1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/mm/slab.c |
4 | * Written by Mark Hemment, 1996/97. |
5 | * (markhe@nextd.demon.co.uk) |
6 | * |
7 | * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli |
8 | * |
9 | * Major cleanup, different bufctl logic, per-cpu arrays |
10 | * (c) 2000 Manfred Spraul |
11 | * |
12 | * Cleanup, make the head arrays unconditional, preparation for NUMA |
13 | * (c) 2002 Manfred Spraul |
14 | * |
15 | * An implementation of the Slab Allocator as described in outline in; |
16 | * UNIX Internals: The New Frontiers by Uresh Vahalia |
17 | * Pub: Prentice Hall ISBN 0-13-101908-2 |
18 | * or with a little more detail in; |
19 | * The Slab Allocator: An Object-Caching Kernel Memory Allocator |
20 | * Jeff Bonwick (Sun Microsystems). |
21 | * Presented at: USENIX Summer 1994 Technical Conference |
22 | * |
23 | * The memory is organized in caches, one cache for each object type. |
24 | * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) |
25 | * Each cache consists out of many slabs (they are small (usually one |
26 | * page long) and always contiguous), and each slab contains multiple |
27 | * initialized objects. |
28 | * |
29 | * This means, that your constructor is used only for newly allocated |
30 | * slabs and you must pass objects with the same initializations to |
31 | * kmem_cache_free. |
32 | * |
33 | * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, |
34 | * normal). If you need a special memory type, then must create a new |
35 | * cache for that memory type. |
36 | * |
37 | * In order to reduce fragmentation, the slabs are sorted in 3 groups: |
38 | * full slabs with 0 free objects |
39 | * partial slabs |
40 | * empty slabs with no allocated objects |
41 | * |
42 | * If partial slabs exist, then new allocations come from these slabs, |
43 | * otherwise from empty slabs or new slabs are allocated. |
44 | * |
45 | * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache |
46 | * during kmem_cache_destroy(). The caller must prevent concurrent allocs. |
47 | * |
48 | * Each cache has a short per-cpu head array, most allocs |
49 | * and frees go into that array, and if that array overflows, then 1/2 |
50 | * of the entries in the array are given back into the global cache. |
51 | * The head array is strictly LIFO and should improve the cache hit rates. |
52 | * On SMP, it additionally reduces the spinlock operations. |
53 | * |
54 | * The c_cpuarray may not be read with enabled local interrupts - |
55 | * it's changed with a smp_call_function(). |
56 | * |
57 | * SMP synchronization: |
58 | * constructors and destructors are called without any locking. |
59 | * Several members in struct kmem_cache and struct slab never change, they |
60 | * are accessed without any locking. |
61 | * The per-cpu arrays are never accessed from the wrong cpu, no locking, |
62 | * and local interrupts are disabled so slab code is preempt-safe. |
63 | * The non-constant members are protected with a per-cache irq spinlock. |
64 | * |
65 | * Many thanks to Mark Hemment, who wrote another per-cpu slab patch |
66 | * in 2000 - many ideas in the current implementation are derived from |
67 | * his patch. |
68 | * |
69 | * Further notes from the original documentation: |
70 | * |
71 | * 11 April '97. Started multi-threading - markhe |
72 | * The global cache-chain is protected by the mutex 'slab_mutex'. |
73 | * The sem is only needed when accessing/extending the cache-chain, which |
74 | * can never happen inside an interrupt (kmem_cache_create(), |
75 | * kmem_cache_shrink() and kmem_cache_reap()). |
76 | * |
77 | * At present, each engine can be growing a cache. This should be blocked. |
78 | * |
79 | * 15 March 2005. NUMA slab allocator. |
80 | * Shai Fultheim <shai@scalex86.org>. |
81 | * Shobhit Dayal <shobhit@calsoftinc.com> |
82 | * Alok N Kataria <alokk@calsoftinc.com> |
83 | * Christoph Lameter <christoph@lameter.com> |
84 | * |
85 | * Modified the slab allocator to be node aware on NUMA systems. |
86 | * Each node has its own list of partial, free and full slabs. |
87 | * All object allocations for a node occur from node specific slab lists. |
88 | */ |
89 | |
90 | #include <linux/slab.h> |
91 | #include <linux/mm.h> |
92 | #include <linux/poison.h> |
93 | #include <linux/swap.h> |
94 | #include <linux/cache.h> |
95 | #include <linux/interrupt.h> |
96 | #include <linux/init.h> |
97 | #include <linux/compiler.h> |
98 | #include <linux/cpuset.h> |
99 | #include <linux/proc_fs.h> |
100 | #include <linux/seq_file.h> |
101 | #include <linux/notifier.h> |
102 | #include <linux/kallsyms.h> |
103 | #include <linux/kfence.h> |
104 | #include <linux/cpu.h> |
105 | #include <linux/sysctl.h> |
106 | #include <linux/module.h> |
107 | #include <linux/rcupdate.h> |
108 | #include <linux/string.h> |
109 | #include <linux/uaccess.h> |
110 | #include <linux/nodemask.h> |
111 | #include <linux/kmemleak.h> |
112 | #include <linux/mempolicy.h> |
113 | #include <linux/mutex.h> |
114 | #include <linux/fault-inject.h> |
115 | #include <linux/rtmutex.h> |
116 | #include <linux/reciprocal_div.h> |
117 | #include <linux/debugobjects.h> |
118 | #include <linux/memory.h> |
119 | #include <linux/prefetch.h> |
120 | #include <linux/sched/task_stack.h> |
121 | |
122 | #include <net/sock.h> |
123 | |
124 | #include <asm/cacheflush.h> |
125 | #include <asm/tlbflush.h> |
126 | #include <asm/page.h> |
127 | |
128 | #include <trace/events/kmem.h> |
129 | |
130 | #include "internal.h" |
131 | |
132 | #include "slab.h" |
133 | |
134 | /* |
135 | * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON. |
136 | * 0 for faster, smaller code (especially in the critical paths). |
137 | * |
138 | * STATS - 1 to collect stats for /proc/slabinfo. |
139 | * 0 for faster, smaller code (especially in the critical paths). |
140 | * |
141 | * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) |
142 | */ |
143 | |
144 | #ifdef CONFIG_DEBUG_SLAB |
145 | #define DEBUG 1 |
146 | #define STATS 1 |
147 | #define FORCED_DEBUG 1 |
148 | #else |
149 | #define DEBUG 0 |
150 | #define STATS 0 |
151 | #define FORCED_DEBUG 0 |
152 | #endif |
153 | |
154 | /* Shouldn't this be in a header file somewhere? */ |
155 | #define BYTES_PER_WORD sizeof(void *) |
156 | #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long)) |
157 | |
158 | #ifndef ARCH_KMALLOC_FLAGS |
159 | #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN |
160 | #endif |
161 | |
162 | #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \ |
163 | <= SLAB_OBJ_MIN_SIZE) ? 1 : 0) |
164 | |
165 | #if FREELIST_BYTE_INDEX |
166 | typedef unsigned char freelist_idx_t; |
167 | #else |
168 | typedef unsigned short freelist_idx_t; |
169 | #endif |
170 | |
171 | #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1) |
172 | |
173 | /* |
174 | * struct array_cache |
175 | * |
176 | * Purpose: |
177 | * - LIFO ordering, to hand out cache-warm objects from _alloc |
178 | * - reduce the number of linked list operations |
179 | * - reduce spinlock operations |
180 | * |
181 | * The limit is stored in the per-cpu structure to reduce the data cache |
182 | * footprint. |
183 | * |
184 | */ |
185 | struct array_cache { |
186 | unsigned int avail; |
187 | unsigned int limit; |
188 | unsigned int batchcount; |
189 | unsigned int touched; |
190 | void *entry[]; /* |
191 | * Must have this definition in here for the proper |
192 | * alignment of array_cache. Also simplifies accessing |
193 | * the entries. |
194 | */ |
195 | }; |
196 | |
197 | struct alien_cache { |
198 | spinlock_t lock; |
199 | struct array_cache ac; |
200 | }; |
201 | |
202 | /* |
203 | * Need this for bootstrapping a per node allocator. |
204 | */ |
205 | #define NUM_INIT_LISTS (2 * MAX_NUMNODES) |
206 | static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS]; |
207 | #define CACHE_CACHE 0 |
208 | #define SIZE_NODE (MAX_NUMNODES) |
209 | |
210 | static int drain_freelist(struct kmem_cache *cache, |
211 | struct kmem_cache_node *n, int tofree); |
212 | static void free_block(struct kmem_cache *cachep, void **objpp, int len, |
213 | int node, struct list_head *list); |
214 | static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list); |
215 | static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); |
216 | static void cache_reap(struct work_struct *unused); |
217 | |
218 | static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, |
219 | void **list); |
220 | static inline void fixup_slab_list(struct kmem_cache *cachep, |
221 | struct kmem_cache_node *n, struct slab *slab, |
222 | void **list); |
223 | |
224 | #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) |
225 | |
226 | static void kmem_cache_node_init(struct kmem_cache_node *parent) |
227 | { |
228 | INIT_LIST_HEAD(list: &parent->slabs_full); |
229 | INIT_LIST_HEAD(list: &parent->slabs_partial); |
230 | INIT_LIST_HEAD(list: &parent->slabs_free); |
231 | parent->total_slabs = 0; |
232 | parent->free_slabs = 0; |
233 | parent->shared = NULL; |
234 | parent->alien = NULL; |
235 | parent->colour_next = 0; |
236 | raw_spin_lock_init(&parent->list_lock); |
237 | parent->free_objects = 0; |
238 | parent->free_touched = 0; |
239 | } |
240 | |
241 | #define MAKE_LIST(cachep, listp, slab, nodeid) \ |
242 | do { \ |
243 | INIT_LIST_HEAD(listp); \ |
244 | list_splice(&get_node(cachep, nodeid)->slab, listp); \ |
245 | } while (0) |
246 | |
247 | #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \ |
248 | do { \ |
249 | MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \ |
250 | MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \ |
251 | MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ |
252 | } while (0) |
253 | |
254 | #define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U) |
255 | #define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U) |
256 | #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB) |
257 | #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) |
258 | |
259 | #define BATCHREFILL_LIMIT 16 |
260 | /* |
261 | * Optimization question: fewer reaps means less probability for unnecessary |
262 | * cpucache drain/refill cycles. |
263 | * |
264 | * OTOH the cpuarrays can contain lots of objects, |
265 | * which could lock up otherwise freeable slabs. |
266 | */ |
267 | #define REAPTIMEOUT_AC (2*HZ) |
268 | #define REAPTIMEOUT_NODE (4*HZ) |
269 | |
270 | #if STATS |
271 | #define STATS_INC_ACTIVE(x) ((x)->num_active++) |
272 | #define STATS_DEC_ACTIVE(x) ((x)->num_active--) |
273 | #define STATS_INC_ALLOCED(x) ((x)->num_allocations++) |
274 | #define STATS_INC_GROWN(x) ((x)->grown++) |
275 | #define STATS_ADD_REAPED(x, y) ((x)->reaped += (y)) |
276 | #define STATS_SET_HIGH(x) \ |
277 | do { \ |
278 | if ((x)->num_active > (x)->high_mark) \ |
279 | (x)->high_mark = (x)->num_active; \ |
280 | } while (0) |
281 | #define STATS_INC_ERR(x) ((x)->errors++) |
282 | #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) |
283 | #define STATS_INC_NODEFREES(x) ((x)->node_frees++) |
284 | #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++) |
285 | #define STATS_SET_FREEABLE(x, i) \ |
286 | do { \ |
287 | if ((x)->max_freeable < i) \ |
288 | (x)->max_freeable = i; \ |
289 | } while (0) |
290 | #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) |
291 | #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) |
292 | #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) |
293 | #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) |
294 | #else |
295 | #define STATS_INC_ACTIVE(x) do { } while (0) |
296 | #define STATS_DEC_ACTIVE(x) do { } while (0) |
297 | #define STATS_INC_ALLOCED(x) do { } while (0) |
298 | #define STATS_INC_GROWN(x) do { } while (0) |
299 | #define STATS_ADD_REAPED(x, y) do { (void)(y); } while (0) |
300 | #define STATS_SET_HIGH(x) do { } while (0) |
301 | #define STATS_INC_ERR(x) do { } while (0) |
302 | #define STATS_INC_NODEALLOCS(x) do { } while (0) |
303 | #define STATS_INC_NODEFREES(x) do { } while (0) |
304 | #define STATS_INC_ACOVERFLOW(x) do { } while (0) |
305 | #define STATS_SET_FREEABLE(x, i) do { } while (0) |
306 | #define STATS_INC_ALLOCHIT(x) do { } while (0) |
307 | #define STATS_INC_ALLOCMISS(x) do { } while (0) |
308 | #define STATS_INC_FREEHIT(x) do { } while (0) |
309 | #define STATS_INC_FREEMISS(x) do { } while (0) |
310 | #endif |
311 | |
312 | #if DEBUG |
313 | |
314 | /* |
315 | * memory layout of objects: |
316 | * 0 : objp |
317 | * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that |
318 | * the end of an object is aligned with the end of the real |
319 | * allocation. Catches writes behind the end of the allocation. |
320 | * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1: |
321 | * redzone word. |
322 | * cachep->obj_offset: The real object. |
323 | * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] |
324 | * cachep->size - 1* BYTES_PER_WORD: last caller address |
325 | * [BYTES_PER_WORD long] |
326 | */ |
327 | static int obj_offset(struct kmem_cache *cachep) |
328 | { |
329 | return cachep->obj_offset; |
330 | } |
331 | |
332 | static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp) |
333 | { |
334 | BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); |
335 | return (unsigned long long *) (objp + obj_offset(cachep) - |
336 | sizeof(unsigned long long)); |
337 | } |
338 | |
339 | static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp) |
340 | { |
341 | BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); |
342 | if (cachep->flags & SLAB_STORE_USER) |
343 | return (unsigned long long *)(objp + cachep->size - |
344 | sizeof(unsigned long long) - |
345 | REDZONE_ALIGN); |
346 | return (unsigned long long *) (objp + cachep->size - |
347 | sizeof(unsigned long long)); |
348 | } |
349 | |
350 | static void **dbg_userword(struct kmem_cache *cachep, void *objp) |
351 | { |
352 | BUG_ON(!(cachep->flags & SLAB_STORE_USER)); |
353 | return (void **)(objp + cachep->size - BYTES_PER_WORD); |
354 | } |
355 | |
356 | #else |
357 | |
358 | #define obj_offset(x) 0 |
359 | #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) |
360 | #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) |
361 | #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) |
362 | |
363 | #endif |
364 | |
365 | /* |
366 | * Do not go above this order unless 0 objects fit into the slab or |
367 | * overridden on the command line. |
368 | */ |
369 | #define SLAB_MAX_ORDER_HI 1 |
370 | #define SLAB_MAX_ORDER_LO 0 |
371 | static int slab_max_order = SLAB_MAX_ORDER_LO; |
372 | static bool slab_max_order_set __initdata; |
373 | |
374 | static inline void *index_to_obj(struct kmem_cache *cache, |
375 | const struct slab *slab, unsigned int idx) |
376 | { |
377 | return slab->s_mem + cache->size * idx; |
378 | } |
379 | |
380 | #define BOOT_CPUCACHE_ENTRIES 1 |
381 | /* internal cache of cache description objs */ |
382 | static struct kmem_cache kmem_cache_boot = { |
383 | .batchcount = 1, |
384 | .limit = BOOT_CPUCACHE_ENTRIES, |
385 | .shared = 1, |
386 | .size = sizeof(struct kmem_cache), |
387 | .name = "kmem_cache" , |
388 | }; |
389 | |
390 | static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); |
391 | |
392 | static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) |
393 | { |
394 | return this_cpu_ptr(cachep->cpu_cache); |
395 | } |
396 | |
397 | /* |
398 | * Calculate the number of objects and left-over bytes for a given buffer size. |
399 | */ |
400 | static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size, |
401 | slab_flags_t flags, size_t *left_over) |
402 | { |
403 | unsigned int num; |
404 | size_t slab_size = PAGE_SIZE << gfporder; |
405 | |
406 | /* |
407 | * The slab management structure can be either off the slab or |
408 | * on it. For the latter case, the memory allocated for a |
409 | * slab is used for: |
410 | * |
411 | * - @buffer_size bytes for each object |
412 | * - One freelist_idx_t for each object |
413 | * |
414 | * We don't need to consider alignment of freelist because |
415 | * freelist will be at the end of slab page. The objects will be |
416 | * at the correct alignment. |
417 | * |
418 | * If the slab management structure is off the slab, then the |
419 | * alignment will already be calculated into the size. Because |
420 | * the slabs are all pages aligned, the objects will be at the |
421 | * correct alignment when allocated. |
422 | */ |
423 | if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) { |
424 | num = slab_size / buffer_size; |
425 | *left_over = slab_size % buffer_size; |
426 | } else { |
427 | num = slab_size / (buffer_size + sizeof(freelist_idx_t)); |
428 | *left_over = slab_size % |
429 | (buffer_size + sizeof(freelist_idx_t)); |
430 | } |
431 | |
432 | return num; |
433 | } |
434 | |
435 | #if DEBUG |
436 | #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) |
437 | |
