1 | /* |
2 | * zsmalloc memory allocator |
3 | * |
4 | * Copyright (C) 2011 Nitin Gupta |
5 | * Copyright (C) 2012, 2013 Minchan Kim |
6 | * |
7 | * This code is released using a dual license strategy: BSD/GPL |
8 | * You can choose the license that better fits your requirements. |
9 | * |
10 | * Released under the terms of 3-clause BSD License |
11 | * Released under the terms of GNU General Public License Version 2.0 |
12 | */ |
13 | |
14 | /* |
15 | * Following is how we use various fields and flags of underlying |
16 | * struct page(s) to form a zspage. |
17 | * |
18 | * Usage of struct page fields: |
19 | * page->private: points to zspage |
20 | * page->index: links together all component pages of a zspage |
21 | * For the huge page, this is always 0, so we use this field |
22 | * to store handle. |
23 | * page->page_type: first object offset in a subpage of zspage |
24 | * |
25 | * Usage of struct page flags: |
26 | * PG_private: identifies the first component page |
27 | * PG_owner_priv_1: identifies the huge component page |
28 | * |
29 | */ |
30 | |
31 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
32 | |
33 | /* |
34 | * lock ordering: |
35 | * page_lock |
36 | * pool->lock |
37 | * zspage->lock |
38 | */ |
39 | |
40 | #include <linux/module.h> |
41 | #include <linux/kernel.h> |
42 | #include <linux/sched.h> |
43 | #include <linux/bitops.h> |
44 | #include <linux/errno.h> |
45 | #include <linux/highmem.h> |
46 | #include <linux/string.h> |
47 | #include <linux/slab.h> |
48 | #include <linux/pgtable.h> |
49 | #include <asm/tlbflush.h> |
50 | #include <linux/cpumask.h> |
51 | #include <linux/cpu.h> |
52 | #include <linux/vmalloc.h> |
53 | #include <linux/preempt.h> |
54 | #include <linux/spinlock.h> |
55 | #include <linux/shrinker.h> |
56 | #include <linux/types.h> |
57 | #include <linux/debugfs.h> |
58 | #include <linux/zsmalloc.h> |
59 | #include <linux/zpool.h> |
60 | #include <linux/migrate.h> |
61 | #include <linux/wait.h> |
62 | #include <linux/pagemap.h> |
63 | #include <linux/fs.h> |
64 | #include <linux/local_lock.h> |
65 | |
66 | #define ZSPAGE_MAGIC 0x58 |
67 | |
68 | /* |
69 | * This must be power of 2 and greater than or equal to sizeof(link_free). |
70 | * These two conditions ensure that any 'struct link_free' itself doesn't |
71 | * span more than 1 page which avoids complex case of mapping 2 pages simply |
72 | * to restore link_free pointer values. |
73 | */ |
74 | #define ZS_ALIGN 8 |
75 | |
76 | #define ZS_HANDLE_SIZE (sizeof(unsigned long)) |
77 | |
78 | /* |
79 | * Object location (<PFN>, <obj_idx>) is encoded as |
80 | * a single (unsigned long) handle value. |
81 | * |
82 | * Note that object index <obj_idx> starts from 0. |
83 | * |
84 | * This is made more complicated by various memory models and PAE. |
85 | */ |
86 | |
87 | #ifndef MAX_POSSIBLE_PHYSMEM_BITS |
88 | #ifdef MAX_PHYSMEM_BITS |
89 | #define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS |
90 | #else |
91 | /* |
92 | * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just |
93 | * be PAGE_SHIFT |
94 | */ |
95 | #define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG |
96 | #endif |
97 | #endif |
98 | |
99 | #define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT) |
100 | |
101 | /* |
102 | * Head in allocated object should have OBJ_ALLOCATED_TAG |
103 | * to identify the object was allocated or not. |
104 | * It's okay to add the status bit in the least bit because |
105 | * header keeps handle which is 4byte-aligned address so we |
106 | * have room for two bit at least. |
107 | */ |
108 | #define OBJ_ALLOCATED_TAG 1 |
109 | |
110 | #define OBJ_TAG_BITS 1 |
111 | #define OBJ_TAG_MASK OBJ_ALLOCATED_TAG |
112 | |
113 | #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS) |
114 | #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) |
115 | |
116 | #define HUGE_BITS 1 |
117 | #define FULLNESS_BITS 4 |
118 | #define CLASS_BITS 8 |
119 | #define ISOLATED_BITS 5 |
120 | #define MAGIC_VAL_BITS 8 |
121 | |
122 | #define MAX(a, b) ((a) >= (b) ? (a) : (b)) |
123 | |
124 | #define ZS_MAX_PAGES_PER_ZSPAGE (_AC(CONFIG_ZSMALLOC_CHAIN_SIZE, UL)) |
125 | |
126 | /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ |
127 | #define ZS_MIN_ALLOC_SIZE \ |
128 | MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) |
129 | /* each chunk includes extra space to keep handle */ |
130 | #define ZS_MAX_ALLOC_SIZE PAGE_SIZE |
131 | |
132 | /* |
133 | * On systems with 4K page size, this gives 255 size classes! There is a |
134 | * trader-off here: |
135 | * - Large number of size classes is potentially wasteful as free page are |
136 | * spread across these classes |
137 | * - Small number of size classes causes large internal fragmentation |
138 | * - Probably its better to use specific size classes (empirically |
139 | * determined). NOTE: all those class sizes must be set as multiple of |
140 | * ZS_ALIGN to make sure link_free itself never has to span 2 pages. |
141 | * |
142 | * ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN |
143 | * (reason above) |
144 | */ |
145 | #define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS) |
146 | #define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \ |
147 | ZS_SIZE_CLASS_DELTA) + 1) |
148 | |
149 | /* |
150 | * Pages are distinguished by the ratio of used memory (that is the ratio |
151 | * of ->inuse objects to all objects that page can store). For example, |
152 | * INUSE_RATIO_10 means that the ratio of used objects is > 0% and <= 10%. |
153 | * |
154 | * The number of fullness groups is not random. It allows us to keep |
155 | * difference between the least busy page in the group (minimum permitted |
156 | * number of ->inuse objects) and the most busy page (maximum permitted |
157 | * number of ->inuse objects) at a reasonable value. |
158 | */ |
159 | enum fullness_group { |
160 | ZS_INUSE_RATIO_0, |
161 | ZS_INUSE_RATIO_10, |
162 | /* NOTE: 8 more fullness groups here */ |
163 | ZS_INUSE_RATIO_99 = 10, |
164 | ZS_INUSE_RATIO_100, |
165 | NR_FULLNESS_GROUPS, |
166 | }; |
167 | |
168 | enum class_stat_type { |
169 | /* NOTE: stats for 12 fullness groups here: from inuse 0 to 100 */ |
170 | ZS_OBJS_ALLOCATED = NR_FULLNESS_GROUPS, |
171 | ZS_OBJS_INUSE, |
172 | NR_CLASS_STAT_TYPES, |
173 | }; |
174 | |
175 | struct zs_size_stat { |
176 | unsigned long objs[NR_CLASS_STAT_TYPES]; |
177 | }; |
178 | |
179 | #ifdef CONFIG_ZSMALLOC_STAT |
180 | static struct dentry *zs_stat_root; |
181 | #endif |
182 | |
183 | static size_t huge_class_size; |
184 | |
185 | struct size_class { |
186 | struct list_head fullness_list[NR_FULLNESS_GROUPS]; |
187 | /* |
188 | * Size of objects stored in this class. Must be multiple |
189 | * of ZS_ALIGN. |
190 | */ |
191 | int size; |
192 | int objs_per_zspage; |
193 | /* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */ |
194 | int pages_per_zspage; |
195 | |
196 | unsigned int index; |
197 | struct zs_size_stat stats; |
198 | }; |
199 | |
200 | /* |
201 | * Placed within free objects to form a singly linked list. |
202 | * For every zspage, zspage->freeobj gives head of this list. |
203 | * |
204 | * This must be power of 2 and less than or equal to ZS_ALIGN |
205 | */ |
206 | struct link_free { |
207 | union { |
208 | /* |
209 | * Free object index; |
210 | * It's valid for non-allocated object |
211 | */ |
212 | unsigned long next; |
213 | /* |
214 | * Handle of allocated object. |
215 | */ |
216 | unsigned long handle; |
217 | }; |
218 | }; |
219 | |
220 | struct zs_pool { |
221 | const char *name; |
222 | |
223 | struct size_class *size_class[ZS_SIZE_CLASSES]; |
224 | struct kmem_cache *handle_cachep; |
225 | struct kmem_cache *zspage_cachep; |
226 | |
227 | atomic_long_t pages_allocated; |
228 | |
229 | struct zs_pool_stats stats; |
230 | |
231 | /* Compact classes */ |
232 | struct shrinker *shrinker; |
233 | |
234 | #ifdef CONFIG_ZSMALLOC_STAT |
235 | struct dentry *stat_dentry; |
236 | #endif |
237 | #ifdef CONFIG_COMPACTION |
238 | struct work_struct free_work; |
239 | #endif |
