocate |
3168 | * a page. |
3169 | */ |
3170 | static struct page * |
3171 | get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, |
3172 | const struct alloc_context *ac) |
3173 | { |
3174 | struct zoneref *z; |
3175 | struct zone *zone; |
3176 | struct pglist_data *last_pgdat = NULL; |
3177 | bool last_pgdat_dirty_ok = false; |
3178 | bool no_fallback; |
3179 | |
3180 | retry: |
3181 | /* |
3182 | * Scan zonelist, looking for a zone with enough free. |
3183 | * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c. |
3184 | */ |
3185 | no_fallback = alloc_flags & ALLOC_NOFRAGMENT; |
3186 | z = ac->preferred_zoneref; |
3187 | for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx, |
3188 | ac->nodemask) { |
3189 | struct page *page; |
3190 | unsigned long mark; |
3191 | |
3192 | if (cpusets_enabled() && |
3193 | (alloc_flags & ALLOC_CPUSET) && |
3194 | !__cpuset_zone_allowed(z: zone, gfp_mask)) |
3195 | continue; |
3196 | /* |
3197 | * When allocating a page cache page for writing, we |
3198 | * want to get it from a node that is within its dirty |
3199 | * limit, such that no single node holds more than its |
3200 | * proportional share of globally allowed dirty pages. |
3201 | * The dirty limits take into account the node's |
3202 | * lowmem reserves and high watermark so that kswapd |
3203 | * should be able to balance it without having to |
3204 | * write pages from its LRU list. |
3205 | * |
3206 | * XXX: For now, allow allocations to potentially |
3207 | * exceed the per-node dirty limit in the slowpath |
3208 | * (spread_dirty_pages unset) before going into reclaim, |
3209 | * which is important when on a NUMA setup the allowed |
3210 | * nodes are together not big enough to reach the |
3211 | * global limit. The proper fix for these situations |
3212 | * will require awareness of nodes in the |
3213 | * dirty-throttling and the flusher threads. |
3214 | */ |
3215 | if (ac->spread_dirty_pages) { |
3216 | if (last_pgdat != zone->zone_pgdat) { |
3217 | last_pgdat = zone->zone_pgdat; |
3218 | last_pgdat_dirty_ok = node_dirty_ok(pgdat: zone->zone_pgdat); |
3219 | } |
3220 | |
3221 | if (!last_pgdat_dirty_ok) |
3222 | continue; |
3223 | } |
3224 | |
3225 | if (no_fallback && nr_online_nodes > 1 && |
3226 | zone != ac->preferred_zoneref->zone) { |
3227 | int local_nid; |
3228 | |
3229 | /* |
3230 | * If moving to a remote node, retry but allow |
3231 | * fragmenting fallbacks. Locality is more important |
3232 | * than fragmentation avoidance. |
3233 | */ |
3234 | local_nid = zone_to_nid(zone: ac->preferred_zoneref->zone); |
3235 | if (zone_to_nid(zone) != local_nid) { |
3236 | alloc_flags &= ~ALLOC_NOFRAGMENT; |
3237 | goto retry; |
3238 | } |
3239 | } |
3240 | |
3241 | /* |
3242 | * Detect whether the number of free pages is below high |
3243 | * watermark. If so, we will decrease pcp->high and free |
3244 | * PCP pages in free path to reduce the possibility of |
3245 | * premature page reclaiming. Detection is done here to |
3246 | * avoid to do that in hotter free path. |
3247 | */ |
3248 | if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) |
3249 | goto check_alloc_wmark; |
3250 | |
3251 | mark = high_wmark_pages(zone); |
3252 | if (zone_watermark_fast(z: zone, order, mark, |
3253 | highest_zoneidx: ac->highest_zoneidx, alloc_flags, |
3254 | gfp_mask)) |
3255 | goto try_this_zone; |
3256 | else |
3257 | set_bit(nr: ZONE_BELOW_HIGH, addr: &zone->flags); |
3258 | |
3259 | check_alloc_wmark: |
3260 | mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); |
3261 | if (!zone_watermark_fast(z: zone, order, mark, |
3262 | highest_zoneidx: ac->highest_zoneidx, alloc_flags, |
3263 | gfp_mask)) { |
3264 | int ret; |
3265 | |
3266 | if (has_unaccepted_memory()) { |
3267 | if (try_to_accept_memory(zone, order)) |
3268 | goto try_this_zone; |
3269 | } |
3270 | |
3271 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT |
3272 | /* |
3273 | * Watermark failed for this zone, but see if we can |
3274 | * grow this zone if it contains deferred pages. |
3275 | */ |
3276 | if (deferred_pages_enabled()) { |
3277 | if (_deferred_grow_zone(zone, order)) |
3278 | goto try_this_zone; |
3279 | } |
3280 | #endif |
3281 | /* Checked here to keep the fast path fast */ |
3282 | BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); |
3283 | if (alloc_flags & ALLOC_NO_WATERMARKS) |
3284 | goto try_this_zone; |
3285 | |
3286 | if (!node_reclaim_enabled() || |
3287 | !zone_allows_reclaim(local_zone: ac->preferred_zoneref->zone, zone)) |
3288 | continue; |
3289 | |
3290 | ret = node_reclaim(zone->zone_pgdat, gfp_mask, order); |
3291 | switch (ret) { |
3292 | case NODE_RECLAIM_NOSCAN: |
3293 | /* did not scan */ |
3294 | continue; |
3295 | case NODE_RECLAIM_FULL: |
3296 | /* scanned but unreclaimable */ |
3297 | continue; |
3298 | default: |
3299 | /* did we reclaim enough */ |
3300 | if (zone_watermark_ok(z: zone, order, mark, |
3301 | highest_zoneidx: ac->highest_zoneidx, alloc_flags)) |
3302 | goto try_this_zone; |
3303 | |
3304 | continue; |
3305 | } |
3306 | } |
3307 | |
3308 | try_this_zone: |
3309 | page = rmqueue(preferred_zone: ac->preferred_zoneref->zone, zone, order, |
3310 | gfp_flags: gfp_mask, alloc_flags, migratetype: ac->migratetype); |
3311 | if (page) { |
3312 | prep_new_page(page, order, gfp_flags: gfp_mask, alloc_flags); |
3313 | |
3314 | /* |
3315 | * If this is a high-order atomic allocation then check |
3316 | * if the pageblock should be reserved for the future |
3317 | */ |
3318 | if (unlikely(alloc_flags & ALLOC_HIGHATOMIC)) |
3319 | reserve_highatomic_pageblock(page, zone); |
3320 | |
3321 | return page; |
3322 | } else { |
3323 | if (has_unaccepted_memory()) { |
3324 | if (try_to_accept_memory(zone, order)) |
3325 | goto try_this_zone; |
3326 | } |
3327 | |
3328 | #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT |
3329 | /* Try again if zone has deferred pages */ |
3330 | if (deferred_pages_enabled()) { |
3331 | if (_deferred_grow_zone(zone, order)) |
3332 | goto try_this_zone; |
3333 | } |
3334 | #endif |
3335 | } |
3336 | } |
3337 | |
3338 | /* |
3339 | * It's possible on a UMA machine to get through all zones that are |
3340 | * fragmented. If avoiding fragmentation, reset and try again. |
3341 | */ |
3342 | if (no_fallback) { |
3343 | alloc_flags &= ~ALLOC_NOFRAGMENT; |
3344 | goto retry; |
3345 | } |
3346 | |
3347 | return NULL; |
3348 | } |
3349 | |
3350 | static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask) |
3351 | { |
3352 | unsigned int filter = SHOW_MEM_FILTER_NODES; |
3353 | |
3354 | /* |
3355 | * This documents exceptions given to allocations in certain |
3356 | * contexts that are allowed to allocate outside current's set |
3357 | * of allowed nodes. |
3358 | */ |
3359 | if (!(gfp_mask & __GFP_NOMEMALLOC)) |
3360 | if (tsk_is_oom_victim(current) || |
3361 | (current->flags & (PF_MEMALLOC | PF_EXITING))) |
3362 | filter &= ~SHOW_MEM_FILTER_NODES; |
3363 | if (!in_task() || !(gfp_mask & __GFP_DIRECT_RECLAIM)) |
3364 | filter &= ~SHOW_MEM_FILTER_NODES; |
3365 | |
3366 | __show_mem(flags: filter, nodemask, max_zone_idx: gfp_zone(flags: gfp_mask)); |
3367 | } |
3368 | |
3369 | void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) |
3370 | { |
3371 | struct va_format vaf; |
3372 | va_list args; |
3373 | static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); |
3374 | |
3375 | if ((gfp_mask & __GFP_NOWARN) || |
3376 | !__ratelimit(&nopage_rs) || |
3377 | ((gfp_mask & __GFP_DMA) && !has_managed_dma())) |
3378 | return; |
3379 | |
3380 | va_start(args, fmt); |
3381 | vaf.fmt = fmt; |
3382 | vaf.va = &args; |
3383 | pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl" , |
3384 | current->comm, &vaf, gfp_mask, &gfp_mask, |
3385 | nodemask_pr_args(nodemask)); |
3386 | va_end(args); |
3387 | |
3388 | cpuset_print_current_mems_allowed(); |
3389 | pr_cont("\n" ); |
3390 | dump_stack(); |
3391 | warn_alloc_show_mem(gfp_mask, nodemask); |
3392 | } |
3393 | |
3394 | static inline struct page * |
3395 | __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order, |
3396 | unsigned int alloc_flags, |
3397 | const struct alloc_context *ac) |
3398 | { |
3399 | struct page *page; |
3400 | |
3401 | page = get_page_from_freelist(gfp_mask, order, |
3402 | alloc_flags: alloc_flags|ALLOC_CPUSET, ac); |
3403 | /* |
3404 | * fallback to ignore cpuset restriction if our nodes |
3405 | * are depleted |
3406 | */ |
3407 | if (!page) |
3408 | page = get_page_from_freelist(gfp_mask, order, |
3409 | alloc_flags, ac); |
3410 | |
3411 | return page; |
3412 | } |
3413 | |
3414 | static inline struct page * |
3415 | __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, |
3416 | const struct alloc_context *ac, unsigned long *did_some_progress) |
3417 | { |
3418 | struct oom_control oc = { |
3419 | .zonelist = ac->zonelist, |
3420 | .nodemask = ac->nodemask, |
3421 | .memcg = NULL, |
3422 | .gfp_mask = gfp_mask, |
3423 | .order = order, |
3424 | }; |
3425 | struct page *page; |
3426 | |
3427 | *did_some_progress = 0; |
3428 | |
3429 | /* |
3430 | * Acquire the oom lock. If that fails, somebody else is |
3431 | * making progress for us. |
3432 | */ |
3433 | if (!mutex_trylock(lock: &oom_lock)) { |
3434 | *did_some_progress = 1; |
3435 | schedule_timeout_uninterruptible(timeout: 1); |
3436 | return NULL; |
3437 | } |
3438 | |
3439 | /* |
3440 | * Go through the zonelist yet one more time, keep very high watermark |
3441 | * here, this is only to catch a parallel oom killing, we must fail if |
3442 | * we're still under heavy pressure. But make sure that this reclaim |
3443 | * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY |
3444 | * allocation which will never fail due to oom_lock already held. |
3445 | */ |
3446 | page = get_page_from_freelist(gfp_mask: (gfp_mask | __GFP_HARDWALL) & |
3447 | ~__GFP_DIRECT_RECLAIM, order, |
3448 | ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac); |
3449 | if (page) |
3450 | goto out; |
3451 | |
3452 | /* Coredumps can quickly deplete all memory reserves */ |
3453 | if (current->flags & PF_DUMPCORE) |
3454 | goto out; |
3455 | /* The OOM killer will not help higher order allocs */ |
3456 | if (order > PAGE_ALLOC_COSTLY_ORDER) |
3457 | goto out; |
3458 | /* |
3459 | * We have already exhausted all our reclaim opportunities without any |
3460 | * success so it is time to admit defeat. We will skip the OOM killer |
3461 | * because it is very likely that the caller has a more reasonable |
3462 | * fallback than shooting a random task. |
3463 | * |
3464 | * The OOM killer may not free memory on a specific node. |
3465 | */ |
3466 | if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE)) |
3467 | goto out; |
3468 | /* The OOM killer does not needlessly kill tasks for lowmem */ |
3469 | if (ac->highest_zoneidx < ZONE_NORMAL) |
3470 | goto out; |
3471 | if (pm_suspended_storage()) |
3472 | goto out; |
3473 | /* |
3474 | * XXX: GFP_NOFS allocations should rather fail than rely on |
3475 | * other request to make a forward progress. |
3476 | * We are in an unfortunate situation where out_of_memory cannot |
3477 | * do much for this context but let's try it to at least get |
3478 | * access to memory reserved if the current task is killed (see |
3479 | * out_of_memory). Once filesystems are ready to handle allocation |
3480 | * failures more gracefully we should just bail out here. |
3481 | */ |
3482 | |
3483 | /* Exhausted what can be done so it's blame time */ |
3484 | if (out_of_memory(oc: &oc) || |
3485 | WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) { |
3486 | *did_some_progress = 1; |
3487 | |
3488 | /* |
3489 | * Help non-failing allocations by giving them access to memory |
3490 | * reserves |
3491 | */ |
3492 | if (gfp_mask & __GFP_NOFAIL) |
3493 | page = __alloc_pages_cpuset_fallback(gfp_mask, order, |
3494 | ALLOC_NO_WATERMARKS, ac); |
3495 | } |
3496 | out: |
3497 | mutex_unlock(lock: &oom_lock); |
3498 | return page; |
3499 | } |
3500 | |
3501 | /* |
3502 | * Maximum number of compaction retries with a progress before OOM |
3503 | * killer is consider as the only way to move forward. |
3504 | */ |
3505 | #define MAX_COMPACT_RETRIES 16 |
3506 | |
3507 | #ifdef CONFIG_COMPACTION |
3508 | /* Try memory compaction for high-order allocations before reclaim */ |
3509 | static struct page * |
3510 | __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, |
3511 | unsigned int alloc_flags, const struct alloc_context *ac, |
3512 | enum compact_priority prio, enum compact_result *compact_result) |
3513 | { |
3514 | struct page *page = NULL; |
3515 | unsigned long pflags; |
3516 | unsigned int noreclaim_flag; |
3517 | |
3518 | if (!order) |
3519 | return NULL; |
3520 | |
3521 | psi_memstall_enter(flags: &pflags); |
3522 | delayacct_compact_start(); |
3523 | noreclaim_flag = memalloc_noreclaim_save(); |
3524 | |
3525 | *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, |
3526 | prio, page: &page); |
3527 | |
3528 | memalloc_noreclaim_restore(flags: noreclaim_flag); |
3529 | psi_memstall_leave(flags: &pflags); |
3530 | delayacct_compact_end(); |
3531 | |
3532 | if (*compact_result == COMPACT_SKIPPED) |
3533 | return NULL; |
3534 | /* |
3535 | * At least in one zone compaction wasn't deferred or skipped, so let's |
3536 | * count a compaction stall |
3537 | */ |
3538 | count_vm_event(item: COMPACTSTALL); |
3539 | |
3540 | /* Prep a captured page if available */ |
3541 | if (page) |
3542 | prep_new_page(page, order, gfp_flags: gfp_mask, alloc_flags); |
3543 | |
3544 | /* Try get a page from the freelist if available */ |
3545 | if (!page) |
3546 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); |
3547 | |
3548 | if (page) { |
3549 | struct zone *zone = page_zone(page); |
3550 | |
3551 | zone->compact_blockskip_flush = false; |
3552 | compaction_defer_reset(zone, order, alloc_success: true); |
3553 | count_vm_event(item: COMPACTSUCCESS); |
3554 | return page; |
3555 | } |
3556 | |
3557 | /* |
3558 | * It's bad if compaction run occurs and fails. The most likely reason |
3559 | * is that pages exist, but not enough to satisfy watermarks. |
3560 | */ |
3561 | count_vm_event(item: COMPACTFAIL); |
3562 | |
3563 | cond_resched(); |
3564 | |
3565 | return NULL; |
3566 | } |
3567 | |
3568 | static inline bool |
3569 | should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, |
3570 | enum compact_result compact_result, |
3571 | enum compact_priority *compact_priority, |
3572 | int *compaction_retries) |
3573 | { |
3574 | int max_retries = MAX_COMPACT_RETRIES; |
3575 | int min_priority; |
3576 | bool ret = false; |
3577 | int retries = *compaction_retries; |
3578 | enum compact_priority priority = *compact_priority; |
3579 | |
3580 | if (!order) |
3581 | return false; |
3582 | |
3583 | if (fatal_signal_pending(current)) |
3584 | return false; |
3585 | |
3586 | /* |
3587 | * Compaction was skipped due to a lack of free order-0 |
3588 | * migration targets. Continue if reclaim can help. |
3589 | */ |
3590 | if (compact_result == COMPACT_SKIPPED) { |
3591 | ret = compaction_zonelist_suitable(ac, order, alloc_flags); |
3592 | goto out; |
3593 | } |
3594 | |
3595 | /* |
3596 | * Compaction managed to coalesce some page blocks, but the |
3597 | * allocation failed presumably due to a race. Retry some. |
3598 | */ |
3599 | if (compact_result == COMPACT_SUCCESS) { |
3600 | /* |
3601 | * !costly requests are much more important than |
3602 | * __GFP_RETRY_MAYFAIL costly ones because they are de |
3603 | * facto nofail and invoke OOM killer to move on while |
3604 | * costly can fail and users are ready to cope with |
3605 | * that. 1/4 retries is rather arbitrary but we would |
3606 | * need much more detailed feedback from compaction to |
3607 | * make a better decision. |
3608 | */ |
3609 | if (order > PAGE_ALLOC_COSTLY_ORDER) |
3610 | max_retries /= 4; |
3611 | |
3612 | if (++(*compaction_retries) <= max_retries) { |
3613 | ret = true; |
3614 | goto out; |
3615 | } |
3616 | } |
3617 | |
3618 | /* |
3619 | * Compaction failed. Retry with increasing priority. |
3620 | */ |
3621 | min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? |
3622 | MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; |
3623 | |
3624 | if (*compact_priority > min_priority) { |
3625 | (*compact_priority)--; |
3626 | *compaction_retries = 0; |
3627 | ret = true; |
3628 | } |
3629 | out: |
3630 | trace_compact_retry(order, priority, result: compact_result, retries, max_retries, ret); |
3631 | return ret; |
3632 | } |
3633 | #else |
3634 | static inline struct page * |
3635 | __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, |
3636 | unsigned int alloc_flags, const struct alloc_context *ac, |
3637 | enum compact_priority prio, enum compact_result *compact_result) |
3638 | { |
3639 | *compact_result = COMPACT_SKIPPED; |