438 | static void __slab_error(const char *function, struct kmem_cache *cachep, |
439 | char *msg) |
440 | { |
441 | pr_err("slab error in %s(): cache `%s': %s\n" , |
442 | function, cachep->name, msg); |
443 | dump_stack(); |
444 | add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
445 | } |
446 | #endif |
447 | |
448 | /* |
449 | * By default on NUMA we use alien caches to stage the freeing of |
450 | * objects allocated from other nodes. This causes massive memory |
451 | * inefficiencies when using fake NUMA setup to split memory into a |
452 | * large number of small nodes, so it can be disabled on the command |
453 | * line |
454 | */ |
455 | |
456 | static int use_alien_caches __read_mostly = 1; |
457 | static int __init noaliencache_setup(char *s) |
458 | { |
459 | use_alien_caches = 0; |
460 | return 1; |
461 | } |
462 | __setup("noaliencache" , noaliencache_setup); |
463 | |
464 | static int __init slab_max_order_setup(char *str) |
465 | { |
466 | get_option(str: &str, pint: &slab_max_order); |
467 | slab_max_order = slab_max_order < 0 ? 0 : |
468 | min(slab_max_order, MAX_ORDER); |
469 | slab_max_order_set = true; |
470 | |
471 | return 1; |
472 | } |
473 | __setup("slab_max_order=" , slab_max_order_setup); |
474 | |
475 | #ifdef CONFIG_NUMA |
476 | /* |
477 | * Special reaping functions for NUMA systems called from cache_reap(). |
478 | * These take care of doing round robin flushing of alien caches (containing |
479 | * objects freed on different nodes from which they were allocated) and the |
480 | * flushing of remote pcps by calling drain_node_pages. |
481 | */ |
482 | static DEFINE_PER_CPU(unsigned long, slab_reap_node); |
483 | |
484 | static void init_reap_node(int cpu) |
485 | { |
486 | per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu), |
487 | node_online_map); |
488 | } |
489 | |
490 | static void next_reap_node(void) |
491 | { |
492 | int node = __this_cpu_read(slab_reap_node); |
493 | |
494 | node = next_node_in(node, node_online_map); |
495 | __this_cpu_write(slab_reap_node, node); |
496 | } |
497 | |
498 | #else |
499 | #define init_reap_node(cpu) do { } while (0) |
500 | #define next_reap_node(void) do { } while (0) |
501 | #endif |
502 | |
503 | /* |
504 | * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz |
505 | * via the workqueue/eventd. |
506 | * Add the CPU number into the expiration time to minimize the possibility of |
507 | * the CPUs getting into lockstep and contending for the global cache chain |
508 | * lock. |
509 | */ |
510 | static void start_cpu_timer(int cpu) |
511 | { |
512 | struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); |
513 | |
514 | if (reap_work->work.func == NULL) { |
515 | init_reap_node(cpu); |
516 | INIT_DEFERRABLE_WORK(reap_work, cache_reap); |
517 | schedule_delayed_work_on(cpu, dwork: reap_work, |
518 | delay: __round_jiffies_relative(HZ, cpu)); |
519 | } |
520 | } |
521 | |
522 | static void init_arraycache(struct array_cache *ac, int limit, int batch) |
523 | { |
524 | if (ac) { |
525 | ac->avail = 0; |
526 | ac->limit = limit; |
527 | ac->batchcount = batch; |
528 | ac->touched = 0; |
529 | } |
530 | } |
531 | |
532 | static struct array_cache *alloc_arraycache(int node, int entries, |
533 | int batchcount, gfp_t gfp) |
534 | { |
535 | size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache); |
536 | struct array_cache *ac = NULL; |
537 | |
538 | ac = kmalloc_node(size: memsize, flags: gfp, node); |
539 | /* |
540 | * The array_cache structures contain pointers to free object. |
541 | * However, when such objects are allocated or transferred to another |
542 | * cache the pointers are not cleared and they could be counted as |
543 | * valid references during a kmemleak scan. Therefore, kmemleak must |
544 | * not scan such objects. |
545 | */ |
546 | kmemleak_no_scan(ptr: ac); |
547 | init_arraycache(ac, limit: entries, batch: batchcount); |
548 | return ac; |
549 | } |
550 | |
551 | static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep, |
552 | struct slab *slab, void *objp) |
553 | { |
554 | struct kmem_cache_node *n; |
555 | int slab_node; |
556 | LIST_HEAD(list); |
557 | |
558 | slab_node = slab_nid(slab); |
559 | n = get_node(s: cachep, node: slab_node); |
560 | |
561 | raw_spin_lock(&n->list_lock); |
562 | free_block(cachep, objpp: &objp, len: 1, node: slab_node, list: &list); |
563 | raw_spin_unlock(&n->list_lock); |
564 | |
565 | slabs_destroy(cachep, list: &list); |
566 | } |
567 | |
568 | /* |
569 | * Transfer objects in one arraycache to another. |
570 | * Locking must be handled by the caller. |
571 | * |
572 | * Return the number of entries transferred. |
573 | */ |
574 | static int transfer_objects(struct array_cache *to, |
575 | struct array_cache *from, unsigned int max) |
576 | { |
577 | /* Figure out how many entries to transfer */ |
578 | int nr = min3(from->avail, max, to->limit - to->avail); |
579 | |
580 | if (!nr) |
581 | return 0; |
582 | |
583 | memcpy(to->entry + to->avail, from->entry + from->avail - nr, |
584 | sizeof(void *) *nr); |
585 | |
586 | from->avail -= nr; |
587 | to->avail += nr; |
588 | return nr; |
589 | } |
590 | |
591 | /* &alien->lock must be held by alien callers. */ |
592 | static __always_inline void __free_one(struct array_cache *ac, void *objp) |
593 | { |
594 | /* Avoid trivial double-free. */ |
595 | if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && |
596 | WARN_ON_ONCE(ac->avail > 0 && ac->entry[ac->avail - 1] == objp)) |
597 | return; |
598 | ac->entry[ac->avail++] = objp; |
599 | } |
600 | |
601 | #ifndef CONFIG_NUMA |
602 | |
603 | #define drain_alien_cache(cachep, alien) do { } while (0) |
604 | #define reap_alien(cachep, n) do { } while (0) |
605 | |
606 | static inline struct alien_cache **alloc_alien_cache(int node, |
607 | int limit, gfp_t gfp) |
608 | { |
609 | return NULL; |
610 | } |
611 | |
612 | static inline void free_alien_cache(struct alien_cache **ac_ptr) |
613 | { |
614 | } |
615 | |
616 | static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) |
617 | { |
618 | return 0; |
619 | } |
620 | |
621 | static inline gfp_t gfp_exact_node(gfp_t flags) |
622 | { |
623 | return flags & ~__GFP_NOFAIL; |
624 | } |
625 | |
626 | #else /* CONFIG_NUMA */ |
627 | |
628 | static struct alien_cache *__alloc_alien_cache(int node, int entries, |
629 | int batch, gfp_t gfp) |
630 | { |
631 | size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache); |
632 | struct alien_cache *alc = NULL; |
633 | |
634 | alc = kmalloc_node(size: memsize, flags: gfp, node); |
635 | if (alc) { |
636 | kmemleak_no_scan(ptr: alc); |
637 | init_arraycache(ac: &alc->ac, limit: entries, batch); |
638 | spin_lock_init(&alc->lock); |
639 | } |
640 | return alc; |
641 | } |
642 | |
643 | static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) |
644 | { |
645 | struct alien_cache **alc_ptr; |
646 | int i; |
647 | |
648 | if (limit > 1) |
649 | limit = 12; |
650 | alc_ptr = kcalloc_node(n: nr_node_ids, size: sizeof(void *), flags: gfp, node); |
651 | if (!alc_ptr) |
652 | return NULL; |
653 | |
654 | for_each_node(i) { |
655 | if (i == node || !node_online(i)) |
656 | continue; |
657 | alc_ptr[i] = __alloc_alien_cache(node, entries: limit, batch: 0xbaadf00d, gfp); |
658 | if (!alc_ptr[i]) { |
659 | for (i--; i >= 0; i--) |
660 | kfree(objp: alc_ptr[i]); |
661 | kfree(objp: alc_ptr); |
662 | return NULL; |
663 | } |
664 | } |
665 | return alc_ptr; |
666 | } |
667 | |
668 | static void free_alien_cache(struct alien_cache **alc_ptr) |
669 | { |
670 | int i; |
671 | |
672 | if (!alc_ptr) |
673 | return; |
674 | for_each_node(i) |
675 | kfree(objp: alc_ptr[i]); |
676 | kfree(objp: alc_ptr); |
677 | } |
678 | |
679 | static void __drain_alien_cache(struct kmem_cache *cachep, |
680 | struct array_cache *ac, int node, |
681 | struct list_head *list) |
682 | { |
683 | struct kmem_cache_node *n = get_node(s: cachep, node); |
684 | |
685 | if (ac->avail) { |
686 | raw_spin_lock(&n->list_lock); |
687 | /* |
688 | * Stuff objects into the remote nodes shared array first. |
689 | * That way we could avoid the overhead of putting the objects |
690 | * into the free lists and getting them back later. |
691 | */ |
692 | if (n->shared) |
693 | transfer_objects(to: n->shared, from: ac, max: ac->limit); |
694 | |
695 | free_block(cachep, objpp: ac->entry, len: ac->avail, node, list); |
696 | ac->avail = 0; |
697 | raw_spin_unlock(&n->list_lock); |
698 | } |
699 | } |
700 | |
701 | /* |
702 | * Called from cache_reap() to regularly drain alien caches round robin. |
703 | */ |
704 | static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n) |
705 | { |
706 | int node = __this_cpu_read(slab_reap_node); |
707 | |
708 | if (n->alien) { |
709 | struct alien_cache *alc = n->alien[node]; |
710 | struct array_cache *ac; |
711 | |
712 | if (alc) { |
713 | ac = &alc->ac; |
714 | if (ac->avail && spin_trylock_irq(lock: &alc->lock)) { |
715 | LIST_HEAD(list); |
716 | |
717 | __drain_alien_cache(cachep, ac, node, list: &list); |
718 | spin_unlock_irq(lock: &alc->lock); |
719 | slabs_destroy(cachep, list: &list); |
720 | } |
721 | } |
722 | } |
723 | } |
724 | |
725 | static void drain_alien_cache(struct kmem_cache *cachep, |
726 | struct alien_cache **alien) |
727 | { |
728 | int i = 0; |
729 | struct alien_cache *alc; |
730 | struct array_cache *ac; |
731 | unsigned long flags; |
732 | |
733 | for_each_online_node(i) { |
734 | alc = alien[i]; |
735 | if (alc) { |
736 | LIST_HEAD(list); |
737 | |
738 | ac = &alc->ac; |
739 | spin_lock_irqsave(&alc->lock, flags); |
740 | __drain_alien_cache(cachep, ac, node: i, list: &list); |
741 | spin_unlock_irqrestore(lock: &alc->lock, flags); |
742 | slabs_destroy(cachep, list: &list); |
743 | } |
744 | } |
745 | } |
746 | |
747 | static int __cache_free_alien(struct kmem_cache *cachep, void *objp, |
748 | int node, int slab_node) |
749 | { |
750 | struct kmem_cache_node *n; |
751 | struct alien_cache *alien = NULL; |
752 | struct array_cache *ac; |
753 | LIST_HEAD(list); |
754 | |
755 | n = get_node(s: cachep, node); |
756 | STATS_INC_NODEFREES(cachep); |
757 | if (n->alien && n->alien[slab_node]) { |
758 | alien = n->alien[slab_node]; |
759 | ac = &alien->ac; |
760 | spin_lock(lock: &alien->lock); |
761 | if (unlikely(ac->avail == ac->limit)) { |
762 | STATS_INC_ACOVERFLOW(cachep); |
763 | __drain_alien_cache(cachep, ac, node: slab_node, list: &list); |
764 | } |
765 | __free_one(ac, objp); |
766 | spin_unlock(lock: &alien->lock); |
767 | slabs_destroy(cachep, list: &list); |
768 | } else { |
769 | n = get_node(s: cachep, node: slab_node); |
770 | raw_spin_lock(&n->list_lock); |
771 | free_block(cachep, objpp: &objp, len: 1, node: slab_node, list: &list); |
772 | raw_spin_unlock(&n->list_lock); |
773 | slabs_destroy(cachep, list: &list); |
774 | } |
775 | return 1; |
776 | } |
777 | |
778 | static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) |
779 | { |
780 | int slab_node = slab_nid(slab: virt_to_slab(addr: objp)); |
781 | int node = numa_mem_id(); |
782 | /* |
783 | * Make sure we are not freeing an object from another node to the array |
784 | * cache on this cpu. |
785 | */ |
786 | if (likely(node == slab_node)) |
787 | return 0; |
788 | |
789 | return __cache_free_alien(cachep, objp, node, slab_node); |
790 | } |
791 | |
792 | /* |
793 | * Construct gfp mask to allocate from a specific node but do not reclaim or |
794 | * warn about failures. |
795 | */ |
796 | static inline gfp_t gfp_exact_node(gfp_t flags) |
797 | { |
798 | return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL); |
799 | } |
800 | #endif |
801 | |
802 | static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp) |
803 | { |
804 | struct kmem_cache_node *n; |
805 | |
806 | /* |
807 | * Set up the kmem_cache_node for cpu before we can |
808 | * begin anything. Make sure some other cpu on this |
809 | * node has not already allocated this |
810 | */ |
811 | n = get_node(s: cachep, node); |
812 | if (n) { |
813 | raw_spin_lock_irq(&n->list_lock); |
814 | n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + |
815 | cachep->num; |
816 | raw_spin_unlock_irq(&n->list_lock); |
817 | |
818 | return 0; |
819 | } |
820 | |
821 | n = kmalloc_node(size: sizeof(struct kmem_cache_node), flags: gfp, node); |
822 | if (!n) |
823 | return -ENOMEM; |
824 | |
825 | kmem_cache_node_init(parent: n); |
826 | n->next_reap = jiffies + REAPTIMEOUT_NODE + |
827 | ((unsigned long)cachep) % REAPTIMEOUT_NODE; |
828 | |
829 | n->free_limit = |
830 | (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; |
831 | |
832 | /* |
833 | * The kmem_cache_nodes don't come and go as CPUs |
834 | * come and go. slab_mutex provides sufficient |
835 | * protection here. |
836 | */ |
837 | cachep->node[node] = n; |
838 | |
839 | return 0; |
840 | } |
841 | |
842 | #if defined(CONFIG_NUMA) || defined(CONFIG_SMP) |
843 | /* |
844 | * Allocates and initializes node for a node on each slab cache, used for |
845 | * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node |
846 | * will be allocated off-node since memory is not yet online for the new node. |
847 | * When hotplugging memory or a cpu, existing nodes are not replaced if |
848 | * already in use. |
849 | * |
850 | * Must hold slab_mutex. |
851 | */ |
852 | static int init_cache_node_node(int node) |
853 | { |
854 | int ret; |
855 | struct kmem_cache *cachep; |
856 | |
857 | list_for_each_entry(cachep, &slab_caches, list) { |
858 | ret = init_cache_node(cachep, node, GFP_KERNEL); |
859 | if (ret) |
860 | return ret; |
861 | } |
862 | |
863 | return 0; |
864 | } |
865 | #endif |
866 | |
867 | static int setup_kmem_cache_node(struct kmem_cache *cachep, |
868 | int node, gfp_t gfp, bool force_change) |
869 | { |
870 | int ret = -ENOMEM; |
871 | struct kmem_cache_node *n; |
872 | struct array_cache *old_shared = NULL; |
873 | struct array_cache *new_shared = NULL; |
874 | struct alien_cache **new_alien = NULL; |
875 | LIST_HEAD(list); |
876 | |
877 | if (use_alien_caches) { |
878 | new_alien = alloc_alien_cache(node, limit: cachep->limit, gfp); |
879 | if (!new_alien) |
880 | goto fail; |
881 | } |
882 | |
883 | if (cachep->shared) { |
884 | new_shared = alloc_arraycache(node, |
885 | entries: cachep->shared * cachep->batchcount, batchcount: 0xbaadf00d, gfp); |
886 | if (!new_shared) |
887 | goto fail; |
888 | } |
889 | |
890 | ret = init_cache_node(cachep, node, gfp); |
891 | if (ret) |
892 | goto fail; |
893 | |
894 | n = get_node(s: cachep, node); |
895 | raw_spin_lock_irq(&n->list_lock); |
896 | if (n->shared && force_change) { |
897 | free_block(cachep, objpp: n->shared->entry, |
898 | len: n->shared->avail, node, list: &list); |
899 | n->shared->avail = 0; |
900 | } |
901 | |
902 | if (!n->shared || force_change) { |
903 | old_shared = n->shared; |
904 | n->shared = new_shared; |
905 | new_shared = NULL; |
906 | } |
907 | |
908 | if (!n->alien) { |
909 | n->alien = new_alien; |
910 | new_alien = NULL; |
911 | } |
912 | |
913 | raw_spin_unlock_irq(&n->list_lock); |
914 | slabs_destroy(cachep, list: &list); |
915 | |
916 | /* |
917 | * To protect lockless access to n->shared during irq disabled context. |
918 | * If n->shared isn't NULL in irq disabled context, accessing to it is |
919 | * guaranteed to be valid until irq is re-enabled, because it will be |
920 | * freed after synchronize_rcu(). |
921 | */ |
922 | if (old_shared && force_change) |
923 | synchronize_rcu(); |
924 | |
925 | fail: |
926 | kfree(objp: old_shared); |
927 | kfree(objp: new_shared); |
928 | free_alien_cache(alc_ptr: new_alien); |
929 | |
930 | return ret; |
931 | } |
932 | |
933 | #ifdef CONFIG_SMP |
934 | |
935 | static void cpuup_canceled(long cpu) |
936 | { |
937 | struct kmem_cache *cachep; |
938 | struct kmem_cache_node *n = NULL; |
939 | int node = cpu_to_mem(cpu); |
940 | const struct cpumask *mask = cpumask_of_node(node); |
941 | |
942 | list_for_each_entry(cachep, &slab_caches, list) { |
943 | struct array_cache *nc; |
944 | struct array_cache *shared; |
945 | struct alien_cache **alien; |
946 | LIST_HEAD(list); |
947 | |
948 | n = get_node(s: cachep, node); |
949 | if (!n) |
950 | continue; |
951 | |
952 | raw_spin_lock_irq(&n->list_lock); |
953 | |
954 | /* Free limit for this kmem_cache_node */ |
955 | n->free_limit -= cachep->batchcount; |
956 | |
957 | /* cpu is dead; no one can alloc from it. */ |
958 | nc = per_cpu_ptr(cachep->cpu_cache, cpu); |
959 | free_block(cachep, objpp: nc->entry, len: nc->avail, node, list: &list); |
960 | nc->avail = 0; |
961 | |
962 | if (!cpumask_empty(srcp: mask)) { |
963 | raw_spin_unlock_irq(&n->list_lock); |
964 | goto free_slab; |
965 | } |
966 | |
967 | shared = n->shared; |
968 | if (shared) { |
969 | free_block(cachep, objpp: shared->entry, |
970 | len: shared->avail, node, list: &list); |
971 | n->shared = NULL; |
972 | } |
973 | |
974 | alien = n->alien; |
975 | n->alien = NULL; |