240 | spinlock_t lock; |
241 | atomic_t compaction_in_progress; |
242 | }; |
243 | |
244 | struct zspage { |
245 | struct { |
246 | unsigned int huge:HUGE_BITS; |
247 | unsigned int fullness:FULLNESS_BITS; |
248 | unsigned int class:CLASS_BITS + 1; |
249 | unsigned int isolated:ISOLATED_BITS; |
250 | unsigned int magic:MAGIC_VAL_BITS; |
251 | }; |
252 | unsigned int inuse; |
253 | unsigned int freeobj; |
254 | struct page *first_page; |
255 | struct list_head list; /* fullness list */ |
256 | struct zs_pool *pool; |
257 | rwlock_t lock; |
258 | }; |
259 | |
260 | struct mapping_area { |
261 | local_lock_t lock; |
262 | char *vm_buf; /* copy buffer for objects that span pages */ |
263 | char *vm_addr; /* address of kmap_atomic()'ed pages */ |
264 | enum zs_mapmode vm_mm; /* mapping mode */ |
265 | }; |
266 | |
267 | /* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */ |
268 | static void SetZsHugePage(struct zspage *zspage) |
269 | { |
270 | zspage->huge = 1; |
271 | } |
272 | |
273 | static bool ZsHugePage(struct zspage *zspage) |
274 | { |
275 | return zspage->huge; |
276 | } |
277 | |
278 | static void migrate_lock_init(struct zspage *zspage); |
279 | static void migrate_read_lock(struct zspage *zspage); |
280 | static void migrate_read_unlock(struct zspage *zspage); |
281 | |
282 | #ifdef CONFIG_COMPACTION |
283 | static void migrate_write_lock(struct zspage *zspage); |
284 | static void migrate_write_lock_nested(struct zspage *zspage); |
285 | static void migrate_write_unlock(struct zspage *zspage); |
286 | static void kick_deferred_free(struct zs_pool *pool); |
287 | static void init_deferred_free(struct zs_pool *pool); |
288 | static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage); |
289 | #else |
290 | static void migrate_write_lock(struct zspage *zspage) {} |
291 | static void migrate_write_lock_nested(struct zspage *zspage) {} |
292 | static void migrate_write_unlock(struct zspage *zspage) {} |
293 | static void kick_deferred_free(struct zs_pool *pool) {} |
294 | static void init_deferred_free(struct zs_pool *pool) {} |
295 | static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {} |
296 | #endif |
297 | |
298 | static int create_cache(struct zs_pool *pool) |
299 | { |
300 | pool->handle_cachep = kmem_cache_create(name: "zs_handle" , ZS_HANDLE_SIZE, |
301 | align: 0, flags: 0, NULL); |
302 | if (!pool->handle_cachep) |
303 | return 1; |
304 | |
305 | pool->zspage_cachep = kmem_cache_create(name: "zspage" , size: sizeof(struct zspage), |
306 | align: 0, flags: 0, NULL); |
307 | if (!pool->zspage_cachep) { |
308 | kmem_cache_destroy(s: pool->handle_cachep); |
309 | pool->handle_cachep = NULL; |
310 | return 1; |
311 | } |
312 | |
313 | return 0; |
314 | } |
315 | |
316 | static void destroy_cache(struct zs_pool *pool) |
317 | { |
318 | kmem_cache_destroy(s: pool->handle_cachep); |
319 | kmem_cache_destroy(s: pool->zspage_cachep); |
320 | } |
321 | |
322 | static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp) |
323 | { |
324 | return (unsigned long)kmem_cache_alloc(cachep: pool->handle_cachep, |
325 | flags: gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); |
326 | } |
327 | |
328 | static void cache_free_handle(struct zs_pool *pool, unsigned long handle) |
329 | { |
330 | kmem_cache_free(s: pool->handle_cachep, objp: (void *)handle); |
331 | } |
332 | |
333 | static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags) |
334 | { |
335 | return kmem_cache_zalloc(k: pool->zspage_cachep, |
336 | flags: flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); |
337 | } |
338 | |
339 | static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage) |
340 | { |
341 | kmem_cache_free(s: pool->zspage_cachep, objp: zspage); |
342 | } |
343 | |
344 | /* pool->lock(which owns the handle) synchronizes races */ |
345 | static void record_obj(unsigned long handle, unsigned long obj) |
346 | { |
347 | *(unsigned long *)handle = obj; |
348 | } |
349 | |
350 | /* zpool driver */ |
351 | |
352 | #ifdef CONFIG_ZPOOL |
353 | |
354 | static void *zs_zpool_create(const char *name, gfp_t gfp) |
355 | { |
356 | /* |
357 | * Ignore global gfp flags: zs_malloc() may be invoked from |
358 | * different contexts and its caller must provide a valid |
359 | * gfp mask. |
360 | */ |
361 | return zs_create_pool(name); |
362 | } |
363 | |
364 | static void zs_zpool_destroy(void *pool) |
365 | { |
366 | zs_destroy_pool(pool); |
367 | } |
368 | |
369 | static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp, |
370 | unsigned long *handle) |
371 | { |
372 | *handle = zs_malloc(pool, size, flags: gfp); |
373 | |
374 | if (IS_ERR_VALUE(*handle)) |
375 | return PTR_ERR(ptr: (void *)*handle); |
376 | return 0; |
377 | } |
378 | static void zs_zpool_free(void *pool, unsigned long handle) |
379 | { |
380 | zs_free(pool, obj: handle); |
381 | } |
382 | |
383 | static void *zs_zpool_map(void *pool, unsigned long handle, |
384 | enum zpool_mapmode mm) |
385 | { |
386 | enum zs_mapmode zs_mm; |
387 | |
388 | switch (mm) { |
389 | case ZPOOL_MM_RO: |
390 | zs_mm = ZS_MM_RO; |
391 | break; |
392 | case ZPOOL_MM_WO: |
393 | zs_mm = ZS_MM_WO; |
394 | break; |
395 | case ZPOOL_MM_RW: |
396 | default: |
397 | zs_mm = ZS_MM_RW; |
398 | break; |
399 | } |
400 | |
401 | return zs_map_object(pool, handle, mm: zs_mm); |
402 | } |
403 | static void zs_zpool_unmap(void *pool, unsigned long handle) |
404 | { |
405 | zs_unmap_object(pool, handle); |
406 | } |
407 | |
408 | static u64 zs_zpool_total_size(void *pool) |
409 | { |
410 | return zs_get_total_pages(pool) << PAGE_SHIFT; |
411 | } |
412 | |
413 | static struct zpool_driver zs_zpool_driver = { |
414 | .type = "zsmalloc" , |
415 | .owner = THIS_MODULE, |
416 | .create = zs_zpool_create, |
417 | .destroy = zs_zpool_destroy, |
418 | .malloc_support_movable = true, |
419 | .malloc = zs_zpool_malloc, |
420 | .free = zs_zpool_free, |
421 | .map = zs_zpool_map, |
422 | .unmap = zs_zpool_unmap, |
423 | .total_size = zs_zpool_total_size, |
424 | }; |
425 | |
426 | MODULE_ALIAS("zpool-zsmalloc" ); |
427 | #endif /* CONFIG_ZPOOL */ |
428 | |
429 | /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ |
430 | static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = { |
431 | .lock = INIT_LOCAL_LOCK(lock), |
432 | }; |
433 | |
434 | static __maybe_unused int is_first_page(struct page *page) |
435 | { |
436 | return PagePrivate(page); |
437 | } |
438 | |
439 | /* Protected by pool->lock */ |
440 | static inline int get_zspage_inuse(struct zspage *zspage) |
441 | { |
442 | return zspage->inuse; |
443 | } |
444 | |
445 | |
446 | static inline void mod_zspage_inuse(struct zspage *zspage, int val) |
447 | { |
448 | zspage->inuse += val; |
449 | } |
450 | |
451 | static inline struct page *get_first_page(struct zspage *zspage) |
452 | { |
453 | struct page *first_page = zspage->first_page; |
454 | |
455 | VM_BUG_ON_PAGE(!is_first_page(first_page), first_page); |
456 | return first_page; |
457 | } |
458 | |
459 | static inline unsigned int get_first_obj_offset(struct page *page) |
460 | { |
461 | return page->page_type; |
462 | } |
463 | |
464 | static inline void set_first_obj_offset(struct page *page, unsigned int offset) |
465 | { |
466 | page->page_type = offset; |
467 | } |
468 | |
469 | static inline unsigned int get_freeobj(struct zspage *zspage) |
470 | { |
471 | return zspage->freeobj; |
472 | } |
473 | |
474 | static inline void set_freeobj(struct zspage *zspage, unsigned int obj) |
475 | { |
476 | zspage->freeobj = obj; |
477 | } |
478 | |
479 | static void get_zspage_mapping(struct zspage *zspage, |
480 | unsigned int *class_idx, |
481 | int *fullness) |
482 | { |
483 | BUG_ON(zspage->magic != ZSPAGE_MAGIC); |
484 | |
485 | *fullness = zspage->fullness; |
486 | *class_idx = zspage->class; |
487 | } |
488 | |
489 | static struct size_class *zspage_class(struct zs_pool *pool, |
490 | struct zspage *zspage) |
491 | { |
492 | return pool->size_class[zspage->class]; |
493 | } |
494 | |
495 | static void set_zspage_mapping(struct zspage *zspage, |