3640 | return NULL; |
3641 | } |
3642 | |
3643 | static inline bool |
3644 | should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags, |
3645 | enum compact_result compact_result, |
3646 | enum compact_priority *compact_priority, |
3647 | int *compaction_retries) |
3648 | { |
3649 | struct zone *zone; |
3650 | struct zoneref *z; |
3651 | |
3652 | if (!order || order > PAGE_ALLOC_COSTLY_ORDER) |
3653 | return false; |
3654 | |
3655 | /* |
3656 | * There are setups with compaction disabled which would prefer to loop |
3657 | * inside the allocator rather than hit the oom killer prematurely. |
3658 | * Let's give them a good hope and keep retrying while the order-0 |
3659 | * watermarks are OK. |
3660 | */ |
3661 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, |
3662 | ac->highest_zoneidx, ac->nodemask) { |
3663 | if (zone_watermark_ok(zone, 0, min_wmark_pages(zone), |
3664 | ac->highest_zoneidx, alloc_flags)) |
3665 | return true; |
3666 | } |
3667 | return false; |
3668 | } |
3669 | #endif /* CONFIG_COMPACTION */ |
3670 | |
3671 | #ifdef CONFIG_LOCKDEP |
3672 | static struct lockdep_map __fs_reclaim_map = |
3673 | STATIC_LOCKDEP_MAP_INIT("fs_reclaim" , &__fs_reclaim_map); |
3674 | |
3675 | static bool __need_reclaim(gfp_t gfp_mask) |
3676 | { |
3677 | /* no reclaim without waiting on it */ |
3678 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) |
3679 | return false; |
3680 | |
3681 | /* this guy won't enter reclaim */ |
3682 | if (current->flags & PF_MEMALLOC) |
3683 | return false; |
3684 | |
3685 | if (gfp_mask & __GFP_NOLOCKDEP) |
3686 | return false; |
3687 | |
3688 | return true; |
3689 | } |
3690 | |
3691 | void __fs_reclaim_acquire(unsigned long ip) |
3692 | { |
3693 | lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip); |
3694 | } |
3695 | |
3696 | void __fs_reclaim_release(unsigned long ip) |
3697 | { |
3698 | lock_release(lock: &__fs_reclaim_map, ip); |
3699 | } |
3700 | |
3701 | void fs_reclaim_acquire(gfp_t gfp_mask) |
3702 | { |
3703 | gfp_mask = current_gfp_context(flags: gfp_mask); |
3704 | |
3705 | if (__need_reclaim(gfp_mask)) { |
3706 | if (gfp_mask & __GFP_FS) |
3707 | __fs_reclaim_acquire(_RET_IP_); |
3708 | |
3709 | #ifdef CONFIG_MMU_NOTIFIER |
3710 | lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); |
3711 | lock_map_release(&__mmu_notifier_invalidate_range_start_map); |
3712 | #endif |
3713 | |
3714 | } |
3715 | } |
3716 | EXPORT_SYMBOL_GPL(fs_reclaim_acquire); |
3717 | |
3718 | void fs_reclaim_release(gfp_t gfp_mask) |
3719 | { |
3720 | gfp_mask = current_gfp_context(flags: gfp_mask); |
3721 | |
3722 | if (__need_reclaim(gfp_mask)) { |
3723 | if (gfp_mask & __GFP_FS) |
3724 | __fs_reclaim_release(_RET_IP_); |
3725 | } |
3726 | } |
3727 | EXPORT_SYMBOL_GPL(fs_reclaim_release); |
3728 | #endif |
3729 | |
3730 | /* |
3731 | * Zonelists may change due to hotplug during allocation. Detect when zonelists |
3732 | * have been rebuilt so allocation retries. Reader side does not lock and |
3733 | * retries the allocation if zonelist changes. Writer side is protected by the |
3734 | * embedded spin_lock. |
3735 | */ |
3736 | static DEFINE_SEQLOCK(zonelist_update_seq); |
3737 | |
3738 | static unsigned int zonelist_iter_begin(void) |
3739 | { |
3740 | if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) |
3741 | return read_seqbegin(sl: &zonelist_update_seq); |
3742 | |
3743 | return 0; |
3744 | } |
3745 | |
3746 | static unsigned int check_retry_zonelist(unsigned int seq) |
3747 | { |
3748 | if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) |
3749 | return read_seqretry(sl: &zonelist_update_seq, start: seq); |
3750 | |
3751 | return seq; |
3752 | } |
3753 | |
3754 | /* Perform direct synchronous page reclaim */ |
3755 | static unsigned long |
3756 | __perform_reclaim(gfp_t gfp_mask, unsigned int order, |
3757 | const struct alloc_context *ac) |
3758 | { |
3759 | unsigned int noreclaim_flag; |
3760 | unsigned long progress; |
3761 | |
3762 | cond_resched(); |
3763 | |
3764 | /* We now go into synchronous reclaim */ |
3765 | cpuset_memory_pressure_bump(); |
3766 | fs_reclaim_acquire(gfp_mask); |
3767 | noreclaim_flag = memalloc_noreclaim_save(); |
3768 | |
3769 | progress = try_to_free_pages(zonelist: ac->zonelist, order, gfp_mask, |
3770 | mask: ac->nodemask); |
3771 | |
3772 | memalloc_noreclaim_restore(flags: noreclaim_flag); |
3773 | fs_reclaim_release(gfp_mask); |
3774 | |
3775 | cond_resched(); |
3776 | |
3777 | return progress; |
3778 | } |
3779 | |
3780 | /* The really slow allocator path where we enter direct reclaim */ |
3781 | static inline struct page * |
3782 | __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, |
3783 | unsigned int alloc_flags, const struct alloc_context *ac, |
3784 | unsigned long *did_some_progress) |
3785 | { |
3786 | struct page *page = NULL; |
3787 | unsigned long pflags; |
3788 | bool drained = false; |
3789 | |
3790 | psi_memstall_enter(flags: &pflags); |
3791 | *did_some_progress = __perform_reclaim(gfp_mask, order, ac); |
3792 | if (unlikely(!(*did_some_progress))) |
3793 | goto out; |
3794 | |
3795 | retry: |
3796 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); |
3797 | |
3798 | /* |
3799 | * If an allocation failed after direct reclaim, it could be because |
3800 | * pages are pinned on the per-cpu lists or in high alloc reserves. |
3801 | * Shrink them and try again |
3802 | */ |
3803 | if (!page && !drained) { |
3804 | unreserve_highatomic_pageblock(ac, force: false); |
3805 | drain_all_pages(NULL); |
3806 | drained = true; |
3807 | goto retry; |
3808 | } |
3809 | out: |
3810 | psi_memstall_leave(flags: &pflags); |
3811 | |
3812 | return page; |
3813 | } |
3814 | |
3815 | static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask, |
3816 | const struct alloc_context *ac) |
3817 | { |
3818 | struct zoneref *z; |
3819 | struct zone *zone; |
3820 | pg_data_t *last_pgdat = NULL; |
3821 | enum zone_type highest_zoneidx = ac->highest_zoneidx; |
3822 | |
3823 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx, |
3824 | ac->nodemask) { |
3825 | if (!managed_zone(zone)) |
3826 | continue; |
3827 | if (last_pgdat != zone->zone_pgdat) { |
3828 | wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx); |
3829 | last_pgdat = zone->zone_pgdat; |
3830 | } |
3831 | } |
3832 | } |
3833 | |
3834 | static inline unsigned int |
3835 | gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) |
3836 | { |
3837 | unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; |
3838 | |
3839 | /* |
3840 | * __GFP_HIGH is assumed to be the same as ALLOC_MIN_RESERVE |
3841 | * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD |
3842 | * to save two branches. |
3843 | */ |
3844 | BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_MIN_RESERVE); |
3845 | BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD); |
3846 | |
3847 | /* |
3848 | * The caller may dip into page reserves a bit more if the caller |
3849 | * cannot run direct reclaim, or if the caller has realtime scheduling |
3850 | * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will |
3851 | * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). |
3852 | */ |
3853 | alloc_flags |= (__force int) |
3854 | (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); |
3855 | |
3856 | if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { |
3857 | /* |
3858 | * Not worth trying to allocate harder for __GFP_NOMEMALLOC even |
3859 | * if it can't schedule. |
3860 | */ |
3861 | if (!(gfp_mask & __GFP_NOMEMALLOC)) { |
3862 | alloc_flags |= ALLOC_NON_BLOCK; |
3863 | |
3864 | if (order > 0) |
3865 | alloc_flags |= ALLOC_HIGHATOMIC; |
3866 | } |
3867 | |
3868 | /* |
3869 | * Ignore cpuset mems for non-blocking __GFP_HIGH (probably |
3870 | * GFP_ATOMIC) rather than fail, see the comment for |
3871 | * cpuset_node_allowed(). |
3872 | */ |
3873 | if (alloc_flags & ALLOC_MIN_RESERVE) |
3874 | alloc_flags &= ~ALLOC_CPUSET; |
3875 | } else if (unlikely(rt_task(current)) && in_task()) |
3876 | alloc_flags |= ALLOC_MIN_RESERVE; |
3877 | |
3878 | alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags); |
3879 | |
3880 | return alloc_flags; |
3881 | } |
3882 | |
3883 | static bool oom_reserves_allowed(struct task_struct *tsk) |
3884 | { |
3885 | if (!tsk_is_oom_victim(tsk)) |
3886 | return false; |
3887 | |
3888 | /* |
3889 | * !MMU doesn't have oom reaper so give access to memory reserves |
3890 | * only to the thread with TIF_MEMDIE set |
3891 | */ |
3892 | if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE)) |
3893 | return false; |
3894 | |
3895 | return true; |
3896 | } |
3897 | |
3898 | /* |
3899 | * Distinguish requests which really need access to full memory |
3900 | * reserves from oom victims which can live with a portion of it |
3901 | */ |
3902 | static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask) |
3903 | { |
3904 | if (unlikely(gfp_mask & __GFP_NOMEMALLOC)) |
3905 | return 0; |
3906 | if (gfp_mask & __GFP_MEMALLOC) |
3907 | return ALLOC_NO_WATERMARKS; |
3908 | if (in_serving_softirq() && (current->flags & PF_MEMALLOC)) |
3909 | return ALLOC_NO_WATERMARKS; |
3910 | if (!in_interrupt()) { |
3911 | if (current->flags & PF_MEMALLOC) |
3912 | return ALLOC_NO_WATERMARKS; |
3913 | else if (oom_reserves_allowed(current)) |
3914 | return ALLOC_OOM; |
3915 | } |
3916 | |
3917 | return 0; |
3918 | } |
3919 | |
3920 | bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) |
3921 | { |
3922 | return !!__gfp_pfmemalloc_flags(gfp_mask); |
3923 | } |
3924 | |
3925 | /* |
3926 | * Checks whether it makes sense to retry the reclaim to make a forward progress |
3927 | * for the given allocation request. |
3928 | * |
3929 | * We give up when we either have tried MAX_RECLAIM_RETRIES in a row |
3930 | * without success, or when we couldn't even meet the watermark if we |
3931 | * reclaimed all remaining pages on the LRU lists. |
3932 | * |
3933 | * Returns true if a retry is viable or false to enter the oom path. |
3934 | */ |
3935 | static inline bool |
3936 | should_reclaim_retry(gfp_t gfp_mask, unsigned order, |
3937 | struct alloc_context *ac, int alloc_flags, |
3938 | bool did_some_progress, int *no_progress_loops) |
3939 | { |
3940 | struct zone *zone; |
3941 | struct zoneref *z; |
3942 | bool ret = false; |
3943 | |
3944 | /* |
3945 | * Costly allocations might have made a progress but this doesn't mean |
3946 | * their order will become available due to high fragmentation so |
3947 | * always increment the no progress counter for them |
3948 | */ |
3949 | if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) |
3950 | *no_progress_loops = 0; |
3951 | else |
3952 | (*no_progress_loops)++; |
3953 | |
3954 | /* |
3955 | * Make sure we converge to OOM if we cannot make any progress |
3956 | * several times in the row. |
3957 | */ |
3958 | if (*no_progress_loops > MAX_RECLAIM_RETRIES) { |
3959 | /* Before OOM, exhaust highatomic_reserve */ |
3960 | return unreserve_highatomic_pageblock(ac, force: true); |
3961 | } |
3962 | |
3963 | /* |
3964 | * Keep reclaiming pages while there is a chance this will lead |
3965 | * somewhere. If none of the target zones can satisfy our allocation |
3966 | * request even if all reclaimable pages are considered then we are |
3967 | * screwed and have to go OOM. |
3968 | */ |
3969 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, |
3970 | ac->highest_zoneidx, ac->nodemask) { |
3971 | unsigned long available; |
3972 | unsigned long reclaimable; |
3973 | unsigned long min_wmark = min_wmark_pages(zone); |
3974 | bool wmark; |
3975 | |
3976 | available = reclaimable = zone_reclaimable_pages(zone); |
3977 | available += zone_page_state_snapshot(zone, item: NR_FREE_PAGES); |
3978 | |
3979 | /* |
3980 | * Would the allocation succeed if we reclaimed all |
3981 | * reclaimable pages? |
3982 | */ |
3983 | wmark = __zone_watermark_ok(z: zone, order, mark: min_wmark, |
3984 | highest_zoneidx: ac->highest_zoneidx, alloc_flags, free_pages: available); |
3985 | trace_reclaim_retry_zone(zoneref: z, order, reclaimable, |
3986 | available, min_wmark, no_progress_loops: *no_progress_loops, wmark_check: wmark); |
3987 | if (wmark) { |
3988 | ret = true; |
3989 | break; |
3990 | } |
3991 | } |
3992 | |
3993 | /* |
3994 | * Memory allocation/reclaim might be called from a WQ context and the |
3995 | * current implementation of the WQ concurrency control doesn't |
3996 | * recognize that a particular WQ is congested if the worker thread is |
3997 | * looping without ever sleeping. Therefore we have to do a short sleep |
3998 | * here rather than calling cond_resched(). |
3999 | */ |
4000 | if (current->flags & PF_WQ_WORKER) |
4001 | schedule_timeout_uninterruptible(timeout: 1); |
4002 | else |
4003 | cond_resched(); |
4004 | return ret; |
4005 | } |
4006 | |
4007 | static inline bool |
4008 | check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) |
4009 | { |
4010 | /* |
4011 | * It's possible that cpuset's mems_allowed and the nodemask from |
4012 | * mempolicy don't intersect. This should be normally dealt with by |
4013 | * policy_nodemask(), but it's possible to race with cpuset update in |
4014 | * such a way the check therein was true, and then it became false |
4015 | * before we got our cpuset_mems_cookie here. |
4016 | * This assumes that for all allocations, ac->nodemask can come only |
4017 | * from MPOL_BIND mempolicy (whose documented semantics is to be ignored |
4018 | * when it does not intersect with the cpuset restrictions) or the |
4019 | * caller can deal with a violated nodemask. |
4020 | */ |
4021 | if (cpusets_enabled() && ac->nodemask && |
4022 | !cpuset_nodemask_valid_mems_allowed(nodemask: ac->nodemask)) { |
4023 | ac->nodemask = NULL; |
4024 | return true; |
4025 | } |
4026 | |
4027 | /* |
4028 | * When updating a task's mems_allowed or mempolicy nodemask, it is |
4029 | * possible to race with parallel threads in such a way that our |
4030 | * allocation can fail while the mask is being updated. If we are about |
4031 | * to fail, check if the cpuset changed during allocation and if so, |
4032 | * retry. |
4033 | */ |
4034 | if (read_mems_allowed_retry(seq: cpuset_mems_cookie)) |
4035 | return true; |
4036 | |
4037 | return false; |
4038 | } |
4039 | |
4040 | static inline struct page * |
4041 | __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, |
4042 | struct alloc_context *ac) |
4043 | { |
4044 | bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; |
4045 | const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; |
4046 | struct page *page = NULL; |
4047 | unsigned int alloc_flags; |
4048 | unsigned long did_some_progress; |
4049 | enum compact_priority compact_priority; |
4050 | enum compact_result compact_result; |
4051 | int compaction_retries; |
4052 | int no_progress_loops; |
4053 | unsigned int cpuset_mems_cookie; |
4054 | unsigned int zonelist_iter_cookie; |
4055 | int reserve_flags; |
4056 | |
4057 | restart: |
4058 | compaction_retries = 0; |
4059 | no_progress_loops = 0; |
4060 | compact_priority = DEF_COMPACT_PRIORITY; |
4061 | cpuset_mems_cookie = read_mems_allowed_begin(); |
4062 | zonelist_iter_cookie = zonelist_iter_begin(); |
4063 | |
4064 | /* |
4065 | * The fast path uses conservative alloc_flags to succeed only until |
4066 | * kswapd needs to be woken up, and to avoid the cost of setting up |
4067 | * alloc_flags precisely. So we do that now. |
4068 | */ |
4069 | alloc_flags = gfp_to_alloc_flags(gfp_mask, order); |
4070 | |
4071 | /* |
4072 | * We need to recalculate the starting point for the zonelist iterator |
4073 | * because we might have used different nodemask in the fast path, or |
4074 | * there was a cpuset modification and we are retrying - otherwise we |
4075 | * could end up iterating over non-eligible zones endlessly. |
4076 | */ |
4077 | ac->preferred_zoneref = first_zones_zonelist(zonelist: ac->zonelist, |
4078 | highest_zoneidx: ac->highest_zoneidx, nodes: ac->nodemask); |
4079 | if (!ac->preferred_zoneref->zone) |
4080 | goto nopage; |
4081 | |
4082 | /* |
4083 | * Check for insane configurations where the cpuset doesn't contain |
4084 | * any suitable zone to satisfy the request - e.g. non-movable |
4085 | * GFP_HIGHUSER allocations from MOVABLE nodes only. |
4086 | */ |
4087 | if (cpusets_insane_config() && (gfp_mask & __GFP_HARDWALL)) { |
4088 | struct zoneref *z = first_zones_zonelist(zonelist: ac->zonelist, |
4089 | highest_zoneidx: ac->highest_zoneidx, |
4090 | nodes: &cpuset_current_mems_allowed); |
4091 | if (!z->zone) |
4092 | goto nopage; |
4093 | } |
4094 | |
4095 | if (alloc_flags & ALLOC_KSWAPD) |
4096 | wake_all_kswapds(order, gfp_mask, ac); |
4097 | |
4098 | /* |
4099 | * The adjusted alloc_flags might result in immediate success, so try |
4100 | * that first |
4101 | */ |