976 | |
977 | raw_spin_unlock_irq(&n->list_lock); |
978 | |
979 | kfree(objp: shared); |
980 | if (alien) { |
981 | drain_alien_cache(cachep, alien); |
982 | free_alien_cache(alc_ptr: alien); |
983 | } |
984 | |
985 | free_slab: |
986 | slabs_destroy(cachep, list: &list); |
987 | } |
988 | /* |
989 | * In the previous loop, all the objects were freed to |
990 | * the respective cache's slabs, now we can go ahead and |
991 | * shrink each nodelist to its limit. |
992 | */ |
993 | list_for_each_entry(cachep, &slab_caches, list) { |
994 | n = get_node(s: cachep, node); |
995 | if (!n) |
996 | continue; |
997 | drain_freelist(cache: cachep, n, INT_MAX); |
998 | } |
999 | } |
1000 | |
1001 | static int cpuup_prepare(long cpu) |
1002 | { |
1003 | struct kmem_cache *cachep; |
1004 | int node = cpu_to_mem(cpu); |
1005 | int err; |
1006 | |
1007 | /* |
1008 | * We need to do this right in the beginning since |
1009 | * alloc_arraycache's are going to use this list. |
1010 | * kmalloc_node allows us to add the slab to the right |
1011 | * kmem_cache_node and not this cpu's kmem_cache_node |
1012 | */ |
1013 | err = init_cache_node_node(node); |
1014 | if (err < 0) |
1015 | goto bad; |
1016 | |
1017 | /* |
1018 | * Now we can go ahead with allocating the shared arrays and |
1019 | * array caches |
1020 | */ |
1021 | list_for_each_entry(cachep, &slab_caches, list) { |
1022 | err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, force_change: false); |
1023 | if (err) |
1024 | goto bad; |
1025 | } |
1026 | |
1027 | return 0; |
1028 | bad: |
1029 | cpuup_canceled(cpu); |
1030 | return -ENOMEM; |
1031 | } |
1032 | |
1033 | int slab_prepare_cpu(unsigned int cpu) |
1034 | { |
1035 | int err; |
1036 | |
1037 | mutex_lock(&slab_mutex); |
1038 | err = cpuup_prepare(cpu); |
1039 | mutex_unlock(&slab_mutex); |
1040 | return err; |
1041 | } |
1042 | |
1043 | /* |
1044 | * This is called for a failed online attempt and for a successful |
1045 | * offline. |
1046 | * |
1047 | * Even if all the cpus of a node are down, we don't free the |
1048 | * kmem_cache_node of any cache. This is to avoid a race between cpu_down, and |
1049 | * a kmalloc allocation from another cpu for memory from the node of |
1050 | * the cpu going down. The kmem_cache_node structure is usually allocated from |
1051 | * kmem_cache_create() and gets destroyed at kmem_cache_destroy(). |
1052 | */ |
1053 | int slab_dead_cpu(unsigned int cpu) |
1054 | { |
1055 | mutex_lock(&slab_mutex); |
1056 | cpuup_canceled(cpu); |
1057 | mutex_unlock(&slab_mutex); |
1058 | return 0; |
1059 | } |
1060 | #endif |
1061 | |
1062 | static int slab_online_cpu(unsigned int cpu) |
1063 | { |
1064 | start_cpu_timer(cpu); |
1065 | return 0; |
1066 | } |
1067 | |
1068 | static int slab_offline_cpu(unsigned int cpu) |
1069 | { |
1070 | /* |
1071 | * Shutdown cache reaper. Note that the slab_mutex is held so |
1072 | * that if cache_reap() is invoked it cannot do anything |
1073 | * expensive but will only modify reap_work and reschedule the |
1074 | * timer. |
1075 | */ |
1076 | cancel_delayed_work_sync(dwork: &per_cpu(slab_reap_work, cpu)); |
1077 | /* Now the cache_reaper is guaranteed to be not running. */ |
1078 | per_cpu(slab_reap_work, cpu).work.func = NULL; |
1079 | return 0; |
1080 | } |
1081 | |
1082 | #if defined(CONFIG_NUMA) |
1083 | /* |
1084 | * Drains freelist for a node on each slab cache, used for memory hot-remove. |
1085 | * Returns -EBUSY if all objects cannot be drained so that the node is not |
1086 | * removed. |
1087 | * |
1088 | * Must hold slab_mutex. |
1089 | */ |
1090 | static int __meminit drain_cache_node_node(int node) |
1091 | { |
1092 | struct kmem_cache *cachep; |
1093 | int ret = 0; |
1094 | |
1095 | list_for_each_entry(cachep, &slab_caches, list) { |
1096 | struct kmem_cache_node *n; |
1097 | |
1098 | n = get_node(s: cachep, node); |
1099 | if (!n) |
1100 | continue; |
1101 | |
1102 | drain_freelist(cache: cachep, n, INT_MAX); |
1103 | |
1104 | if (!list_empty(head: &n->slabs_full) || |
1105 | !list_empty(head: &n->slabs_partial)) { |
1106 | ret = -EBUSY; |
1107 | break; |
1108 | } |
1109 | } |
1110 | return ret; |
1111 | } |
1112 | |
1113 | static int __meminit slab_memory_callback(struct notifier_block *self, |
1114 | unsigned long action, void *arg) |
1115 | { |
1116 | struct memory_notify *mnb = arg; |
1117 | int ret = 0; |
1118 | int nid; |
1119 | |
1120 | nid = mnb->status_change_nid; |
1121 | if (nid < 0) |
1122 | goto out; |
1123 | |
1124 | switch (action) { |
1125 | case MEM_GOING_ONLINE: |
1126 | mutex_lock(&slab_mutex); |
1127 | ret = init_cache_node_node(node: nid); |
1128 | mutex_unlock(lock: &slab_mutex); |
1129 | break; |
1130 | case MEM_GOING_OFFLINE: |
1131 | mutex_lock(&slab_mutex); |
1132 | ret = drain_cache_node_node(node: nid); |
1133 | mutex_unlock(lock: &slab_mutex); |
1134 | break; |
1135 | case MEM_ONLINE: |
1136 | case MEM_OFFLINE: |
1137 | case MEM_CANCEL_ONLINE: |
1138 | case MEM_CANCEL_OFFLINE: |
1139 | break; |
1140 | } |
1141 | out: |
1142 | return notifier_from_errno(err: ret); |
1143 | } |
1144 | #endif /* CONFIG_NUMA */ |
1145 | |
1146 | /* |
1147 | * swap the static kmem_cache_node with kmalloced memory |
1148 | */ |
1149 | static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list, |
1150 | int nodeid) |
1151 | { |
1152 | struct kmem_cache_node *ptr; |
1153 | |
1154 | ptr = kmalloc_node(size: sizeof(struct kmem_cache_node), GFP_NOWAIT, node: nodeid); |
1155 | BUG_ON(!ptr); |
1156 | |
1157 | memcpy(ptr, list, sizeof(struct kmem_cache_node)); |
1158 | /* |
1159 | * Do not assume that spinlocks can be initialized via memcpy: |
1160 | */ |
1161 | raw_spin_lock_init(&ptr->list_lock); |
1162 | |
1163 | MAKE_ALL_LISTS(cachep, ptr, nodeid); |
1164 | cachep->node[nodeid] = ptr; |
1165 | } |
1166 | |
1167 | /* |
1168 | * For setting up all the kmem_cache_node for cache whose buffer_size is same as |
1169 | * size of kmem_cache_node. |
1170 | */ |
1171 | static void __init set_up_node(struct kmem_cache *cachep, int index) |
1172 | { |
1173 | int node; |
1174 | |
1175 | for_each_online_node(node) { |
1176 | cachep->node[node] = &init_kmem_cache_node[index + node]; |
1177 | cachep->node[node]->next_reap = jiffies + |
1178 | REAPTIMEOUT_NODE + |
1179 | ((unsigned long)cachep) % REAPTIMEOUT_NODE; |
1180 | } |
1181 | } |
1182 | |
1183 | /* |
1184 | * Initialisation. Called after the page allocator have been initialised and |
1185 | * before smp_init(). |
1186 | */ |
1187 | void __init kmem_cache_init(void) |
1188 | { |
1189 | int i; |
1190 | |
1191 | kmem_cache = &kmem_cache_boot; |
1192 | |
1193 | if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1) |
1194 | use_alien_caches = 0; |
1195 | |
1196 | for (i = 0; i < NUM_INIT_LISTS; i++) |
1197 | kmem_cache_node_init(parent: &init_kmem_cache_node[i]); |
1198 | |
1199 | /* |
1200 | * Fragmentation resistance on low memory - only use bigger |
1201 | * page orders on machines with more than 32MB of memory if |
1202 | * not overridden on the command line. |
1203 | */ |
1204 | if (!slab_max_order_set && totalram_pages() > (32 << 20) >> PAGE_SHIFT) |
1205 | slab_max_order = SLAB_MAX_ORDER_HI; |
1206 | |
1207 | /* Bootstrap is tricky, because several objects are allocated |
1208 | * from caches that do not exist yet: |
1209 | * 1) initialize the kmem_cache cache: it contains the struct |
1210 | * kmem_cache structures of all caches, except kmem_cache itself: |
1211 | * kmem_cache is statically allocated. |
1212 | * Initially an __init data area is used for the head array and the |
1213 | * kmem_cache_node structures, it's replaced with a kmalloc allocated |
1214 | * array at the end of the bootstrap. |
1215 | * 2) Create the first kmalloc cache. |
1216 | * The struct kmem_cache for the new cache is allocated normally. |
1217 | * An __init data area is used for the head array. |
1218 | * 3) Create the remaining kmalloc caches, with minimally sized |
1219 | * head arrays. |
1220 | * 4) Replace the __init data head arrays for kmem_cache and the first |
1221 | * kmalloc cache with kmalloc allocated arrays. |
1222 | * 5) Replace the __init data for kmem_cache_node for kmem_cache and |
1223 | * the other cache's with kmalloc allocated memory. |
1224 | * 6) Resize the head arrays of the kmalloc caches to their final sizes. |
1225 | */ |
1226 | |
1227 | /* 1) create the kmem_cache */ |
1228 | |
1229 | /* |
1230 | * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids |
1231 | */ |
1232 | create_boot_cache(kmem_cache, name: "kmem_cache" , |
1233 | offsetof(struct kmem_cache, node) + |
1234 | nr_node_ids * sizeof(struct kmem_cache_node *), |
1235 | SLAB_HWCACHE_ALIGN, useroffset: 0, usersize: 0); |
1236 | list_add(new: &kmem_cache->list, head: &slab_caches); |
1237 | slab_state = PARTIAL; |
1238 | |
1239 | /* |
1240 | * Initialize the caches that provide memory for the kmem_cache_node |
1241 | * structures first. Without this, further allocations will bug. |
1242 | */ |
1243 | new_kmalloc_cache(INDEX_NODE, type: KMALLOC_NORMAL, ARCH_KMALLOC_FLAGS); |
1244 | slab_state = PARTIAL_NODE; |
1245 | setup_kmalloc_cache_index_table(); |
1246 | |
1247 | /* 5) Replace the bootstrap kmem_cache_node */ |
1248 | { |
1249 | int nid; |
1250 | |
1251 | for_each_online_node(nid) { |
1252 | init_list(cachep: kmem_cache, list: &init_kmem_cache_node[CACHE_CACHE + nid], nodeid: nid); |
1253 | |
1254 | init_list(cachep: kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE], |
1255 | list: &init_kmem_cache_node[SIZE_NODE + nid], nodeid: nid); |
1256 | } |
1257 | } |
1258 | |
1259 | create_kmalloc_caches(ARCH_KMALLOC_FLAGS); |
1260 | } |
1261 | |
1262 | void __init kmem_cache_init_late(void) |
1263 | { |
1264 | struct kmem_cache *cachep; |
1265 | |
1266 | /* 6) resize the head arrays to their final sizes */ |
1267 | mutex_lock(&slab_mutex); |
1268 | list_for_each_entry(cachep, &slab_caches, list) |
1269 | if (enable_cpucache(cachep, GFP_NOWAIT)) |
1270 | BUG(); |
1271 | mutex_unlock(lock: &slab_mutex); |
1272 | |
1273 | /* Done! */ |
1274 | slab_state = FULL; |
1275 | |
1276 | #ifdef CONFIG_NUMA |
1277 | /* |
1278 | * Register a memory hotplug callback that initializes and frees |
1279 | * node. |
1280 | */ |
1281 | hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); |
1282 | #endif |
1283 | |
1284 | /* |
1285 | * The reap timers are started later, with a module init call: That part |
1286 | * of the kernel is not yet operational. |
1287 | */ |
1288 | } |
1289 | |
1290 | static int __init cpucache_init(void) |
1291 | { |
1292 | int ret; |
1293 | |
1294 | /* |
1295 | * Register the timers that return unneeded pages to the page allocator |
1296 | */ |
1297 | ret = cpuhp_setup_state(state: CPUHP_AP_ONLINE_DYN, name: "SLAB online" , |
1298 | startup: slab_online_cpu, teardown: slab_offline_cpu); |
1299 | WARN_ON(ret < 0); |
1300 | |
1301 | return 0; |
1302 | } |
1303 | __initcall(cpucache_init); |
1304 | |
1305 | static noinline void |
1306 | slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) |
1307 | { |
1308 | #if DEBUG |
1309 | struct kmem_cache_node *n; |
1310 | unsigned long flags; |
1311 | int node; |
1312 | static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL, |
1313 | DEFAULT_RATELIMIT_BURST); |
1314 | |
1315 | if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs)) |
1316 | return; |
1317 | |
1318 | pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n" , |
1319 | nodeid, gfpflags, &gfpflags); |
1320 | pr_warn(" cache: %s, object size: %d, order: %d\n" , |
1321 | cachep->name, cachep->size, cachep->gfporder); |
1322 | |
1323 | for_each_kmem_cache_node(cachep, node, n) { |
1324 | unsigned long total_slabs, free_slabs, free_objs; |
1325 | |
1326 | raw_spin_lock_irqsave(&n->list_lock, flags); |
1327 | total_slabs = n->total_slabs; |
1328 | free_slabs = n->free_slabs; |
1329 | free_objs = n->free_objects; |
1330 | raw_spin_unlock_irqrestore(&n->list_lock, flags); |
1331 | |
1332 | pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n" , |
1333 | node, total_slabs - free_slabs, total_slabs, |
1334 | (total_slabs * cachep->num) - free_objs, |
1335 | total_slabs * cachep->num); |
1336 | } |
1337 | #endif |
1338 | } |
1339 | |
1340 | /* |
1341 | * Interface to system's page allocator. No need to hold the |
1342 | * kmem_cache_node ->list_lock. |
1343 | * |
1344 | * If we requested dmaable memory, we will get it. Even if we |
1345 | * did not request dmaable memory, we might get it, but that |
1346 | * would be relatively rare and ignorable. |
1347 | */ |
1348 | static struct slab *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, |
1349 | int nodeid) |
1350 | { |
1351 | struct folio *folio; |
1352 | struct slab *slab; |
1353 | |
1354 | flags |= cachep->allocflags; |
1355 | |
1356 | folio = (struct folio *) __alloc_pages_node(nid: nodeid, gfp_mask: flags, order: cachep->gfporder); |
1357 | if (!folio) { |
1358 | slab_out_of_memory(cachep, gfpflags: flags, nodeid); |
1359 | return NULL; |
1360 | } |
1361 | |
1362 | slab = folio_slab(folio); |
1363 | |
1364 | account_slab(slab, order: cachep->gfporder, s: cachep, gfp: flags); |
1365 | __folio_set_slab(folio); |
1366 | /* Make the flag visible before any changes to folio->mapping */ |
1367 | smp_wmb(); |
1368 | /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ |
1369 | if (sk_memalloc_socks() && folio_is_pfmemalloc(folio)) |
1370 | slab_set_pfmemalloc(slab); |
1371 | |
1372 | return slab; |
1373 | } |
1374 | |
1375 | /* |
1376 | * Interface to system's page release. |
1377 | */ |
1378 | static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab) |
1379 | { |
1380 | int order = cachep->gfporder; |
1381 | struct folio *folio = slab_folio(slab); |
1382 | |
1383 | BUG_ON(!folio_test_slab(folio)); |
1384 | __slab_clear_pfmemalloc(slab); |
1385 | page_mapcount_reset(page: &folio->page); |
1386 | folio->mapping = NULL; |
1387 | /* Make the mapping reset visible before clearing the flag */ |
1388 | smp_wmb(); |
1389 | __folio_clear_slab(folio); |
1390 | |
1391 | mm_account_reclaimed_pages(pages: 1 << order); |
1392 | unaccount_slab(slab, order, s: cachep); |
1393 | __free_pages(page: &folio->page, order); |
1394 | } |
1395 | |
1396 | static void kmem_rcu_free(struct rcu_head *head) |
1397 | { |
1398 | struct kmem_cache *cachep; |
1399 | struct slab *slab; |
1400 | |
1401 | slab = container_of(head, struct slab, rcu_head); |
1402 | cachep = slab->slab_cache; |
1403 | |
1404 | kmem_freepages(cachep, slab); |
1405 | } |
1406 | |
1407 | #if DEBUG |
1408 | static inline bool is_debug_pagealloc_cache(struct kmem_cache *cachep) |
1409 | { |
1410 | return debug_pagealloc_enabled_static() && OFF_SLAB(cachep) && |
1411 | ((cachep->size % PAGE_SIZE) == 0); |
1412 | } |
1413 | |
1414 | #ifdef CONFIG_DEBUG_PAGEALLOC |
1415 | static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map) |
1416 | { |
1417 | if (!is_debug_pagealloc_cache(cachep)) |
1418 | return; |
1419 | |
1420 | __kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map); |
1421 | } |
1422 | |
1423 | #else |
1424 | static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp, |
1425 | int map) {} |
1426 | |
1427 | #endif |
1428 | |
1429 | static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) |
1430 | { |
1431 | int size = cachep->object_size; |
1432 | addr = &((char *)addr)[obj_offset(cachep)]; |
1433 | |
1434 | memset(addr, val, size); |
1435 | *(unsigned char *)(addr + size - 1) = POISON_END; |
1436 | } |
1437 | |
1438 | static void dump_line(char *data, int offset, int limit) |
1439 | { |
1440 | int i; |
1441 | unsigned char error = 0; |
1442 | int bad_count = 0; |
1443 | |
1444 | pr_err("%03x: " , offset); |
1445 | for (i = 0; i < limit; i++) { |
1446 | if (data[offset + i] != POISON_FREE) { |
1447 | error = data[offset + i]; |
1448 | bad_count++; |
1449 | } |
1450 | } |
1451 | print_hex_dump(KERN_CONT, "" , 0, 16, 1, |
1452 | &data[offset], limit, 1); |
1453 | |
1454 | if (bad_count == 1) { |
1455 | error ^= POISON_FREE; |
1456 | if (!(error & (error - 1))) { |
1457 | pr_err("Single bit error detected. Probably bad RAM.\n" ); |
1458 | #ifdef CONFIG_X86 |
1459 | pr_err("Run memtest86+ or a similar memory test tool.\n" ); |
1460 | #else |
1461 | pr_err("Run a memory test tool.\n" ); |
1462 | #endif |
1463 | } |
1464 | } |
1465 | } |
1466 | #endif |
1467 | |
1468 | #if DEBUG |
1469 | |
1470 | static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) |
1471 | { |
1472 | int i, size; |
1473 | char *realobj; |
1474 | |
1475 | if (cachep->flags & SLAB_RED_ZONE) { |
1476 | pr_err("Redzone: 0x%llx/0x%llx\n" , |
1477 | *dbg_redzone1(cachep, objp), |
1478 | *dbg_redzone2(cachep, objp)); |
1479 | } |
1480 | |
1481 | if (cachep->flags & SLAB_STORE_USER) |
1482 | pr_err("Last user: (%pSR)\n" , *dbg_userword(cachep, objp)); |
1483 | realobj = (char *)objp + obj_offset(cachep); |
1484 | size = cachep->object_size; |