496 | unsigned int class_idx, |
497 | int fullness) |
498 | { |
499 | zspage->class = class_idx; |
500 | zspage->fullness = fullness; |
501 | } |
502 | |
503 | /* |
504 | * zsmalloc divides the pool into various size classes where each |
505 | * class maintains a list of zspages where each zspage is divided |
506 | * into equal sized chunks. Each allocation falls into one of these |
507 | * classes depending on its size. This function returns index of the |
508 | * size class which has chunk size big enough to hold the given size. |
509 | */ |
510 | static int get_size_class_index(int size) |
511 | { |
512 | int idx = 0; |
513 | |
514 | if (likely(size > ZS_MIN_ALLOC_SIZE)) |
515 | idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE, |
516 | ZS_SIZE_CLASS_DELTA); |
517 | |
518 | return min_t(int, ZS_SIZE_CLASSES - 1, idx); |
519 | } |
520 | |
521 | static inline void class_stat_inc(struct size_class *class, |
522 | int type, unsigned long cnt) |
523 | { |
524 | class->stats.objs[type] += cnt; |
525 | } |
526 | |
527 | static inline void class_stat_dec(struct size_class *class, |
528 | int type, unsigned long cnt) |
529 | { |
530 | class->stats.objs[type] -= cnt; |
531 | } |
532 | |
533 | static inline unsigned long zs_stat_get(struct size_class *class, int type) |
534 | { |
535 | return class->stats.objs[type]; |
536 | } |
537 | |
538 | #ifdef CONFIG_ZSMALLOC_STAT |
539 | |
540 | static void __init zs_stat_init(void) |
541 | { |
542 | if (!debugfs_initialized()) { |
543 | pr_warn("debugfs not available, stat dir not created\n" ); |
544 | return; |
545 | } |
546 | |
547 | zs_stat_root = debugfs_create_dir(name: "zsmalloc" , NULL); |
548 | } |
549 | |
550 | static void __exit zs_stat_exit(void) |
551 | { |
552 | debugfs_remove_recursive(dentry: zs_stat_root); |
553 | } |
554 | |
555 | static unsigned long zs_can_compact(struct size_class *class); |
556 | |
557 | static int zs_stats_size_show(struct seq_file *s, void *v) |
558 | { |
559 | int i, fg; |
560 | struct zs_pool *pool = s->private; |
561 | struct size_class *class; |
562 | int objs_per_zspage; |
563 | unsigned long obj_allocated, obj_used, pages_used, freeable; |
564 | unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0; |
565 | unsigned long total_freeable = 0; |
566 | unsigned long inuse_totals[NR_FULLNESS_GROUPS] = {0, }; |
567 | |
568 | seq_printf(m: s, fmt: " %5s %5s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %13s %10s %10s %16s %8s\n" , |
569 | "class" , "size" , "10%" , "20%" , "30%" , "40%" , |
570 | "50%" , "60%" , "70%" , "80%" , "90%" , "99%" , "100%" , |
571 | "obj_allocated" , "obj_used" , "pages_used" , |
572 | "pages_per_zspage" , "freeable" ); |
573 | |
574 | for (i = 0; i < ZS_SIZE_CLASSES; i++) { |
575 | |
576 | class = pool->size_class[i]; |
577 | |
578 | if (class->index != i) |
579 | continue; |
580 | |
581 | spin_lock(lock: &pool->lock); |
582 | |
583 | seq_printf(m: s, fmt: " %5u %5u " , i, class->size); |
584 | for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++) { |
585 | inuse_totals[fg] += zs_stat_get(class, type: fg); |
586 | seq_printf(m: s, fmt: "%9lu " , zs_stat_get(class, type: fg)); |
587 | } |
588 | |
589 | obj_allocated = zs_stat_get(class, type: ZS_OBJS_ALLOCATED); |
590 | obj_used = zs_stat_get(class, type: ZS_OBJS_INUSE); |
591 | freeable = zs_can_compact(class); |
592 | spin_unlock(lock: &pool->lock); |
593 | |
594 | objs_per_zspage = class->objs_per_zspage; |
595 | pages_used = obj_allocated / objs_per_zspage * |
596 | class->pages_per_zspage; |
597 | |
598 | seq_printf(m: s, fmt: "%13lu %10lu %10lu %16d %8lu\n" , |
599 | obj_allocated, obj_used, pages_used, |
600 | class->pages_per_zspage, freeable); |
601 | |
602 | total_objs += obj_allocated; |
603 | total_used_objs += obj_used; |
604 | total_pages += pages_used; |
605 | total_freeable += freeable; |
606 | } |
607 | |
608 | seq_puts(m: s, s: "\n" ); |
609 | seq_printf(m: s, fmt: " %5s %5s " , "Total" , "" ); |
610 | |
611 | for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++) |
612 | seq_printf(m: s, fmt: "%9lu " , inuse_totals[fg]); |
613 | |
614 | seq_printf(m: s, fmt: "%13lu %10lu %10lu %16s %8lu\n" , |
615 | total_objs, total_used_objs, total_pages, "" , |
616 | total_freeable); |
617 | |
618 | return 0; |
619 | } |
620 | DEFINE_SHOW_ATTRIBUTE(zs_stats_size); |
621 | |
622 | static void zs_pool_stat_create(struct zs_pool *pool, const char *name) |
623 | { |
624 | if (!zs_stat_root) { |
625 | pr_warn("no root stat dir, not creating <%s> stat dir\n" , name); |
626 | return; |
627 | } |
628 | |
629 | pool->stat_dentry = debugfs_create_dir(name, parent: zs_stat_root); |
630 | |
631 | debugfs_create_file(name: "classes" , S_IFREG | 0444, parent: pool->stat_dentry, data: pool, |
632 | fops: &zs_stats_size_fops); |
633 | } |
634 | |
635 | static void zs_pool_stat_destroy(struct zs_pool *pool) |
636 | { |
637 | debugfs_remove_recursive(dentry: pool->stat_dentry); |
638 | } |
639 | |
640 | #else /* CONFIG_ZSMALLOC_STAT */ |
641 | static void __init zs_stat_init(void) |
642 | { |
643 | } |
644 | |
645 | static void __exit zs_stat_exit(void) |
646 | { |
647 | } |
648 | |
649 | static inline void zs_pool_stat_create(struct zs_pool *pool, const char *name) |
650 | { |
651 | } |
652 | |
653 | static inline void zs_pool_stat_destroy(struct zs_pool *pool) |
654 | { |
655 | } |
656 | #endif |
657 | |
658 | |
659 | /* |
660 | * For each size class, zspages are divided into different groups |
661 | * depending on their usage ratio. This function returns fullness |
662 | * status of the given page. |
663 | */ |
664 | static int get_fullness_group(struct size_class *class, struct zspage *zspage) |
665 | { |
666 | int inuse, objs_per_zspage, ratio; |
667 | |
668 | inuse = get_zspage_inuse(zspage); |
669 | objs_per_zspage = class->objs_per_zspage; |
670 | |
671 | if (inuse == 0) |
672 | return ZS_INUSE_RATIO_0; |
673 | if (inuse == objs_per_zspage) |
674 | return ZS_INUSE_RATIO_100; |
675 | |
676 | ratio = 100 * inuse / objs_per_zspage; |
677 | /* |
678 | * Take integer division into consideration: a page with one inuse |
679 | * object out of 127 possible, will end up having 0 usage ratio, |
680 | * which is wrong as it belongs in ZS_INUSE_RATIO_10 fullness group. |
681 | */ |
682 | return ratio / 10 + 1; |
683 | } |
684 | |
685 | /* |
686 | * Each size class maintains various freelists and zspages are assigned |
687 | * to one of these freelists based on the number of live objects they |
688 | * have. This functions inserts the given zspage into the freelist |
689 | * identified by <class, fullness_group>. |
690 | */ |
691 | static void insert_zspage(struct size_class *class, |
692 | struct zspage *zspage, |
693 | int fullness) |
694 | { |
695 | class_stat_inc(class, type: fullness, cnt: 1); |
696 | list_add(new: &zspage->list, head: &class->fullness_list[fullness]); |
697 | } |
698 | |
699 | /* |
700 | * This function removes the given zspage from the freelist identified |
701 | * by <class, fullness_group>. |
702 | */ |
703 | static void remove_zspage(struct size_class *class, |
704 | struct zspage *zspage, |
705 | int fullness) |
706 | { |
707 | VM_BUG_ON(list_empty(&class->fullness_list[fullness])); |
708 | |
709 | list_del_init(entry: &zspage->list); |
710 | class_stat_dec(class, type: fullness, cnt: 1); |
711 | } |
712 | |
713 | /* |
714 | * Each size class maintains zspages in different fullness groups depending |
715 | * on the number of live objects they contain. When allocating or freeing |
716 | * objects, the fullness status of the page can change, for instance, from |
717 | * INUSE_RATIO_80 to INUSE_RATIO_70 when freeing an object. This function |
718 | * checks if such a status change has occurred for the given page and |
719 | * accordingly moves the page from the list of the old fullness group to that |
720 | * of the new fullness group. |
721 | */ |
722 | static int fix_fullness_group(struct size_class *class, struct zspage *zspage) |
723 | { |
724 | int class_idx; |
725 | int currfg, newfg; |
726 | |