4102 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); |
4103 | if (page) |
4104 | goto got_pg; |
4105 | |
4106 | /* |
4107 | * For costly allocations, try direct compaction first, as it's likely |
4108 | * that we have enough base pages and don't need to reclaim. For non- |
4109 | * movable high-order allocations, do that as well, as compaction will |
4110 | * try prevent permanent fragmentation by migrating from blocks of the |
4111 | * same migratetype. |
4112 | * Don't try this for allocations that are allowed to ignore |
4113 | * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen. |
4114 | */ |
4115 | if (can_direct_reclaim && |
4116 | (costly_order || |
4117 | (order > 0 && ac->migratetype != MIGRATE_MOVABLE)) |
4118 | && !gfp_pfmemalloc_allowed(gfp_mask)) { |
4119 | page = __alloc_pages_direct_compact(gfp_mask, order, |
4120 | alloc_flags, ac, |
4121 | prio: INIT_COMPACT_PRIORITY, |
4122 | compact_result: &compact_result); |
4123 | if (page) |
4124 | goto got_pg; |
4125 | |
4126 | /* |
4127 | * Checks for costly allocations with __GFP_NORETRY, which |
4128 | * includes some THP page fault allocations |
4129 | */ |
4130 | if (costly_order && (gfp_mask & __GFP_NORETRY)) { |
4131 | /* |
4132 | * If allocating entire pageblock(s) and compaction |
4133 | * failed because all zones are below low watermarks |
4134 | * or is prohibited because it recently failed at this |
4135 | * order, fail immediately unless the allocator has |
4136 | * requested compaction and reclaim retry. |
4137 | * |
4138 | * Reclaim is |
4139 | * - potentially very expensive because zones are far |
4140 | * below their low watermarks or this is part of very |
4141 | * bursty high order allocations, |
4142 | * - not guaranteed to help because isolate_freepages() |
4143 | * may not iterate over freed pages as part of its |
4144 | * linear scan, and |
4145 | * - unlikely to make entire pageblocks free on its |
4146 | * own. |
4147 | */ |
4148 | if (compact_result == COMPACT_SKIPPED || |
4149 | compact_result == COMPACT_DEFERRED) |
4150 | goto nopage; |
4151 | |
4152 | /* |
4153 | * Looks like reclaim/compaction is worth trying, but |
4154 | * sync compaction could be very expensive, so keep |
4155 | * using async compaction. |
4156 | */ |
4157 | compact_priority = INIT_COMPACT_PRIORITY; |
4158 | } |
4159 | } |
4160 | |
4161 | retry: |
4162 | /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ |
4163 | if (alloc_flags & ALLOC_KSWAPD) |
4164 | wake_all_kswapds(order, gfp_mask, ac); |
4165 | |
4166 | reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); |
4167 | if (reserve_flags) |
4168 | alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags: reserve_flags) | |
4169 | (alloc_flags & ALLOC_KSWAPD); |
4170 | |
4171 | /* |
4172 | * Reset the nodemask and zonelist iterators if memory policies can be |
4173 | * ignored. These allocations are high priority and system rather than |
4174 | * user oriented. |
4175 | */ |
4176 | if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) { |
4177 | ac->nodemask = NULL; |
4178 | ac->preferred_zoneref = first_zones_zonelist(zonelist: ac->zonelist, |
4179 | highest_zoneidx: ac->highest_zoneidx, nodes: ac->nodemask); |
4180 | } |
4181 | |
4182 | /* Attempt with potentially adjusted zonelist and alloc_flags */ |
4183 | page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); |
4184 | if (page) |
4185 | goto got_pg; |
4186 | |
4187 | /* Caller is not willing to reclaim, we can't balance anything */ |
4188 | if (!can_direct_reclaim) |
4189 | goto nopage; |
4190 | |
4191 | /* Avoid recursion of direct reclaim */ |
4192 | if (current->flags & PF_MEMALLOC) |
4193 | goto nopage; |
4194 | |
4195 | /* Try direct reclaim and then allocating */ |
4196 | page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, |
4197 | did_some_progress: &did_some_progress); |
4198 | if (page) |
4199 | goto got_pg; |
4200 | |
4201 | /* Try direct compaction and then allocating */ |
4202 | page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, |
4203 | prio: compact_priority, compact_result: &compact_result); |
4204 | if (page) |
4205 | goto got_pg; |
4206 | |
4207 | /* Do not loop if specifically requested */ |
4208 | if (gfp_mask & __GFP_NORETRY) |
4209 | goto nopage; |
4210 | |
4211 | /* |
4212 | * Do not retry costly high order allocations unless they are |
4213 | * __GFP_RETRY_MAYFAIL |
4214 | */ |
4215 | if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL)) |
4216 | goto nopage; |
4217 | |
4218 | if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, |
4219 | did_some_progress: did_some_progress > 0, no_progress_loops: &no_progress_loops)) |
4220 | goto retry; |
4221 | |
4222 | /* |
4223 | * It doesn't make any sense to retry for the compaction if the order-0 |
4224 | * reclaim is not able to make any progress because the current |
4225 | * implementation of the compaction depends on the sufficient amount |
4226 | * of free memory (see __compaction_suitable) |
4227 | */ |
4228 | if (did_some_progress > 0 && |
4229 | should_compact_retry(ac, order, alloc_flags, |
4230 | compact_result, compact_priority: &compact_priority, |
4231 | compaction_retries: &compaction_retries)) |
4232 | goto retry; |
4233 | |
4234 | |
4235 | /* |
4236 | * Deal with possible cpuset update races or zonelist updates to avoid |
4237 | * a unnecessary OOM kill. |
4238 | */ |
4239 | if (check_retry_cpuset(cpuset_mems_cookie, ac) || |
4240 | check_retry_zonelist(seq: zonelist_iter_cookie)) |
4241 | goto restart; |
4242 | |
4243 | /* Reclaim has failed us, start killing things */ |
4244 | page = __alloc_pages_may_oom(gfp_mask, order, ac, did_some_progress: &did_some_progress); |
4245 | if (page) |
4246 | goto got_pg; |
4247 | |
4248 | /* Avoid allocations with no watermarks from looping endlessly */ |
4249 | if (tsk_is_oom_victim(current) && |
4250 | (alloc_flags & ALLOC_OOM || |
4251 | (gfp_mask & __GFP_NOMEMALLOC))) |
4252 | goto nopage; |
4253 | |
4254 | /* Retry as long as the OOM killer is making progress */ |
4255 | if (did_some_progress) { |
4256 | no_progress_loops = 0; |
4257 | goto retry; |
4258 | } |
4259 | |
4260 | nopage: |
4261 | /* |
4262 | * Deal with possible cpuset update races or zonelist updates to avoid |
4263 | * a unnecessary OOM kill. |
4264 | */ |
4265 | if (check_retry_cpuset(cpuset_mems_cookie, ac) || |
4266 | check_retry_zonelist(seq: zonelist_iter_cookie)) |
4267 | goto restart; |
4268 | |
4269 | /* |
4270 | * Make sure that __GFP_NOFAIL request doesn't leak out and make sure |
4271 | * we always retry |
4272 | */ |
4273 | if (gfp_mask & __GFP_NOFAIL) { |
4274 | /* |
4275 | * All existing users of the __GFP_NOFAIL are blockable, so warn |
4276 | * of any new users that actually require GFP_NOWAIT |
4277 | */ |
4278 | if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask)) |
4279 | goto fail; |
4280 | |
4281 | /* |
4282 | * PF_MEMALLOC request from this context is rather bizarre |
4283 | * because we cannot reclaim anything and only can loop waiting |
4284 | * for somebody to do a work for us |
4285 | */ |
4286 | WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask); |
4287 | |
4288 | /* |
4289 | * non failing costly orders are a hard requirement which we |
4290 | * are not prepared for much so let's warn about these users |
4291 | * so that we can identify them and convert them to something |
4292 | * else. |
4293 | */ |
4294 | WARN_ON_ONCE_GFP(costly_order, gfp_mask); |
4295 | |
4296 | /* |
4297 | * Help non-failing allocations by giving some access to memory |
4298 | * reserves normally used for high priority non-blocking |
4299 | * allocations but do not use ALLOC_NO_WATERMARKS because this |
4300 | * could deplete whole memory reserves which would just make |
4301 | * the situation worse. |
4302 | */ |
4303 | page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac); |
4304 | if (page) |
4305 | goto got_pg; |
4306 | |
4307 | cond_resched(); |
4308 | goto retry; |
4309 | } |
4310 | fail: |
4311 | warn_alloc(gfp_mask, nodemask: ac->nodemask, |
4312 | fmt: "page allocation failure: order:%u" , order); |
4313 | got_pg: |
4314 | return page; |
4315 | } |
4316 | |
4317 | static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, |
4318 | int preferred_nid, nodemask_t *nodemask, |
4319 | struct alloc_context *ac, gfp_t *alloc_gfp, |
4320 | unsigned int *alloc_flags) |
4321 | { |
4322 | ac->highest_zoneidx = gfp_zone(flags: gfp_mask); |
4323 | ac->zonelist = node_zonelist(nid: preferred_nid, flags: gfp_mask); |
4324 | ac->nodemask = nodemask; |
4325 | ac->migratetype = gfp_migratetype(gfp_flags: gfp_mask); |
4326 | |
4327 | if (cpusets_enabled()) { |
4328 | *alloc_gfp |= __GFP_HARDWALL; |
4329 | /* |
4330 | * When we are in the interrupt context, it is irrelevant |
4331 | * to the current task context. It means that any node ok. |
4332 | */ |
4333 | if (in_task() && !ac->nodemask) |
4334 | ac->nodemask = &cpuset_current_mems_allowed; |
4335 | else |
4336 | *alloc_flags |= ALLOC_CPUSET; |
4337 | } |
4338 | |
4339 | might_alloc(gfp_mask); |
4340 | |
4341 | if (should_fail_alloc_page(gfp_mask, order)) |
4342 | return false; |
4343 | |
4344 | *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags: *alloc_flags); |
4345 | |
4346 | /* Dirty zone balancing only done in the fast path */ |
4347 | ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE); |
4348 | |
4349 | /* |
4350 | * The preferred zone is used for statistics but crucially it is |
4351 | * also used as the starting point for the zonelist iterator. It |
4352 | * may get reset for allocations that ignore memory policies. |
4353 | */ |
4354 | ac->preferred_zoneref = first_zones_zonelist(zonelist: ac->zonelist, |
4355 | highest_zoneidx: ac->highest_zoneidx, nodes: ac->nodemask); |
4356 | |
4357 | return true; |
4358 | } |
4359 | |
4360 | /* |
4361 | * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array |
4362 | * @gfp: GFP flags for the allocation |
4363 | * @preferred_nid: The preferred NUMA node ID to allocate from |
4364 | * @nodemask: Set of nodes to allocate from, may be NULL |
4365 | * @nr_pages: The number of pages desired on the list or array |
4366 | * @page_list: Optional list to store the allocated pages |
4367 | * @page_array: Optional array to store the pages |
4368 | * |
4369 | * This is a batched version of the page allocator that attempts to |
4370 | * allocate nr_pages quickly. Pages are added to page_list if page_list |
4371 | * is not NULL, otherwise it is assumed that the page_array is valid. |
4372 | * |
4373 | * For lists, nr_pages is the number of pages that should be allocated. |
4374 | * |
4375 | * For arrays, only NULL elements are populated with pages and nr_pages |
4376 | * is the maximum number of pages that will be stored in the array. |
4377 | * |
4378 | * Returns the number of pages on the list or array. |
4379 | */ |
4380 | unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, |
4381 | nodemask_t *nodemask, int nr_pages, |
4382 | struct list_head *page_list, |
4383 | struct page **page_array) |
4384 | { |
4385 | struct page *page; |
4386 | unsigned long __maybe_unused UP_flags; |
4387 | struct zone *zone; |
4388 | struct zoneref *z; |
4389 | struct per_cpu_pages *pcp; |
4390 | struct list_head *pcp_list; |
4391 | struct alloc_context ac; |
4392 | gfp_t alloc_gfp; |
4393 | unsigned int alloc_flags = ALLOC_WMARK_LOW; |
4394 | int nr_populated = 0, nr_account = 0; |
4395 | |
4396 | /* |
4397 | * Skip populated array elements to determine if any pages need |
4398 | * to be allocated before disabling IRQs. |
4399 | */ |
4400 | while (page_array && nr_populated < nr_pages && page_array[nr_populated]) |
4401 | nr_populated++; |
4402 | |
4403 | /* No pages requested? */ |
4404 | if (unlikely(nr_pages <= 0)) |
4405 | goto out; |
4406 | |
4407 | /* Already populated array? */ |
4408 | if (unlikely(page_array && nr_pages - nr_populated == 0)) |
4409 | goto out; |
4410 | |
4411 | /* Bulk allocator does not support memcg accounting. */ |
4412 | if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT)) |
4413 | goto failed; |
4414 | |
4415 | /* Use the single page allocator for one page. */ |
4416 | if (nr_pages - nr_populated == 1) |
4417 | goto failed; |
4418 | |
4419 | #ifdef CONFIG_PAGE_OWNER |
4420 | /* |
4421 | * PAGE_OWNER may recurse into the allocator to allocate space to |
4422 | * save the stack with pagesets.lock held. Releasing/reacquiring |
4423 | * removes much of the performance benefit of bulk allocation so |
4424 | * force the caller to allocate one page at a time as it'll have |
4425 | * similar performance to added complexity to the bulk allocator. |
4426 | */ |
4427 | if (static_branch_unlikely(&page_owner_inited)) |
4428 | goto failed; |
4429 | #endif |
4430 | |
4431 | /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ |
4432 | gfp &= gfp_allowed_mask; |
4433 | alloc_gfp = gfp; |
4434 | if (!prepare_alloc_pages(gfp_mask: gfp, order: 0, preferred_nid, nodemask, ac: &ac, alloc_gfp: &alloc_gfp, alloc_flags: &alloc_flags)) |
4435 | goto out; |
4436 | gfp = alloc_gfp; |
4437 | |
4438 | /* Find an allowed local zone that meets the low watermark. */ |
4439 | for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) { |
4440 | unsigned long mark; |
4441 | |
4442 | if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && |
4443 | !__cpuset_zone_allowed(z: zone, gfp_mask: gfp)) { |
4444 | continue; |
4445 | } |
4446 | |
4447 | if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone && |
4448 | zone_to_nid(zone) != zone_to_nid(zone: ac.preferred_zoneref->zone)) { |
4449 | goto failed; |
4450 | } |
4451 | |
4452 | mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages; |
4453 | if (zone_watermark_fast(z: zone, order: 0, mark, |
4454 | highest_zoneidx: zonelist_zone_idx(zoneref: ac.preferred_zoneref), |
4455 | alloc_flags, gfp_mask: gfp)) { |
4456 | break; |
4457 | } |
4458 | } |
4459 | |
4460 | /* |
4461 | * If there are no allowed local zones that meets the watermarks then |
4462 | * try to allocate a single page and reclaim if necessary. |
4463 | */ |
4464 | if (unlikely(!zone)) |
4465 | goto failed; |
4466 | |
4467 | /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ |
4468 | pcp_trylock_prepare(UP_flags); |
4469 | pcp = pcp_spin_trylock(zone->per_cpu_pageset); |
4470 | if (!pcp) |
4471 | goto failed_irq; |
4472 | |
4473 | /* Attempt the batch allocation */ |
4474 | pcp_list = &pcp->lists[order_to_pindex(migratetype: ac.migratetype, order: 0)]; |
4475 | while (nr_populated < nr_pages) { |
4476 | |
4477 | /* Skip existing pages */ |
4478 | if (page_array && page_array[nr_populated]) { |
4479 | nr_populated++; |
4480 | continue; |
4481 | } |
4482 | |
4483 | page = __rmqueue_pcplist(zone, order: 0, migratetype: ac.migratetype, alloc_flags, |
4484 | pcp, list: pcp_list); |
4485 | if (unlikely(!page)) { |
4486 | /* Try and allocate at least one page */ |
4487 | if (!nr_account) { |
4488 | pcp_spin_unlock(pcp); |
4489 | goto failed_irq; |
4490 | } |
4491 | break; |
4492 | } |
4493 | nr_account++; |
4494 | |
4495 | prep_new_page(page, order: 0, gfp_flags: gfp, alloc_flags: 0); |
4496 | if (page_list) |
4497 | list_add(new: &page->lru, head: page_list); |
4498 | else |
4499 | page_array[nr_populated] = page; |
4500 | nr_populated++; |
4501 | } |
4502 | |
4503 | pcp_spin_unlock(pcp); |
4504 | pcp_trylock_finish(UP_flags); |
4505 | |
4506 | __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account); |
4507 | zone_statistics(preferred_zone: ac.preferred_zoneref->zone, z: zone, nr_account); |
4508 | |
4509 | out: |
4510 | return nr_populated; |
4511 | |
4512 | failed_irq: |
4513 | pcp_trylock_finish(UP_flags); |
4514 | |
4515 | failed: |
4516 | page = __alloc_pages(gfp, order: 0, preferred_nid, nodemask); |
4517 | if (page) { |
4518 | if (page_list) |
4519 | list_add(new: &page->lru, head: page_list); |
4520 | else |
4521 | page_array[nr_populated] = page; |
4522 | nr_populated++; |
4523 | } |
4524 | |
4525 | goto out; |
4526 | } |
4527 | EXPORT_SYMBOL_GPL(__alloc_pages_bulk); |
4528 | |
4529 | /* |
4530 | * This is the 'heart' of the zoned buddy allocator. |
4531 | */ |
4532 | struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, |
4533 | nodemask_t *nodemask) |
4534 | { |
4535 | struct page *page; |
4536 | unsigned int alloc_flags = ALLOC_WMARK_LOW; |
4537 | gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */ |
4538 | struct alloc_context ac = { }; |
4539 | |
4540 | /* |
4541 | * There are several places where we assume that the order value is sane |
4542 | * so bail out early if the request is out of bound. |
4543 | */ |
4544 | if (WARN_ON_ONCE_GFP(order > MAX_ORDER, gfp)) |
4545 | return NULL; |
4546 | |
4547 | gfp &= gfp_allowed_mask; |
4548 | /* |
4549 | * Apply scoped allocation constraints. This is mainly about GFP_NOFS |