1485 | for (i = 0; i < size && lines; i += 16, lines--) { |
1486 | int limit; |
1487 | limit = 16; |
1488 | if (i + limit > size) |
1489 | limit = size - i; |
1490 | dump_line(realobj, i, limit); |
1491 | } |
1492 | } |
1493 | |
1494 | static void check_poison_obj(struct kmem_cache *cachep, void *objp) |
1495 | { |
1496 | char *realobj; |
1497 | int size, i; |
1498 | int lines = 0; |
1499 | |
1500 | if (is_debug_pagealloc_cache(cachep)) |
1501 | return; |
1502 | |
1503 | realobj = (char *)objp + obj_offset(cachep); |
1504 | size = cachep->object_size; |
1505 | |
1506 | for (i = 0; i < size; i++) { |
1507 | char exp = POISON_FREE; |
1508 | if (i == size - 1) |
1509 | exp = POISON_END; |
1510 | if (realobj[i] != exp) { |
1511 | int limit; |
1512 | /* Mismatch ! */ |
1513 | /* Print header */ |
1514 | if (lines == 0) { |
1515 | pr_err("Slab corruption (%s): %s start=%px, len=%d\n" , |
1516 | print_tainted(), cachep->name, |
1517 | realobj, size); |
1518 | print_objinfo(cachep, objp, 0); |
1519 | } |
1520 | /* Hexdump the affected line */ |
1521 | i = (i / 16) * 16; |
1522 | limit = 16; |
1523 | if (i + limit > size) |
1524 | limit = size - i; |
1525 | dump_line(realobj, i, limit); |
1526 | i += 16; |
1527 | lines++; |
1528 | /* Limit to 5 lines */ |
1529 | if (lines > 5) |
1530 | break; |
1531 | } |
1532 | } |
1533 | if (lines != 0) { |
1534 | /* Print some data about the neighboring objects, if they |
1535 | * exist: |
1536 | */ |
1537 | struct slab *slab = virt_to_slab(objp); |
1538 | unsigned int objnr; |
1539 | |
1540 | objnr = obj_to_index(cachep, slab, objp); |
1541 | if (objnr) { |
1542 | objp = index_to_obj(cachep, slab, objnr - 1); |
1543 | realobj = (char *)objp + obj_offset(cachep); |
1544 | pr_err("Prev obj: start=%px, len=%d\n" , realobj, size); |
1545 | print_objinfo(cachep, objp, 2); |
1546 | } |
1547 | if (objnr + 1 < cachep->num) { |
1548 | objp = index_to_obj(cachep, slab, objnr + 1); |
1549 | realobj = (char *)objp + obj_offset(cachep); |
1550 | pr_err("Next obj: start=%px, len=%d\n" , realobj, size); |
1551 | print_objinfo(cachep, objp, 2); |
1552 | } |
1553 | } |
1554 | } |
1555 | #endif |
1556 | |
1557 | #if DEBUG |
1558 | static void slab_destroy_debugcheck(struct kmem_cache *cachep, |
1559 | struct slab *slab) |
1560 | { |
1561 | int i; |
1562 | |
1563 | if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) { |
1564 | poison_obj(cachep, slab->freelist - obj_offset(cachep), |
1565 | POISON_FREE); |
1566 | } |
1567 | |
1568 | for (i = 0; i < cachep->num; i++) { |
1569 | void *objp = index_to_obj(cachep, slab, i); |
1570 | |
1571 | if (cachep->flags & SLAB_POISON) { |
1572 | check_poison_obj(cachep, objp); |
1573 | slab_kernel_map(cachep, objp, 1); |
1574 | } |
1575 | if (cachep->flags & SLAB_RED_ZONE) { |
1576 | if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) |
1577 | slab_error(cachep, "start of a freed object was overwritten" ); |
1578 | if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) |
1579 | slab_error(cachep, "end of a freed object was overwritten" ); |
1580 | } |
1581 | } |
1582 | } |
1583 | #else |
1584 | static void slab_destroy_debugcheck(struct kmem_cache *cachep, |
1585 | struct slab *slab) |
1586 | { |
1587 | } |
1588 | #endif |
1589 | |
1590 | /** |
1591 | * slab_destroy - destroy and release all objects in a slab |
1592 | * @cachep: cache pointer being destroyed |
1593 | * @slab: slab being destroyed |
1594 | * |
1595 | * Destroy all the objs in a slab, and release the mem back to the system. |
1596 | * Before calling the slab must have been unlinked from the cache. The |
1597 | * kmem_cache_node ->list_lock is not held/needed. |
1598 | */ |
1599 | static void slab_destroy(struct kmem_cache *cachep, struct slab *slab) |
1600 | { |
1601 | void *freelist; |
1602 | |
1603 | freelist = slab->freelist; |
1604 | slab_destroy_debugcheck(cachep, slab); |
1605 | if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU)) |
1606 | call_rcu(head: &slab->rcu_head, func: kmem_rcu_free); |
1607 | else |
1608 | kmem_freepages(cachep, slab); |
1609 | |
1610 | /* |
1611 | * From now on, we don't use freelist |
1612 | * although actual page can be freed in rcu context |
1613 | */ |
1614 | if (OFF_SLAB(cachep)) |
1615 | kfree(objp: freelist); |
1616 | } |
1617 | |
1618 | /* |
1619 | * Update the size of the caches before calling slabs_destroy as it may |
1620 | * recursively call kfree. |
1621 | */ |
1622 | static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list) |
1623 | { |
1624 | struct slab *slab, *n; |
1625 | |
1626 | list_for_each_entry_safe(slab, n, list, slab_list) { |
1627 | list_del(entry: &slab->slab_list); |
1628 | slab_destroy(cachep, slab); |
1629 | } |
1630 | } |
1631 | |
1632 | /** |
1633 | * calculate_slab_order - calculate size (page order) of slabs |
1634 | * @cachep: pointer to the cache that is being created |
1635 | * @size: size of objects to be created in this cache. |
1636 | * @flags: slab allocation flags |
1637 | * |
1638 | * Also calculates the number of objects per slab. |
1639 | * |
1640 | * This could be made much more intelligent. For now, try to avoid using |
1641 | * high order pages for slabs. When the gfp() functions are more friendly |
1642 | * towards high-order requests, this should be changed. |
1643 | * |
1644 | * Return: number of left-over bytes in a slab |
1645 | */ |
1646 | static size_t calculate_slab_order(struct kmem_cache *cachep, |
1647 | size_t size, slab_flags_t flags) |
1648 | { |
1649 | size_t left_over = 0; |
1650 | int gfporder; |
1651 | |
1652 | for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { |
1653 | unsigned int num; |
1654 | size_t remainder; |
1655 | |
1656 | num = cache_estimate(gfporder, buffer_size: size, flags, left_over: &remainder); |
1657 | if (!num) |
1658 | continue; |
1659 | |
1660 | /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */ |
1661 | if (num > SLAB_OBJ_MAX_NUM) |
1662 | break; |
1663 | |
1664 | if (flags & CFLGS_OFF_SLAB) { |
1665 | struct kmem_cache *freelist_cache; |
1666 | size_t freelist_size; |
1667 | size_t freelist_cache_size; |
1668 | |
1669 | freelist_size = num * sizeof(freelist_idx_t); |
1670 | if (freelist_size > KMALLOC_MAX_CACHE_SIZE) { |
1671 | freelist_cache_size = PAGE_SIZE << get_order(size: freelist_size); |
1672 | } else { |
1673 | freelist_cache = kmalloc_slab(size: freelist_size, flags: 0u, _RET_IP_); |
1674 | if (!freelist_cache) |
1675 | continue; |
1676 | freelist_cache_size = freelist_cache->size; |
1677 | |
1678 | /* |
1679 | * Needed to avoid possible looping condition |
1680 | * in cache_grow_begin() |
1681 | */ |
1682 | if (OFF_SLAB(freelist_cache)) |
1683 | continue; |
1684 | } |
1685 | |
1686 | /* check if off slab has enough benefit */ |
1687 | if (freelist_cache_size > cachep->size / 2) |
1688 | continue; |
1689 | } |
1690 | |
1691 | /* Found something acceptable - save it away */ |
1692 | cachep->num = num; |
1693 | cachep->gfporder = gfporder; |
1694 | left_over = remainder; |
1695 | |
1696 | /* |
1697 | * A VFS-reclaimable slab tends to have most allocations |
1698 | * as GFP_NOFS and we really don't want to have to be allocating |
1699 | * higher-order pages when we are unable to shrink dcache. |
1700 | */ |
1701 | if (flags & SLAB_RECLAIM_ACCOUNT) |
1702 | break; |
1703 | |
1704 | /* |
1705 | * Large number of objects is good, but very large slabs are |
1706 | * currently bad for the gfp()s. |
1707 | */ |
1708 | if (gfporder >= slab_max_order) |
1709 | break; |
1710 | |
1711 | /* |
1712 | * Acceptable internal fragmentation? |
1713 | */ |
1714 | if (left_over * 8 <= (PAGE_SIZE << gfporder)) |
1715 | break; |
1716 | } |
1717 | return left_over; |
1718 | } |
1719 | |
1720 | static struct array_cache __percpu *alloc_kmem_cache_cpus( |
1721 | struct kmem_cache *cachep, int entries, int batchcount) |
1722 | { |
1723 | int cpu; |
1724 | size_t size; |
1725 | struct array_cache __percpu *cpu_cache; |
1726 | |
1727 | size = sizeof(void *) * entries + sizeof(struct array_cache); |
1728 | cpu_cache = __alloc_percpu(size, align: sizeof(void *)); |
1729 | |
1730 | if (!cpu_cache) |
1731 | return NULL; |
1732 | |
1733 | for_each_possible_cpu(cpu) { |
1734 | init_arraycache(per_cpu_ptr(cpu_cache, cpu), |
1735 | limit: entries, batch: batchcount); |
1736 | } |
1737 | |
1738 | return cpu_cache; |
1739 | } |
1740 | |
1741 | static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) |
1742 | { |
1743 | if (slab_state >= FULL) |
1744 | return enable_cpucache(cachep, gfp); |
1745 | |
1746 | cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, entries: 1, batchcount: 1); |
1747 | if (!cachep->cpu_cache) |
1748 | return 1; |
1749 | |
1750 | if (slab_state == DOWN) { |
1751 | /* Creation of first cache (kmem_cache). */ |
1752 | set_up_node(cachep: kmem_cache, CACHE_CACHE); |
1753 | } else if (slab_state == PARTIAL) { |
1754 | /* For kmem_cache_node */ |
1755 | set_up_node(cachep, SIZE_NODE); |
1756 | } else { |
1757 | int node; |
1758 | |
1759 | for_each_online_node(node) { |
1760 | cachep->node[node] = kmalloc_node( |
1761 | size: sizeof(struct kmem_cache_node), flags: gfp, node); |
1762 | BUG_ON(!cachep->node[node]); |
1763 | kmem_cache_node_init(parent: cachep->node[node]); |
1764 | } |
1765 | } |
1766 | |
1767 | cachep->node[numa_mem_id()]->next_reap = |
1768 | jiffies + REAPTIMEOUT_NODE + |
1769 | ((unsigned long)cachep) % REAPTIMEOUT_NODE; |
1770 | |
1771 | cpu_cache_get(cachep)->avail = 0; |
1772 | cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; |
1773 | cpu_cache_get(cachep)->batchcount = 1; |
1774 | cpu_cache_get(cachep)->touched = 0; |
1775 | cachep->batchcount = 1; |
1776 | cachep->limit = BOOT_CPUCACHE_ENTRIES; |
1777 | return 0; |
1778 | } |
1779 | |
1780 | slab_flags_t kmem_cache_flags(unsigned int object_size, |
1781 | slab_flags_t flags, const char *name) |
1782 | { |
1783 | return flags; |
1784 | } |
1785 | |
1786 | struct kmem_cache * |
1787 | __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, |
1788 | slab_flags_t flags, void (*ctor)(void *)) |
1789 | { |
1790 | struct kmem_cache *cachep; |
1791 | |
1792 | cachep = find_mergeable(size, align, flags, name, ctor); |
1793 | if (cachep) { |
1794 | cachep->refcount++; |
1795 | |
1796 | /* |
1797 | * Adjust the object sizes so that we clear |
1798 | * the complete object on kzalloc. |
1799 | */ |
1800 | cachep->object_size = max_t(int, cachep->object_size, size); |
1801 | } |
1802 | return cachep; |
1803 | } |
1804 | |
1805 | static bool set_objfreelist_slab_cache(struct kmem_cache *cachep, |
1806 | size_t size, slab_flags_t flags) |
1807 | { |
1808 | size_t left; |
1809 | |
1810 | cachep->num = 0; |
1811 | |
1812 | /* |
1813 | * If slab auto-initialization on free is enabled, store the freelist |
1814 | * off-slab, so that its contents don't end up in one of the allocated |
1815 | * objects. |
1816 | */ |
1817 | if (unlikely(slab_want_init_on_free(cachep))) |
1818 | return false; |
1819 | |
1820 | if (cachep->ctor || flags & SLAB_TYPESAFE_BY_RCU) |
1821 | return false; |
1822 | |
1823 | left = calculate_slab_order(cachep, size, |
1824 | flags: flags | CFLGS_OBJFREELIST_SLAB); |
1825 | if (!cachep->num) |
1826 | return false; |
1827 | |
1828 | if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size) |
1829 | return false; |
1830 | |
1831 | cachep->colour = left / cachep->colour_off; |
1832 | |
1833 | return true; |
1834 | } |
1835 | |
1836 | static bool set_off_slab_cache(struct kmem_cache *cachep, |
1837 | size_t size, slab_flags_t flags) |
1838 | { |
1839 | size_t left; |
1840 | |
1841 | cachep->num = 0; |
1842 | |
1843 | /* |
1844 | * Always use on-slab management when SLAB_NOLEAKTRACE |
1845 | * to avoid recursive calls into kmemleak. |
1846 | */ |
1847 | if (flags & SLAB_NOLEAKTRACE) |
1848 | return false; |
1849 | |
1850 | /* |
1851 | * Size is large, assume best to place the slab management obj |
1852 | * off-slab (should allow better packing of objs). |
1853 | */ |
1854 | left = calculate_slab_order(cachep, size, flags: flags | CFLGS_OFF_SLAB); |
1855 | if (!cachep->num) |
1856 | return false; |
1857 | |
1858 | /* |
1859 | * If the slab has been placed off-slab, and we have enough space then |
1860 | * move it on-slab. This is at the expense of any extra colouring. |
1861 | */ |
1862 | if (left >= cachep->num * sizeof(freelist_idx_t)) |
1863 | return false; |
1864 | |
1865 | cachep->colour = left / cachep->colour_off; |
1866 | |
1867 | return true; |
1868 | } |
1869 | |
1870 | static bool set_on_slab_cache(struct kmem_cache *cachep, |
1871 | size_t size, slab_flags_t flags) |
1872 | { |
1873 | size_t left; |
1874 | |
1875 | cachep->num = 0; |
1876 | |
1877 | left = calculate_slab_order(cachep, size, flags); |
1878 | if (!cachep->num) |
1879 | return false; |
1880 | |
1881 | cachep->colour = left / cachep->colour_off; |
1882 | |
1883 | return true; |
1884 | } |
1885 | |
1886 | /* |
1887 | * __kmem_cache_create - Create a cache. |
1888 | * @cachep: cache management descriptor |
1889 | * @flags: SLAB flags |
1890 | * |
1891 | * Returns zero on success, nonzero on failure. |
1892 | * |
1893 | * The flags are |
1894 | * |
1895 | * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) |
1896 | * to catch references to uninitialised memory. |
1897 | * |
1898 | * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check |
1899 | * for buffer overruns. |
1900 | * |
1901 | * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware |
1902 | * cacheline. This can be beneficial if you're counting cycles as closely |
1903 | * as davem. |
1904 | */ |
1905 | int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags) |
1906 | { |
1907 | size_t ralign = BYTES_PER_WORD; |
1908 | gfp_t gfp; |
1909 | int err; |
1910 | unsigned int size = cachep->size; |
1911 | |
1912 | #if DEBUG |
1913 | #if FORCED_DEBUG |
1914 | /* |
1915 | * Enable redzoning and last user accounting, except for caches with |
1916 | * large objects, if the increased size would increase the object size |
1917 | * above the next power of two: caches with object sizes just above a |
1918 | * power of two have a significant amount of internal fragmentation. |
1919 | */ |
1920 | if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + |
1921 | 2 * sizeof(unsigned long long))) |
1922 | flags |= SLAB_RED_ZONE | SLAB_STORE_USER; |
1923 | if (!(flags & SLAB_TYPESAFE_BY_RCU)) |
1924 | flags |= SLAB_POISON; |
1925 | #endif |
1926 | #endif |
1927 | |
1928 | /* |
1929 | * Check that size is in terms of words. This is needed to avoid |
1930 | * unaligned accesses for some archs when redzoning is used, and makes |
1931 | * sure any on-slab bufctl's are also correctly aligned. |
1932 | */ |
1933 | size = ALIGN(size, BYTES_PER_WORD); |
1934 | |
1935 | if (flags & SLAB_RED_ZONE) { |
1936 | ralign = REDZONE_ALIGN; |
1937 | /* If redzoning, ensure that the second redzone is suitably |
1938 | * aligned, by adjusting the object size accordingly. */ |
1939 | size = ALIGN(size, REDZONE_ALIGN); |
1940 | } |
1941 | |
1942 | /* 3) caller mandated alignment */ |
1943 | if (ralign < cachep->align) { |
1944 | ralign = cachep->align; |
1945 | } |
1946 | /* disable debug if necessary */ |
1947 | if (ralign > __alignof__(unsigned long long)) |
1948 | flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); |
1949 | /* |
1950 | * 4) Store it. |
1951 | */ |
1952 | cachep->align = ralign; |
1953 | cachep->colour_off = cache_line_size(); |
1954 | /* Offset must be a multiple of the alignment. */ |
1955 | if (cachep->colour_off < cachep->align) |
1956 | cachep->colour_off = cachep->align; |
1957 | |
1958 | if (slab_is_available()) |
1959 | gfp = GFP_KERNEL; |
1960 | else |
1961 | gfp = GFP_NOWAIT; |
1962 | |
1963 | #if DEBUG |
1964 | |
1965 | /* |
1966 | * Both debugging options require word-alignment which is calculated |
1967 | * into align above. |
1968 | */ |
1969 | if (flags & SLAB_RED_ZONE) { |
1970 | /* add space for red zone words */ |
1971 | cachep->obj_offset += sizeof(unsigned long long); |
1972 | size += 2 * sizeof(unsigned long long); |
1973 | } |
1974 | if (flags & SLAB_STORE_USER) { |
1975 | /* user store requires one word storage behind the end of |
1976 | * the real object. But if the second red zone needs to be |
1977 | * aligned to 64 bits, we must allow that much space. |
1978 | */ |
1979 | if (flags & SLAB_RED_ZONE) |
1980 | size += REDZONE_ALIGN; |
1981 | else |
1982 | size += BYTES_PER_WORD; |
1983 | } |
1984 | #endif |
1985 | |
1986 | kasan_cache_create(cache: cachep, size: &size, flags: &flags); |
1987 | |
1988 | size = ALIGN(size, cachep->align); |
1989 | /* |
1990 | * We should restrict the number of objects in a slab to implement |
1991 | * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. |
1992 | */ |
1993 | if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) |
1994 | size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); |
1995 | |