727 | get_zspage_mapping(zspage, class_idx: &class_idx, fullness: &currfg); |
728 | newfg = get_fullness_group(class, zspage); |
729 | if (newfg == currfg) |
730 | goto out; |
731 | |
732 | remove_zspage(class, zspage, fullness: currfg); |
733 | insert_zspage(class, zspage, fullness: newfg); |
734 | set_zspage_mapping(zspage, class_idx, fullness: newfg); |
735 | out: |
736 | return newfg; |
737 | } |
738 | |
739 | static struct zspage *get_zspage(struct page *page) |
740 | { |
741 | struct zspage *zspage = (struct zspage *)page_private(page); |
742 | |
743 | BUG_ON(zspage->magic != ZSPAGE_MAGIC); |
744 | return zspage; |
745 | } |
746 | |
747 | static struct page *get_next_page(struct page *page) |
748 | { |
749 | struct zspage *zspage = get_zspage(page); |
750 | |
751 | if (unlikely(ZsHugePage(zspage))) |
752 | return NULL; |
753 | |
754 | return (struct page *)page->index; |
755 | } |
756 | |
757 | /** |
758 | * obj_to_location - get (<page>, <obj_idx>) from encoded object value |
759 | * @obj: the encoded object value |
760 | * @page: page object resides in zspage |
761 | * @obj_idx: object index |
762 | */ |
763 | static void obj_to_location(unsigned long obj, struct page **page, |
764 | unsigned int *obj_idx) |
765 | { |
766 | obj >>= OBJ_TAG_BITS; |
767 | *page = pfn_to_page(obj >> OBJ_INDEX_BITS); |
768 | *obj_idx = (obj & OBJ_INDEX_MASK); |
769 | } |
770 | |
771 | static void obj_to_page(unsigned long obj, struct page **page) |
772 | { |
773 | obj >>= OBJ_TAG_BITS; |
774 | *page = pfn_to_page(obj >> OBJ_INDEX_BITS); |
775 | } |
776 | |
777 | /** |
778 | * location_to_obj - get obj value encoded from (<page>, <obj_idx>) |
779 | * @page: page object resides in zspage |
780 | * @obj_idx: object index |
781 | */ |
782 | static unsigned long location_to_obj(struct page *page, unsigned int obj_idx) |
783 | { |
784 | unsigned long obj; |
785 | |
786 | obj = page_to_pfn(page) << OBJ_INDEX_BITS; |
787 | obj |= obj_idx & OBJ_INDEX_MASK; |
788 | obj <<= OBJ_TAG_BITS; |
789 | |
790 | return obj; |
791 | } |
792 | |
793 | static unsigned long handle_to_obj(unsigned long handle) |
794 | { |
795 | return *(unsigned long *)handle; |
796 | } |
797 | |
798 | static inline bool obj_allocated(struct page *page, void *obj, |
799 | unsigned long *phandle) |
800 | { |
801 | unsigned long handle; |
802 | struct zspage *zspage = get_zspage(page); |
803 | |
804 | if (unlikely(ZsHugePage(zspage))) { |
805 | VM_BUG_ON_PAGE(!is_first_page(page), page); |
806 | handle = page->index; |
807 | } else |
808 | handle = *(unsigned long *)obj; |
809 | |
810 | if (!(handle & OBJ_ALLOCATED_TAG)) |
811 | return false; |
812 | |
813 | /* Clear all tags before returning the handle */ |
814 | *phandle = handle & ~OBJ_TAG_MASK; |
815 | return true; |
816 | } |
817 | |
818 | static void reset_page(struct page *page) |
819 | { |
820 | __ClearPageMovable(page); |
821 | ClearPagePrivate(page); |
822 | set_page_private(page, private: 0); |
823 | page_mapcount_reset(page); |
824 | page->index = 0; |
825 | } |
826 | |
827 | static int trylock_zspage(struct zspage *zspage) |
828 | { |
829 | struct page *cursor, *fail; |
830 | |
831 | for (cursor = get_first_page(zspage); cursor != NULL; cursor = |
832 | get_next_page(page: cursor)) { |
833 | if (!trylock_page(page: cursor)) { |
834 | fail = cursor; |
835 | goto unlock; |
836 | } |
837 | } |
838 | |
839 | return 1; |
840 | unlock: |
841 | for (cursor = get_first_page(zspage); cursor != fail; cursor = |
842 | get_next_page(page: cursor)) |
843 | unlock_page(page: cursor); |
844 | |
845 | return 0; |
846 | } |
847 | |
848 | static void __free_zspage(struct zs_pool *pool, struct size_class *class, |
849 | struct zspage *zspage) |
850 | { |
851 | struct page *page, *next; |
852 | int fg; |
853 | unsigned int class_idx; |
854 | |
855 | get_zspage_mapping(zspage, class_idx: &class_idx, fullness: &fg); |
856 | |
857 | assert_spin_locked(&pool->lock); |
858 | |
859 | VM_BUG_ON(get_zspage_inuse(zspage)); |
860 | VM_BUG_ON(fg != ZS_INUSE_RATIO_0); |
861 | |
862 | next = page = get_first_page(zspage); |
863 | do { |
864 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
865 | next = get_next_page(page); |
866 | reset_page(page); |
867 | unlock_page(page); |
868 | dec_zone_page_state(page, NR_ZSPAGES); |
869 | put_page(page); |
870 | page = next; |
871 | } while (page != NULL); |
872 | |
873 | cache_free_zspage(pool, zspage); |
874 | |
875 | class_stat_dec(class, type: ZS_OBJS_ALLOCATED, cnt: class->objs_per_zspage); |
876 | atomic_long_sub(i: class->pages_per_zspage, v: &pool->pages_allocated); |
877 | } |
878 | |
879 | static void free_zspage(struct zs_pool *pool, struct size_class *class, |
880 | struct zspage *zspage) |
881 | { |
882 | VM_BUG_ON(get_zspage_inuse(zspage)); |
883 | VM_BUG_ON(list_empty(&zspage->list)); |
884 | |
885 | /* |
886 | * Since zs_free couldn't be sleepable, this function cannot call |
887 | * lock_page. The page locks trylock_zspage got will be released |
888 | * by __free_zspage. |
889 | */ |
890 | if (!trylock_zspage(zspage)) { |
891 | kick_deferred_free(pool); |
892 | return; |
893 | } |
894 | |
895 | remove_zspage(class, zspage, fullness: ZS_INUSE_RATIO_0); |
896 | __free_zspage(pool, class, zspage); |
897 | } |
898 | |
899 | /* Initialize a newly allocated zspage */ |
900 | static void init_zspage(struct size_class *class, struct zspage *zspage) |
901 | { |
902 | unsigned int freeobj = 1; |
903 | unsigned long off = 0; |
904 | struct page *page = get_first_page(zspage); |
905 | |
906 | while (page) { |
907 | struct page *next_page; |
908 | struct link_free *link; |
909 | void *vaddr; |
910 | |
911 | set_first_obj_offset(page, offset: off); |
912 | |
913 | vaddr = kmap_atomic(page); |
914 | link = (struct link_free *)vaddr + off / sizeof(*link); |
915 | |
916 | while ((off += class->size) < PAGE_SIZE) { |
917 | link->next = freeobj++ << OBJ_TAG_BITS; |
918 | link += class->size / sizeof(*link); |
919 | } |
920 | |
921 | /* |
922 | * We now come to the last (full or partial) object on this |
923 | * page, which must point to the first object on the next |
924 | * page (if present) |
925 | */ |
926 | next_page = get_next_page(page); |
927 | if (next_page) { |
928 | link->next = freeobj++ << OBJ_TAG_BITS; |
929 | } else { |
930 | /* |
931 | * Reset OBJ_TAG_BITS bit to last link to tell |
932 | * whether it's allocated object or not. |
933 | */ |
934 | link->next = -1UL << OBJ_TAG_BITS; |
935 | } |
936 | kunmap_atomic(vaddr); |
937 | page = next_page; |
938 | off %= PAGE_SIZE; |
939 | } |
940 | |
941 | set_freeobj(zspage, obj: 0); |
942 | } |
943 | |
944 | static void create_page_chain(struct size_class *class, struct zspage *zspage, |
945 | struct page *pages[]) |
946 | { |
947 | int i; |
948 | struct page *page; |
949 | struct page *prev_page = NULL; |
950 | int nr_pages = class->pages_per_zspage; |
951 | |
952 | /* |
953 | * Allocate individual pages and link them together as: |
954 | * 1. all pages are linked together using page->index |
955 | * 2. each sub-page point to zspage using page->private |
956 | * |
957 | * we set PG_private to identify the first page (i.e. no other sub-page |
958 | * has this flag set). |
959 | */ |
960 | for (i = 0; i < nr_pages; i++) { |
961 | page = pages[i]; |
962 | set_page_private(page, private: (unsigned long)zspage); |
963 | page->index = 0; |
964 | if (i == 0) { |
965 | zspage->first_page = page; |
966 | SetPagePrivate(page); |
967 | if (unlikely(class->objs_per_zspage == 1 && |
968 | class->pages_per_zspage == 1)) |
969 | SetZsHugePage(zspage); |
970 | } else { |
971 | prev_page->index = (unsigned long)page; |
972 | } |
973 | prev_page = page; |
974 | } |
975 | } |
976 | |
977 | /* |
978 | * Allocate a zspage for the given size class |
979 | */ |
980 | static struct zspage *alloc_zspage(struct zs_pool *pool, |
981 | struct size_class *class, |
982 | gfp_t gfp) |
983 | { |
984 | int i; |
985 | struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE]; |
986 | struct zspage *zspage = cache_alloc_zspage(pool, flags: gfp); |