4550 | * resp. GFP_NOIO which has to be inherited for all allocation requests |
4551 | * from a particular context which has been marked by |
4552 | * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures |
4553 | * movable zones are not used during allocation. |
4554 | */ |
4555 | gfp = current_gfp_context(flags: gfp); |
4556 | alloc_gfp = gfp; |
4557 | if (!prepare_alloc_pages(gfp_mask: gfp, order, preferred_nid, nodemask, ac: &ac, |
4558 | alloc_gfp: &alloc_gfp, alloc_flags: &alloc_flags)) |
4559 | return NULL; |
4560 | |
4561 | /* |
4562 | * Forbid the first pass from falling back to types that fragment |
4563 | * memory until all local zones are considered. |
4564 | */ |
4565 | alloc_flags |= alloc_flags_nofragment(zone: ac.preferred_zoneref->zone, gfp_mask: gfp); |
4566 | |
4567 | /* First allocation attempt */ |
4568 | page = get_page_from_freelist(gfp_mask: alloc_gfp, order, alloc_flags, ac: &ac); |
4569 | if (likely(page)) |
4570 | goto out; |
4571 | |
4572 | alloc_gfp = gfp; |
4573 | ac.spread_dirty_pages = false; |
4574 | |
4575 | /* |
4576 | * Restore the original nodemask if it was potentially replaced with |
4577 | * &cpuset_current_mems_allowed to optimize the fast-path attempt. |
4578 | */ |
4579 | ac.nodemask = nodemask; |
4580 | |
4581 | page = __alloc_pages_slowpath(gfp_mask: alloc_gfp, order, ac: &ac); |
4582 | |
4583 | out: |
4584 | if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page && |
4585 | unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) { |
4586 | __free_pages(page, order); |
4587 | page = NULL; |
4588 | } |
4589 | |
4590 | trace_mm_page_alloc(page, order, gfp_flags: alloc_gfp, migratetype: ac.migratetype); |
4591 | kmsan_alloc_page(page, order, flags: alloc_gfp); |
4592 | |
4593 | return page; |
4594 | } |
4595 | EXPORT_SYMBOL(__alloc_pages); |
4596 | |
4597 | struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid, |
4598 | nodemask_t *nodemask) |
4599 | { |
4600 | struct page *page = __alloc_pages(gfp | __GFP_COMP, order, |
4601 | preferred_nid, nodemask); |
4602 | return page_rmappable_folio(page); |
4603 | } |
4604 | EXPORT_SYMBOL(__folio_alloc); |
4605 | |
4606 | /* |
4607 | * Common helper functions. Never use with __GFP_HIGHMEM because the returned |
4608 | * address cannot represent highmem pages. Use alloc_pages and then kmap if |
4609 | * you need to access high mem. |
4610 | */ |
4611 | unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order) |
4612 | { |
4613 | struct page *page; |
4614 | |
4615 | page = alloc_pages(gfp: gfp_mask & ~__GFP_HIGHMEM, order); |
4616 | if (!page) |
4617 | return 0; |
4618 | return (unsigned long) page_address(page); |
4619 | } |
4620 | EXPORT_SYMBOL(__get_free_pages); |
4621 | |
4622 | unsigned long get_zeroed_page(gfp_t gfp_mask) |
4623 | { |
4624 | return __get_free_page(gfp_mask | __GFP_ZERO); |
4625 | } |
4626 | EXPORT_SYMBOL(get_zeroed_page); |
4627 | |
4628 | /** |
4629 | * __free_pages - Free pages allocated with alloc_pages(). |
4630 | * @page: The page pointer returned from alloc_pages(). |
4631 | * @order: The order of the allocation. |
4632 | * |
4633 | * This function can free multi-page allocations that are not compound |
4634 | * pages. It does not check that the @order passed in matches that of |
4635 | * the allocation, so it is easy to leak memory. Freeing more memory |
4636 | * than was allocated will probably emit a warning. |
4637 | * |
4638 | * If the last reference to this page is speculative, it will be released |
4639 | * by put_page() which only frees the first page of a non-compound |
4640 | * allocation. To prevent the remaining pages from being leaked, we free |
4641 | * the subsequent pages here. If you want to use the page's reference |
4642 | * count to decide when to free the allocation, you should allocate a |
4643 | * compound page, and use put_page() instead of __free_pages(). |
4644 | * |
4645 | * Context: May be called in interrupt context or while holding a normal |
4646 | * spinlock, but not in NMI context or while holding a raw spinlock. |
4647 | */ |
4648 | void __free_pages(struct page *page, unsigned int order) |
4649 | { |
4650 | /* get PageHead before we drop reference */ |
4651 | int head = PageHead(page); |
4652 | |
4653 | if (put_page_testzero(page)) |
4654 | free_the_page(page, order); |
4655 | else if (!head) |
4656 | while (order-- > 0) |
4657 | free_the_page(page: page + (1 << order), order); |
4658 | } |
4659 | EXPORT_SYMBOL(__free_pages); |
4660 | |
4661 | void free_pages(unsigned long addr, unsigned int order) |
4662 | { |
4663 | if (addr != 0) { |
4664 | VM_BUG_ON(!virt_addr_valid((void *)addr)); |
4665 | __free_pages(virt_to_page((void *)addr), order); |
4666 | } |
4667 | } |
4668 | |
4669 | EXPORT_SYMBOL(free_pages); |
4670 | |
4671 | /* |
4672 | * Page Fragment: |
4673 | * An arbitrary-length arbitrary-offset area of memory which resides |
4674 | * within a 0 or higher order page. Multiple fragments within that page |
4675 | * are individually refcounted, in the page's reference counter. |
4676 | * |
4677 | * The page_frag functions below provide a simple allocation framework for |
4678 | * page fragments. This is used by the network stack and network device |
4679 | * drivers to provide a backing region of memory for use as either an |
4680 | * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. |
4681 | */ |
4682 | static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, |
4683 | gfp_t gfp_mask) |
4684 | { |
4685 | struct page *page = NULL; |
4686 | gfp_t gfp = gfp_mask; |
4687 | |
4688 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) |
4689 | gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | |
4690 | __GFP_NOMEMALLOC; |
4691 | page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, |
4692 | PAGE_FRAG_CACHE_MAX_ORDER); |
4693 | nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; |
4694 | #endif |
4695 | if (unlikely(!page)) |
4696 | page = alloc_pages_node(NUMA_NO_NODE, gfp_mask: gfp, order: 0); |
4697 | |
4698 | nc->va = page ? page_address(page) : NULL; |
4699 | |
4700 | return page; |
4701 | } |
4702 | |
4703 | void __page_frag_cache_drain(struct page *page, unsigned int count) |
4704 | { |
4705 | VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); |
4706 | |
4707 | if (page_ref_sub_and_test(page, nr: count)) |
4708 | free_the_page(page, order: compound_order(page)); |
4709 | } |
4710 | EXPORT_SYMBOL(__page_frag_cache_drain); |
4711 | |
4712 | void *page_frag_alloc_align(struct page_frag_cache *nc, |
4713 | unsigned int fragsz, gfp_t gfp_mask, |
4714 | unsigned int align_mask) |
4715 | { |
4716 | unsigned int size = PAGE_SIZE; |
4717 | struct page *page; |
4718 | int offset; |
4719 | |
4720 | if (unlikely(!nc->va)) { |
4721 | refill: |
4722 | page = __page_frag_cache_refill(nc, gfp_mask); |
4723 | if (!page) |
4724 | return NULL; |
4725 | |
4726 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) |
4727 | /* if size can vary use size else just use PAGE_SIZE */ |
4728 | size = nc->size; |
4729 | #endif |
4730 | /* Even if we own the page, we do not use atomic_set(). |
4731 | * This would break get_page_unless_zero() users. |
4732 | */ |
4733 | page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); |
4734 | |
4735 | /* reset page count bias and offset to start of new frag */ |
4736 | nc->pfmemalloc = page_is_pfmemalloc(page); |
4737 | nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; |
4738 | nc->offset = size; |
4739 | } |
4740 | |
4741 | offset = nc->offset - fragsz; |
4742 | if (unlikely(offset < 0)) { |
4743 | page = virt_to_page(nc->va); |
4744 | |
4745 | if (!page_ref_sub_and_test(page, nr: nc->pagecnt_bias)) |
4746 | goto refill; |
4747 | |
4748 | if (unlikely(nc->pfmemalloc)) { |
4749 | free_the_page(page, order: compound_order(page)); |
4750 | goto refill; |
4751 | } |
4752 | |
4753 | #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) |
4754 | /* if size can vary use size else just use PAGE_SIZE */ |
4755 | size = nc->size; |
4756 | #endif |
4757 | /* OK, page count is 0, we can safely set it */ |
4758 | set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); |
4759 | |
4760 | /* reset page count bias and offset to start of new frag */ |
4761 | nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; |
4762 | offset = size - fragsz; |
4763 | if (unlikely(offset < 0)) { |
4764 | /* |
4765 | * The caller is trying to allocate a fragment |
4766 | * with fragsz > PAGE_SIZE but the cache isn't big |
4767 | * enough to satisfy the request, this may |
4768 | * happen in low memory conditions. |
4769 | * We don't release the cache page because |
4770 | * it could make memory pressure worse |
4771 | * so we simply return NULL here. |
4772 | */ |
4773 | return NULL; |
4774 | } |
4775 | } |
4776 | |
4777 | nc->pagecnt_bias--; |
4778 | offset &= align_mask; |
4779 | nc->offset = offset; |
4780 | |
4781 | return nc->va + offset; |
4782 | } |
4783 | EXPORT_SYMBOL(page_frag_alloc_align); |
4784 | |
4785 | /* |
4786 | * Frees a page fragment allocated out of either a compound or order 0 page. |
4787 | */ |
4788 | void page_frag_free(void *addr) |
4789 | { |
4790 | struct page *page = virt_to_head_page(x: addr); |
4791 | |
4792 | if (unlikely(put_page_testzero(page))) |
4793 | free_the_page(page, order: compound_order(page)); |
4794 | } |
4795 | EXPORT_SYMBOL(page_frag_free); |
4796 | |
4797 | static void *make_alloc_exact(unsigned long addr, unsigned int order, |
4798 | size_t size) |
4799 | { |
4800 | if (addr) { |
4801 | unsigned long nr = DIV_ROUND_UP(size, PAGE_SIZE); |
4802 | struct page *page = virt_to_page((void *)addr); |
4803 | struct page *last = page + nr; |
4804 | |
4805 | split_page_owner(page, nr: 1 << order); |
4806 | split_page_memcg(head: page, nr: 1 << order); |
4807 | while (page < --last) |
4808 | set_page_refcounted(last); |
4809 | |
4810 | last = page + (1UL << order); |
4811 | for (page += nr; page < last; page++) |
4812 | __free_pages_ok(page, order: 0, FPI_TO_TAIL); |
4813 | } |
4814 | return (void *)addr; |
4815 | } |
4816 | |
4817 | /** |
4818 | * alloc_pages_exact - allocate an exact number physically-contiguous pages. |
4819 | * @size: the number of bytes to allocate |
4820 | * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP |
4821 | * |
4822 | * This function is similar to alloc_pages(), except that it allocates the |
4823 | * minimum number of pages to satisfy the request. alloc_pages() can only |
4824 | * allocate memory in power-of-two pages. |
4825 | * |
4826 | * This function is also limited by MAX_ORDER. |
4827 | * |
4828 | * Memory allocated by this function must be released by free_pages_exact(). |
4829 | * |
4830 | * Return: pointer to the allocated area or %NULL in case of error. |
4831 | */ |
4832 | void *alloc_pages_exact(size_t size, gfp_t gfp_mask) |
4833 | { |
4834 | unsigned int order = get_order(size); |
4835 | unsigned long addr; |
4836 | |
4837 | if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) |
4838 | gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); |
4839 | |
4840 | addr = __get_free_pages(gfp_mask, order); |
4841 | return make_alloc_exact(addr, order, size); |
4842 | } |
4843 | EXPORT_SYMBOL(alloc_pages_exact); |
4844 | |
4845 | /** |
4846 | * alloc_pages_exact_nid - allocate an exact number of physically-contiguous |
4847 | * pages on a node. |
4848 | * @nid: the preferred node ID where memory should be allocated |
4849 | * @size: the number of bytes to allocate |
4850 | * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP |
4851 | * |
4852 | * Like alloc_pages_exact(), but try to allocate on node nid first before falling |
4853 | * back. |
4854 | * |
4855 | * Return: pointer to the allocated area or %NULL in case of error. |
4856 | */ |
4857 | void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) |
4858 | { |
4859 | unsigned int order = get_order(size); |
4860 | struct page *p; |
4861 | |
4862 | if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) |
4863 | gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); |
4864 | |
4865 | p = alloc_pages_node(nid, gfp_mask, order); |
4866 | if (!p) |
4867 | return NULL; |
4868 | return make_alloc_exact(addr: (unsigned long)page_address(p), order, size); |
4869 | } |
4870 | |
4871 | /** |
4872 | * free_pages_exact - release memory allocated via alloc_pages_exact() |
4873 | * @virt: the value returned by alloc_pages_exact. |
4874 | * @size: size of allocation, same value as passed to alloc_pages_exact(). |
4875 | * |
4876 | * Release the memory allocated by a previous call to alloc_pages_exact. |
4877 | */ |
4878 | void free_pages_exact(void *virt, size_t size) |
4879 | { |
4880 | unsigned long addr = (unsigned long)virt; |
4881 | unsigned long end = addr + PAGE_ALIGN(size); |
4882 | |
4883 | while (addr < end) { |
4884 | free_page(addr); |
4885 | addr += PAGE_SIZE; |
4886 | } |
4887 | } |
4888 | EXPORT_SYMBOL(free_pages_exact); |
4889 | |
4890 | /** |
4891 | * nr_free_zone_pages - count number of pages beyond high watermark |
4892 | * @offset: The zone index of the highest zone |
4893 | * |
4894 | * nr_free_zone_pages() counts the number of pages which are beyond the |
4895 | * high watermark within all zones at or below a given zone index. For each |
4896 | * zone, the number of pages is calculated as: |
4897 | * |
4898 | * nr_free_zone_pages = managed_pages - high_pages |
4899 | * |
4900 | * Return: number of pages beyond high watermark. |
4901 | */ |
4902 | static unsigned long nr_free_zone_pages(int offset) |
4903 | { |
4904 | struct zoneref *z; |
4905 | struct zone *zone; |
4906 | |
4907 | /* Just pick one node, since fallback list is circular */ |
4908 | unsigned long sum = 0; |
4909 | |
4910 | struct zonelist *zonelist = node_zonelist(nid: numa_node_id(), GFP_KERNEL); |
4911 | |
4912 | for_each_zone_zonelist(zone, z, zonelist, offset) { |
4913 | unsigned long size = zone_managed_pages(zone); |
4914 | unsigned long high = high_wmark_pages(zone); |
4915 | if (size > high) |
4916 | sum += size - high; |
4917 | } |
4918 | |
4919 | return sum; |
4920 | } |
4921 | |
4922 | /** |
4923 | * nr_free_buffer_pages - count number of pages beyond high watermark |
4924 | * |
4925 | * nr_free_buffer_pages() counts the number of pages which are beyond the high |
4926 | * watermark within ZONE_DMA and ZONE_NORMAL. |
4927 | * |
4928 | * Return: number of pages beyond high watermark within ZONE_DMA and |
4929 | * ZONE_NORMAL. |
4930 | */ |
4931 | unsigned long nr_free_buffer_pages(void) |
4932 | { |
4933 | return nr_free_zone_pages(offset: gfp_zone(GFP_USER)); |
4934 | } |
4935 | EXPORT_SYMBOL_GPL(nr_free_buffer_pages); |
4936 | |
4937 | static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) |
4938 | { |
4939 | zoneref->zone = zone; |
4940 | zoneref->zone_idx = zone_idx(zone); |
4941 | } |
4942 | |
4943 | /* |
4944 | * Builds allocation fallback zone lists. |
4945 | * |
4946 | * Add all populated zones of a node to the zonelist. |
4947 | */ |
4948 | static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) |
4949 | { |
4950 | struct zone *zone; |
4951 | enum zone_type zone_type = MAX_NR_ZONES; |
4952 | int nr_zones = 0; |
4953 | |
4954 | do { |
4955 | zone_type--; |
4956 | zone = pgdat->node_zones + zone_type; |
4957 | if (populated_zone(zone)) { |
4958 | zoneref_set_zone(zone, zoneref: &zonerefs[nr_zones++]); |
4959 | check_highest_zone(k: zone_type); |
4960 | } |
4961 | } while (zone_type); |
4962 | |
4963 | return nr_zones; |
4964 | } |
4965 | |
4966 | #ifdef CONFIG_NUMA |
4967 | |
4968 | static int __parse_numa_zonelist_order(char *s) |
4969 | { |
4970 | /* |
4971 | * We used to support different zonelists modes but they turned |
4972 | * out to be just not useful. Let's keep the warning in place |
4973 | * if somebody still use the cmd line parameter so that we do |
4974 | * not fail it silently |
4975 | */ |
4976 | if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) { |
4977 | pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n" , s); |
4978 | return -EINVAL; |
4979 | } |
4980 | return 0; |
4981 | } |
4982 | |
4983 | static char numa_zonelist_order[] = "Node" ; |
4984 | #define NUMA_ZONELIST_ORDER_LEN 16 |
4985 | /* |
4986 | * sysctl handler for numa_zonelist_order |
4987 | */ |
4988 | static int numa_zonelist_order_handler(struct ctl_table *table, int write, |
4989 | void *buffer, size_t *length, loff_t *ppos) |
4990 | { |
4991 | if (write) |
4992 | return __parse_numa_zonelist_order(s: buffer); |
4993 | return proc_dostring(table, write, buffer, length, ppos); |
4994 | } |
4995 | |
4996 | static int node_load[MAX_NUMNODES]; |
4997 | |
4998 | /** |
4999 | * find_next_best_node - find the next node that should appear in a given node's fallback list |
5000 | * @node: node whose fallback list we're appending |
5001 | * @used_node_mask: nodemask_t of already used nodes |