1996 | #if DEBUG |
1997 | /* |
1998 | * To activate debug pagealloc, off-slab management is necessary |
1999 | * requirement. In early phase of initialization, small sized slab |
2000 | * doesn't get initialized so it would not be possible. So, we need |
2001 | * to check size >= 256. It guarantees that all necessary small |
2002 | * sized slab is initialized in current slab initialization sequence. |
2003 | */ |
2004 | if (debug_pagealloc_enabled_static() && (flags & SLAB_POISON) && |
2005 | size >= 256 && cachep->object_size > cache_line_size()) { |
2006 | if (size < PAGE_SIZE || size % PAGE_SIZE == 0) { |
2007 | size_t tmp_size = ALIGN(size, PAGE_SIZE); |
2008 | |
2009 | if (set_off_slab_cache(cachep, tmp_size, flags)) { |
2010 | flags |= CFLGS_OFF_SLAB; |
2011 | cachep->obj_offset += tmp_size - size; |
2012 | size = tmp_size; |
2013 | goto done; |
2014 | } |
2015 | } |
2016 | } |
2017 | #endif |
2018 | |
2019 | if (set_objfreelist_slab_cache(cachep, size, flags)) { |
2020 | flags |= CFLGS_OBJFREELIST_SLAB; |
2021 | goto done; |
2022 | } |
2023 | |
2024 | if (set_off_slab_cache(cachep, size, flags)) { |
2025 | flags |= CFLGS_OFF_SLAB; |
2026 | goto done; |
2027 | } |
2028 | |
2029 | if (set_on_slab_cache(cachep, size, flags)) |
2030 | goto done; |
2031 | |
2032 | return -E2BIG; |
2033 | |
2034 | done: |
2035 | cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); |
2036 | cachep->flags = flags; |
2037 | cachep->allocflags = __GFP_COMP; |
2038 | if (flags & SLAB_CACHE_DMA) |
2039 | cachep->allocflags |= GFP_DMA; |
2040 | if (flags & SLAB_CACHE_DMA32) |
2041 | cachep->allocflags |= GFP_DMA32; |
2042 | if (flags & SLAB_RECLAIM_ACCOUNT) |
2043 | cachep->allocflags |= __GFP_RECLAIMABLE; |
2044 | cachep->size = size; |
2045 | cachep->reciprocal_buffer_size = reciprocal_value(d: size); |
2046 | |
2047 | #if DEBUG |
2048 | /* |
2049 | * If we're going to use the generic kernel_map_pages() |
2050 | * poisoning, then it's going to smash the contents of |
2051 | * the redzone and userword anyhow, so switch them off. |
2052 | */ |
2053 | if (IS_ENABLED(CONFIG_PAGE_POISONING) && |
2054 | (cachep->flags & SLAB_POISON) && |
2055 | is_debug_pagealloc_cache(cachep)) |
2056 | cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); |
2057 | #endif |
2058 | |
2059 | err = setup_cpu_cache(cachep, gfp); |
2060 | if (err) { |
2061 | __kmem_cache_release(cachep); |
2062 | return err; |
2063 | } |
2064 | |
2065 | return 0; |
2066 | } |
2067 | |
2068 | #if DEBUG |
2069 | static void check_irq_off(void) |
2070 | { |
2071 | BUG_ON(!irqs_disabled()); |
2072 | } |
2073 | |
2074 | static void check_irq_on(void) |
2075 | { |
2076 | BUG_ON(irqs_disabled()); |
2077 | } |
2078 | |
2079 | static void check_mutex_acquired(void) |
2080 | { |
2081 | BUG_ON(!mutex_is_locked(&slab_mutex)); |
2082 | } |
2083 | |
2084 | static void check_spinlock_acquired(struct kmem_cache *cachep) |
2085 | { |
2086 | #ifdef CONFIG_SMP |
2087 | check_irq_off(); |
2088 | assert_raw_spin_locked(&get_node(cachep, numa_mem_id())->list_lock); |
2089 | #endif |
2090 | } |
2091 | |
2092 | static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) |
2093 | { |
2094 | #ifdef CONFIG_SMP |
2095 | check_irq_off(); |
2096 | assert_raw_spin_locked(&get_node(cachep, node)->list_lock); |
2097 | #endif |
2098 | } |
2099 | |
2100 | #else |
2101 | #define check_irq_off() do { } while(0) |
2102 | #define check_irq_on() do { } while(0) |
2103 | #define check_mutex_acquired() do { } while(0) |
2104 | #define check_spinlock_acquired(x) do { } while(0) |
2105 | #define check_spinlock_acquired_node(x, y) do { } while(0) |
2106 | #endif |
2107 | |
2108 | static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac, |
2109 | int node, bool free_all, struct list_head *list) |
2110 | { |
2111 | int tofree; |
2112 | |
2113 | if (!ac || !ac->avail) |
2114 | return; |
2115 | |
2116 | tofree = free_all ? ac->avail : (ac->limit + 4) / 5; |
2117 | if (tofree > ac->avail) |
2118 | tofree = (ac->avail + 1) / 2; |
2119 | |
2120 | free_block(cachep, objpp: ac->entry, len: tofree, node, list); |
2121 | ac->avail -= tofree; |
2122 | memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail); |
2123 | } |
2124 | |
2125 | static void do_drain(void *arg) |
2126 | { |
2127 | struct kmem_cache *cachep = arg; |
2128 | struct array_cache *ac; |
2129 | int node = numa_mem_id(); |
2130 | struct kmem_cache_node *n; |
2131 | LIST_HEAD(list); |
2132 | |
2133 | check_irq_off(); |
2134 | ac = cpu_cache_get(cachep); |
2135 | n = get_node(s: cachep, node); |
2136 | raw_spin_lock(&n->list_lock); |
2137 | free_block(cachep, objpp: ac->entry, len: ac->avail, node, list: &list); |
2138 | raw_spin_unlock(&n->list_lock); |
2139 | ac->avail = 0; |
2140 | slabs_destroy(cachep, list: &list); |
2141 | } |
2142 | |
2143 | static void drain_cpu_caches(struct kmem_cache *cachep) |
2144 | { |
2145 | struct kmem_cache_node *n; |
2146 | int node; |
2147 | LIST_HEAD(list); |
2148 | |
2149 | on_each_cpu(func: do_drain, info: cachep, wait: 1); |
2150 | check_irq_on(); |
2151 | for_each_kmem_cache_node(cachep, node, n) |
2152 | if (n->alien) |
2153 | drain_alien_cache(cachep, alien: n->alien); |
2154 | |
2155 | for_each_kmem_cache_node(cachep, node, n) { |
2156 | raw_spin_lock_irq(&n->list_lock); |
2157 | drain_array_locked(cachep, ac: n->shared, node, free_all: true, list: &list); |
2158 | raw_spin_unlock_irq(&n->list_lock); |
2159 | |
2160 | slabs_destroy(cachep, list: &list); |
2161 | } |
2162 | } |
2163 | |
2164 | /* |
2165 | * Remove slabs from the list of free slabs. |
2166 | * Specify the number of slabs to drain in tofree. |
2167 | * |
2168 | * Returns the actual number of slabs released. |
2169 | */ |
2170 | static int drain_freelist(struct kmem_cache *cache, |
2171 | struct kmem_cache_node *n, int tofree) |
2172 | { |
2173 | struct list_head *p; |
2174 | int nr_freed; |
2175 | struct slab *slab; |
2176 | |
2177 | nr_freed = 0; |
2178 | while (nr_freed < tofree && !list_empty(head: &n->slabs_free)) { |
2179 | |
2180 | raw_spin_lock_irq(&n->list_lock); |
2181 | p = n->slabs_free.prev; |
2182 | if (p == &n->slabs_free) { |
2183 | raw_spin_unlock_irq(&n->list_lock); |
2184 | goto out; |
2185 | } |
2186 | |
2187 | slab = list_entry(p, struct slab, slab_list); |
2188 | list_del(entry: &slab->slab_list); |
2189 | n->free_slabs--; |
2190 | n->total_slabs--; |
2191 | /* |
2192 | * Safe to drop the lock. The slab is no longer linked |
2193 | * to the cache. |
2194 | */ |
2195 | n->free_objects -= cache->num; |
2196 | raw_spin_unlock_irq(&n->list_lock); |
2197 | slab_destroy(cachep: cache, slab); |
2198 | nr_freed++; |
2199 | |
2200 | cond_resched(); |
2201 | } |
2202 | out: |
2203 | return nr_freed; |
2204 | } |
2205 | |
2206 | bool __kmem_cache_empty(struct kmem_cache *s) |
2207 | { |
2208 | int node; |
2209 | struct kmem_cache_node *n; |
2210 | |
2211 | for_each_kmem_cache_node(s, node, n) |
2212 | if (!list_empty(head: &n->slabs_full) || |
2213 | !list_empty(head: &n->slabs_partial)) |
2214 | return false; |
2215 | return true; |
2216 | } |
2217 | |
2218 | int __kmem_cache_shrink(struct kmem_cache *cachep) |
2219 | { |
2220 | int ret = 0; |
2221 | int node; |
2222 | struct kmem_cache_node *n; |
2223 | |
2224 | drain_cpu_caches(cachep); |
2225 | |
2226 | check_irq_on(); |
2227 | for_each_kmem_cache_node(cachep, node, n) { |
2228 | drain_freelist(cache: cachep, n, INT_MAX); |
2229 | |
2230 | ret += !list_empty(head: &n->slabs_full) || |
2231 | !list_empty(head: &n->slabs_partial); |
2232 | } |
2233 | return (ret ? 1 : 0); |
2234 | } |
2235 | |
2236 | int __kmem_cache_shutdown(struct kmem_cache *cachep) |
2237 | { |
2238 | return __kmem_cache_shrink(cachep); |
2239 | } |
2240 | |
2241 | void __kmem_cache_release(struct kmem_cache *cachep) |
2242 | { |
2243 | int i; |
2244 | struct kmem_cache_node *n; |
2245 | |
2246 | cache_random_seq_destroy(cachep); |
2247 | |
2248 | free_percpu(pdata: cachep->cpu_cache); |
2249 | |
2250 | /* NUMA: free the node structures */ |
2251 | for_each_kmem_cache_node(cachep, i, n) { |
2252 | kfree(objp: n->shared); |
2253 | free_alien_cache(alc_ptr: n->alien); |
2254 | kfree(objp: n); |
2255 | cachep->node[i] = NULL; |
2256 | } |
2257 | } |
2258 | |
2259 | /* |
2260 | * Get the memory for a slab management obj. |
2261 | * |
2262 | * For a slab cache when the slab descriptor is off-slab, the |
2263 | * slab descriptor can't come from the same cache which is being created, |
2264 | * Because if it is the case, that means we defer the creation of |
2265 | * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point. |
2266 | * And we eventually call down to __kmem_cache_create(), which |
2267 | * in turn looks up in the kmalloc_{dma,}_caches for the desired-size one. |
2268 | * This is a "chicken-and-egg" problem. |
2269 | * |
2270 | * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches, |
2271 | * which are all initialized during kmem_cache_init(). |
2272 | */ |
2273 | static void *alloc_slabmgmt(struct kmem_cache *cachep, |
2274 | struct slab *slab, int colour_off, |
2275 | gfp_t local_flags, int nodeid) |
2276 | { |
2277 | void *freelist; |
2278 | void *addr = slab_address(slab); |
2279 | |
2280 | slab->s_mem = addr + colour_off; |
2281 | slab->active = 0; |
2282 | |
2283 | if (OBJFREELIST_SLAB(cachep)) |
2284 | freelist = NULL; |
2285 | else if (OFF_SLAB(cachep)) { |
2286 | /* Slab management obj is off-slab. */ |
2287 | freelist = kmalloc_node(size: cachep->freelist_size, |
2288 | flags: local_flags, node: nodeid); |
2289 | } else { |
2290 | /* We will use last bytes at the slab for freelist */ |
2291 | freelist = addr + (PAGE_SIZE << cachep->gfporder) - |
2292 | cachep->freelist_size; |
2293 | } |
2294 | |
2295 | return freelist; |
2296 | } |
2297 | |
2298 | static inline freelist_idx_t get_free_obj(struct slab *slab, unsigned int idx) |
2299 | { |
2300 | return ((freelist_idx_t *) slab->freelist)[idx]; |
2301 | } |
2302 | |
2303 | static inline void set_free_obj(struct slab *slab, |
2304 | unsigned int idx, freelist_idx_t val) |
2305 | { |
2306 | ((freelist_idx_t *)(slab->freelist))[idx] = val; |
2307 | } |
2308 | |
2309 | static void cache_init_objs_debug(struct kmem_cache *cachep, struct slab *slab) |
2310 | { |
2311 | #if DEBUG |
2312 | int i; |
2313 | |
2314 | for (i = 0; i < cachep->num; i++) { |
2315 | void *objp = index_to_obj(cachep, slab, i); |
2316 | |
2317 | if (cachep->flags & SLAB_STORE_USER) |
2318 | *dbg_userword(cachep, objp) = NULL; |
2319 | |
2320 | if (cachep->flags & SLAB_RED_ZONE) { |
2321 | *dbg_redzone1(cachep, objp) = RED_INACTIVE; |
2322 | *dbg_redzone2(cachep, objp) = RED_INACTIVE; |
2323 | } |
2324 | /* |
2325 | * Constructors are not allowed to allocate memory from the same |
2326 | * cache which they are a constructor for. Otherwise, deadlock. |
2327 | * They must also be threaded. |
2328 | */ |
2329 | if (cachep->ctor && !(cachep->flags & SLAB_POISON)) { |
2330 | kasan_unpoison_object_data(cachep, |
2331 | objp + obj_offset(cachep)); |
2332 | cachep->ctor(objp + obj_offset(cachep)); |
2333 | kasan_poison_object_data( |
2334 | cachep, objp + obj_offset(cachep)); |
2335 | } |
2336 | |
2337 | if (cachep->flags & SLAB_RED_ZONE) { |
2338 | if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) |
2339 | slab_error(cachep, "constructor overwrote the end of an object" ); |
2340 | if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) |
2341 | slab_error(cachep, "constructor overwrote the start of an object" ); |
2342 | } |
2343 | /* need to poison the objs? */ |
2344 | if (cachep->flags & SLAB_POISON) { |
2345 | poison_obj(cachep, objp, POISON_FREE); |
2346 | slab_kernel_map(cachep, objp, 0); |
2347 | } |
2348 | } |
2349 | #endif |
2350 | } |
2351 | |
2352 | #ifdef CONFIG_SLAB_FREELIST_RANDOM |
2353 | /* Hold information during a freelist initialization */ |
2354 | struct freelist_init_state { |
2355 | unsigned int pos; |
2356 | unsigned int *list; |
2357 | unsigned int count; |
2358 | }; |
2359 | |
2360 | /* |
2361 | * Initialize the state based on the randomization method available. |
2362 | * return true if the pre-computed list is available, false otherwise. |
2363 | */ |
2364 | static bool freelist_state_initialize(struct freelist_init_state *state, |
2365 | struct kmem_cache *cachep, |
2366 | unsigned int count) |
2367 | { |
2368 | bool ret; |
2369 | if (!cachep->random_seq) { |
2370 | ret = false; |
2371 | } else { |
2372 | state->list = cachep->random_seq; |
2373 | state->count = count; |
2374 | state->pos = get_random_u32_below(count); |
2375 | ret = true; |
2376 | } |
2377 | return ret; |
2378 | } |
2379 | |
2380 | /* Get the next entry on the list and randomize it using a random shift */ |
2381 | static freelist_idx_t next_random_slot(struct freelist_init_state *state) |
2382 | { |
2383 | if (state->pos >= state->count) |
2384 | state->pos = 0; |
2385 | return state->list[state->pos++]; |
2386 | } |
2387 | |
2388 | /* Swap two freelist entries */ |
2389 | static void swap_free_obj(struct slab *slab, unsigned int a, unsigned int b) |
2390 | { |
2391 | swap(((freelist_idx_t *) slab->freelist)[a], |
2392 | ((freelist_idx_t *) slab->freelist)[b]); |
2393 | } |
2394 | |
2395 | /* |
2396 | * Shuffle the freelist initialization state based on pre-computed lists. |
2397 | * return true if the list was successfully shuffled, false otherwise. |
2398 | */ |
2399 | static bool shuffle_freelist(struct kmem_cache *cachep, struct slab *slab) |
2400 | { |
2401 | unsigned int objfreelist = 0, i, rand, count = cachep->num; |
2402 | struct freelist_init_state state; |
2403 | bool precomputed; |
2404 | |
2405 | if (count < 2) |
2406 | return false; |
2407 | |
2408 | precomputed = freelist_state_initialize(&state, cachep, count); |
2409 | |
2410 | /* Take a random entry as the objfreelist */ |
2411 | if (OBJFREELIST_SLAB(cachep)) { |
2412 | if (!precomputed) |
2413 | objfreelist = count - 1; |
2414 | else |
2415 | objfreelist = next_random_slot(&state); |
2416 | slab->freelist = index_to_obj(cachep, slab, objfreelist) + |
2417 | obj_offset(cachep); |
2418 | count--; |
2419 | } |
2420 | |
2421 | /* |
2422 | * On early boot, generate the list dynamically. |
2423 | * Later use a pre-computed list for speed. |
2424 | */ |
2425 | if (!precomputed) { |
2426 | for (i = 0; i < count; i++) |
2427 | set_free_obj(slab, i, i); |
2428 | |
2429 | /* Fisher-Yates shuffle */ |
2430 | for (i = count - 1; i > 0; i--) { |
2431 | rand = get_random_u32_below(i + 1); |
2432 | swap_free_obj(slab, i, rand); |
2433 | } |
2434 | } else { |
2435 | for (i = 0; i < count; i++) |
2436 | set_free_obj(slab, i, next_random_slot(&state)); |
2437 | } |
2438 | |
2439 | if (OBJFREELIST_SLAB(cachep)) |
2440 | set_free_obj(slab, cachep->num - 1, objfreelist); |
2441 | |
2442 | return true; |
2443 | } |
2444 | #else |
2445 | static inline bool shuffle_freelist(struct kmem_cache *cachep, |
2446 | struct slab *slab) |
2447 | { |
2448 | return false; |
2449 | } |
2450 | #endif /* CONFIG_SLAB_FREELIST_RANDOM */ |
2451 | |
2452 | static void cache_init_objs(struct kmem_cache *cachep, |
2453 | struct slab *slab) |
2454 | { |
2455 | int i; |
2456 | void *objp; |
2457 | bool shuffled; |
2458 | |
2459 | cache_init_objs_debug(cachep, slab); |
2460 | |
2461 | /* Try to randomize the freelist if enabled */ |
2462 | shuffled = shuffle_freelist(cachep, slab); |
2463 | |
2464 | if (!shuffled && OBJFREELIST_SLAB(cachep)) { |
2465 | slab->freelist = index_to_obj(cache: cachep, slab, idx: cachep->num - 1) + |
2466 | obj_offset(cachep); |
2467 | } |
2468 | |
2469 | for (i = 0; i < cachep->num; i++) { |
2470 | objp = index_to_obj(cache: cachep, slab, idx: i); |
2471 | objp = kasan_init_slab_obj(cache: cachep, object: objp); |
2472 | |
2473 | /* constructor could break poison info */ |
2474 | if (DEBUG == 0 && cachep->ctor) { |
2475 | kasan_unpoison_object_data(cache: cachep, object: objp); |
2476 | cachep->ctor(objp); |
2477 | kasan_poison_object_data(cache: cachep, object: objp); |
2478 | } |
2479 | |
2480 | if (!shuffled) |
2481 | set_free_obj(slab, idx: i, val: i); |
2482 | } |
2483 | } |
2484 | |
2485 | static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slab) |
2486 | { |
2487 | void *objp; |
2488 | |
2489 | objp = index_to_obj(cache: cachep, slab, idx: get_free_obj(slab, idx: slab->active)); |
2490 | slab->active++; |
2491 | |
2492 | return objp; |
2493 | } |
2494 | |
2495 | static void slab_put_obj(struct kmem_cache *cachep, |
2496 | struct slab *slab, void *objp) |
2497 | { |
2498 | unsigned int objnr = obj_to_index(cache: cachep, slab, obj: objp); |
2499 | #if DEBUG |
2500 | unsigned int i; |
2501 | |
2502 | /* Verify double free bug */ |
2503 | for (i = slab->active; i < cachep->num; i++) { |
2504 | if (get_free_obj(slab, i) == objnr) { |
2505 | pr_err("slab: double free detected in cache '%s', objp %px\n" , |
2506 | cachep->name, objp); |
2507 | BUG(); |