987 | |
988 | if (!zspage) |
989 | return NULL; |
990 | |
991 | zspage->magic = ZSPAGE_MAGIC; |
992 | migrate_lock_init(zspage); |
993 | |
994 | for (i = 0; i < class->pages_per_zspage; i++) { |
995 | struct page *page; |
996 | |
997 | page = alloc_page(gfp); |
998 | if (!page) { |
999 | while (--i >= 0) { |
1000 | dec_zone_page_state(pages[i], NR_ZSPAGES); |
1001 | __free_page(pages[i]); |
1002 | } |
1003 | cache_free_zspage(pool, zspage); |
1004 | return NULL; |
1005 | } |
1006 | |
1007 | inc_zone_page_state(page, NR_ZSPAGES); |
1008 | pages[i] = page; |
1009 | } |
1010 | |
1011 | create_page_chain(class, zspage, pages); |
1012 | init_zspage(class, zspage); |
1013 | zspage->pool = pool; |
1014 | |
1015 | return zspage; |
1016 | } |
1017 | |
1018 | static struct zspage *find_get_zspage(struct size_class *class) |
1019 | { |
1020 | int i; |
1021 | struct zspage *zspage; |
1022 | |
1023 | for (i = ZS_INUSE_RATIO_99; i >= ZS_INUSE_RATIO_0; i--) { |
1024 | zspage = list_first_entry_or_null(&class->fullness_list[i], |
1025 | struct zspage, list); |
1026 | if (zspage) |
1027 | break; |
1028 | } |
1029 | |
1030 | return zspage; |
1031 | } |
1032 | |
1033 | static inline int __zs_cpu_up(struct mapping_area *area) |
1034 | { |
1035 | /* |
1036 | * Make sure we don't leak memory if a cpu UP notification |
1037 | * and zs_init() race and both call zs_cpu_up() on the same cpu |
1038 | */ |
1039 | if (area->vm_buf) |
1040 | return 0; |
1041 | area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL); |
1042 | if (!area->vm_buf) |
1043 | return -ENOMEM; |
1044 | return 0; |
1045 | } |
1046 | |
1047 | static inline void __zs_cpu_down(struct mapping_area *area) |
1048 | { |
1049 | kfree(objp: area->vm_buf); |
1050 | area->vm_buf = NULL; |
1051 | } |
1052 | |
1053 | static void *__zs_map_object(struct mapping_area *area, |
1054 | struct page *pages[2], int off, int size) |
1055 | { |
1056 | int sizes[2]; |
1057 | void *addr; |
1058 | char *buf = area->vm_buf; |
1059 | |
1060 | /* disable page faults to match kmap_atomic() return conditions */ |
1061 | pagefault_disable(); |
1062 | |
1063 | /* no read fastpath */ |
1064 | if (area->vm_mm == ZS_MM_WO) |
1065 | goto out; |
1066 | |
1067 | sizes[0] = PAGE_SIZE - off; |
1068 | sizes[1] = size - sizes[0]; |
1069 | |
1070 | /* copy object to per-cpu buffer */ |
1071 | addr = kmap_atomic(page: pages[0]); |
1072 | memcpy(buf, addr + off, sizes[0]); |
1073 | kunmap_atomic(addr); |
1074 | addr = kmap_atomic(page: pages[1]); |
1075 | memcpy(buf + sizes[0], addr, sizes[1]); |
1076 | kunmap_atomic(addr); |
1077 | out: |
1078 | return area->vm_buf; |
1079 | } |
1080 | |
1081 | static void __zs_unmap_object(struct mapping_area *area, |
1082 | struct page *pages[2], int off, int size) |
1083 | { |
1084 | int sizes[2]; |
1085 | void *addr; |
1086 | char *buf; |
1087 | |
1088 | /* no write fastpath */ |
1089 | if (area->vm_mm == ZS_MM_RO) |
1090 | goto out; |
1091 | |
1092 | buf = area->vm_buf; |
1093 | buf = buf + ZS_HANDLE_SIZE; |
1094 | size -= ZS_HANDLE_SIZE; |
1095 | off += ZS_HANDLE_SIZE; |
1096 | |
1097 | sizes[0] = PAGE_SIZE - off; |
1098 | sizes[1] = size - sizes[0]; |
1099 | |
1100 | /* copy per-cpu buffer to object */ |
1101 | addr = kmap_atomic(page: pages[0]); |
1102 | memcpy(addr + off, buf, sizes[0]); |
1103 | kunmap_atomic(addr); |
1104 | addr = kmap_atomic(page: pages[1]); |
1105 | memcpy(addr, buf + sizes[0], sizes[1]); |
1106 | kunmap_atomic(addr); |
1107 | |
1108 | out: |
1109 | /* enable page faults to match kunmap_atomic() return conditions */ |
1110 | pagefault_enable(); |
1111 | } |
1112 | |
1113 | static int zs_cpu_prepare(unsigned int cpu) |
1114 | { |
1115 | struct mapping_area *area; |
1116 | |
1117 | area = &per_cpu(zs_map_area, cpu); |
1118 | return __zs_cpu_up(area); |
1119 | } |
1120 | |
1121 | static int zs_cpu_dead(unsigned int cpu) |
1122 | { |
1123 | struct mapping_area *area; |
1124 | |
1125 | area = &per_cpu(zs_map_area, cpu); |
1126 | __zs_cpu_down(area); |
1127 | return 0; |
1128 | } |
1129 | |
1130 | static bool can_merge(struct size_class *prev, int pages_per_zspage, |
1131 | int objs_per_zspage) |
1132 | { |
1133 | if (prev->pages_per_zspage == pages_per_zspage && |
1134 | prev->objs_per_zspage == objs_per_zspage) |
1135 | return true; |
1136 | |
1137 | return false; |
1138 | } |
1139 | |
1140 | static bool zspage_full(struct size_class *class, struct zspage *zspage) |
1141 | { |
1142 | return get_zspage_inuse(zspage) == class->objs_per_zspage; |
1143 | } |
1144 | |
1145 | static bool zspage_empty(struct zspage *zspage) |
1146 | { |
1147 | return get_zspage_inuse(zspage) == 0; |
1148 | } |
1149 | |
1150 | /** |
1151 | * zs_lookup_class_index() - Returns index of the zsmalloc &size_class |
1152 | * that hold objects of the provided size. |
1153 | * @pool: zsmalloc pool to use |
1154 | * @size: object size |
1155 | * |
1156 | * Context: Any context. |
1157 | * |
1158 | * Return: the index of the zsmalloc &size_class that hold objects of the |
1159 | * provided size. |
1160 | */ |
1161 | unsigned int zs_lookup_class_index(struct zs_pool *pool, unsigned int size) |
1162 | { |
1163 | struct size_class *class; |
1164 | |
1165 | class = pool->size_class[get_size_class_index(size)]; |
1166 | |
1167 | return class->index; |
1168 | } |
1169 | EXPORT_SYMBOL_GPL(zs_lookup_class_index); |
1170 | |
1171 | unsigned long zs_get_total_pages(struct zs_pool *pool) |
1172 | { |
1173 | return atomic_long_read(v: &pool->pages_allocated); |
1174 | } |
1175 | EXPORT_SYMBOL_GPL(zs_get_total_pages); |
1176 | |
1177 | /** |
1178 | * zs_map_object - get address of allocated object from handle. |
1179 | * @pool: pool from which the object was allocated |
1180 | * @handle: handle returned from zs_malloc |
1181 | * @mm: mapping mode to use |
1182 | * |
1183 | * Before using an object allocated from zs_malloc, it must be mapped using |
1184 | * this function. When done with the object, it must be unmapped using |
1185 | * zs_unmap_object. |
1186 | * |
1187 | * Only one object can be mapped per cpu at a time. There is no protection |
1188 | * against nested mappings. |
1189 | * |
1190 | * This function returns with preemption and page faults disabled. |
1191 | */ |
1192 | void *zs_map_object(struct zs_pool *pool, unsigned long handle, |
1193 | enum zs_mapmode mm) |
1194 | { |
1195 | struct zspage *zspage; |
1196 | struct page *page; |
1197 | unsigned long obj, off; |
1198 | unsigned int obj_idx; |
1199 | |
1200 | struct size_class *class; |
1201 | struct mapping_area *area; |
1202 | struct page *pages[2]; |
1203 | void *ret; |
1204 | |
1205 | /* |
1206 | * Because we use per-cpu mapping areas shared among the |
1207 | * pools/users, we can't allow mapping in interrupt context |
1208 | * because it can corrupt another users mappings. |
1209 | */ |
1210 | BUG_ON(in_interrupt()); |
1211 | |
1212 | /* It guarantees it can get zspage from handle safely */ |
1213 | spin_lock(lock: &pool->lock); |
1214 | obj = handle_to_obj(handle); |
1215 | obj_to_location(obj, page: &page, obj_idx: &obj_idx); |
1216 | zspage = get_zspage(page); |
1217 | |
1218 | /* |
1219 | * migration cannot move any zpages in this zspage. Here, pool->lock |
1220 | * is too heavy since callers would take some time until they calls |
1221 | * zs_unmap_object API so delegate the locking from class to zspage |
1222 | * which is smaller granularity. |
1223 | */ |
1224 | migrate_read_lock(zspage); |
1225 | spin_unlock(lock: &pool->lock); |
1226 | |
1227 | class = zspage_class(pool, zspage); |
1228 | off = offset_in_page(class->size * obj_idx); |
1229 | |
1230 | local_lock(&zs_map_area.lock); |
1231 | area = this_cpu_ptr(&zs_map_area); |
1232 | area->vm_mm = mm; |
1233 | if (off + class->size <= PAGE_SIZE) { |
1234 | /* this object is contained entirely within a page */ |
1235 | area->vm_addr = kmap_atomic(page); |
1236 | ret = area->vm_addr + off; |
1237 | goto out; |
1238 | } |
1239 | |
1240 | /* this object spans two pages */ |
1241 | pages[0] = page; |
1242 | pages[1] = get_next_page(page); |