5002 | * |
5003 | * We use a number of factors to determine which is the next node that should |
5004 | * appear on a given node's fallback list. The node should not have appeared |
5005 | * already in @node's fallback list, and it should be the next closest node |
5006 | * according to the distance array (which contains arbitrary distance values |
5007 | * from each node to each node in the system), and should also prefer nodes |
5008 | * with no CPUs, since presumably they'll have very little allocation pressure |
5009 | * on them otherwise. |
5010 | * |
5011 | * Return: node id of the found node or %NUMA_NO_NODE if no node is found. |
5012 | */ |
5013 | int find_next_best_node(int node, nodemask_t *used_node_mask) |
5014 | { |
5015 | int n, val; |
5016 | int min_val = INT_MAX; |
5017 | int best_node = NUMA_NO_NODE; |
5018 | |
5019 | /* |
5020 | * Use the local node if we haven't already, but for memoryless local |
5021 | * node, we should skip it and fall back to other nodes. |
5022 | */ |
5023 | if (!node_isset(node, *used_node_mask) && node_state(node, state: N_MEMORY)) { |
5024 | node_set(node, *used_node_mask); |
5025 | return node; |
5026 | } |
5027 | |
5028 | for_each_node_state(n, N_MEMORY) { |
5029 | |
5030 | /* Don't want a node to appear more than once */ |
5031 | if (node_isset(n, *used_node_mask)) |
5032 | continue; |
5033 | |
5034 | /* Use the distance array to find the distance */ |
5035 | val = node_distance(node, n); |
5036 | |
5037 | /* Penalize nodes under us ("prefer the next node") */ |
5038 | val += (n < node); |
5039 | |
5040 | /* Give preference to headless and unused nodes */ |
5041 | if (!cpumask_empty(srcp: cpumask_of_node(node: n))) |
5042 | val += PENALTY_FOR_NODE_WITH_CPUS; |
5043 | |
5044 | /* Slight preference for less loaded node */ |
5045 | val *= MAX_NUMNODES; |
5046 | val += node_load[n]; |
5047 | |
5048 | if (val < min_val) { |
5049 | min_val = val; |
5050 | best_node = n; |
5051 | } |
5052 | } |
5053 | |
5054 | if (best_node >= 0) |
5055 | node_set(best_node, *used_node_mask); |
5056 | |
5057 | return best_node; |
5058 | } |
5059 | |
5060 | |
5061 | /* |
5062 | * Build zonelists ordered by node and zones within node. |
5063 | * This results in maximum locality--normal zone overflows into local |
5064 | * DMA zone, if any--but risks exhausting DMA zone. |
5065 | */ |
5066 | static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, |
5067 | unsigned nr_nodes) |
5068 | { |
5069 | struct zoneref *zonerefs; |
5070 | int i; |
5071 | |
5072 | zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; |
5073 | |
5074 | for (i = 0; i < nr_nodes; i++) { |
5075 | int nr_zones; |
5076 | |
5077 | pg_data_t *node = NODE_DATA(node_order[i]); |
5078 | |
5079 | nr_zones = build_zonerefs_node(pgdat: node, zonerefs); |
5080 | zonerefs += nr_zones; |
5081 | } |
5082 | zonerefs->zone = NULL; |
5083 | zonerefs->zone_idx = 0; |
5084 | } |
5085 | |
5086 | /* |
5087 | * Build gfp_thisnode zonelists |
5088 | */ |
5089 | static void build_thisnode_zonelists(pg_data_t *pgdat) |
5090 | { |
5091 | struct zoneref *zonerefs; |
5092 | int nr_zones; |
5093 | |
5094 | zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; |
5095 | nr_zones = build_zonerefs_node(pgdat, zonerefs); |
5096 | zonerefs += nr_zones; |
5097 | zonerefs->zone = NULL; |
5098 | zonerefs->zone_idx = 0; |
5099 | } |
5100 | |
5101 | /* |
5102 | * Build zonelists ordered by zone and nodes within zones. |
5103 | * This results in conserving DMA zone[s] until all Normal memory is |
5104 | * exhausted, but results in overflowing to remote node while memory |
5105 | * may still exist in local DMA zone. |
5106 | */ |
5107 | |
5108 | static void build_zonelists(pg_data_t *pgdat) |
5109 | { |
5110 | static int node_order[MAX_NUMNODES]; |
5111 | int node, nr_nodes = 0; |
5112 | nodemask_t used_mask = NODE_MASK_NONE; |
5113 | int local_node, prev_node; |
5114 | |
5115 | /* NUMA-aware ordering of nodes */ |
5116 | local_node = pgdat->node_id; |
5117 | prev_node = local_node; |
5118 | |
5119 | memset(node_order, 0, sizeof(node_order)); |
5120 | while ((node = find_next_best_node(node: local_node, used_node_mask: &used_mask)) >= 0) { |
5121 | /* |
5122 | * We don't want to pressure a particular node. |
5123 | * So adding penalty to the first node in same |
5124 | * distance group to make it round-robin. |
5125 | */ |
5126 | if (node_distance(local_node, node) != |
5127 | node_distance(local_node, prev_node)) |
5128 | node_load[node] += 1; |
5129 | |
5130 | node_order[nr_nodes++] = node; |
5131 | prev_node = node; |
5132 | } |
5133 | |
5134 | build_zonelists_in_node_order(pgdat, node_order, nr_nodes); |
5135 | build_thisnode_zonelists(pgdat); |
5136 | pr_info("Fallback order for Node %d: " , local_node); |
5137 | for (node = 0; node < nr_nodes; node++) |
5138 | pr_cont("%d " , node_order[node]); |
5139 | pr_cont("\n" ); |
5140 | } |
5141 | |
5142 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES |
5143 | /* |
5144 | * Return node id of node used for "local" allocations. |
5145 | * I.e., first node id of first zone in arg node's generic zonelist. |
5146 | * Used for initializing percpu 'numa_mem', which is used primarily |
5147 | * for kernel allocations, so use GFP_KERNEL flags to locate zonelist. |
5148 | */ |
5149 | int local_memory_node(int node) |
5150 | { |
5151 | struct zoneref *z; |
5152 | |
5153 | z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL), |
5154 | gfp_zone(GFP_KERNEL), |
5155 | NULL); |
5156 | return zone_to_nid(z->zone); |
5157 | } |
5158 | #endif |
5159 | |
5160 | static void setup_min_unmapped_ratio(void); |
5161 | static void setup_min_slab_ratio(void); |
5162 | #else /* CONFIG_NUMA */ |
5163 | |
5164 | static void build_zonelists(pg_data_t *pgdat) |
5165 | { |
5166 | int node, local_node; |
5167 | struct zoneref *zonerefs; |
5168 | int nr_zones; |
5169 | |
5170 | local_node = pgdat->node_id; |
5171 | |
5172 | zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; |
5173 | nr_zones = build_zonerefs_node(pgdat, zonerefs); |
5174 | zonerefs += nr_zones; |
5175 | |
5176 | /* |
5177 | * Now we build the zonelist so that it contains the zones |
5178 | * of all the other nodes. |
5179 | * We don't want to pressure a particular node, so when |
5180 | * building the zones for node N, we make sure that the |
5181 | * zones coming right after the local ones are those from |
5182 | * node N+1 (modulo N) |
5183 | */ |
5184 | for (node = local_node + 1; node < MAX_NUMNODES; node++) { |
5185 | if (!node_online(node)) |
5186 | continue; |
5187 | nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); |
5188 | zonerefs += nr_zones; |
5189 | } |
5190 | for (node = 0; node < local_node; node++) { |
5191 | if (!node_online(node)) |
5192 | continue; |
5193 | nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); |
5194 | zonerefs += nr_zones; |
5195 | } |
5196 | |
5197 | zonerefs->zone = NULL; |
5198 | zonerefs->zone_idx = 0; |
5199 | } |
5200 | |
5201 | #endif /* CONFIG_NUMA */ |
5202 | |
5203 | /* |
5204 | * Boot pageset table. One per cpu which is going to be used for all |
5205 | * zones and all nodes. The parameters will be set in such a way |
5206 | * that an item put on a list will immediately be handed over to |
5207 | * the buddy list. This is safe since pageset manipulation is done |
5208 | * with interrupts disabled. |
5209 | * |
5210 | * The boot_pagesets must be kept even after bootup is complete for |
5211 | * unused processors and/or zones. They do play a role for bootstrapping |
5212 | * hotplugged processors. |
5213 | * |
5214 | * zoneinfo_show() and maybe other functions do |
5215 | * not check if the processor is online before following the pageset pointer. |
5216 | * Other parts of the kernel may not check if the zone is available. |
5217 | */ |
5218 | static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats); |
5219 | /* These effectively disable the pcplists in the boot pageset completely */ |
5220 | #define BOOT_PAGESET_HIGH 0 |
5221 | #define BOOT_PAGESET_BATCH 1 |
5222 | static DEFINE_PER_CPU(struct per_cpu_pages, boot_pageset); |
5223 | static DEFINE_PER_CPU(struct per_cpu_zonestat, boot_zonestats); |
5224 | |
5225 | static void __build_all_zonelists(void *data) |
5226 | { |
5227 | int nid; |
5228 | int __maybe_unused cpu; |
5229 | pg_data_t *self = data; |
5230 | unsigned long flags; |
5231 | |
5232 | /* |
5233 | * The zonelist_update_seq must be acquired with irqsave because the |
5234 | * reader can be invoked from IRQ with GFP_ATOMIC. |
5235 | */ |
5236 | write_seqlock_irqsave(&zonelist_update_seq, flags); |
5237 | /* |
5238 | * Also disable synchronous printk() to prevent any printk() from |
5239 | * trying to hold port->lock, for |
5240 | * tty_insert_flip_string_and_push_buffer() on other CPU might be |
5241 | * calling kmalloc(GFP_ATOMIC | __GFP_NOWARN) with port->lock held. |
5242 | */ |
5243 | printk_deferred_enter(); |
5244 | |
5245 | #ifdef CONFIG_NUMA |
5246 | memset(node_load, 0, sizeof(node_load)); |
5247 | #endif |
5248 | |
5249 | /* |
5250 | * This node is hotadded and no memory is yet present. So just |
5251 | * building zonelists is fine - no need to touch other nodes. |
5252 | */ |
5253 | if (self && !node_online(self->node_id)) { |
5254 | build_zonelists(pgdat: self); |
5255 | } else { |
5256 | /* |
5257 | * All possible nodes have pgdat preallocated |
5258 | * in free_area_init |
5259 | */ |
5260 | for_each_node(nid) { |
5261 | pg_data_t *pgdat = NODE_DATA(nid); |
5262 | |
5263 | build_zonelists(pgdat); |
5264 | } |
5265 | |
5266 | #ifdef CONFIG_HAVE_MEMORYLESS_NODES |
5267 | /* |
5268 | * We now know the "local memory node" for each node-- |
5269 | * i.e., the node of the first zone in the generic zonelist. |
5270 | * Set up numa_mem percpu variable for on-line cpus. During |
5271 | * boot, only the boot cpu should be on-line; we'll init the |
5272 | * secondary cpus' numa_mem as they come on-line. During |
5273 | * node/memory hotplug, we'll fixup all on-line cpus. |
5274 | */ |
5275 | for_each_online_cpu(cpu) |
5276 | set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); |
5277 | #endif |
5278 | } |
5279 | |
5280 | printk_deferred_exit(); |
5281 | write_sequnlock_irqrestore(sl: &zonelist_update_seq, flags); |
5282 | } |
5283 | |
5284 | static noinline void __init |
5285 | build_all_zonelists_init(void) |
5286 | { |
5287 | int cpu; |
5288 | |
5289 | __build_all_zonelists(NULL); |
5290 | |
5291 | /* |
5292 | * Initialize the boot_pagesets that are going to be used |
5293 | * for bootstrapping processors. The real pagesets for |
5294 | * each zone will be allocated later when the per cpu |
5295 | * allocator is available. |
5296 | * |
5297 | * boot_pagesets are used also for bootstrapping offline |
5298 | * cpus if the system is already booted because the pagesets |
5299 | * are needed to initialize allocators on a specific cpu too. |
5300 | * F.e. the percpu allocator needs the page allocator which |
5301 | * needs the percpu allocator in order to allocate its pagesets |
5302 | * (a chicken-egg dilemma). |
5303 | */ |
5304 | for_each_possible_cpu(cpu) |
5305 | per_cpu_pages_init(pcp: &per_cpu(boot_pageset, cpu), pzstats: &per_cpu(boot_zonestats, cpu)); |
5306 | |
5307 | mminit_verify_zonelist(); |
5308 | cpuset_init_current_mems_allowed(); |
5309 | } |
5310 | |
5311 | /* |
5312 | * unless system_state == SYSTEM_BOOTING. |
5313 | * |
5314 | * __ref due to call of __init annotated helper build_all_zonelists_init |
5315 | * [protected by SYSTEM_BOOTING]. |
5316 | */ |
5317 | void __ref build_all_zonelists(pg_data_t *pgdat) |
5318 | { |
5319 | unsigned long vm_total_pages; |
5320 | |
5321 | if (system_state == SYSTEM_BOOTING) { |
5322 | build_all_zonelists_init(); |
5323 | } else { |
5324 | __build_all_zonelists(data: pgdat); |
5325 | /* cpuset refresh routine should be here */ |
5326 | } |
5327 | /* Get the number of free pages beyond high watermark in all zones. */ |
5328 | vm_total_pages = nr_free_zone_pages(offset: gfp_zone(GFP_HIGHUSER_MOVABLE)); |
5329 | /* |
5330 | * Disable grouping by mobility if the number of pages in the |
5331 | * system is too low to allow the mechanism to work. It would be |
5332 | * more accurate, but expensive to check per-zone. This check is |
5333 | * made on memory-hotadd so a system can start with mobility |
5334 | * disabled and enable it later |
5335 | */ |
5336 | if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES)) |
5337 | page_group_by_mobility_disabled = 1; |
5338 | else |
5339 | page_group_by_mobility_disabled = 0; |
5340 | |
5341 | pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n" , |
5342 | nr_online_nodes, |
5343 | page_group_by_mobility_disabled ? "off" : "on" , |
5344 | vm_total_pages); |
5345 | #ifdef CONFIG_NUMA |
5346 | pr_info("Policy zone: %s\n" , zone_names[policy_zone]); |
5347 | #endif |
5348 | } |
5349 | |
5350 | static int zone_batchsize(struct zone *zone) |
5351 | { |
5352 | #ifdef CONFIG_MMU |
5353 | int batch; |
5354 | |
5355 | /* |
5356 | * The number of pages to batch allocate is either ~0.1% |
5357 | * of the zone or 1MB, whichever is smaller. The batch |
5358 | * size is striking a balance between allocation latency |
5359 | * and zone lock contention. |
5360 | */ |
5361 | batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE); |
5362 | batch /= 4; /* We effectively *= 4 below */ |
5363 | if (batch < 1) |
5364 | batch = 1; |
5365 | |
5366 | /* |
5367 | * Clamp the batch to a 2^n - 1 value. Having a power |
5368 | * of 2 value was found to be more likely to have |
5369 | * suboptimal cache aliasing properties in some cases. |
5370 | * |
5371 | * For example if 2 tasks are alternately allocating |
5372 | * batches of pages, one task can end up with a lot |
5373 | * of pages of one half of the possible page colors |
5374 | * and the other with pages of the other colors. |
5375 | */ |
5376 | batch = rounddown_pow_of_two(batch + batch/2) - 1; |
5377 | |
5378 | return batch; |
5379 | |
5380 | #else |
5381 | /* The deferral and batching of frees should be suppressed under NOMMU |
5382 | * conditions. |
5383 | * |
5384 | * The problem is that NOMMU needs to be able to allocate large chunks |
5385 | * of contiguous memory as there's no hardware page translation to |
5386 | * assemble apparent contiguous memory from discontiguous pages. |
5387 | * |
5388 | * Queueing large contiguous runs of pages for batching, however, |
5389 | * causes the pages to actually be freed in smaller chunks. As there |
5390 | * can be a significant delay between the individual batches being |
5391 | * recycled, this leads to the once large chunks of space being |
5392 | * fragmented and becoming unavailable for high-order allocations. |
5393 | */ |
5394 | return 0; |
5395 | #endif |
5396 | } |
5397 | |
5398 | static int percpu_pagelist_high_fraction; |
5399 | static int zone_highsize(struct zone *zone, int batch, int cpu_online, |
5400 | int high_fraction) |
5401 | { |
5402 | #ifdef CONFIG_MMU |
5403 | int high; |
5404 | int nr_split_cpus; |
5405 | unsigned long total_pages; |
5406 | |
5407 | if (!high_fraction) { |
5408 | /* |
5409 | * By default, the high value of the pcp is based on the zone |
5410 | * low watermark so that if they are full then background |
5411 | * reclaim will not be started prematurely. |
5412 | */ |
5413 | total_pages = low_wmark_pages(zone); |
5414 | } else { |
5415 | /* |
5416 | * If percpu_pagelist_high_fraction is configured, the high |
5417 | * value is based on a fraction of the managed pages in the |
5418 | * zone. |
5419 | */ |
5420 | total_pages = zone_managed_pages(zone) / high_fraction; |
5421 | } |
5422 | |
5423 | /* |
5424 | * Split the high value across all online CPUs local to the zone. Note |
5425 | * that early in boot that CPUs may not be online yet and that during |
5426 | * CPU hotplug that the cpumask is not yet updated when a CPU is being |
5427 | * onlined. For memory nodes that have no CPUs, split the high value |
5428 | * across all online CPUs to mitigate the risk that reclaim is triggered |
5429 | * prematurely due to pages stored on pcp lists. |
5430 | */ |
5431 | nr_split_cpus = cpumask_weight(srcp: cpumask_of_node(node: zone_to_nid(zone))) + cpu_online; |
5432 | if (!nr_split_cpus) |
5433 | nr_split_cpus = num_online_cpus(); |
5434 | high = total_pages / nr_split_cpus; |
5435 | |
5436 | /* |
5437 | * Ensure high is at least batch*4. The multiple is based on the |
5438 | * historical relationship between high and batch. |
5439 | */ |
5440 | high = max(high, batch << 2); |
5441 | |
5442 | return high; |
5443 | #else |
5444 | return 0; |
5445 | #endif |
5446 | } |
5447 | |
5448 | /* |
5449 | * pcp->high and pcp->batch values are related and generally batch is lower |
5450 | * than high. They are also related to pcp->count such that count is lower |