2508 | } |
2509 | } |
2510 | #endif |
2511 | slab->active--; |
2512 | if (!slab->freelist) |
2513 | slab->freelist = objp + obj_offset(cachep); |
2514 | |
2515 | set_free_obj(slab, idx: slab->active, val: objnr); |
2516 | } |
2517 | |
2518 | /* |
2519 | * Grow (by 1) the number of slabs within a cache. This is called by |
2520 | * kmem_cache_alloc() when there are no active objs left in a cache. |
2521 | */ |
2522 | static struct slab *cache_grow_begin(struct kmem_cache *cachep, |
2523 | gfp_t flags, int nodeid) |
2524 | { |
2525 | void *freelist; |
2526 | size_t offset; |
2527 | gfp_t local_flags; |
2528 | int slab_node; |
2529 | struct kmem_cache_node *n; |
2530 | struct slab *slab; |
2531 | |
2532 | /* |
2533 | * Be lazy and only check for valid flags here, keeping it out of the |
2534 | * critical path in kmem_cache_alloc(). |
2535 | */ |
2536 | if (unlikely(flags & GFP_SLAB_BUG_MASK)) |
2537 | flags = kmalloc_fix_flags(flags); |
2538 | |
2539 | WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); |
2540 | local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); |
2541 | |
2542 | check_irq_off(); |
2543 | if (gfpflags_allow_blocking(gfp_flags: local_flags)) |
2544 | local_irq_enable(); |
2545 | |
2546 | /* |
2547 | * Get mem for the objs. Attempt to allocate a physical page from |
2548 | * 'nodeid'. |
2549 | */ |
2550 | slab = kmem_getpages(cachep, flags: local_flags, nodeid); |
2551 | if (!slab) |
2552 | goto failed; |
2553 | |
2554 | slab_node = slab_nid(slab); |
2555 | n = get_node(s: cachep, node: slab_node); |
2556 | |
2557 | /* Get colour for the slab, and cal the next value. */ |
2558 | n->colour_next++; |
2559 | if (n->colour_next >= cachep->colour) |
2560 | n->colour_next = 0; |
2561 | |
2562 | offset = n->colour_next; |
2563 | if (offset >= cachep->colour) |
2564 | offset = 0; |
2565 | |
2566 | offset *= cachep->colour_off; |
2567 | |
2568 | /* |
2569 | * Call kasan_poison_slab() before calling alloc_slabmgmt(), so |
2570 | * page_address() in the latter returns a non-tagged pointer, |
2571 | * as it should be for slab pages. |
2572 | */ |
2573 | kasan_poison_slab(slab); |
2574 | |
2575 | /* Get slab management. */ |
2576 | freelist = alloc_slabmgmt(cachep, slab, colour_off: offset, |
2577 | local_flags: local_flags & ~GFP_CONSTRAINT_MASK, nodeid: slab_node); |
2578 | if (OFF_SLAB(cachep) && !freelist) |
2579 | goto opps1; |
2580 | |
2581 | slab->slab_cache = cachep; |
2582 | slab->freelist = freelist; |
2583 | |
2584 | cache_init_objs(cachep, slab); |
2585 | |
2586 | if (gfpflags_allow_blocking(gfp_flags: local_flags)) |
2587 | local_irq_disable(); |
2588 | |
2589 | return slab; |
2590 | |
2591 | opps1: |
2592 | kmem_freepages(cachep, slab); |
2593 | failed: |
2594 | if (gfpflags_allow_blocking(gfp_flags: local_flags)) |
2595 | local_irq_disable(); |
2596 | return NULL; |
2597 | } |
2598 | |
2599 | static void cache_grow_end(struct kmem_cache *cachep, struct slab *slab) |
2600 | { |
2601 | struct kmem_cache_node *n; |
2602 | void *list = NULL; |
2603 | |
2604 | check_irq_off(); |
2605 | |
2606 | if (!slab) |
2607 | return; |
2608 | |
2609 | INIT_LIST_HEAD(list: &slab->slab_list); |
2610 | n = get_node(s: cachep, node: slab_nid(slab)); |
2611 | |
2612 | raw_spin_lock(&n->list_lock); |
2613 | n->total_slabs++; |
2614 | if (!slab->active) { |
2615 | list_add_tail(new: &slab->slab_list, head: &n->slabs_free); |
2616 | n->free_slabs++; |
2617 | } else |
2618 | fixup_slab_list(cachep, n, slab, list: &list); |
2619 | |
2620 | STATS_INC_GROWN(cachep); |
2621 | n->free_objects += cachep->num - slab->active; |
2622 | raw_spin_unlock(&n->list_lock); |
2623 | |
2624 | fixup_objfreelist_debug(cachep, list: &list); |
2625 | } |
2626 | |
2627 | #if DEBUG |
2628 | |
2629 | /* |
2630 | * Perform extra freeing checks: |
2631 | * - detect bad pointers. |
2632 | * - POISON/RED_ZONE checking |
2633 | */ |
2634 | static void kfree_debugcheck(const void *objp) |
2635 | { |
2636 | if (!virt_addr_valid(objp)) { |
2637 | pr_err("kfree_debugcheck: out of range ptr %lxh\n" , |
2638 | (unsigned long)objp); |
2639 | BUG(); |
2640 | } |
2641 | } |
2642 | |
2643 | static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) |
2644 | { |
2645 | unsigned long long redzone1, redzone2; |
2646 | |
2647 | redzone1 = *dbg_redzone1(cache, obj); |
2648 | redzone2 = *dbg_redzone2(cache, obj); |
2649 | |
2650 | /* |
2651 | * Redzone is ok. |
2652 | */ |
2653 | if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) |
2654 | return; |
2655 | |
2656 | if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) |
2657 | slab_error(cache, "double free detected" ); |
2658 | else |
2659 | slab_error(cache, "memory outside object was overwritten" ); |
2660 | |
2661 | pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n" , |
2662 | obj, redzone1, redzone2); |
2663 | } |
2664 | |
2665 | static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, |
2666 | unsigned long caller) |
2667 | { |
2668 | unsigned int objnr; |
2669 | struct slab *slab; |
2670 | |
2671 | BUG_ON(virt_to_cache(objp) != cachep); |
2672 | |
2673 | objp -= obj_offset(cachep); |
2674 | kfree_debugcheck(objp); |
2675 | slab = virt_to_slab(objp); |
2676 | |
2677 | if (cachep->flags & SLAB_RED_ZONE) { |
2678 | verify_redzone_free(cachep, objp); |
2679 | *dbg_redzone1(cachep, objp) = RED_INACTIVE; |
2680 | *dbg_redzone2(cachep, objp) = RED_INACTIVE; |
2681 | } |
2682 | if (cachep->flags & SLAB_STORE_USER) |
2683 | *dbg_userword(cachep, objp) = (void *)caller; |
2684 | |
2685 | objnr = obj_to_index(cachep, slab, objp); |
2686 | |
2687 | BUG_ON(objnr >= cachep->num); |
2688 | BUG_ON(objp != index_to_obj(cachep, slab, objnr)); |
2689 | |
2690 | if (cachep->flags & SLAB_POISON) { |
2691 | poison_obj(cachep, objp, POISON_FREE); |
2692 | slab_kernel_map(cachep, objp, 0); |
2693 | } |
2694 | return objp; |
2695 | } |
2696 | |
2697 | #else |
2698 | #define kfree_debugcheck(x) do { } while(0) |
2699 | #define cache_free_debugcheck(x, objp, z) (objp) |
2700 | #endif |
2701 | |
2702 | static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, |
2703 | void **list) |
2704 | { |
2705 | #if DEBUG |
2706 | void *next = *list; |
2707 | void *objp; |
2708 | |
2709 | while (next) { |
2710 | objp = next - obj_offset(cachep); |
2711 | next = *(void **)next; |
2712 | poison_obj(cachep, objp, POISON_FREE); |
2713 | } |
2714 | #endif |
2715 | } |
2716 | |
2717 | static inline void fixup_slab_list(struct kmem_cache *cachep, |
2718 | struct kmem_cache_node *n, struct slab *slab, |
2719 | void **list) |
2720 | { |
2721 | /* move slabp to correct slabp list: */ |
2722 | list_del(entry: &slab->slab_list); |
2723 | if (slab->active == cachep->num) { |
2724 | list_add(new: &slab->slab_list, head: &n->slabs_full); |
2725 | if (OBJFREELIST_SLAB(cachep)) { |
2726 | #if DEBUG |
2727 | /* Poisoning will be done without holding the lock */ |
2728 | if (cachep->flags & SLAB_POISON) { |
2729 | void **objp = slab->freelist; |
2730 | |
2731 | *objp = *list; |
2732 | *list = objp; |
2733 | } |
2734 | #endif |
2735 | slab->freelist = NULL; |
2736 | } |
2737 | } else |
2738 | list_add(new: &slab->slab_list, head: &n->slabs_partial); |
2739 | } |
2740 | |
2741 | /* Try to find non-pfmemalloc slab if needed */ |
2742 | static noinline struct slab *get_valid_first_slab(struct kmem_cache_node *n, |
2743 | struct slab *slab, bool pfmemalloc) |
2744 | { |
2745 | if (!slab) |
2746 | return NULL; |
2747 | |
2748 | if (pfmemalloc) |
2749 | return slab; |
2750 | |
2751 | if (!slab_test_pfmemalloc(slab)) |
2752 | return slab; |
2753 | |
2754 | /* No need to keep pfmemalloc slab if we have enough free objects */ |
2755 | if (n->free_objects > n->free_limit) { |
2756 | slab_clear_pfmemalloc(slab); |
2757 | return slab; |
2758 | } |
2759 | |
2760 | /* Move pfmemalloc slab to the end of list to speed up next search */ |
2761 | list_del(entry: &slab->slab_list); |
2762 | if (!slab->active) { |
2763 | list_add_tail(new: &slab->slab_list, head: &n->slabs_free); |
2764 | n->free_slabs++; |
2765 | } else |
2766 | list_add_tail(new: &slab->slab_list, head: &n->slabs_partial); |
2767 | |
2768 | list_for_each_entry(slab, &n->slabs_partial, slab_list) { |
2769 | if (!slab_test_pfmemalloc(slab)) |
2770 | return slab; |
2771 | } |
2772 | |
2773 | n->free_touched = 1; |
2774 | list_for_each_entry(slab, &n->slabs_free, slab_list) { |
2775 | if (!slab_test_pfmemalloc(slab)) { |
2776 | n->free_slabs--; |
2777 | return slab; |
2778 | } |
2779 | } |
2780 | |
2781 | return NULL; |
2782 | } |
2783 | |
2784 | static struct slab *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc) |
2785 | { |
2786 | struct slab *slab; |
2787 | |
2788 | assert_raw_spin_locked(&n->list_lock); |
2789 | slab = list_first_entry_or_null(&n->slabs_partial, struct slab, |
2790 | slab_list); |
2791 | if (!slab) { |
2792 | n->free_touched = 1; |
2793 | slab = list_first_entry_or_null(&n->slabs_free, struct slab, |
2794 | slab_list); |
2795 | if (slab) |
2796 | n->free_slabs--; |
2797 | } |
2798 | |
2799 | if (sk_memalloc_socks()) |
2800 | slab = get_valid_first_slab(n, slab, pfmemalloc); |
2801 | |
2802 | return slab; |
2803 | } |
2804 | |
2805 | static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, |
2806 | struct kmem_cache_node *n, gfp_t flags) |
2807 | { |
2808 | struct slab *slab; |
2809 | void *obj; |
2810 | void *list = NULL; |
2811 | |
2812 | if (!gfp_pfmemalloc_allowed(gfp_mask: flags)) |
2813 | return NULL; |
2814 | |
2815 | raw_spin_lock(&n->list_lock); |
2816 | slab = get_first_slab(n, pfmemalloc: true); |
2817 | if (!slab) { |
2818 | raw_spin_unlock(&n->list_lock); |
2819 | return NULL; |
2820 | } |
2821 | |
2822 | obj = slab_get_obj(cachep, slab); |
2823 | n->free_objects--; |
2824 | |
2825 | fixup_slab_list(cachep, n, slab, list: &list); |
2826 | |
2827 | raw_spin_unlock(&n->list_lock); |
2828 | fixup_objfreelist_debug(cachep, list: &list); |
2829 | |
2830 | return obj; |
2831 | } |
2832 | |
2833 | /* |
2834 | * Slab list should be fixed up by fixup_slab_list() for existing slab |
2835 | * or cache_grow_end() for new slab |
2836 | */ |
2837 | static __always_inline int alloc_block(struct kmem_cache *cachep, |
2838 | struct array_cache *ac, struct slab *slab, int batchcount) |
2839 | { |
2840 | /* |
2841 | * There must be at least one object available for |
2842 | * allocation. |
2843 | */ |
2844 | BUG_ON(slab->active >= cachep->num); |
2845 | |
2846 | while (slab->active < cachep->num && batchcount--) { |
2847 | STATS_INC_ALLOCED(cachep); |
2848 | STATS_INC_ACTIVE(cachep); |
2849 | STATS_SET_HIGH(cachep); |
2850 | |
2851 | ac->entry[ac->avail++] = slab_get_obj(cachep, slab); |
2852 | } |
2853 | |
2854 | return batchcount; |
2855 | } |
2856 | |
2857 | static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) |
2858 | { |
2859 | int batchcount; |
2860 | struct kmem_cache_node *n; |
2861 | struct array_cache *ac, *shared; |
2862 | int node; |
2863 | void *list = NULL; |
2864 | struct slab *slab; |
2865 | |
2866 | check_irq_off(); |
2867 | node = numa_mem_id(); |
2868 | |
2869 | ac = cpu_cache_get(cachep); |
2870 | batchcount = ac->batchcount; |
2871 | if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { |
2872 | /* |
2873 | * If there was little recent activity on this cache, then |
2874 | * perform only a partial refill. Otherwise we could generate |
2875 | * refill bouncing. |
2876 | */ |
2877 | batchcount = BATCHREFILL_LIMIT; |
2878 | } |
2879 | n = get_node(s: cachep, node); |
2880 | |
2881 | BUG_ON(ac->avail > 0 || !n); |
2882 | shared = READ_ONCE(n->shared); |
2883 | if (!n->free_objects && (!shared || !shared->avail)) |
2884 | goto direct_grow; |
2885 | |
2886 | raw_spin_lock(&n->list_lock); |
2887 | shared = READ_ONCE(n->shared); |
2888 | |
2889 | /* See if we can refill from the shared array */ |
2890 | if (shared && transfer_objects(to: ac, from: shared, max: batchcount)) { |
2891 | shared->touched = 1; |
2892 | goto alloc_done; |
2893 | } |
2894 | |
2895 | while (batchcount > 0) { |
2896 | /* Get slab alloc is to come from. */ |
2897 | slab = get_first_slab(n, pfmemalloc: false); |
2898 | if (!slab) |
2899 | goto must_grow; |
2900 | |
2901 | check_spinlock_acquired(cachep); |
2902 | |
2903 | batchcount = alloc_block(cachep, ac, slab, batchcount); |
2904 | fixup_slab_list(cachep, n, slab, list: &list); |
2905 | } |
2906 | |
2907 | must_grow: |
2908 | n->free_objects -= ac->avail; |
2909 | alloc_done: |
2910 | raw_spin_unlock(&n->list_lock); |
2911 | fixup_objfreelist_debug(cachep, list: &list); |
2912 | |
2913 | direct_grow: |
2914 | if (unlikely(!ac->avail)) { |
2915 | /* Check if we can use obj in pfmemalloc slab */ |
2916 | if (sk_memalloc_socks()) { |
2917 | void *obj = cache_alloc_pfmemalloc(cachep, n, flags); |
2918 | |
2919 | if (obj) |
2920 | return obj; |
2921 | } |
2922 | |
2923 | slab = cache_grow_begin(cachep, flags: gfp_exact_node(flags), nodeid: node); |
2924 | |
2925 | /* |
2926 | * cache_grow_begin() can reenable interrupts, |
2927 | * then ac could change. |
2928 | */ |
2929 | ac = cpu_cache_get(cachep); |
2930 | if (!ac->avail && slab) |
2931 | alloc_block(cachep, ac, slab, batchcount); |
2932 | cache_grow_end(cachep, slab); |
2933 | |
2934 | if (!ac->avail) |
2935 | return NULL; |
2936 | } |
2937 | ac->touched = 1; |
2938 | |
2939 | return ac->entry[--ac->avail]; |
2940 | } |
2941 | |
2942 | #if DEBUG |
2943 | static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, |
2944 | gfp_t flags, void *objp, unsigned long caller) |
2945 | { |
2946 | WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); |
2947 | if (!objp || is_kfence_address(objp)) |
2948 | return objp; |
2949 | if (cachep->flags & SLAB_POISON) { |
2950 | check_poison_obj(cachep, objp); |
2951 | slab_kernel_map(cachep, objp, 1); |
2952 | poison_obj(cachep, objp, POISON_INUSE); |
2953 | } |
2954 | if (cachep->flags & SLAB_STORE_USER) |
2955 | *dbg_userword(cachep, objp) = (void *)caller; |
2956 | |
2957 | if (cachep->flags & SLAB_RED_ZONE) { |
2958 | if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || |
2959 | *dbg_redzone2(cachep, objp) != RED_INACTIVE) { |
2960 | slab_error(cachep, "double free, or memory outside object was overwritten" ); |
2961 | pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n" , |
2962 | objp, *dbg_redzone1(cachep, objp), |
2963 | *dbg_redzone2(cachep, objp)); |
2964 | } |
2965 | *dbg_redzone1(cachep, objp) = RED_ACTIVE; |
2966 | *dbg_redzone2(cachep, objp) = RED_ACTIVE; |
2967 | } |
2968 | |
2969 | objp += obj_offset(cachep); |
2970 | if (cachep->ctor && cachep->flags & SLAB_POISON) |
2971 | cachep->ctor(objp); |
2972 | if ((unsigned long)objp & (arch_slab_minalign() - 1)) { |
2973 | pr_err("0x%px: not aligned to arch_slab_minalign()=%u\n" , objp, |
2974 | arch_slab_minalign()); |
2975 | } |
2976 | return objp; |
2977 | } |
2978 | #else |
2979 | #define cache_alloc_debugcheck_after(a, b, objp, d) (objp) |
2980 | #endif |
2981 | |
2982 | static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) |
2983 | { |
2984 | void *objp; |
2985 | struct array_cache *ac; |
2986 | |
2987 | check_irq_off(); |
2988 | |
2989 | ac = cpu_cache_get(cachep); |
2990 | if (likely(ac->avail)) { |
2991 | ac->touched = 1; |
2992 | objp = ac->entry[--ac->avail]; |
2993 | |
2994 | STATS_INC_ALLOCHIT(cachep); |
2995 | goto out; |
2996 | } |
2997 | |
2998 | STATS_INC_ALLOCMISS(cachep); |
2999 | objp = cache_alloc_refill(cachep, flags); |
3000 | /* |
3001 | * the 'ac' may be updated by cache_alloc_refill(), |
3002 | * and kmemleak_erase() requires its correct value. |
3003 | */ |
3004 | ac = cpu_cache_get(cachep); |
3005 | |
3006 | out: |
3007 | /* |
3008 | * To avoid a false negative, if an object that is in one of the |
3009 | * per-CPU caches is leaked, we need to make sure kmemleak doesn't |
3010 | * treat the array pointers as a reference to the object. |
3011 | */ |
3012 | if (objp) |
3013 | kmemleak_erase(ptr: &ac->entry[ac->avail]); |
3014 | return objp; |
3015 | } |
3016 | |
3017 | #ifdef CONFIG_NUMA |
3018 | static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); |
3019 | |
3020 | /* |
3021 | * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set. |
3022 | * |
3023 | * If we are in_interrupt, then process context, including cpusets and |
3024 | * mempolicy, may not apply and should not be used for allocation policy. |
3025 | */ |
3026 | static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) |
3027 | { |
3028 | int nid_alloc, nid_here; |
3029 | |
3030 | if (in_interrupt() || (flags & __GFP_THISNODE)) |
3031 | return NULL; |
3032 | nid_alloc = nid_here = numa_mem_id(); |
3033 | if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) |
3034 | nid_alloc = cpuset_slab_spread_node(); |
3035 | else if (current->mempolicy) |
3036 | nid_alloc = mempolicy_slab_node(); |
3037 | if (nid_alloc != nid_here) |
3038 | return ____cache_alloc_node(cachep, flags, nid_alloc); |