1243 | BUG_ON(!pages[1]); |
1244 | |
1245 | ret = __zs_map_object(area, pages, off, size: class->size); |
1246 | out: |
1247 | if (likely(!ZsHugePage(zspage))) |
1248 | ret += ZS_HANDLE_SIZE; |
1249 | |
1250 | return ret; |
1251 | } |
1252 | EXPORT_SYMBOL_GPL(zs_map_object); |
1253 | |
1254 | void zs_unmap_object(struct zs_pool *pool, unsigned long handle) |
1255 | { |
1256 | struct zspage *zspage; |
1257 | struct page *page; |
1258 | unsigned long obj, off; |
1259 | unsigned int obj_idx; |
1260 | |
1261 | struct size_class *class; |
1262 | struct mapping_area *area; |
1263 | |
1264 | obj = handle_to_obj(handle); |
1265 | obj_to_location(obj, page: &page, obj_idx: &obj_idx); |
1266 | zspage = get_zspage(page); |
1267 | class = zspage_class(pool, zspage); |
1268 | off = offset_in_page(class->size * obj_idx); |
1269 | |
1270 | area = this_cpu_ptr(&zs_map_area); |
1271 | if (off + class->size <= PAGE_SIZE) |
1272 | kunmap_atomic(area->vm_addr); |
1273 | else { |
1274 | struct page *pages[2]; |
1275 | |
1276 | pages[0] = page; |
1277 | pages[1] = get_next_page(page); |
1278 | BUG_ON(!pages[1]); |
1279 | |
1280 | __zs_unmap_object(area, pages, off, size: class->size); |
1281 | } |
1282 | local_unlock(&zs_map_area.lock); |
1283 | |
1284 | migrate_read_unlock(zspage); |
1285 | } |
1286 | EXPORT_SYMBOL_GPL(zs_unmap_object); |
1287 | |
1288 | /** |
1289 | * zs_huge_class_size() - Returns the size (in bytes) of the first huge |
1290 | * zsmalloc &size_class. |
1291 | * @pool: zsmalloc pool to use |
1292 | * |
1293 | * The function returns the size of the first huge class - any object of equal |
1294 | * or bigger size will be stored in zspage consisting of a single physical |
1295 | * page. |
1296 | * |
1297 | * Context: Any context. |
1298 | * |
1299 | * Return: the size (in bytes) of the first huge zsmalloc &size_class. |
1300 | */ |
1301 | size_t zs_huge_class_size(struct zs_pool *pool) |
1302 | { |
1303 | return huge_class_size; |
1304 | } |
1305 | EXPORT_SYMBOL_GPL(zs_huge_class_size); |
1306 | |
1307 | static unsigned long obj_malloc(struct zs_pool *pool, |
1308 | struct zspage *zspage, unsigned long handle) |
1309 | { |
1310 | int i, nr_page, offset; |
1311 | unsigned long obj; |
1312 | struct link_free *link; |
1313 | struct size_class *class; |
1314 | |
1315 | struct page *m_page; |
1316 | unsigned long m_offset; |
1317 | void *vaddr; |
1318 | |
1319 | class = pool->size_class[zspage->class]; |
1320 | handle |= OBJ_ALLOCATED_TAG; |
1321 | obj = get_freeobj(zspage); |
1322 | |
1323 | offset = obj * class->size; |
1324 | nr_page = offset >> PAGE_SHIFT; |
1325 | m_offset = offset_in_page(offset); |
1326 | m_page = get_first_page(zspage); |
1327 | |
1328 | for (i = 0; i < nr_page; i++) |
1329 | m_page = get_next_page(page: m_page); |
1330 | |
1331 | vaddr = kmap_atomic(page: m_page); |
1332 | link = (struct link_free *)vaddr + m_offset / sizeof(*link); |
1333 | set_freeobj(zspage, obj: link->next >> OBJ_TAG_BITS); |
1334 | if (likely(!ZsHugePage(zspage))) |
1335 | /* record handle in the header of allocated chunk */ |
1336 | link->handle = handle; |
1337 | else |
1338 | /* record handle to page->index */ |
1339 | zspage->first_page->index = handle; |
1340 | |
1341 | kunmap_atomic(vaddr); |
1342 | mod_zspage_inuse(zspage, val: 1); |
1343 | |
1344 | obj = location_to_obj(page: m_page, obj_idx: obj); |
1345 | |
1346 | return obj; |
1347 | } |
1348 | |
1349 | |
1350 | /** |
1351 | * zs_malloc - Allocate block of given size from pool. |
1352 | * @pool: pool to allocate from |
1353 | * @size: size of block to allocate |
1354 | * @gfp: gfp flags when allocating object |
1355 | * |
1356 | * On success, handle to the allocated object is returned, |
1357 | * otherwise an ERR_PTR(). |
1358 | * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail. |
1359 | */ |
1360 | unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp) |
1361 | { |
1362 | unsigned long handle, obj; |
1363 | struct size_class *class; |
1364 | int newfg; |
1365 | struct zspage *zspage; |
1366 | |
1367 | if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE)) |
1368 | return (unsigned long)ERR_PTR(error: -EINVAL); |
1369 | |
1370 | handle = cache_alloc_handle(pool, gfp); |
1371 | if (!handle) |
1372 | return (unsigned long)ERR_PTR(error: -ENOMEM); |
1373 | |
1374 | /* extra space in chunk to keep the handle */ |
1375 | size += ZS_HANDLE_SIZE; |
1376 | class = pool->size_class[get_size_class_index(size)]; |
1377 | |
1378 | /* pool->lock effectively protects the zpage migration */ |
1379 | spin_lock(lock: &pool->lock); |
1380 | zspage = find_get_zspage(class); |
1381 | if (likely(zspage)) { |
1382 | obj = obj_malloc(pool, zspage, handle); |
1383 | /* Now move the zspage to another fullness group, if required */ |
1384 | fix_fullness_group(class, zspage); |
1385 | record_obj(handle, obj); |
1386 | class_stat_inc(class, type: ZS_OBJS_INUSE, cnt: 1); |
1387 | |
1388 | goto out; |
1389 | } |
1390 | |
1391 | spin_unlock(lock: &pool->lock); |
1392 | |
1393 | zspage = alloc_zspage(pool, class, gfp); |
1394 | if (!zspage) { |
1395 | cache_free_handle(pool, handle); |
1396 | return (unsigned long)ERR_PTR(error: -ENOMEM); |
1397 | } |
1398 | |
1399 | spin_lock(lock: &pool->lock); |
1400 | obj = obj_malloc(pool, zspage, handle); |
1401 | newfg = get_fullness_group(class, zspage); |
1402 | insert_zspage(class, zspage, fullness: newfg); |
1403 | set_zspage_mapping(zspage, class_idx: class->index, fullness: newfg); |
1404 | record_obj(handle, obj); |
1405 | atomic_long_add(i: class->pages_per_zspage, v: &pool->pages_allocated); |
1406 | class_stat_inc(class, type: ZS_OBJS_ALLOCATED, cnt: class->objs_per_zspage); |
1407 | class_stat_inc(class, type: ZS_OBJS_INUSE, cnt: 1); |
1408 | |
1409 | /* We completely set up zspage so mark them as movable */ |
1410 | SetZsPageMovable(pool, zspage); |
1411 | out: |
1412 | spin_unlock(lock: &pool->lock); |
1413 | |
1414 | return handle; |
1415 | } |
1416 | EXPORT_SYMBOL_GPL(zs_malloc); |
1417 | |
1418 | static void obj_free(int class_size, unsigned long obj) |
1419 | { |
1420 | struct link_free *link; |
1421 | struct zspage *zspage; |
1422 | struct page *f_page; |
1423 | unsigned long f_offset; |
1424 | unsigned int f_objidx; |
1425 | void *vaddr; |
1426 | |
1427 | obj_to_location(obj, page: &f_page, obj_idx: &f_objidx); |
1428 | f_offset = offset_in_page(class_size * f_objidx); |
1429 | zspage = get_zspage(page: f_page); |
1430 | |
1431 | vaddr = kmap_atomic(page: f_page); |
1432 | link = (struct link_free *)(vaddr + f_offset); |
1433 | |
1434 | /* Insert this object in containing zspage's freelist */ |
1435 | if (likely(!ZsHugePage(zspage))) |
1436 | link->next = get_freeobj(zspage) << OBJ_TAG_BITS; |
1437 | else |
1438 | f_page->index = 0; |
1439 | set_freeobj(zspage, obj: f_objidx); |
1440 | |
1441 | kunmap_atomic(vaddr); |
1442 | mod_zspage_inuse(zspage, val: -1); |
1443 | } |
1444 | |
1445 | void zs_free(struct zs_pool *pool, unsigned long handle) |
1446 | { |
1447 | struct zspage *zspage; |
1448 | struct page *f_page; |
1449 | unsigned long obj; |
1450 | struct size_class *class; |
1451 | int fullness; |
1452 | |
1453 | if (IS_ERR_OR_NULL(ptr: (void *)handle)) |
1454 | return; |
1455 | |
1456 | /* |
1457 | * The pool->lock protects the race with zpage's migration |
1458 | * so it's safe to get the page from handle. |
1459 | */ |
1460 | spin_lock(lock: &pool->lock); |
1461 | obj = handle_to_obj(handle); |
1462 | obj_to_page(obj, page: &f_page); |
1463 | zspage = get_zspage(page: f_page); |
1464 | class = zspage_class(pool, zspage); |
1465 | |
1466 | class_stat_dec(class, type: ZS_OBJS_INUSE, cnt: 1); |
1467 | obj_free(class_size: class->size, obj); |
1468 | |
1469 | fullness = fix_fullness_group(class, zspage); |
1470 | if (fullness == ZS_INUSE_RATIO_0) |
1471 | free_zspage(pool, class, zspage); |
1472 | |
1473 | spin_unlock(lock: &pool->lock); |
1474 | cache_free_handle(pool, handle); |
1475 | } |
1476 | EXPORT_SYMBOL_GPL(zs_free); |
1477 | |
1478 | static void zs_object_copy(struct size_class *class, unsigned long dst, |