5451 | * than high, and as soon as it reaches high, the pcplist is flushed. |
5452 | * |
5453 | * However, guaranteeing these relations at all times would require e.g. write |
5454 | * barriers here but also careful usage of read barriers at the read side, and |
5455 | * thus be prone to error and bad for performance. Thus the update only prevents |
5456 | * store tearing. Any new users of pcp->batch, pcp->high_min and pcp->high_max |
5457 | * should ensure they can cope with those fields changing asynchronously, and |
5458 | * fully trust only the pcp->count field on the local CPU with interrupts |
5459 | * disabled. |
5460 | * |
5461 | * mutex_is_locked(&pcp_batch_high_lock) required when calling this function |
5462 | * outside of boot time (or some other assurance that no concurrent updaters |
5463 | * exist). |
5464 | */ |
5465 | static void pageset_update(struct per_cpu_pages *pcp, unsigned long high_min, |
5466 | unsigned long high_max, unsigned long batch) |
5467 | { |
5468 | WRITE_ONCE(pcp->batch, batch); |
5469 | WRITE_ONCE(pcp->high_min, high_min); |
5470 | WRITE_ONCE(pcp->high_max, high_max); |
5471 | } |
5472 | |
5473 | static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats) |
5474 | { |
5475 | int pindex; |
5476 | |
5477 | memset(pcp, 0, sizeof(*pcp)); |
5478 | memset(pzstats, 0, sizeof(*pzstats)); |
5479 | |
5480 | spin_lock_init(&pcp->lock); |
5481 | for (pindex = 0; pindex < NR_PCP_LISTS; pindex++) |
5482 | INIT_LIST_HEAD(list: &pcp->lists[pindex]); |
5483 | |
5484 | /* |
5485 | * Set batch and high values safe for a boot pageset. A true percpu |
5486 | * pageset's initialization will update them subsequently. Here we don't |
5487 | * need to be as careful as pageset_update() as nobody can access the |
5488 | * pageset yet. |
5489 | */ |
5490 | pcp->high_min = BOOT_PAGESET_HIGH; |
5491 | pcp->high_max = BOOT_PAGESET_HIGH; |
5492 | pcp->batch = BOOT_PAGESET_BATCH; |
5493 | pcp->free_count = 0; |
5494 | } |
5495 | |
5496 | static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high_min, |
5497 | unsigned long high_max, unsigned long batch) |
5498 | { |
5499 | struct per_cpu_pages *pcp; |
5500 | int cpu; |
5501 | |
5502 | for_each_possible_cpu(cpu) { |
5503 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); |
5504 | pageset_update(pcp, high_min, high_max, batch); |
5505 | } |
5506 | } |
5507 | |
5508 | /* |
5509 | * Calculate and set new high and batch values for all per-cpu pagesets of a |
5510 | * zone based on the zone's size. |
5511 | */ |
5512 | static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online) |
5513 | { |
5514 | int new_high_min, new_high_max, new_batch; |
5515 | |
5516 | new_batch = max(1, zone_batchsize(zone)); |
5517 | if (percpu_pagelist_high_fraction) { |
5518 | new_high_min = zone_highsize(zone, batch: new_batch, cpu_online, |
5519 | high_fraction: percpu_pagelist_high_fraction); |
5520 | /* |
5521 | * PCP high is tuned manually, disable auto-tuning via |
5522 | * setting high_min and high_max to the manual value. |
5523 | */ |
5524 | new_high_max = new_high_min; |
5525 | } else { |
5526 | new_high_min = zone_highsize(zone, batch: new_batch, cpu_online, high_fraction: 0); |
5527 | new_high_max = zone_highsize(zone, batch: new_batch, cpu_online, |
5528 | MIN_PERCPU_PAGELIST_HIGH_FRACTION); |
5529 | } |
5530 | |
5531 | if (zone->pageset_high_min == new_high_min && |
5532 | zone->pageset_high_max == new_high_max && |
5533 | zone->pageset_batch == new_batch) |
5534 | return; |
5535 | |
5536 | zone->pageset_high_min = new_high_min; |
5537 | zone->pageset_high_max = new_high_max; |
5538 | zone->pageset_batch = new_batch; |
5539 | |
5540 | __zone_set_pageset_high_and_batch(zone, high_min: new_high_min, high_max: new_high_max, |
5541 | batch: new_batch); |
5542 | } |
5543 | |
5544 | void __meminit setup_zone_pageset(struct zone *zone) |
5545 | { |
5546 | int cpu; |
5547 | |
5548 | /* Size may be 0 on !SMP && !NUMA */ |
5549 | if (sizeof(struct per_cpu_zonestat) > 0) |
5550 | zone->per_cpu_zonestats = alloc_percpu(struct per_cpu_zonestat); |
5551 | |
5552 | zone->per_cpu_pageset = alloc_percpu(struct per_cpu_pages); |
5553 | for_each_possible_cpu(cpu) { |
5554 | struct per_cpu_pages *pcp; |
5555 | struct per_cpu_zonestat *pzstats; |
5556 | |
5557 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); |
5558 | pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); |
5559 | per_cpu_pages_init(pcp, pzstats); |
5560 | } |
5561 | |
5562 | zone_set_pageset_high_and_batch(zone, cpu_online: 0); |
5563 | } |
5564 | |
5565 | /* |
5566 | * The zone indicated has a new number of managed_pages; batch sizes and percpu |
5567 | * page high values need to be recalculated. |
5568 | */ |
5569 | static void zone_pcp_update(struct zone *zone, int cpu_online) |
5570 | { |
5571 | mutex_lock(&pcp_batch_high_lock); |
5572 | zone_set_pageset_high_and_batch(zone, cpu_online); |
5573 | mutex_unlock(lock: &pcp_batch_high_lock); |
5574 | } |
5575 | |
5576 | static void zone_pcp_update_cacheinfo(struct zone *zone) |
5577 | { |
5578 | int cpu; |
5579 | struct per_cpu_pages *pcp; |
5580 | struct cpu_cacheinfo *cci; |
5581 | |
5582 | for_each_online_cpu(cpu) { |
5583 | pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); |
5584 | cci = get_cpu_cacheinfo(cpu); |
5585 | /* |
5586 | * If data cache slice of CPU is large enough, "pcp->batch" |
5587 | * pages can be preserved in PCP before draining PCP for |
5588 | * consecutive high-order pages freeing without allocation. |
5589 | * This can reduce zone lock contention without hurting |
5590 | * cache-hot pages sharing. |
5591 | */ |
5592 | spin_lock(lock: &pcp->lock); |
5593 | if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch) |
5594 | pcp->flags |= PCPF_FREE_HIGH_BATCH; |
5595 | else |
5596 | pcp->flags &= ~PCPF_FREE_HIGH_BATCH; |
5597 | spin_unlock(lock: &pcp->lock); |
5598 | } |
5599 | } |
5600 | |
5601 | void setup_pcp_cacheinfo(void) |
5602 | { |
5603 | struct zone *zone; |
5604 | |
5605 | for_each_populated_zone(zone) |
5606 | zone_pcp_update_cacheinfo(zone); |
5607 | } |
5608 | |
5609 | /* |
5610 | * Allocate per cpu pagesets and initialize them. |
5611 | * Before this call only boot pagesets were available. |
5612 | */ |
5613 | void __init setup_per_cpu_pageset(void) |
5614 | { |
5615 | struct pglist_data *pgdat; |
5616 | struct zone *zone; |
5617 | int __maybe_unused cpu; |
5618 | |
5619 | for_each_populated_zone(zone) |
5620 | setup_zone_pageset(zone); |
5621 | |
5622 | #ifdef CONFIG_NUMA |
5623 | /* |
5624 | * Unpopulated zones continue using the boot pagesets. |
5625 | * The numa stats for these pagesets need to be reset. |
5626 | * Otherwise, they will end up skewing the stats of |
5627 | * the nodes these zones are associated with. |
5628 | */ |
5629 | for_each_possible_cpu(cpu) { |
5630 | struct per_cpu_zonestat *pzstats = &per_cpu(boot_zonestats, cpu); |
5631 | memset(pzstats->vm_numa_event, 0, |
5632 | sizeof(pzstats->vm_numa_event)); |
5633 | } |
5634 | #endif |
5635 | |
5636 | for_each_online_pgdat(pgdat) |
5637 | pgdat->per_cpu_nodestats = |
5638 | alloc_percpu(struct per_cpu_nodestat); |
5639 | } |
5640 | |
5641 | __meminit void zone_pcp_init(struct zone *zone) |
5642 | { |
5643 | /* |
5644 | * per cpu subsystem is not up at this point. The following code |
5645 | * relies on the ability of the linker to provide the |
5646 | * offset of a (static) per cpu variable into the per cpu area. |
5647 | */ |
5648 | zone->per_cpu_pageset = &boot_pageset; |
5649 | zone->per_cpu_zonestats = &boot_zonestats; |
5650 | zone->pageset_high_min = BOOT_PAGESET_HIGH; |
5651 | zone->pageset_high_max = BOOT_PAGESET_HIGH; |
5652 | zone->pageset_batch = BOOT_PAGESET_BATCH; |
5653 | |
5654 | if (populated_zone(zone)) |
5655 | pr_debug(" %s zone: %lu pages, LIFO batch:%u\n" , zone->name, |
5656 | zone->present_pages, zone_batchsize(zone)); |
5657 | } |
5658 | |
5659 | void adjust_managed_page_count(struct page *page, long count) |
5660 | { |
5661 | atomic_long_add(i: count, v: &page_zone(page)->managed_pages); |
5662 | totalram_pages_add(count); |
5663 | #ifdef CONFIG_HIGHMEM |
5664 | if (PageHighMem(page)) |
5665 | totalhigh_pages_add(count); |
5666 | #endif |
5667 | } |
5668 | EXPORT_SYMBOL(adjust_managed_page_count); |
5669 | |
5670 | unsigned long free_reserved_area(void *start, void *end, int poison, const char *s) |
5671 | { |
5672 | void *pos; |
5673 | unsigned long pages = 0; |
5674 | |
5675 | start = (void *)PAGE_ALIGN((unsigned long)start); |
5676 | end = (void *)((unsigned long)end & PAGE_MASK); |
5677 | for (pos = start; pos < end; pos += PAGE_SIZE, pages++) { |
5678 | struct page *page = virt_to_page(pos); |
5679 | void *direct_map_addr; |
5680 | |
5681 | /* |
5682 | * 'direct_map_addr' might be different from 'pos' |
5683 | * because some architectures' virt_to_page() |
5684 | * work with aliases. Getting the direct map |
5685 | * address ensures that we get a _writeable_ |
5686 | * alias for the memset(). |
5687 | */ |
5688 | direct_map_addr = page_address(page); |
5689 | /* |
5690 | * Perform a kasan-unchecked memset() since this memory |
5691 | * has not been initialized. |
5692 | */ |
5693 | direct_map_addr = kasan_reset_tag(addr: direct_map_addr); |
5694 | if ((unsigned int)poison <= 0xFF) |
5695 | memset(direct_map_addr, poison, PAGE_SIZE); |
5696 | |
5697 | free_reserved_page(page); |
5698 | } |
5699 | |
5700 | if (pages && s) |
5701 | pr_info("Freeing %s memory: %ldK\n" , s, K(pages)); |
5702 | |
5703 | return pages; |
5704 | } |
5705 | |
5706 | static int page_alloc_cpu_dead(unsigned int cpu) |
5707 | { |
5708 | struct zone *zone; |
5709 | |
5710 | lru_add_drain_cpu(cpu); |
5711 | mlock_drain_remote(cpu); |
5712 | drain_pages(cpu); |
5713 | |
5714 | /* |
5715 | * Spill the event counters of the dead processor |
5716 | * into the current processors event counters. |
5717 | * This artificially elevates the count of the current |
5718 | * processor. |
5719 | */ |
5720 | vm_events_fold_cpu(cpu); |
5721 | |
5722 | /* |
5723 | * Zero the differential counters of the dead processor |
5724 | * so that the vm statistics are consistent. |
5725 | * |
5726 | * This is only okay since the processor is dead and cannot |
5727 | * race with what we are doing. |
5728 | */ |
5729 | cpu_vm_stats_fold(cpu); |
5730 | |
5731 | for_each_populated_zone(zone) |
5732 | zone_pcp_update(zone, cpu_online: 0); |
5733 | |
5734 | return 0; |
5735 | } |
5736 | |
5737 | static int page_alloc_cpu_online(unsigned int cpu) |
5738 | { |
5739 | struct zone *zone; |
5740 | |
5741 | for_each_populated_zone(zone) |
5742 | zone_pcp_update(zone, cpu_online: 1); |
5743 | return 0; |
5744 | } |
5745 | |
5746 | void __init page_alloc_init_cpuhp(void) |
5747 | { |
5748 | int ret; |
5749 | |
5750 | ret = cpuhp_setup_state_nocalls(state: CPUHP_PAGE_ALLOC, |
5751 | name: "mm/page_alloc:pcp" , |
5752 | startup: page_alloc_cpu_online, |
5753 | teardown: page_alloc_cpu_dead); |
5754 | WARN_ON(ret < 0); |
5755 | } |
5756 | |
5757 | /* |
5758 | * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio |
5759 | * or min_free_kbytes changes. |
5760 | */ |
5761 | static void calculate_totalreserve_pages(void) |
5762 | { |
5763 | struct pglist_data *pgdat; |
5764 | unsigned long reserve_pages = 0; |
5765 | enum zone_type i, j; |
5766 | |
5767 | for_each_online_pgdat(pgdat) { |
5768 | |
5769 | pgdat->totalreserve_pages = 0; |
5770 | |
5771 | for (i = 0; i < MAX_NR_ZONES; i++) { |
5772 | struct zone *zone = pgdat->node_zones + i; |
5773 | long max = 0; |
5774 | unsigned long managed_pages = zone_managed_pages(zone); |
5775 | |
5776 | /* Find valid and maximum lowmem_reserve in the zone */ |
5777 | for (j = i; j < MAX_NR_ZONES; j++) { |
5778 | if (zone->lowmem_reserve[j] > max) |
5779 | max = zone->lowmem_reserve[j]; |
5780 | } |
5781 | |
5782 | /* we treat the high watermark as reserved pages. */ |
5783 | max += high_wmark_pages(zone); |
5784 | |
5785 | if (max > managed_pages) |
5786 | max = managed_pages; |
5787 | |
5788 | pgdat->totalreserve_pages += max; |
5789 | |
5790 | reserve_pages += max; |
5791 | } |
5792 | } |
5793 | totalreserve_pages = reserve_pages; |
5794 | } |
5795 | |
5796 | /* |
5797 | * setup_per_zone_lowmem_reserve - called whenever |
5798 | * sysctl_lowmem_reserve_ratio changes. Ensures that each zone |
5799 | * has a correct pages reserved value, so an adequate number of |
5800 | * pages are left in the zone after a successful __alloc_pages(). |
5801 | */ |
5802 | static void setup_per_zone_lowmem_reserve(void) |
5803 | { |
5804 | struct pglist_data *pgdat; |
5805 | enum zone_type i, j; |
5806 | |
5807 | for_each_online_pgdat(pgdat) { |
5808 | for (i = 0; i < MAX_NR_ZONES - 1; i++) { |
5809 | struct zone *zone = &pgdat->node_zones[i]; |
5810 | int ratio = sysctl_lowmem_reserve_ratio[i]; |
5811 | bool clear = !ratio || !zone_managed_pages(zone); |
5812 | unsigned long managed_pages = 0; |
5813 | |
5814 | for (j = i + 1; j < MAX_NR_ZONES; j++) { |
5815 | struct zone *upper_zone = &pgdat->node_zones[j]; |
5816 | |
5817 | managed_pages += zone_managed_pages(upper_zone); |
5818 | |
5819 | if (clear) |
5820 | zone->lowmem_reserve[j] = 0; |
5821 | else |
5822 | zone->lowmem_reserve[j] = managed_pages / ratio; |
5823 | } |
5824 | } |
5825 | } |
5826 | |
5827 | /* update totalreserve_pages */ |
5828 | calculate_totalreserve_pages(); |
5829 | } |
5830 | |
5831 | static void __setup_per_zone_wmarks(void) |
5832 | { |
5833 | unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10); |
5834 | unsigned long lowmem_pages = 0; |
5835 | struct zone *zone; |
5836 | unsigned long flags; |
5837 | |
5838 | /* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */ |
5839 | for_each_zone(zone) { |
5840 | if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE) |
5841 | lowmem_pages += zone_managed_pages(zone); |
5842 | } |
5843 | |
5844 | for_each_zone(zone) { |
5845 | u64 tmp; |
5846 | |
5847 | spin_lock_irqsave(&zone->lock, flags); |
5848 | tmp = (u64)pages_min * zone_managed_pages(zone); |
5849 | do_div(tmp, lowmem_pages); |
5850 | if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) { |
5851 | /* |
5852 | * __GFP_HIGH and PF_MEMALLOC allocations usually don't |
5853 | * need highmem and movable zones pages, so cap pages_min |
5854 | * to a small value here. |
5855 | * |
5856 | * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN) |
5857 | * deltas control async page reclaim, and so should |
5858 | * not be capped for highmem and movable zones. |
5859 | */ |
5860 | unsigned long min_pages; |
5861 | |
5862 | min_pages = zone_managed_pages(zone) / 1024; |
5863 | min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL); |
5864 | zone->_watermark[WMARK_MIN] = min_pages; |
5865 | } else { |
5866 | /* |
5867 | * If it's a lowmem zone, reserve a number of pages |
5868 | * proportionate to the zone's size. |
5869 | */ |
5870 | zone->_watermark[WMARK_MIN] = tmp; |
5871 | } |
5872 | |
5873 | /* |
5874 | * Set the kswapd watermarks distance according to the |
5875 | * scale factor in proportion to available memory, but |
5876 | * ensure a minimum size on small systems. |
5877 | */ |
5878 | tmp = max_t(u64, tmp >> 2, |
5879 | mult_frac(zone_managed_pages(zone), |
5880 | watermark_scale_factor, 10000)); |
5881 | |
5882 | zone->watermark_boost = 0; |
5883 | zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; |
5884 | zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp; |
5885 | zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp; |
5886 | |
5887 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
5888 | } |
5889 | |
5890 | /* update totalreserve_pages */ |
5891 | calculate_totalreserve_pages(); |
5892 | } |
5893 | |
5894 | /** |
5895 | * setup_per_zone_wmarks - called when min_free_kbytes changes |
5896 | * or when memory is hot-{added|removed} |
5897 | * |
5898 | * Ensures that the watermark[min,low,high] values for each zone are set |
5899 | * correctly with respect to min_free_kbytes. |
5900 | */ |
5901 | void setup_per_zone_wmarks(void) |
5902 | { |
5903 | struct zone *zone; |
5904 | static DEFINE_SPINLOCK(lock); |
5905 | |
5906 | spin_lock(lock: &lock); |
5907 | __setup_per_zone_wmarks(); |
5908 | spin_unlock(lock: &lock); |
5909 | |
5910 | /* |
5911 | * The watermark size have changed so update the pcpu batch |
5912 | * and high limits or the limits may be inappropriate. |
5913 | */ |
5914 | for_each_zone(zone) |
5915 | zone_pcp_update(zone, cpu_online: 0); |
5916 | } |
5917 | |
5918 | /* |
5919 | * Initialise min_free_kbytes. |
5920 | * |
5921 | * For small machines we want it small (128k min). For large machines |
5922 | * we want it large (256MB max). But it is not linear, because network |
5923 | * bandwidth does not increase linearly with machine size. We use |
5924 | * |