3039 | return NULL; |
3040 | } |
3041 | |
3042 | /* |
3043 | * Fallback function if there was no memory available and no objects on a |
3044 | * certain node and fall back is permitted. First we scan all the |
3045 | * available node for available objects. If that fails then we |
3046 | * perform an allocation without specifying a node. This allows the page |
3047 | * allocator to do its reclaim / fallback magic. We then insert the |
3048 | * slab into the proper nodelist and then allocate from it. |
3049 | */ |
3050 | static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) |
3051 | { |
3052 | struct zonelist *zonelist; |
3053 | struct zoneref *z; |
3054 | struct zone *zone; |
3055 | enum zone_type highest_zoneidx = gfp_zone(flags); |
3056 | void *obj = NULL; |
3057 | struct slab *slab; |
3058 | int nid; |
3059 | unsigned int cpuset_mems_cookie; |
3060 | |
3061 | if (flags & __GFP_THISNODE) |
3062 | return NULL; |
3063 | |
3064 | retry_cpuset: |
3065 | cpuset_mems_cookie = read_mems_allowed_begin(); |
3066 | zonelist = node_zonelist(nid: mempolicy_slab_node(), flags); |
3067 | |
3068 | retry: |
3069 | /* |
3070 | * Look through allowed nodes for objects available |
3071 | * from existing per node queues. |
3072 | */ |
3073 | for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) { |
3074 | nid = zone_to_nid(zone); |
3075 | |
3076 | if (cpuset_zone_allowed(z: zone, gfp_mask: flags) && |
3077 | get_node(s: cache, node: nid) && |
3078 | get_node(s: cache, node: nid)->free_objects) { |
3079 | obj = ____cache_alloc_node(cache, |
3080 | gfp_exact_node(flags), nid); |
3081 | if (obj) |
3082 | break; |
3083 | } |
3084 | } |
3085 | |
3086 | if (!obj) { |
3087 | /* |
3088 | * This allocation will be performed within the constraints |
3089 | * of the current cpuset / memory policy requirements. |
3090 | * We may trigger various forms of reclaim on the allowed |
3091 | * set and go into memory reserves if necessary. |
3092 | */ |
3093 | slab = cache_grow_begin(cachep: cache, flags, nodeid: numa_mem_id()); |
3094 | cache_grow_end(cachep: cache, slab); |
3095 | if (slab) { |
3096 | nid = slab_nid(slab); |
3097 | obj = ____cache_alloc_node(cache, |
3098 | gfp_exact_node(flags), nid); |
3099 | |
3100 | /* |
3101 | * Another processor may allocate the objects in |
3102 | * the slab since we are not holding any locks. |
3103 | */ |
3104 | if (!obj) |
3105 | goto retry; |
3106 | } |
3107 | } |
3108 | |
3109 | if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie))) |
3110 | goto retry_cpuset; |
3111 | return obj; |
3112 | } |
3113 | |
3114 | /* |
3115 | * An interface to enable slab creation on nodeid |
3116 | */ |
3117 | static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, |
3118 | int nodeid) |
3119 | { |
3120 | struct slab *slab; |
3121 | struct kmem_cache_node *n; |
3122 | void *obj = NULL; |
3123 | void *list = NULL; |
3124 | |
3125 | VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES); |
3126 | n = get_node(s: cachep, node: nodeid); |
3127 | BUG_ON(!n); |
3128 | |
3129 | check_irq_off(); |
3130 | raw_spin_lock(&n->list_lock); |
3131 | slab = get_first_slab(n, pfmemalloc: false); |
3132 | if (!slab) |
3133 | goto must_grow; |
3134 | |
3135 | check_spinlock_acquired_node(cachep, nodeid); |
3136 | |
3137 | STATS_INC_NODEALLOCS(cachep); |
3138 | STATS_INC_ACTIVE(cachep); |
3139 | STATS_SET_HIGH(cachep); |
3140 | |
3141 | BUG_ON(slab->active == cachep->num); |
3142 | |
3143 | obj = slab_get_obj(cachep, slab); |
3144 | n->free_objects--; |
3145 | |
3146 | fixup_slab_list(cachep, n, slab, list: &list); |
3147 | |
3148 | raw_spin_unlock(&n->list_lock); |
3149 | fixup_objfreelist_debug(cachep, list: &list); |
3150 | return obj; |
3151 | |
3152 | must_grow: |
3153 | raw_spin_unlock(&n->list_lock); |
3154 | slab = cache_grow_begin(cachep, flags: gfp_exact_node(flags), nodeid); |
3155 | if (slab) { |
3156 | /* This slab isn't counted yet so don't update free_objects */ |
3157 | obj = slab_get_obj(cachep, slab); |
3158 | } |
3159 | cache_grow_end(cachep, slab); |
3160 | |
3161 | return obj ? obj : fallback_alloc(cache: cachep, flags); |
3162 | } |
3163 | |
3164 | static __always_inline void * |
3165 | __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags, int nodeid) |
3166 | { |
3167 | void *objp = NULL; |
3168 | int slab_node = numa_mem_id(); |
3169 | |
3170 | if (nodeid == NUMA_NO_NODE) { |
3171 | if (current->mempolicy || cpuset_do_slab_mem_spread()) { |
3172 | objp = alternate_node_alloc(cachep, flags); |
3173 | if (objp) |
3174 | goto out; |
3175 | } |
3176 | /* |
3177 | * Use the locally cached objects if possible. |
3178 | * However ____cache_alloc does not allow fallback |
3179 | * to other nodes. It may fail while we still have |
3180 | * objects on other nodes available. |
3181 | */ |
3182 | objp = ____cache_alloc(cachep, flags); |
3183 | nodeid = slab_node; |
3184 | } else if (nodeid == slab_node) { |
3185 | objp = ____cache_alloc(cachep, flags); |
3186 | } else if (!get_node(s: cachep, node: nodeid)) { |
3187 | /* Node not bootstrapped yet */ |
3188 | objp = fallback_alloc(cache: cachep, flags); |
3189 | goto out; |
3190 | } |
3191 | |
3192 | /* |
3193 | * We may just have run out of memory on the local node. |
3194 | * ____cache_alloc_node() knows how to locate memory on other nodes |
3195 | */ |
3196 | if (!objp) |
3197 | objp = ____cache_alloc_node(cachep, flags, nodeid); |
3198 | out: |
3199 | return objp; |
3200 | } |
3201 | #else |
3202 | |
3203 | static __always_inline void * |
3204 | __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags, int nodeid __maybe_unused) |
3205 | { |
3206 | return ____cache_alloc(cachep, flags); |
3207 | } |
3208 | |
3209 | #endif /* CONFIG_NUMA */ |
3210 | |
3211 | static __always_inline void * |
3212 | slab_alloc_node(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags, |
3213 | int nodeid, size_t orig_size, unsigned long caller) |
3214 | { |
3215 | unsigned long save_flags; |
3216 | void *objp; |
3217 | struct obj_cgroup *objcg = NULL; |
3218 | bool init = false; |
3219 | |
3220 | flags &= gfp_allowed_mask; |
3221 | cachep = slab_pre_alloc_hook(s: cachep, lru, objcgp: &objcg, size: 1, flags); |
3222 | if (unlikely(!cachep)) |
3223 | return NULL; |
3224 | |
3225 | objp = kfence_alloc(s: cachep, size: orig_size, flags); |
3226 | if (unlikely(objp)) |
3227 | goto out; |
3228 | |
3229 | local_irq_save(save_flags); |
3230 | objp = __do_cache_alloc(cachep, flags, nodeid); |
3231 | local_irq_restore(save_flags); |
3232 | objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); |
3233 | prefetchw(x: objp); |
3234 | init = slab_want_init_on_alloc(flags, c: cachep); |
3235 | |
3236 | out: |
3237 | slab_post_alloc_hook(s: cachep, objcg, flags, size: 1, p: &objp, init, |
3238 | orig_size: cachep->object_size); |
3239 | return objp; |
3240 | } |
3241 | |
3242 | static __always_inline void * |
3243 | slab_alloc(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags, |
3244 | size_t orig_size, unsigned long caller) |
3245 | { |
3246 | return slab_alloc_node(cachep, lru, flags, NUMA_NO_NODE, orig_size, |
3247 | caller); |
3248 | } |
3249 | |
3250 | /* |
3251 | * Caller needs to acquire correct kmem_cache_node's list_lock |
3252 | * @list: List of detached free slabs should be freed by caller |
3253 | */ |
3254 | static void free_block(struct kmem_cache *cachep, void **objpp, |
3255 | int nr_objects, int node, struct list_head *list) |
3256 | { |
3257 | int i; |
3258 | struct kmem_cache_node *n = get_node(s: cachep, node); |
3259 | struct slab *slab; |
3260 | |
3261 | n->free_objects += nr_objects; |
3262 | |
3263 | for (i = 0; i < nr_objects; i++) { |
3264 | void *objp; |
3265 | struct slab *slab; |
3266 | |
3267 | objp = objpp[i]; |
3268 | |
3269 | slab = virt_to_slab(addr: objp); |
3270 | list_del(entry: &slab->slab_list); |
3271 | check_spinlock_acquired_node(cachep, node); |
3272 | slab_put_obj(cachep, slab, objp); |
3273 | STATS_DEC_ACTIVE(cachep); |
3274 | |
3275 | /* fixup slab chains */ |
3276 | if (slab->active == 0) { |
3277 | list_add(new: &slab->slab_list, head: &n->slabs_free); |
3278 | n->free_slabs++; |
3279 | } else { |
3280 | /* Unconditionally move a slab to the end of the |
3281 | * partial list on free - maximum time for the |
3282 | * other objects to be freed, too. |
3283 | */ |
3284 | list_add_tail(new: &slab->slab_list, head: &n->slabs_partial); |
3285 | } |
3286 | } |
3287 | |
3288 | while (n->free_objects > n->free_limit && !list_empty(head: &n->slabs_free)) { |
3289 | n->free_objects -= cachep->num; |
3290 | |
3291 | slab = list_last_entry(&n->slabs_free, struct slab, slab_list); |
3292 | list_move(list: &slab->slab_list, head: list); |
3293 | n->free_slabs--; |
3294 | n->total_slabs--; |
3295 | } |
3296 | } |
3297 | |
3298 | static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) |
3299 | { |
3300 | int batchcount; |
3301 | struct kmem_cache_node *n; |
3302 | int node = numa_mem_id(); |
3303 | LIST_HEAD(list); |
3304 | |
3305 | batchcount = ac->batchcount; |
3306 | |
3307 | check_irq_off(); |
3308 | n = get_node(s: cachep, node); |
3309 | raw_spin_lock(&n->list_lock); |
3310 | if (n->shared) { |
3311 | struct array_cache *shared_array = n->shared; |
3312 | int max = shared_array->limit - shared_array->avail; |
3313 | if (max) { |
3314 | if (batchcount > max) |
3315 | batchcount = max; |
3316 | memcpy(&(shared_array->entry[shared_array->avail]), |
3317 | ac->entry, sizeof(void *) * batchcount); |
3318 | shared_array->avail += batchcount; |
3319 | goto free_done; |
3320 | } |
3321 | } |
3322 | |
3323 | free_block(cachep, objpp: ac->entry, nr_objects: batchcount, node, list: &list); |
3324 | free_done: |
3325 | #if STATS |
3326 | { |
3327 | int i = 0; |
3328 | struct slab *slab; |
3329 | |
3330 | list_for_each_entry(slab, &n->slabs_free, slab_list) { |
3331 | BUG_ON(slab->active); |
3332 | |
3333 | i++; |
3334 | } |
3335 | STATS_SET_FREEABLE(cachep, i); |
3336 | } |
3337 | #endif |
3338 | raw_spin_unlock(&n->list_lock); |
3339 | ac->avail -= batchcount; |
3340 | memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); |
3341 | slabs_destroy(cachep, list: &list); |
3342 | } |
3343 | |
3344 | /* |
3345 | * Release an obj back to its cache. If the obj has a constructed state, it must |
3346 | * be in this state _before_ it is released. Called with disabled ints. |
3347 | */ |
3348 | static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, |
3349 | unsigned long caller) |
3350 | { |
3351 | bool init; |
3352 | |
3353 | memcg_slab_free_hook(s: cachep, slab: virt_to_slab(addr: objp), p: &objp, objects: 1); |
3354 | |
3355 | if (is_kfence_address(addr: objp)) { |
3356 | kmemleak_free_recursive(ptr: objp, flags: cachep->flags); |
3357 | __kfence_free(addr: objp); |
3358 | return; |
3359 | } |
3360 | |
3361 | /* |
3362 | * As memory initialization might be integrated into KASAN, |
3363 | * kasan_slab_free and initialization memset must be |
3364 | * kept together to avoid discrepancies in behavior. |
3365 | */ |
3366 | init = slab_want_init_on_free(c: cachep); |
3367 | if (init && !kasan_has_integrated_init()) |
3368 | memset(objp, 0, cachep->object_size); |
3369 | /* KASAN might put objp into memory quarantine, delaying its reuse. */ |
3370 | if (kasan_slab_free(s: cachep, object: objp, init)) |
3371 | return; |
3372 | |
3373 | /* Use KCSAN to help debug racy use-after-free. */ |
3374 | if (!(cachep->flags & SLAB_TYPESAFE_BY_RCU)) |
3375 | __kcsan_check_access(ptr: objp, size: cachep->object_size, |
3376 | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT); |
3377 | |
3378 | ___cache_free(cache: cachep, x: objp, addr: caller); |
3379 | } |
3380 | |
3381 | void ___cache_free(struct kmem_cache *cachep, void *objp, |
3382 | unsigned long caller) |
3383 | { |
3384 | struct array_cache *ac = cpu_cache_get(cachep); |
3385 | |
3386 | check_irq_off(); |
3387 | kmemleak_free_recursive(ptr: objp, flags: cachep->flags); |
3388 | objp = cache_free_debugcheck(cachep, objp, caller); |
3389 | |
3390 | /* |
3391 | * Skip calling cache_free_alien() when the platform is not numa. |
3392 | * This will avoid cache misses that happen while accessing slabp (which |
3393 | * is per page memory reference) to get nodeid. Instead use a global |
3394 | * variable to skip the call, which is mostly likely to be present in |
3395 | * the cache. |
3396 | */ |
3397 | if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) |
3398 | return; |
3399 | |
3400 | if (ac->avail < ac->limit) { |
3401 | STATS_INC_FREEHIT(cachep); |
3402 | } else { |
3403 | STATS_INC_FREEMISS(cachep); |
3404 | cache_flusharray(cachep, ac); |
3405 | } |
3406 | |
3407 | if (sk_memalloc_socks()) { |
3408 | struct slab *slab = virt_to_slab(addr: objp); |
3409 | |
3410 | if (unlikely(slab_test_pfmemalloc(slab))) { |
3411 | cache_free_pfmemalloc(cachep, slab, objp); |
3412 | return; |
3413 | } |
3414 | } |
3415 | |
3416 | __free_one(ac, objp); |
3417 | } |
3418 | |
3419 | static __always_inline |
3420 | void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru, |
3421 | gfp_t flags) |
3422 | { |
3423 | void *ret = slab_alloc(cachep, lru, flags, orig_size: cachep->object_size, _RET_IP_); |
3424 | |
3425 | trace_kmem_cache_alloc(_RET_IP_, ptr: ret, s: cachep, gfp_flags: flags, NUMA_NO_NODE); |
3426 | |
3427 | return ret; |
3428 | } |
3429 | |
3430 | void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) |
3431 | { |
3432 | return __kmem_cache_alloc_lru(cachep, NULL, flags); |
3433 | } |
3434 | EXPORT_SYMBOL(kmem_cache_alloc); |
3435 | |
3436 | void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru, |
3437 | gfp_t flags) |
3438 | { |
3439 | return __kmem_cache_alloc_lru(cachep, lru, flags); |
3440 | } |
3441 | EXPORT_SYMBOL(kmem_cache_alloc_lru); |
3442 | |
3443 | static __always_inline void |
3444 | cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags, |
3445 | size_t size, void **p, unsigned long caller) |
3446 | { |
3447 | size_t i; |
3448 | |
3449 | for (i = 0; i < size; i++) |
3450 | p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller); |
3451 | } |
3452 | |
3453 | int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, |
3454 | void **p) |
3455 | { |
3456 | struct obj_cgroup *objcg = NULL; |
3457 | unsigned long irqflags; |
3458 | size_t i; |
3459 | |
3460 | s = slab_pre_alloc_hook(s, NULL, objcgp: &objcg, size, flags); |
3461 | if (!s) |
3462 | return 0; |
3463 | |
3464 | local_irq_save(irqflags); |
3465 | for (i = 0; i < size; i++) { |
3466 | void *objp = kfence_alloc(s, size: s->object_size, flags) ?: |
3467 | __do_cache_alloc(cachep: s, flags, NUMA_NO_NODE); |
3468 | |
3469 | if (unlikely(!objp)) |
3470 | goto error; |
3471 | p[i] = objp; |
3472 | } |
3473 | local_irq_restore(irqflags); |
3474 | |
3475 | cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_); |
3476 | |
3477 | /* |
3478 | * memcg and kmem_cache debug support and memory initialization. |
3479 | * Done outside of the IRQ disabled section. |
3480 | */ |
3481 | slab_post_alloc_hook(s, objcg, flags, size, p, |
3482 | init: slab_want_init_on_alloc(flags, c: s), orig_size: s->object_size); |
3483 | /* FIXME: Trace call missing. Christoph would like a bulk variant */ |
3484 | return size; |
3485 | error: |
3486 | local_irq_restore(irqflags); |
3487 | cache_alloc_debugcheck_after_bulk(s, flags, size: i, p, _RET_IP_); |
3488 | slab_post_alloc_hook(s, objcg, flags, size: i, p, init: false, orig_size: s->object_size); |
3489 | kmem_cache_free_bulk(s, size: i, p); |
3490 | return 0; |
3491 | } |
3492 | EXPORT_SYMBOL(kmem_cache_alloc_bulk); |
3493 | |
3494 | /** |
3495 | * kmem_cache_alloc_node - Allocate an object on the specified node |
3496 | * @cachep: The cache to allocate from. |
3497 | * @flags: See kmalloc(). |
3498 | * @nodeid: node number of the target node. |
3499 | * |
3500 | * Identical to kmem_cache_alloc but it will allocate memory on the given |
3501 | * node, which can improve the performance for cpu bound structures. |
3502 | * |
3503 | * Fallback to other node is possible if __GFP_THISNODE is not set. |
3504 | * |
3505 | * Return: pointer to the new object or %NULL in case of error |
3506 | */ |
3507 | void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) |
3508 | { |
3509 | void *ret = slab_alloc_node(cachep, NULL, flags, nodeid, orig_size: cachep->object_size, _RET_IP_); |
3510 | |
3511 | trace_kmem_cache_alloc(_RET_IP_, ptr: ret, s: cachep, gfp_flags: flags, node: nodeid); |
3512 | |
3513 | return ret; |
3514 | } |
3515 | EXPORT_SYMBOL(kmem_cache_alloc_node); |
3516 | |
3517 | void *__kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, |
3518 | int nodeid, size_t orig_size, |
3519 | unsigned long caller) |
3520 | { |
3521 | return slab_alloc_node(cachep, NULL, flags, nodeid, |
3522 | orig_size, caller); |
3523 | } |
3524 | |
3525 | #ifdef CONFIG_PRINTK |
3526 | void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) |