1479 | unsigned long src) |
1480 | { |
1481 | struct page *s_page, *d_page; |
1482 | unsigned int s_objidx, d_objidx; |
1483 | unsigned long s_off, d_off; |
1484 | void *s_addr, *d_addr; |
1485 | int s_size, d_size, size; |
1486 | int written = 0; |
1487 | |
1488 | s_size = d_size = class->size; |
1489 | |
1490 | obj_to_location(obj: src, page: &s_page, obj_idx: &s_objidx); |
1491 | obj_to_location(obj: dst, page: &d_page, obj_idx: &d_objidx); |
1492 | |
1493 | s_off = offset_in_page(class->size * s_objidx); |
1494 | d_off = offset_in_page(class->size * d_objidx); |
1495 | |
1496 | if (s_off + class->size > PAGE_SIZE) |
1497 | s_size = PAGE_SIZE - s_off; |
1498 | |
1499 | if (d_off + class->size > PAGE_SIZE) |
1500 | d_size = PAGE_SIZE - d_off; |
1501 | |
1502 | s_addr = kmap_atomic(page: s_page); |
1503 | d_addr = kmap_atomic(page: d_page); |
1504 | |
1505 | while (1) { |
1506 | size = min(s_size, d_size); |
1507 | memcpy(d_addr + d_off, s_addr + s_off, size); |
1508 | written += size; |
1509 | |
1510 | if (written == class->size) |
1511 | break; |
1512 | |
1513 | s_off += size; |
1514 | s_size -= size; |
1515 | d_off += size; |
1516 | d_size -= size; |
1517 | |
1518 | /* |
1519 | * Calling kunmap_atomic(d_addr) is necessary. kunmap_atomic() |
1520 | * calls must occurs in reverse order of calls to kmap_atomic(). |
1521 | * So, to call kunmap_atomic(s_addr) we should first call |
1522 | * kunmap_atomic(d_addr). For more details see |
1523 | * Documentation/mm/highmem.rst. |
1524 | */ |
1525 | if (s_off >= PAGE_SIZE) { |
1526 | kunmap_atomic(d_addr); |
1527 | kunmap_atomic(s_addr); |
1528 | s_page = get_next_page(page: s_page); |
1529 | s_addr = kmap_atomic(page: s_page); |
1530 | d_addr = kmap_atomic(page: d_page); |
1531 | s_size = class->size - written; |
1532 | s_off = 0; |
1533 | } |
1534 | |
1535 | if (d_off >= PAGE_SIZE) { |
1536 | kunmap_atomic(d_addr); |
1537 | d_page = get_next_page(page: d_page); |
1538 | d_addr = kmap_atomic(page: d_page); |
1539 | d_size = class->size - written; |
1540 | d_off = 0; |
1541 | } |
1542 | } |
1543 | |
1544 | kunmap_atomic(d_addr); |
1545 | kunmap_atomic(s_addr); |
1546 | } |
1547 | |
1548 | /* |
1549 | * Find alloced object in zspage from index object and |
1550 | * return handle. |
1551 | */ |
1552 | static unsigned long find_alloced_obj(struct size_class *class, |
1553 | struct page *page, int *obj_idx) |
1554 | { |
1555 | unsigned int offset; |
1556 | int index = *obj_idx; |
1557 | unsigned long handle = 0; |
1558 | void *addr = kmap_atomic(page); |
1559 | |
1560 | offset = get_first_obj_offset(page); |
1561 | offset += class->size * index; |
1562 | |
1563 | while (offset < PAGE_SIZE) { |
1564 | if (obj_allocated(page, obj: addr + offset, phandle: &handle)) |
1565 | break; |
1566 | |
1567 | offset += class->size; |
1568 | index++; |
1569 | } |
1570 | |
1571 | kunmap_atomic(addr); |
1572 | |
1573 | *obj_idx = index; |
1574 | |
1575 | return handle; |
1576 | } |
1577 | |
1578 | static void migrate_zspage(struct zs_pool *pool, struct zspage *src_zspage, |
1579 | struct zspage *dst_zspage) |
1580 | { |
1581 | unsigned long used_obj, free_obj; |
1582 | unsigned long handle; |
1583 | int obj_idx = 0; |
1584 | struct page *s_page = get_first_page(zspage: src_zspage); |
1585 | struct size_class *class = pool->size_class[src_zspage->class]; |
1586 | |
1587 | while (1) { |
1588 | handle = find_alloced_obj(class, page: s_page, obj_idx: &obj_idx); |
1589 | if (!handle) { |
1590 | s_page = get_next_page(page: s_page); |
1591 | if (!s_page) |
1592 | break; |
1593 | obj_idx = 0; |
1594 | continue; |
1595 | } |
1596 | |
1597 | used_obj = handle_to_obj(handle); |
1598 | free_obj = obj_malloc(pool, zspage: dst_zspage, handle); |
1599 | zs_object_copy(class, dst: free_obj, src: used_obj); |
1600 | obj_idx++; |
1601 | record_obj(handle, obj: free_obj); |
1602 | obj_free(class_size: class->size, obj: used_obj); |
1603 | |
1604 | /* Stop if there is no more space */ |
1605 | if (zspage_full(class, zspage: dst_zspage)) |
1606 | break; |
1607 | |
1608 | /* Stop if there are no more objects to migrate */ |
1609 | if (zspage_empty(zspage: src_zspage)) |
1610 | break; |
1611 | } |
1612 | } |
1613 | |
1614 | static struct zspage *isolate_src_zspage(struct size_class *class) |
1615 | { |
1616 | struct zspage *zspage; |
1617 | int fg; |
1618 | |
1619 | for (fg = ZS_INUSE_RATIO_10; fg <= ZS_INUSE_RATIO_99; fg++) { |
1620 | zspage = list_first_entry_or_null(&class->fullness_list[fg], |
1621 | struct zspage, list); |
1622 | if (zspage) { |
1623 | remove_zspage(class, zspage, fullness: fg); |
1624 | return zspage; |
1625 | } |
1626 | } |
1627 | |
1628 | return zspage; |
1629 | } |
1630 | |
1631 | static struct zspage *isolate_dst_zspage(struct size_class *class) |
1632 | { |
1633 | struct zspage *zspage; |
1634 | int fg; |
1635 | |
1636 | for (fg = ZS_INUSE_RATIO_99; fg >= ZS_INUSE_RATIO_10; fg--) { |
1637 | zspage = list_first_entry_or_null(&class->fullness_list[fg], |
1638 | struct zspage, list); |
1639 | if (zspage) { |
1640 | remove_zspage(class, zspage, fullness: fg); |
1641 | return zspage; |
1642 | } |
1643 | } |
1644 | |
1645 | return zspage; |
1646 | } |
1647 | |
1648 | /* |
1649 | * putback_zspage - add @zspage into right class's fullness list |
1650 | * @class: destination class |
1651 | * @zspage: target page |
1652 | * |
1653 | * Return @zspage's fullness status |
1654 | */ |
1655 | static int putback_zspage(struct size_class *class, struct zspage *zspage) |
1656 | { |
1657 | int fullness; |
1658 | |
1659 | fullness = get_fullness_group(class, zspage); |
1660 | insert_zspage(class, zspage, fullness); |
1661 | set_zspage_mapping(zspage, class_idx: class->index, fullness); |
1662 | |
1663 | return fullness; |
1664 | } |
1665 | |
1666 | #ifdef CONFIG_COMPACTION |
1667 | /* |
1668 | * To prevent zspage destroy during migration, zspage freeing should |
1669 | * hold locks of all pages in the zspage. |
1670 | */ |
1671 | static void lock_zspage(struct zspage *zspage) |
1672 | { |
1673 | struct page *curr_page, *page; |
1674 | |
1675 | /* |
1676 | * Pages we haven't locked yet can be migrated off the list while we're |
1677 | * trying to lock them, so we need to be careful and only attempt to |
1678 | * lock each page under migrate_read_lock(). Otherwise, the page we lock |
1679 | * may no longer belong to the zspage. This means that we may wait for |
1680 | * the wrong page to unlock, so we must take a reference to the page |
1681 | * prior to waiting for it to unlock outside migrate_read_lock(). |
1682 | */ |
1683 | while (1) { |
1684 | migrate_read_lock(zspage); |
1685 | page = get_first_page(zspage); |
1686 | if (trylock_page(page)) |
1687 | break; |
1688 | get_page(page); |
1689 | migrate_read_unlock(zspage); |
1690 | wait_on_page_locked(page); |
1691 | put_page(page); |
1692 | } |
1693 | |
1694 | curr_page = page; |
1695 | while ((page = get_next_page(page: curr_page))) { |
1696 | if (trylock_page(page)) { |
1697 | curr_page = page; |
1698 | } else { |
1699 | get_page(page); |
1700 | migrate_read_unlock(zspage); |
1701 | wait_on_page_locked(page); |
1702 | put_page(page); |
1703 | migrate_read_lock(zspage); |
1704 | } |
1705 | } |
1706 | migrate_read_unlock(zspage); |
1707 | } |
1708 | #endif /* CONFIG_COMPACTION */ |
1709 | |
1710 | static void migrate_lock_init(struct zspage *zspage) |
1711 | { |
1712 | rwlock_init(&zspage->lock); |
1713 | } |
1714 | |
1715 | static void migrate_read_lock(struct zspage *zspage) __acquires(&zspage->lock) |
1716 | { |
1717 | read_lock(&zspage->lock); |
1718 | } |
1719 | |
1720 | static void migrate_read_unlock(struct zspage *zspage) __releases(&zspage->lock) |
1721 | { |
1722 | read_unlock(&zspage->lock); |
1723 | } |
1724 | |
1725 | #ifdef CONFIG_COMPACTION |
1726 | static void migrate_write_lock(struct zspage *zspage) |
1727 | { |
1728 | write_lock(&zspage->lock); |
1729 | } |
1730 | |
1731 | static void migrate_write_lock_nested(struct zspage *zspage) |
1732 | { |
1733 | write_lock_nested(&zspage->lock, SINGLE_DEPTH_NESTING); |