5925 | * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy: |
5926 | * min_free_kbytes = sqrt(lowmem_kbytes * 16) |
5927 | * |
5928 | * which yields |
5929 | * |
5930 | * 16MB: 512k |
5931 | * 32MB: 724k |
5932 | * 64MB: 1024k |
5933 | * 128MB: 1448k |
5934 | * 256MB: 2048k |
5935 | * 512MB: 2896k |
5936 | * 1024MB: 4096k |
5937 | * 2048MB: 5792k |
5938 | * 4096MB: 8192k |
5939 | * 8192MB: 11584k |
5940 | * 16384MB: 16384k |
5941 | */ |
5942 | void calculate_min_free_kbytes(void) |
5943 | { |
5944 | unsigned long lowmem_kbytes; |
5945 | int new_min_free_kbytes; |
5946 | |
5947 | lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10); |
5948 | new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16); |
5949 | |
5950 | if (new_min_free_kbytes > user_min_free_kbytes) |
5951 | min_free_kbytes = clamp(new_min_free_kbytes, 128, 262144); |
5952 | else |
5953 | pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n" , |
5954 | new_min_free_kbytes, user_min_free_kbytes); |
5955 | |
5956 | } |
5957 | |
5958 | int __meminit init_per_zone_wmark_min(void) |
5959 | { |
5960 | calculate_min_free_kbytes(); |
5961 | setup_per_zone_wmarks(); |
5962 | refresh_zone_stat_thresholds(); |
5963 | setup_per_zone_lowmem_reserve(); |
5964 | |
5965 | #ifdef CONFIG_NUMA |
5966 | setup_min_unmapped_ratio(); |
5967 | setup_min_slab_ratio(); |
5968 | #endif |
5969 | |
5970 | khugepaged_min_free_kbytes_update(); |
5971 | |
5972 | return 0; |
5973 | } |
5974 | postcore_initcall(init_per_zone_wmark_min) |
5975 | |
5976 | /* |
5977 | * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so |
5978 | * that we can call two helper functions whenever min_free_kbytes |
5979 | * changes. |
5980 | */ |
5981 | static int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write, |
5982 | void *buffer, size_t *length, loff_t *ppos) |
5983 | { |
5984 | int rc; |
5985 | |
5986 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); |
5987 | if (rc) |
5988 | return rc; |
5989 | |
5990 | if (write) { |
5991 | user_min_free_kbytes = min_free_kbytes; |
5992 | setup_per_zone_wmarks(); |
5993 | } |
5994 | return 0; |
5995 | } |
5996 | |
5997 | static int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write, |
5998 | void *buffer, size_t *length, loff_t *ppos) |
5999 | { |
6000 | int rc; |
6001 | |
6002 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); |
6003 | if (rc) |
6004 | return rc; |
6005 | |
6006 | if (write) |
6007 | setup_per_zone_wmarks(); |
6008 | |
6009 | return 0; |
6010 | } |
6011 | |
6012 | #ifdef CONFIG_NUMA |
6013 | static void setup_min_unmapped_ratio(void) |
6014 | { |
6015 | pg_data_t *pgdat; |
6016 | struct zone *zone; |
6017 | |
6018 | for_each_online_pgdat(pgdat) |
6019 | pgdat->min_unmapped_pages = 0; |
6020 | |
6021 | for_each_zone(zone) |
6022 | zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) * |
6023 | sysctl_min_unmapped_ratio) / 100; |
6024 | } |
6025 | |
6026 | |
6027 | static int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write, |
6028 | void *buffer, size_t *length, loff_t *ppos) |
6029 | { |
6030 | int rc; |
6031 | |
6032 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); |
6033 | if (rc) |
6034 | return rc; |
6035 | |
6036 | setup_min_unmapped_ratio(); |
6037 | |
6038 | return 0; |
6039 | } |
6040 | |
6041 | static void setup_min_slab_ratio(void) |
6042 | { |
6043 | pg_data_t *pgdat; |
6044 | struct zone *zone; |
6045 | |
6046 | for_each_online_pgdat(pgdat) |
6047 | pgdat->min_slab_pages = 0; |
6048 | |
6049 | for_each_zone(zone) |
6050 | zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) * |
6051 | sysctl_min_slab_ratio) / 100; |
6052 | } |
6053 | |
6054 | static int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write, |
6055 | void *buffer, size_t *length, loff_t *ppos) |
6056 | { |
6057 | int rc; |
6058 | |
6059 | rc = proc_dointvec_minmax(table, write, buffer, length, ppos); |
6060 | if (rc) |
6061 | return rc; |
6062 | |
6063 | setup_min_slab_ratio(); |
6064 | |
6065 | return 0; |
6066 | } |
6067 | #endif |
6068 | |
6069 | /* |
6070 | * lowmem_reserve_ratio_sysctl_handler - just a wrapper around |
6071 | * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve() |
6072 | * whenever sysctl_lowmem_reserve_ratio changes. |
6073 | * |
6074 | * The reserve ratio obviously has absolutely no relation with the |
6075 | * minimum watermarks. The lowmem reserve ratio can only make sense |
6076 | * if in function of the boot time zone sizes. |
6077 | */ |
6078 | static int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, |
6079 | int write, void *buffer, size_t *length, loff_t *ppos) |
6080 | { |
6081 | int i; |
6082 | |
6083 | proc_dointvec_minmax(table, write, buffer, length, ppos); |
6084 | |
6085 | for (i = 0; i < MAX_NR_ZONES; i++) { |
6086 | if (sysctl_lowmem_reserve_ratio[i] < 1) |
6087 | sysctl_lowmem_reserve_ratio[i] = 0; |
6088 | } |
6089 | |
6090 | setup_per_zone_lowmem_reserve(); |
6091 | return 0; |
6092 | } |
6093 | |
6094 | /* |
6095 | * percpu_pagelist_high_fraction - changes the pcp->high for each zone on each |
6096 | * cpu. It is the fraction of total pages in each zone that a hot per cpu |
6097 | * pagelist can have before it gets flushed back to buddy allocator. |
6098 | */ |
6099 | static int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *table, |
6100 | int write, void *buffer, size_t *length, loff_t *ppos) |
6101 | { |
6102 | struct zone *zone; |
6103 | int old_percpu_pagelist_high_fraction; |
6104 | int ret; |
6105 | |
6106 | mutex_lock(&pcp_batch_high_lock); |
6107 | old_percpu_pagelist_high_fraction = percpu_pagelist_high_fraction; |
6108 | |
6109 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
6110 | if (!write || ret < 0) |
6111 | goto out; |
6112 | |
6113 | /* Sanity checking to avoid pcp imbalance */ |
6114 | if (percpu_pagelist_high_fraction && |
6115 | percpu_pagelist_high_fraction < MIN_PERCPU_PAGELIST_HIGH_FRACTION) { |
6116 | percpu_pagelist_high_fraction = old_percpu_pagelist_high_fraction; |
6117 | ret = -EINVAL; |
6118 | goto out; |
6119 | } |
6120 | |
6121 | /* No change? */ |
6122 | if (percpu_pagelist_high_fraction == old_percpu_pagelist_high_fraction) |
6123 | goto out; |
6124 | |
6125 | for_each_populated_zone(zone) |
6126 | zone_set_pageset_high_and_batch(zone, cpu_online: 0); |
6127 | out: |
6128 | mutex_unlock(lock: &pcp_batch_high_lock); |
6129 | return ret; |
6130 | } |
6131 | |
6132 | static struct ctl_table page_alloc_sysctl_table[] = { |
6133 | { |
6134 | .procname = "min_free_kbytes" , |
6135 | .data = &min_free_kbytes, |
6136 | .maxlen = sizeof(min_free_kbytes), |
6137 | .mode = 0644, |
6138 | .proc_handler = min_free_kbytes_sysctl_handler, |
6139 | .extra1 = SYSCTL_ZERO, |
6140 | }, |
6141 | { |
6142 | .procname = "watermark_boost_factor" , |
6143 | .data = &watermark_boost_factor, |
6144 | .maxlen = sizeof(watermark_boost_factor), |
6145 | .mode = 0644, |
6146 | .proc_handler = proc_dointvec_minmax, |
6147 | .extra1 = SYSCTL_ZERO, |
6148 | }, |
6149 | { |
6150 | .procname = "watermark_scale_factor" , |
6151 | .data = &watermark_scale_factor, |
6152 | .maxlen = sizeof(watermark_scale_factor), |
6153 | .mode = 0644, |
6154 | .proc_handler = watermark_scale_factor_sysctl_handler, |
6155 | .extra1 = SYSCTL_ONE, |
6156 | .extra2 = SYSCTL_THREE_THOUSAND, |
6157 | }, |
6158 | { |
6159 | .procname = "percpu_pagelist_high_fraction" , |
6160 | .data = &percpu_pagelist_high_fraction, |
6161 | .maxlen = sizeof(percpu_pagelist_high_fraction), |
6162 | .mode = 0644, |
6163 | .proc_handler = percpu_pagelist_high_fraction_sysctl_handler, |
6164 | .extra1 = SYSCTL_ZERO, |
6165 | }, |
6166 | { |
6167 | .procname = "lowmem_reserve_ratio" , |
6168 | .data = &sysctl_lowmem_reserve_ratio, |
6169 | .maxlen = sizeof(sysctl_lowmem_reserve_ratio), |
6170 | .mode = 0644, |
6171 | .proc_handler = lowmem_reserve_ratio_sysctl_handler, |
6172 | }, |
6173 | #ifdef CONFIG_NUMA |
6174 | { |
6175 | .procname = "numa_zonelist_order" , |
6176 | .data = &numa_zonelist_order, |
6177 | .maxlen = NUMA_ZONELIST_ORDER_LEN, |
6178 | .mode = 0644, |
6179 | .proc_handler = numa_zonelist_order_handler, |
6180 | }, |
6181 | { |
6182 | .procname = "min_unmapped_ratio" , |
6183 | .data = &sysctl_min_unmapped_ratio, |
6184 | .maxlen = sizeof(sysctl_min_unmapped_ratio), |
6185 | .mode = 0644, |
6186 | .proc_handler = sysctl_min_unmapped_ratio_sysctl_handler, |
6187 | .extra1 = SYSCTL_ZERO, |
6188 | .extra2 = SYSCTL_ONE_HUNDRED, |
6189 | }, |
6190 | { |
6191 | .procname = "min_slab_ratio" , |
6192 | .data = &sysctl_min_slab_ratio, |
6193 | .maxlen = sizeof(sysctl_min_slab_ratio), |
6194 | .mode = 0644, |
6195 | .proc_handler = sysctl_min_slab_ratio_sysctl_handler, |
6196 | .extra1 = SYSCTL_ZERO, |
6197 | .extra2 = SYSCTL_ONE_HUNDRED, |
6198 | }, |
6199 | #endif |
6200 | {} |
6201 | }; |
6202 | |
6203 | void __init page_alloc_sysctl_init(void) |
6204 | { |
6205 | register_sysctl_init("vm" , page_alloc_sysctl_table); |
6206 | } |
6207 | |
6208 | #ifdef CONFIG_CONTIG_ALLOC |
6209 | /* Usage: See admin-guide/dynamic-debug-howto.rst */ |
6210 | static void alloc_contig_dump_pages(struct list_head *page_list) |
6211 | { |
6212 | DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure" ); |
6213 | |
6214 | if (DYNAMIC_DEBUG_BRANCH(descriptor)) { |
6215 | struct page *page; |
6216 | |
6217 | dump_stack(); |
6218 | list_for_each_entry(page, page_list, lru) |
6219 | dump_page(page, reason: "migration failure" ); |
6220 | } |
6221 | } |
6222 | |
6223 | /* [start, end) must belong to a single zone. */ |
6224 | int __alloc_contig_migrate_range(struct compact_control *cc, |
6225 | unsigned long start, unsigned long end) |
6226 | { |
6227 | /* This function is based on compact_zone() from compaction.c. */ |
6228 | unsigned int nr_reclaimed; |
6229 | unsigned long pfn = start; |
6230 | unsigned int tries = 0; |
6231 | int ret = 0; |
6232 | struct migration_target_control mtc = { |
6233 | .nid = zone_to_nid(zone: cc->zone), |
6234 | .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, |
6235 | }; |
6236 | |
6237 | lru_cache_disable(); |
6238 | |
6239 | while (pfn < end || !list_empty(head: &cc->migratepages)) { |
6240 | if (fatal_signal_pending(current)) { |
6241 | ret = -EINTR; |
6242 | break; |
6243 | } |
6244 | |
6245 | if (list_empty(head: &cc->migratepages)) { |
6246 | cc->nr_migratepages = 0; |
6247 | ret = isolate_migratepages_range(cc, low_pfn: pfn, end_pfn: end); |
6248 | if (ret && ret != -EAGAIN) |
6249 | break; |
6250 | pfn = cc->migrate_pfn; |
6251 | tries = 0; |
6252 | } else if (++tries == 5) { |
6253 | ret = -EBUSY; |
6254 | break; |
6255 | } |
6256 | |
6257 | nr_reclaimed = reclaim_clean_pages_from_list(zone: cc->zone, |
6258 | folio_list: &cc->migratepages); |
6259 | cc->nr_migratepages -= nr_reclaimed; |
6260 | |
6261 | ret = migrate_pages(l: &cc->migratepages, new: alloc_migration_target, |
6262 | NULL, private: (unsigned long)&mtc, mode: cc->mode, reason: MR_CONTIG_RANGE, NULL); |
6263 | |
6264 | /* |
6265 | * On -ENOMEM, migrate_pages() bails out right away. It is pointless |
6266 | * to retry again over this error, so do the same here. |
6267 | */ |
6268 | if (ret == -ENOMEM) |
6269 | break; |
6270 | } |
6271 | |
6272 | lru_cache_enable(); |
6273 | if (ret < 0) { |
6274 | if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY) |
6275 | alloc_contig_dump_pages(page_list: &cc->migratepages); |
6276 | putback_movable_pages(l: &cc->migratepages); |
6277 | return ret; |
6278 | } |
6279 | return 0; |
6280 | } |
6281 | |
6282 | /** |
6283 | * alloc_contig_range() -- tries to allocate given range of pages |
6284 | * @start: start PFN to allocate |
6285 | * @end: one-past-the-last PFN to allocate |
6286 | * @migratetype: migratetype of the underlying pageblocks (either |
6287 | * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks |
6288 | * in range must have the same migratetype and it must |
6289 | * be either of the two. |
6290 | * @gfp_mask: GFP mask to use during compaction |
6291 | * |
6292 | * The PFN range does not have to be pageblock aligned. The PFN range must |
6293 | * belong to a single zone. |
6294 | * |
6295 | * The first thing this routine does is attempt to MIGRATE_ISOLATE all |
6296 | * pageblocks in the range. Once isolated, the pageblocks should not |
6297 | * be modified by others. |
6298 | * |
6299 | * Return: zero on success or negative error code. On success all |
6300 | * pages which PFN is in [start, end) are allocated for the caller and |
6301 | * need to be freed with free_contig_range(). |
6302 | */ |
6303 | int alloc_contig_range(unsigned long start, unsigned long end, |
6304 | unsigned migratetype, gfp_t gfp_mask) |
6305 | { |
6306 | unsigned long outer_start, outer_end; |
6307 | int order; |
6308 | int ret = 0; |
6309 | |
6310 | struct compact_control cc = { |
6311 | .nr_migratepages = 0, |
6312 | .order = -1, |
6313 | .zone = page_zone(pfn_to_page(start)), |
6314 | .mode = MIGRATE_SYNC, |
6315 | .ignore_skip_hint = true, |
6316 | .no_set_skip_hint = true, |
6317 | .gfp_mask = current_gfp_context(flags: gfp_mask), |
6318 | .alloc_contig = true, |
6319 | }; |
6320 | INIT_LIST_HEAD(list: &cc.migratepages); |
6321 | |
6322 | /* |
6323 | * What we do here is we mark all pageblocks in range as |
6324 | * MIGRATE_ISOLATE. Because pageblock and max order pages may |
6325 | * have different sizes, and due to the way page allocator |
6326 | * work, start_isolate_page_range() has special handlings for this. |
6327 | * |
6328 | * Once the pageblocks are marked as MIGRATE_ISOLATE, we |
6329 | * migrate the pages from an unaligned range (ie. pages that |
6330 | * we are interested in). This will put all the pages in |
6331 | * range back to page allocator as MIGRATE_ISOLATE. |
6332 | * |
6333 | * When this is done, we take the pages in range from page |
6334 | * allocator removing them from the buddy system. This way |
6335 | * page allocator will never consider using them. |
6336 | * |
6337 | * This lets us mark the pageblocks back as |
6338 | * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the |
6339 | * aligned range but not in the unaligned, original range are |
6340 | * put back to page allocator so that buddy can use them. |
6341 | */ |
6342 | |
6343 | ret = start_isolate_page_range(start_pfn: start, end_pfn: end, migratetype, flags: 0, gfp_flags: gfp_mask); |
6344 | if (ret) |
6345 | goto done; |
6346 | |
6347 | drain_all_pages(zone: cc.zone); |
6348 | |
6349 | /* |
6350 | * In case of -EBUSY, we'd like to know which page causes problem. |
6351 | * So, just fall through. test_pages_isolated() has a tracepoint |
6352 | * which will report the busy page. |
6353 | * |
6354 | * It is possible that busy pages could become available before |
6355 | * the call to test_pages_isolated, and the range will actually be |
6356 | * allocated. So, if we fall through be sure to clear ret so that |
6357 | * -EBUSY is not accidentally used or returned to caller. |
6358 | */ |
6359 | ret = __alloc_contig_migrate_range(cc: &cc, start, end); |
6360 | if (ret && ret != -EBUSY) |
6361 | goto done; |
6362 | ret = 0; |
6363 | |
6364 | /* |
6365 | * Pages from [start, end) are within a pageblock_nr_pages |
6366 | * aligned blocks that are marked as MIGRATE_ISOLATE. What's |
6367 | * more, all pages in [start, end) are free in page allocator. |
6368 | * What we are going to do is to allocate all pages from |
6369 | * [start, end) (that is remove them from page allocator). |
6370 | * |
6371 | * The only problem is that pages at the beginning and at the |
6372 | * end of interesting range may be not aligned with pages that |
6373 | * page allocator holds, ie. they can be part of higher order |
6374 | * pages. Because of this, we reserve the bigger range and |
6375 | * once this is done free the pages we are not interested in. |
6376 | * |
6377 | * We don't have to hold zone->lock here because the pages are |
6378 | * isolated thus they won't get removed from buddy. |
6379 | */ |
6380 | |
6381 | order = 0; |
6382 | outer_start = start; |
6383 | while (!PageBuddy(pfn_to_page(outer_start))) { |
6384 | if (++order > MAX_ORDER) { |
6385 | outer_start = start; |
6386 | break; |
6387 | } |
6388 | outer_start &= ~0UL << order; |
6389 | } |
6390 | |
6391 | if (outer_start != start) { |
6392 | order = buddy_order(pfn_to_page(outer_start)); |
6393 | |
6394 | /* |
6395 | * outer_start page could be small order buddy page and |
6396 | * it doesn't include start page. Adjust outer_start |
6397 | * in this case to report failed page properly |
6398 | * on tracepoint in test_pages_isolated() |
6399 | */ |
6400 | if (outer_start + (1UL << order) <= start) |
6401 | outer_start = start; |
6402 | } |
6403 | |
6404 | /* Make sure the range is really isolated. */ |
6405 | if (test_pages_isolated(start_pfn: outer_start, end_pfn: end, isol_flags: 0)) { |