3527 | { |
3528 | struct kmem_cache *cachep; |
3529 | unsigned int objnr; |
3530 | void *objp; |
3531 | |
3532 | kpp->kp_ptr = object; |
3533 | kpp->kp_slab = slab; |
3534 | cachep = slab->slab_cache; |
3535 | kpp->kp_slab_cache = cachep; |
3536 | objp = object - obj_offset(cachep); |
3537 | kpp->kp_data_offset = obj_offset(cachep); |
3538 | slab = virt_to_slab(addr: objp); |
3539 | objnr = obj_to_index(cache: cachep, slab, obj: objp); |
3540 | objp = index_to_obj(cache: cachep, slab, idx: objnr); |
3541 | kpp->kp_objp = objp; |
3542 | if (DEBUG && cachep->flags & SLAB_STORE_USER) |
3543 | kpp->kp_ret = *dbg_userword(cachep, objp); |
3544 | } |
3545 | #endif |
3546 | |
3547 | static __always_inline |
3548 | void __do_kmem_cache_free(struct kmem_cache *cachep, void *objp, |
3549 | unsigned long caller) |
3550 | { |
3551 | unsigned long flags; |
3552 | |
3553 | local_irq_save(flags); |
3554 | debug_check_no_locks_freed(from: objp, len: cachep->object_size); |
3555 | if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) |
3556 | debug_check_no_obj_freed(address: objp, size: cachep->object_size); |
3557 | __cache_free(cachep, objp, caller); |
3558 | local_irq_restore(flags); |
3559 | } |
3560 | |
3561 | void __kmem_cache_free(struct kmem_cache *cachep, void *objp, |
3562 | unsigned long caller) |
3563 | { |
3564 | __do_kmem_cache_free(cachep, objp, caller); |
3565 | } |
3566 | |
3567 | /** |
3568 | * kmem_cache_free - Deallocate an object |
3569 | * @cachep: The cache the allocation was from. |
3570 | * @objp: The previously allocated object. |
3571 | * |
3572 | * Free an object which was previously allocated from this |
3573 | * cache. |
3574 | */ |
3575 | void kmem_cache_free(struct kmem_cache *cachep, void *objp) |
3576 | { |
3577 | cachep = cache_from_obj(s: cachep, x: objp); |
3578 | if (!cachep) |
3579 | return; |
3580 | |
3581 | trace_kmem_cache_free(_RET_IP_, ptr: objp, s: cachep); |
3582 | __do_kmem_cache_free(cachep, objp, _RET_IP_); |
3583 | } |
3584 | EXPORT_SYMBOL(kmem_cache_free); |
3585 | |
3586 | void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) |
3587 | { |
3588 | unsigned long flags; |
3589 | |
3590 | local_irq_save(flags); |
3591 | for (int i = 0; i < size; i++) { |
3592 | void *objp = p[i]; |
3593 | struct kmem_cache *s; |
3594 | |
3595 | if (!orig_s) { |
3596 | struct folio *folio = virt_to_folio(x: objp); |
3597 | |
3598 | /* called via kfree_bulk */ |
3599 | if (!folio_test_slab(folio)) { |
3600 | local_irq_restore(flags); |
3601 | free_large_kmalloc(folio, object: objp); |
3602 | local_irq_save(flags); |
3603 | continue; |
3604 | } |
3605 | s = folio_slab(folio)->slab_cache; |
3606 | } else { |
3607 | s = cache_from_obj(s: orig_s, x: objp); |
3608 | } |
3609 | |
3610 | if (!s) |
3611 | continue; |
3612 | |
3613 | debug_check_no_locks_freed(from: objp, len: s->object_size); |
3614 | if (!(s->flags & SLAB_DEBUG_OBJECTS)) |
3615 | debug_check_no_obj_freed(address: objp, size: s->object_size); |
3616 | |
3617 | __cache_free(cachep: s, objp, _RET_IP_); |
3618 | } |
3619 | local_irq_restore(flags); |
3620 | |
3621 | /* FIXME: add tracing */ |
3622 | } |
3623 | EXPORT_SYMBOL(kmem_cache_free_bulk); |
3624 | |
3625 | /* |
3626 | * This initializes kmem_cache_node or resizes various caches for all nodes. |
3627 | */ |
3628 | static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp) |
3629 | { |
3630 | int ret; |
3631 | int node; |
3632 | struct kmem_cache_node *n; |
3633 | |
3634 | for_each_online_node(node) { |
3635 | ret = setup_kmem_cache_node(cachep, node, gfp, force_change: true); |
3636 | if (ret) |
3637 | goto fail; |
3638 | |
3639 | } |
3640 | |
3641 | return 0; |
3642 | |
3643 | fail: |
3644 | if (!cachep->list.next) { |
3645 | /* Cache is not active yet. Roll back what we did */ |
3646 | node--; |
3647 | while (node >= 0) { |
3648 | n = get_node(s: cachep, node); |
3649 | if (n) { |
3650 | kfree(objp: n->shared); |
3651 | free_alien_cache(alc_ptr: n->alien); |
3652 | kfree(objp: n); |
3653 | cachep->node[node] = NULL; |
3654 | } |
3655 | node--; |
3656 | } |
3657 | } |
3658 | return -ENOMEM; |
3659 | } |
3660 | |
3661 | /* Always called with the slab_mutex held */ |
3662 | static int do_tune_cpucache(struct kmem_cache *cachep, int limit, |
3663 | int batchcount, int shared, gfp_t gfp) |
3664 | { |
3665 | struct array_cache __percpu *cpu_cache, *prev; |
3666 | int cpu; |
3667 | |
3668 | cpu_cache = alloc_kmem_cache_cpus(cachep, entries: limit, batchcount); |
3669 | if (!cpu_cache) |
3670 | return -ENOMEM; |
3671 | |
3672 | prev = cachep->cpu_cache; |
3673 | cachep->cpu_cache = cpu_cache; |
3674 | /* |
3675 | * Without a previous cpu_cache there's no need to synchronize remote |
3676 | * cpus, so skip the IPIs. |
3677 | */ |
3678 | if (prev) |
3679 | kick_all_cpus_sync(); |
3680 | |
3681 | check_irq_on(); |
3682 | cachep->batchcount = batchcount; |
3683 | cachep->limit = limit; |
3684 | cachep->shared = shared; |
3685 | |
3686 | if (!prev) |
3687 | goto setup_node; |
3688 | |
3689 | for_each_online_cpu(cpu) { |
3690 | LIST_HEAD(list); |
3691 | int node; |
3692 | struct kmem_cache_node *n; |
3693 | struct array_cache *ac = per_cpu_ptr(prev, cpu); |
3694 | |
3695 | node = cpu_to_mem(cpu); |
3696 | n = get_node(s: cachep, node); |
3697 | raw_spin_lock_irq(&n->list_lock); |
3698 | free_block(cachep, objpp: ac->entry, nr_objects: ac->avail, node, list: &list); |
3699 | raw_spin_unlock_irq(&n->list_lock); |
3700 | slabs_destroy(cachep, list: &list); |
3701 | } |
3702 | free_percpu(pdata: prev); |
3703 | |
3704 | setup_node: |
3705 | return setup_kmem_cache_nodes(cachep, gfp); |
3706 | } |
3707 | |
3708 | /* Called with slab_mutex held always */ |
3709 | static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) |
3710 | { |
3711 | int err; |
3712 | int limit = 0; |
3713 | int shared = 0; |
3714 | int batchcount = 0; |
3715 | |
3716 | err = cache_random_seq_create(cachep, count: cachep->num, gfp); |
3717 | if (err) |
3718 | goto end; |
3719 | |
3720 | /* |
3721 | * The head array serves three purposes: |
3722 | * - create a LIFO ordering, i.e. return objects that are cache-warm |
3723 | * - reduce the number of spinlock operations. |
3724 | * - reduce the number of linked list operations on the slab and |
3725 | * bufctl chains: array operations are cheaper. |
3726 | * The numbers are guessed, we should auto-tune as described by |
3727 | * Bonwick. |
3728 | */ |
3729 | if (cachep->size > 131072) |
3730 | limit = 1; |
3731 | else if (cachep->size > PAGE_SIZE) |
3732 | limit = 8; |
3733 | else if (cachep->size > 1024) |
3734 | limit = 24; |
3735 | else if (cachep->size > 256) |
3736 | limit = 54; |
3737 | else |
3738 | limit = 120; |
3739 | |
3740 | /* |
3741 | * CPU bound tasks (e.g. network routing) can exhibit cpu bound |
3742 | * allocation behaviour: Most allocs on one cpu, most free operations |
3743 | * on another cpu. For these cases, an efficient object passing between |
3744 | * cpus is necessary. This is provided by a shared array. The array |
3745 | * replaces Bonwick's magazine layer. |
3746 | * On uniprocessor, it's functionally equivalent (but less efficient) |
3747 | * to a larger limit. Thus disabled by default. |
3748 | */ |
3749 | shared = 0; |
3750 | if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1) |
3751 | shared = 8; |
3752 | |
3753 | #if DEBUG |
3754 | /* |
3755 | * With debugging enabled, large batchcount lead to excessively long |
3756 | * periods with disabled local interrupts. Limit the batchcount |
3757 | */ |
3758 | if (limit > 32) |
3759 | limit = 32; |
3760 | #endif |
3761 | batchcount = (limit + 1) / 2; |
3762 | err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp); |
3763 | end: |
3764 | if (err) |
3765 | pr_err("enable_cpucache failed for %s, error %d\n" , |
3766 | cachep->name, -err); |
3767 | return err; |
3768 | } |
3769 | |
3770 | /* |
3771 | * Drain an array if it contains any elements taking the node lock only if |
3772 | * necessary. Note that the node listlock also protects the array_cache |
3773 | * if drain_array() is used on the shared array. |
3774 | */ |
3775 | static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, |
3776 | struct array_cache *ac, int node) |
3777 | { |
3778 | LIST_HEAD(list); |
3779 | |
3780 | /* ac from n->shared can be freed if we don't hold the slab_mutex. */ |
3781 | check_mutex_acquired(); |
3782 | |
3783 | if (!ac || !ac->avail) |
3784 | return; |
3785 | |
3786 | if (ac->touched) { |
3787 | ac->touched = 0; |
3788 | return; |
3789 | } |
3790 | |
3791 | raw_spin_lock_irq(&n->list_lock); |
3792 | drain_array_locked(cachep, ac, node, free_all: false, list: &list); |
3793 | raw_spin_unlock_irq(&n->list_lock); |
3794 | |
3795 | slabs_destroy(cachep, list: &list); |
3796 | } |
3797 | |
3798 | /** |
3799 | * cache_reap - Reclaim memory from caches. |
3800 | * @w: work descriptor |
3801 | * |
3802 | * Called from workqueue/eventd every few seconds. |
3803 | * Purpose: |
3804 | * - clear the per-cpu caches for this CPU. |
3805 | * - return freeable pages to the main free memory pool. |
3806 | * |
3807 | * If we cannot acquire the cache chain mutex then just give up - we'll try |
3808 | * again on the next iteration. |
3809 | */ |
3810 | static void cache_reap(struct work_struct *w) |
3811 | { |
3812 | struct kmem_cache *searchp; |
3813 | struct kmem_cache_node *n; |
3814 | int node = numa_mem_id(); |
3815 | struct delayed_work *work = to_delayed_work(work: w); |
3816 | |
3817 | if (!mutex_trylock(lock: &slab_mutex)) |
3818 | /* Give up. Setup the next iteration. */ |
3819 | goto out; |
3820 | |
3821 | list_for_each_entry(searchp, &slab_caches, list) { |
3822 | check_irq_on(); |
3823 | |
3824 | /* |
3825 | * We only take the node lock if absolutely necessary and we |
3826 | * have established with reasonable certainty that |
3827 | * we can do some work if the lock was obtained. |
3828 | */ |
3829 | n = get_node(s: searchp, node); |
3830 | |
3831 | reap_alien(cachep: searchp, n); |
3832 | |
3833 | drain_array(cachep: searchp, n, ac: cpu_cache_get(cachep: searchp), node); |
3834 | |
3835 | /* |
3836 | * These are racy checks but it does not matter |
3837 | * if we skip one check or scan twice. |
3838 | */ |
3839 | if (time_after(n->next_reap, jiffies)) |
3840 | goto next; |
3841 | |
3842 | n->next_reap = jiffies + REAPTIMEOUT_NODE; |
3843 | |
3844 | drain_array(cachep: searchp, n, ac: n->shared, node); |
3845 | |
3846 | if (n->free_touched) |
3847 | n->free_touched = 0; |
3848 | else { |
3849 | int freed; |
3850 | |
3851 | freed = drain_freelist(cache: searchp, n, tofree: (n->free_limit + |
3852 | 5 * searchp->num - 1) / (5 * searchp->num)); |
3853 | STATS_ADD_REAPED(searchp, freed); |
3854 | } |
3855 | next: |
3856 | cond_resched(); |
3857 | } |
3858 | check_irq_on(); |
3859 | mutex_unlock(lock: &slab_mutex); |
3860 | next_reap_node(); |
3861 | out: |
3862 | /* Set up the next iteration */ |
3863 | schedule_delayed_work_on(smp_processor_id(), dwork: work, |
3864 | delay: round_jiffies_relative(REAPTIMEOUT_AC)); |
3865 | } |
3866 | |
3867 | void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) |
3868 | { |
3869 | unsigned long active_objs, num_objs, active_slabs; |
3870 | unsigned long total_slabs = 0, free_objs = 0, shared_avail = 0; |
3871 | unsigned long free_slabs = 0; |
3872 | int node; |
3873 | struct kmem_cache_node *n; |
3874 | |
3875 | for_each_kmem_cache_node(cachep, node, n) { |
3876 | check_irq_on(); |
3877 | raw_spin_lock_irq(&n->list_lock); |
3878 | |
3879 | total_slabs += n->total_slabs; |
3880 | free_slabs += n->free_slabs; |
3881 | free_objs += n->free_objects; |
3882 | |
3883 | if (n->shared) |
3884 | shared_avail += n->shared->avail; |
3885 | |
3886 | raw_spin_unlock_irq(&n->list_lock); |
3887 | } |
3888 | num_objs = total_slabs * cachep->num; |
3889 | active_slabs = total_slabs - free_slabs; |
3890 | active_objs = num_objs - free_objs; |
3891 | |
3892 | sinfo->active_objs = active_objs; |
3893 | sinfo->num_objs = num_objs; |
3894 | sinfo->active_slabs = active_slabs; |
3895 | sinfo->num_slabs = total_slabs; |
3896 | sinfo->shared_avail = shared_avail; |
3897 | sinfo->limit = cachep->limit; |
3898 | sinfo->batchcount = cachep->batchcount; |
3899 | sinfo->shared = cachep->shared; |
3900 | sinfo->objects_per_slab = cachep->num; |
3901 | sinfo->cache_order = cachep->gfporder; |
3902 | } |
3903 | |
3904 | void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep) |
3905 | { |
3906 | #if STATS |
3907 | { /* node stats */ |
3908 | unsigned long high = cachep->high_mark; |
3909 | unsigned long allocs = cachep->num_allocations; |
3910 | unsigned long grown = cachep->grown; |
3911 | unsigned long reaped = cachep->reaped; |
3912 | unsigned long errors = cachep->errors; |
3913 | unsigned long max_freeable = cachep->max_freeable; |
3914 | unsigned long node_allocs = cachep->node_allocs; |
3915 | unsigned long node_frees = cachep->node_frees; |
3916 | unsigned long overflows = cachep->node_overflow; |
3917 | |
3918 | seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu" , |
3919 | allocs, high, grown, |
3920 | reaped, errors, max_freeable, node_allocs, |
3921 | node_frees, overflows); |
3922 | } |
3923 | /* cpu stats */ |
3924 | { |
3925 | unsigned long allochit = atomic_read(&cachep->allochit); |
3926 | unsigned long allocmiss = atomic_read(&cachep->allocmiss); |
3927 | unsigned long freehit = atomic_read(&cachep->freehit); |
3928 | unsigned long freemiss = atomic_read(&cachep->freemiss); |
3929 | |
3930 | seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu" , |
3931 | allochit, allocmiss, freehit, freemiss); |
3932 | } |
3933 | #endif |
3934 | } |
3935 | |
3936 | #define MAX_SLABINFO_WRITE 128 |
3937 | /** |
3938 | * slabinfo_write - Tuning for the slab allocator |
3939 | * @file: unused |
3940 | * @buffer: user buffer |
3941 | * @count: data length |
3942 | * @ppos: unused |
3943 | * |
3944 | * Return: %0 on success, negative error code otherwise. |
3945 | */ |
3946 | ssize_t slabinfo_write(struct file *file, const char __user *buffer, |
3947 | size_t count, loff_t *ppos) |
3948 | { |
3949 | char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; |
3950 | int limit, batchcount, shared, res; |
3951 | struct kmem_cache *cachep; |
3952 | |
3953 | if (count > MAX_SLABINFO_WRITE) |
3954 | return -EINVAL; |
3955 | if (copy_from_user(to: &kbuf, from: buffer, n: count)) |
3956 | return -EFAULT; |
3957 | kbuf[MAX_SLABINFO_WRITE] = '\0'; |
3958 | |
3959 | tmp = strchr(kbuf, ' '); |
3960 | if (!tmp) |
3961 | return -EINVAL; |
3962 | *tmp = '\0'; |
3963 | tmp++; |
3964 | if (sscanf(tmp, " %d %d %d" , &limit, &batchcount, &shared) != 3) |
3965 | return -EINVAL; |
3966 | |
3967 | /* Find the cache in the chain of caches. */ |
3968 | mutex_lock(&slab_mutex); |
3969 | res = -EINVAL; |
3970 | list_for_each_entry(cachep, &slab_caches, list) { |
3971 | if (!strcmp(cachep->name, kbuf)) { |
3972 | if (limit < 1 || batchcount < 1 || |
3973 | batchcount > limit || shared < 0) { |
3974 | res = 0; |
3975 | } else { |
3976 | res = do_tune_cpucache(cachep, limit, |
3977 | batchcount, shared, |
3978 | GFP_KERNEL); |
3979 | } |
3980 | break; |
3981 | } |
3982 | } |
3983 | mutex_unlock(lock: &slab_mutex); |
3984 | if (res >= 0) |
3985 | res = count; |
3986 | return res; |
3987 | } |
3988 | |
3989 | #ifdef CONFIG_HARDENED_USERCOPY |
3990 | /* |
3991 | * Rejects incorrectly sized objects and objects that are to be copied |
3992 | * to/from userspace but do not fall entirely within the containing slab |
3993 | * cache's usercopy region. |
3994 | * |
3995 | * Returns NULL if check passes, otherwise const char * to name of cache |
3996 | * to indicate an error. |
3997 | */ |
3998 | void __check_heap_object(const void *ptr, unsigned long n, |
3999 | const struct slab *slab, bool to_user) |
4000 | { |
4001 | struct kmem_cache *cachep; |
4002 | unsigned int objnr; |
4003 | unsigned long offset; |
4004 | |
4005 | ptr = kasan_reset_tag(addr: ptr); |
4006 | |
4007 | /* Find and validate object. */ |
4008 | cachep = slab->slab_cache; |
4009 | objnr = obj_to_index(cache: cachep, slab, obj: (void *)ptr); |
4010 | BUG_ON(objnr >= cachep->num); |
4011 | |
4012 | /* Find offset within object. */ |
4013 | if (is_kfence_address(addr: ptr)) |
4014 | offset = ptr - kfence_object_start(addr: ptr); |
4015 | else |
4016 | offset = ptr - index_to_obj(cache: cachep, slab, idx: objnr) - obj_offset(cachep); |
4017 | |
4018 | /* Allow address range falling entirely within usercopy region. */ |
4019 | if (offset >= cachep->useroffset && |
4020 | offset - cachep->useroffset <= cachep->usersize && |
4021 | n <= cachep->useroffset - offset + cachep->usersize) |
4022 | return; |
4023 | |
4024 | usercopy_abort(name: "SLAB object" , detail: cachep->name, to_user, offset, len: n); |
4025 | } |
4026 | #endif /* CONFIG_HARDENED_USERCOPY */ |
4027 | |