6406 | ret = -EBUSY; |
6407 | goto done; |
6408 | } |
6409 | |
6410 | /* Grab isolated pages from freelists. */ |
6411 | outer_end = isolate_freepages_range(cc: &cc, start_pfn: outer_start, end_pfn: end); |
6412 | if (!outer_end) { |
6413 | ret = -EBUSY; |
6414 | goto done; |
6415 | } |
6416 | |
6417 | /* Free head and tail (if any) */ |
6418 | if (start != outer_start) |
6419 | free_contig_range(pfn: outer_start, nr_pages: start - outer_start); |
6420 | if (end != outer_end) |
6421 | free_contig_range(pfn: end, nr_pages: outer_end - end); |
6422 | |
6423 | done: |
6424 | undo_isolate_page_range(start_pfn: start, end_pfn: end, migratetype); |
6425 | return ret; |
6426 | } |
6427 | EXPORT_SYMBOL(alloc_contig_range); |
6428 | |
6429 | static int __alloc_contig_pages(unsigned long start_pfn, |
6430 | unsigned long nr_pages, gfp_t gfp_mask) |
6431 | { |
6432 | unsigned long end_pfn = start_pfn + nr_pages; |
6433 | |
6434 | return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, |
6435 | gfp_mask); |
6436 | } |
6437 | |
6438 | static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn, |
6439 | unsigned long nr_pages) |
6440 | { |
6441 | unsigned long i, end_pfn = start_pfn + nr_pages; |
6442 | struct page *page; |
6443 | |
6444 | for (i = start_pfn; i < end_pfn; i++) { |
6445 | page = pfn_to_online_page(pfn: i); |
6446 | if (!page) |
6447 | return false; |
6448 | |
6449 | if (page_zone(page) != z) |
6450 | return false; |
6451 | |
6452 | if (PageReserved(page)) |
6453 | return false; |
6454 | |
6455 | if (PageHuge(page)) |
6456 | return false; |
6457 | } |
6458 | return true; |
6459 | } |
6460 | |
6461 | static bool zone_spans_last_pfn(const struct zone *zone, |
6462 | unsigned long start_pfn, unsigned long nr_pages) |
6463 | { |
6464 | unsigned long last_pfn = start_pfn + nr_pages - 1; |
6465 | |
6466 | return zone_spans_pfn(zone, pfn: last_pfn); |
6467 | } |
6468 | |
6469 | /** |
6470 | * alloc_contig_pages() -- tries to find and allocate contiguous range of pages |
6471 | * @nr_pages: Number of contiguous pages to allocate |
6472 | * @gfp_mask: GFP mask to limit search and used during compaction |
6473 | * @nid: Target node |
6474 | * @nodemask: Mask for other possible nodes |
6475 | * |
6476 | * This routine is a wrapper around alloc_contig_range(). It scans over zones |
6477 | * on an applicable zonelist to find a contiguous pfn range which can then be |
6478 | * tried for allocation with alloc_contig_range(). This routine is intended |
6479 | * for allocation requests which can not be fulfilled with the buddy allocator. |
6480 | * |
6481 | * The allocated memory is always aligned to a page boundary. If nr_pages is a |
6482 | * power of two, then allocated range is also guaranteed to be aligned to same |
6483 | * nr_pages (e.g. 1GB request would be aligned to 1GB). |
6484 | * |
6485 | * Allocated pages can be freed with free_contig_range() or by manually calling |
6486 | * __free_page() on each allocated page. |
6487 | * |
6488 | * Return: pointer to contiguous pages on success, or NULL if not successful. |
6489 | */ |
6490 | struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask, |
6491 | int nid, nodemask_t *nodemask) |
6492 | { |
6493 | unsigned long ret, pfn, flags; |
6494 | struct zonelist *zonelist; |
6495 | struct zone *zone; |
6496 | struct zoneref *z; |
6497 | |
6498 | zonelist = node_zonelist(nid, flags: gfp_mask); |
6499 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
6500 | gfp_zone(gfp_mask), nodemask) { |
6501 | spin_lock_irqsave(&zone->lock, flags); |
6502 | |
6503 | pfn = ALIGN(zone->zone_start_pfn, nr_pages); |
6504 | while (zone_spans_last_pfn(zone, start_pfn: pfn, nr_pages)) { |
6505 | if (pfn_range_valid_contig(z: zone, start_pfn: pfn, nr_pages)) { |
6506 | /* |
6507 | * We release the zone lock here because |
6508 | * alloc_contig_range() will also lock the zone |
6509 | * at some point. If there's an allocation |
6510 | * spinning on this lock, it may win the race |
6511 | * and cause alloc_contig_range() to fail... |
6512 | */ |
6513 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6514 | ret = __alloc_contig_pages(start_pfn: pfn, nr_pages, |
6515 | gfp_mask); |
6516 | if (!ret) |
6517 | return pfn_to_page(pfn); |
6518 | spin_lock_irqsave(&zone->lock, flags); |
6519 | } |
6520 | pfn += nr_pages; |
6521 | } |
6522 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6523 | } |
6524 | return NULL; |
6525 | } |
6526 | #endif /* CONFIG_CONTIG_ALLOC */ |
6527 | |
6528 | void free_contig_range(unsigned long pfn, unsigned long nr_pages) |
6529 | { |
6530 | unsigned long count = 0; |
6531 | |
6532 | for (; nr_pages--; pfn++) { |
6533 | struct page *page = pfn_to_page(pfn); |
6534 | |
6535 | count += page_count(page) != 1; |
6536 | __free_page(page); |
6537 | } |
6538 | WARN(count != 0, "%lu pages are still in use!\n" , count); |
6539 | } |
6540 | EXPORT_SYMBOL(free_contig_range); |
6541 | |
6542 | /* |
6543 | * Effectively disable pcplists for the zone by setting the high limit to 0 |
6544 | * and draining all cpus. A concurrent page freeing on another CPU that's about |
6545 | * to put the page on pcplist will either finish before the drain and the page |
6546 | * will be drained, or observe the new high limit and skip the pcplist. |
6547 | * |
6548 | * Must be paired with a call to zone_pcp_enable(). |
6549 | */ |
6550 | void zone_pcp_disable(struct zone *zone) |
6551 | { |
6552 | mutex_lock(&pcp_batch_high_lock); |
6553 | __zone_set_pageset_high_and_batch(zone, high_min: 0, high_max: 0, batch: 1); |
6554 | __drain_all_pages(zone, force_all_cpus: true); |
6555 | } |
6556 | |
6557 | void zone_pcp_enable(struct zone *zone) |
6558 | { |
6559 | __zone_set_pageset_high_and_batch(zone, high_min: zone->pageset_high_min, |
6560 | high_max: zone->pageset_high_max, batch: zone->pageset_batch); |
6561 | mutex_unlock(lock: &pcp_batch_high_lock); |
6562 | } |
6563 | |
6564 | void zone_pcp_reset(struct zone *zone) |
6565 | { |
6566 | int cpu; |
6567 | struct per_cpu_zonestat *pzstats; |
6568 | |
6569 | if (zone->per_cpu_pageset != &boot_pageset) { |
6570 | for_each_online_cpu(cpu) { |
6571 | pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); |
6572 | drain_zonestat(zone, pzstats); |
6573 | } |
6574 | free_percpu(pdata: zone->per_cpu_pageset); |
6575 | zone->per_cpu_pageset = &boot_pageset; |
6576 | if (zone->per_cpu_zonestats != &boot_zonestats) { |
6577 | free_percpu(pdata: zone->per_cpu_zonestats); |
6578 | zone->per_cpu_zonestats = &boot_zonestats; |
6579 | } |
6580 | } |
6581 | } |
6582 | |
6583 | #ifdef CONFIG_MEMORY_HOTREMOVE |
6584 | /* |
6585 | * All pages in the range must be in a single zone, must not contain holes, |
6586 | * must span full sections, and must be isolated before calling this function. |
6587 | */ |
6588 | void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) |
6589 | { |
6590 | unsigned long pfn = start_pfn; |
6591 | struct page *page; |
6592 | struct zone *zone; |
6593 | unsigned int order; |
6594 | unsigned long flags; |
6595 | |
6596 | offline_mem_sections(start_pfn: pfn, end_pfn); |
6597 | zone = page_zone(pfn_to_page(pfn)); |
6598 | spin_lock_irqsave(&zone->lock, flags); |
6599 | while (pfn < end_pfn) { |
6600 | page = pfn_to_page(pfn); |
6601 | /* |
6602 | * The HWPoisoned page may be not in buddy system, and |
6603 | * page_count() is not 0. |
6604 | */ |
6605 | if (unlikely(!PageBuddy(page) && PageHWPoison(page))) { |
6606 | pfn++; |
6607 | continue; |
6608 | } |
6609 | /* |
6610 | * At this point all remaining PageOffline() pages have a |
6611 | * reference count of 0 and can simply be skipped. |
6612 | */ |
6613 | if (PageOffline(page)) { |
6614 | BUG_ON(page_count(page)); |
6615 | BUG_ON(PageBuddy(page)); |
6616 | pfn++; |
6617 | continue; |
6618 | } |
6619 | |
6620 | BUG_ON(page_count(page)); |
6621 | BUG_ON(!PageBuddy(page)); |
6622 | order = buddy_order(page); |
6623 | del_page_from_free_list(page, zone, order); |
6624 | pfn += (1 << order); |
6625 | } |
6626 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6627 | } |
6628 | #endif |
6629 | |
6630 | /* |
6631 | * This function returns a stable result only if called under zone lock. |
6632 | */ |
6633 | bool is_free_buddy_page(struct page *page) |
6634 | { |
6635 | unsigned long pfn = page_to_pfn(page); |
6636 | unsigned int order; |
6637 | |
6638 | for (order = 0; order <= MAX_ORDER; order++) { |
6639 | struct page *page_head = page - (pfn & ((1 << order) - 1)); |
6640 | |
6641 | if (PageBuddy(page: page_head) && |
6642 | buddy_order_unsafe(page_head) >= order) |
6643 | break; |
6644 | } |
6645 | |
6646 | return order <= MAX_ORDER; |
6647 | } |
6648 | EXPORT_SYMBOL(is_free_buddy_page); |
6649 | |
6650 | #ifdef CONFIG_MEMORY_FAILURE |
6651 | /* |
6652 | * Break down a higher-order page in sub-pages, and keep our target out of |
6653 | * buddy allocator. |
6654 | */ |
6655 | static void break_down_buddy_pages(struct zone *zone, struct page *page, |
6656 | struct page *target, int low, int high, |
6657 | int migratetype) |
6658 | { |
6659 | unsigned long size = 1 << high; |
6660 | struct page *current_buddy; |
6661 | |
6662 | while (high > low) { |
6663 | high--; |
6664 | size >>= 1; |
6665 | |
6666 | if (target >= &page[size]) { |
6667 | current_buddy = page; |
6668 | page = page + size; |
6669 | } else { |
6670 | current_buddy = page + size; |
6671 | } |
6672 | |
6673 | if (set_page_guard(zone, page: current_buddy, order: high, migratetype)) |
6674 | continue; |
6675 | |
6676 | add_to_free_list(page: current_buddy, zone, order: high, migratetype); |
6677 | set_buddy_order(page: current_buddy, order: high); |
6678 | } |
6679 | } |
6680 | |
6681 | /* |
6682 | * Take a page that will be marked as poisoned off the buddy allocator. |
6683 | */ |
6684 | bool take_page_off_buddy(struct page *page) |
6685 | { |
6686 | struct zone *zone = page_zone(page); |
6687 | unsigned long pfn = page_to_pfn(page); |
6688 | unsigned long flags; |
6689 | unsigned int order; |
6690 | bool ret = false; |
6691 | |
6692 | spin_lock_irqsave(&zone->lock, flags); |
6693 | for (order = 0; order <= MAX_ORDER; order++) { |
6694 | struct page *page_head = page - (pfn & ((1 << order) - 1)); |
6695 | int page_order = buddy_order(page: page_head); |
6696 | |
6697 | if (PageBuddy(page: page_head) && page_order >= order) { |
6698 | unsigned long pfn_head = page_to_pfn(page_head); |
6699 | int migratetype = get_pfnblock_migratetype(page: page_head, |
6700 | pfn: pfn_head); |
6701 | |
6702 | del_page_from_free_list(page: page_head, zone, order: page_order); |
6703 | break_down_buddy_pages(zone, page: page_head, target: page, low: 0, |
6704 | high: page_order, migratetype); |
6705 | SetPageHWPoisonTakenOff(page); |
6706 | if (!is_migrate_isolate(migratetype)) |
6707 | __mod_zone_freepage_state(zone, nr_pages: -1, migratetype); |
6708 | ret = true; |
6709 | break; |
6710 | } |
6711 | if (page_count(page: page_head) > 0) |
6712 | break; |
6713 | } |
6714 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6715 | return ret; |
6716 | } |
6717 | |
6718 | /* |
6719 | * Cancel takeoff done by take_page_off_buddy(). |
6720 | */ |
6721 | bool put_page_back_buddy(struct page *page) |
6722 | { |
6723 | struct zone *zone = page_zone(page); |
6724 | unsigned long pfn = page_to_pfn(page); |
6725 | unsigned long flags; |
6726 | int migratetype = get_pfnblock_migratetype(page, pfn); |
6727 | bool ret = false; |
6728 | |
6729 | spin_lock_irqsave(&zone->lock, flags); |
6730 | if (put_page_testzero(page)) { |
6731 | ClearPageHWPoisonTakenOff(page); |
6732 | __free_one_page(page, pfn, zone, order: 0, migratetype, FPI_NONE); |
6733 | if (TestClearPageHWPoison(page)) { |
6734 | ret = true; |
6735 | } |
6736 | } |
6737 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6738 | |
6739 | return ret; |
6740 | } |
6741 | #endif |
6742 | |
6743 | #ifdef CONFIG_ZONE_DMA |
6744 | bool has_managed_dma(void) |
6745 | { |
6746 | struct pglist_data *pgdat; |
6747 | |
6748 | for_each_online_pgdat(pgdat) { |
6749 | struct zone *zone = &pgdat->node_zones[ZONE_DMA]; |
6750 | |
6751 | if (managed_zone(zone)) |
6752 | return true; |
6753 | } |
6754 | return false; |
6755 | } |
6756 | #endif /* CONFIG_ZONE_DMA */ |
6757 | |
6758 | #ifdef CONFIG_UNACCEPTED_MEMORY |
6759 | |
6760 | /* Counts number of zones with unaccepted pages. */ |
6761 | static DEFINE_STATIC_KEY_FALSE(zones_with_unaccepted_pages); |
6762 | |
6763 | static bool lazy_accept = true; |
6764 | |
6765 | static int __init accept_memory_parse(char *p) |
6766 | { |
6767 | if (!strcmp(p, "lazy" )) { |
6768 | lazy_accept = true; |
6769 | return 0; |
6770 | } else if (!strcmp(p, "eager" )) { |
6771 | lazy_accept = false; |
6772 | return 0; |
6773 | } else { |
6774 | return -EINVAL; |
6775 | } |
6776 | } |
6777 | early_param("accept_memory" , accept_memory_parse); |
6778 | |
6779 | static bool page_contains_unaccepted(struct page *page, unsigned int order) |
6780 | { |
6781 | phys_addr_t start = page_to_phys(page); |
6782 | phys_addr_t end = start + (PAGE_SIZE << order); |
6783 | |
6784 | return range_contains_unaccepted_memory(start, end); |
6785 | } |
6786 | |
6787 | static void accept_page(struct page *page, unsigned int order) |
6788 | { |
6789 | phys_addr_t start = page_to_phys(page); |
6790 | |
6791 | accept_memory(start, end: start + (PAGE_SIZE << order)); |
6792 | } |
6793 | |
6794 | static bool try_to_accept_memory_one(struct zone *zone) |
6795 | { |
6796 | unsigned long flags; |
6797 | struct page *page; |
6798 | bool last; |
6799 | |
6800 | if (list_empty(head: &zone->unaccepted_pages)) |
6801 | return false; |
6802 | |
6803 | spin_lock_irqsave(&zone->lock, flags); |
6804 | page = list_first_entry_or_null(&zone->unaccepted_pages, |
6805 | struct page, lru); |
6806 | if (!page) { |
6807 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6808 | return false; |
6809 | } |
6810 | |
6811 | list_del(entry: &page->lru); |
6812 | last = list_empty(head: &zone->unaccepted_pages); |
6813 | |
6814 | __mod_zone_freepage_state(zone, nr_pages: -MAX_ORDER_NR_PAGES, migratetype: MIGRATE_MOVABLE); |
6815 | __mod_zone_page_state(zone, item: NR_UNACCEPTED, -MAX_ORDER_NR_PAGES); |
6816 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6817 | |
6818 | accept_page(page, MAX_ORDER); |
6819 | |
6820 | __free_pages_ok(page, MAX_ORDER, FPI_TO_TAIL); |
6821 | |
6822 | if (last) |
6823 | static_branch_dec(&zones_with_unaccepted_pages); |
6824 | |
6825 | return true; |
6826 | } |
6827 | |
6828 | static bool try_to_accept_memory(struct zone *zone, unsigned int order) |
6829 | { |
6830 | long to_accept; |
6831 | int ret = false; |
6832 | |
6833 | /* How much to accept to get to high watermark? */ |
6834 | to_accept = high_wmark_pages(zone) - |
6835 | (zone_page_state(zone, item: NR_FREE_PAGES) - |
6836 | __zone_watermark_unusable_free(z: zone, order, alloc_flags: 0)); |
6837 | |
6838 | /* Accept at least one page */ |
6839 | do { |
6840 | if (!try_to_accept_memory_one(zone)) |
6841 | break; |
6842 | ret = true; |
6843 | to_accept -= MAX_ORDER_NR_PAGES; |
6844 | } while (to_accept > 0); |
6845 | |
6846 | return ret; |
6847 | } |
6848 | |
6849 | static inline bool has_unaccepted_memory(void) |
6850 | { |
6851 | return static_branch_unlikely(&zones_with_unaccepted_pages); |
6852 | } |
6853 | |
6854 | static bool __free_unaccepted(struct page *page) |
6855 | { |
6856 | struct zone *zone = page_zone(page); |
6857 | unsigned long flags; |
6858 | bool first = false; |
6859 | |
6860 | if (!lazy_accept) |
6861 | return false; |
6862 | |
6863 | spin_lock_irqsave(&zone->lock, flags); |
6864 | first = list_empty(head: &zone->unaccepted_pages); |
6865 | list_add_tail(new: &page->lru, head: &zone->unaccepted_pages); |
6866 | __mod_zone_freepage_state(zone, MAX_ORDER_NR_PAGES, migratetype: MIGRATE_MOVABLE); |
6867 | __mod_zone_page_state(zone, item: NR_UNACCEPTED, MAX_ORDER_NR_PAGES); |
6868 | spin_unlock_irqrestore(lock: &zone->lock, flags); |
6869 | |
6870 | if (first) |
6871 | static_branch_inc(&zones_with_unaccepted_pages); |
6872 | |
6873 | return true; |
6874 | } |
6875 | |
6876 | #else |
6877 | |
6878 | static bool page_contains_unaccepted(struct page *page, unsigned int order) |
6879 | { |
6880 | return false; |
6881 | } |
6882 | |
6883 | static void accept_page(struct page *page, unsigned int order) |
6884 | { |
6885 | } |
6886 | |
6887 | static bool try_to_accept_memory(struct zone *zone, unsigned int order) |
6888 | { |
6889 | return false; |
6890 | } |
6891 | |
6892 | static inline bool has_unaccepted_memory(void) |
6893 | { |
6894 | return false; |
6895 | } |
6896 | |
6897 | static bool __free_unaccepted(struct page *page) |
6898 | { |
6899 | BUILD_BUG(); |
6900 | return false; |
6901 | } |
6902 | |
6903 | #endif /* CONFIG_UNACCEPTED_MEMORY */ |
6904 | |