1734 | } |
1735 | |
1736 | static void migrate_write_unlock(struct zspage *zspage) |
1737 | { |
1738 | write_unlock(&zspage->lock); |
1739 | } |
1740 | |
1741 | /* Number of isolated subpage for *page migration* in this zspage */ |
1742 | static void inc_zspage_isolation(struct zspage *zspage) |
1743 | { |
1744 | zspage->isolated++; |
1745 | } |
1746 | |
1747 | static void dec_zspage_isolation(struct zspage *zspage) |
1748 | { |
1749 | VM_BUG_ON(zspage->isolated == 0); |
1750 | zspage->isolated--; |
1751 | } |
1752 | |
1753 | static const struct movable_operations zsmalloc_mops; |
1754 | |
1755 | static void replace_sub_page(struct size_class *class, struct zspage *zspage, |
1756 | struct page *newpage, struct page *oldpage) |
1757 | { |
1758 | struct page *page; |
1759 | struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, }; |
1760 | int idx = 0; |
1761 | |
1762 | page = get_first_page(zspage); |
1763 | do { |
1764 | if (page == oldpage) |
1765 | pages[idx] = newpage; |
1766 | else |
1767 | pages[idx] = page; |
1768 | idx++; |
1769 | } while ((page = get_next_page(page)) != NULL); |
1770 | |
1771 | create_page_chain(class, zspage, pages); |
1772 | set_first_obj_offset(page: newpage, offset: get_first_obj_offset(page: oldpage)); |
1773 | if (unlikely(ZsHugePage(zspage))) |
1774 | newpage->index = oldpage->index; |
1775 | __SetPageMovable(page: newpage, ops: &zsmalloc_mops); |
1776 | } |
1777 | |
1778 | static bool zs_page_isolate(struct page *page, isolate_mode_t mode) |
1779 | { |
1780 | struct zs_pool *pool; |
1781 | struct zspage *zspage; |
1782 | |
1783 | /* |
1784 | * Page is locked so zspage couldn't be destroyed. For detail, look at |
1785 | * lock_zspage in free_zspage. |
1786 | */ |
1787 | VM_BUG_ON_PAGE(PageIsolated(page), page); |
1788 | |
1789 | zspage = get_zspage(page); |
1790 | pool = zspage->pool; |
1791 | spin_lock(lock: &pool->lock); |
1792 | inc_zspage_isolation(zspage); |
1793 | spin_unlock(lock: &pool->lock); |
1794 | |
1795 | return true; |
1796 | } |
1797 | |
1798 | static int zs_page_migrate(struct page *newpage, struct page *page, |
1799 | enum migrate_mode mode) |
1800 | { |
1801 | struct zs_pool *pool; |
1802 | struct size_class *class; |
1803 | struct zspage *zspage; |
1804 | struct page *dummy; |
1805 | void *s_addr, *d_addr, *addr; |
1806 | unsigned int offset; |
1807 | unsigned long handle; |
1808 | unsigned long old_obj, new_obj; |
1809 | unsigned int obj_idx; |
1810 | |
1811 | /* |
1812 | * We cannot support the _NO_COPY case here, because copy needs to |
1813 | * happen under the zs lock, which does not work with |
1814 | * MIGRATE_SYNC_NO_COPY workflow. |
1815 | */ |
1816 | if (mode == MIGRATE_SYNC_NO_COPY) |
1817 | return -EINVAL; |
1818 | |
1819 | VM_BUG_ON_PAGE(!PageIsolated(page), page); |
1820 | |
1821 | /* The page is locked, so this pointer must remain valid */ |
1822 | zspage = get_zspage(page); |
1823 | pool = zspage->pool; |
1824 | |
1825 | /* |
1826 | * The pool's lock protects the race between zpage migration |
1827 | * and zs_free. |
1828 | */ |
1829 | spin_lock(lock: &pool->lock); |
1830 | class = zspage_class(pool, zspage); |
1831 | |
1832 | /* the migrate_write_lock protects zpage access via zs_map_object */ |
1833 | migrate_write_lock(zspage); |
1834 | |
1835 | offset = get_first_obj_offset(page); |
1836 | s_addr = kmap_atomic(page); |
1837 | |
1838 | /* |
1839 | * Here, any user cannot access all objects in the zspage so let's move. |
1840 | */ |
1841 | d_addr = kmap_atomic(page: newpage); |
1842 | copy_page(to: d_addr, from: s_addr); |
1843 | kunmap_atomic(d_addr); |
1844 | |
1845 | for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE; |
1846 | addr += class->size) { |
1847 | if (obj_allocated(page, obj: addr, phandle: &handle)) { |
1848 | |
1849 | old_obj = handle_to_obj(handle); |
1850 | obj_to_location(obj: old_obj, page: &dummy, obj_idx: &obj_idx); |
1851 | new_obj = (unsigned long)location_to_obj(page: newpage, |
1852 | obj_idx); |
1853 | record_obj(handle, obj: new_obj); |
1854 | } |
1855 | } |
1856 | kunmap_atomic(s_addr); |
1857 | |
1858 | replace_sub_page(class, zspage, newpage, oldpage: page); |
1859 | dec_zspage_isolation(zspage); |
1860 | /* |
1861 | * Since we complete the data copy and set up new zspage structure, |
1862 | * it's okay to release the pool's lock. |
1863 | */ |
1864 | spin_unlock(lock: &pool->lock); |
1865 | migrate_write_unlock(zspage); |
1866 | |
1867 | get_page(page: newpage); |
1868 | if (page_zone(page: newpage) != page_zone(page)) { |
1869 | dec_zone_page_state(page, NR_ZSPAGES); |
1870 | inc_zone_page_state(newpage, NR_ZSPAGES); |
1871 | } |
1872 | |
1873 | reset_page(page); |
1874 | put_page(page); |
1875 | |
1876 | return MIGRATEPAGE_SUCCESS; |
1877 | } |
1878 | |
1879 | static void zs_page_putback(struct page *page) |
1880 | { |
1881 | struct zs_pool *pool; |
1882 | struct zspage *zspage; |
1883 | |
1884 | VM_BUG_ON_PAGE(!PageIsolated(page), page); |
1885 | |
1886 | zspage = get_zspage(page); |
1887 | pool = zspage->pool; |
1888 | spin_lock(lock: &pool->lock); |
1889 | dec_zspage_isolation(zspage); |
1890 | spin_unlock(lock: &pool->lock); |
1891 | } |
1892 | |
1893 | static const struct movable_operations zsmalloc_mops = { |
1894 | .isolate_page = zs_page_isolate, |
1895 | .migrate_page = zs_page_migrate, |
1896 | .putback_page = zs_page_putback, |
1897 | }; |
1898 | |
1899 | /* |
1900 | * Caller should hold page_lock of all pages in the zspage |
1901 | * In here, we cannot use zspage meta data. |
1902 | */ |
1903 | static void async_free_zspage(struct work_struct *work) |
1904 | { |
1905 | int i; |
1906 | struct size_class *class; |
1907 | unsigned int class_idx; |
1908 | int fullness; |
1909 | struct zspage *zspage, *tmp; |
1910 | LIST_HEAD(free_pages); |
1911 | struct zs_pool *pool = container_of(work, struct zs_pool, |
1912 | free_work); |
1913 | |
1914 | for (i = 0; i < ZS_SIZE_CLASSES; i++) { |
1915 | class = pool->size_class[i]; |
1916 | if (class->index != i) |
1917 | continue; |
1918 | |
1919 | spin_lock(lock: &pool->lock); |
1920 | list_splice_init(list: &class->fullness_list[ZS_INUSE_RATIO_0], |
1921 | head: &free_pages); |
1922 | spin_unlock(lock: &pool->lock); |
1923 | } |
1924 | |
1925 | list_for_each_entry_safe(zspage, tmp, &free_pages, list) { |
1926 | list_del(entry: &zspage->list); |
1927 | lock_zspage(zspage); |
1928 | |
1929 | get_zspage_mapping(zspage, class_idx: &class_idx, fullness: &fullness); |
1930 | VM_BUG_ON(fullness != ZS_INUSE_RATIO_0); |
1931 | class = pool->size_class[class_idx]; |
1932 | spin_lock(lock: &pool->lock); |
1933 | __free_zspage(pool, class, zspage); |
1934 | spin_unlock(lock: &pool->lock); |
1935 | } |
1936 | }; |
1937 | |
1938 | static void kick_deferred_free(struct zs_pool *pool) |
1939 | { |
1940 | schedule_work(work: &pool->free_work); |
1941 | } |
1942 | |
1943 | static void zs_flush_migration(struct zs_pool *pool) |
1944 | { |
1945 | flush_work(work: &pool->free_work); |
1946 | } |
1947 | |
1948 | static void init_deferred_free(struct zs_pool *pool) |
1949 | { |
1950 | INIT_WORK(&pool->free_work, async_free_zspage); |
1951 | } |
1952 | |
1953 | static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) |
1954 | { |
1955 | struct page *page = get_first_page(zspage); |
1956 | |
1957 | do { |
1958 | WARN_ON(!trylock_page(page)); |
1959 | __SetPageMovable(page, ops: &zsmalloc_mops); |
1960 | unlock_page(page); |
1961 | } while ((page = get_next_page(page)) != NULL); |
1962 | } |
1963 | #else |
1964 | static inline void zs_flush_migration(struct zs_pool *pool) { } |
1965 | #endif |
1966 | |
1967 | /* |
1968 | * |
1969 | * Based on the number of unused allocated objects calculate |
1970 | * and return the number of pages that we can free. |
1971 | */ |
1972 | static unsigned long zs_can_compact(struct size_class *class) |
1973 | { |
1974 | unsigned long obj_wasted; |
1975 | unsigned long obj_allocated = zs_stat_get(class, type: ZS_OBJS_ALLOCATED); |
1976 | unsigned long obj_used = zs_stat_get(class, type: ZS_OBJS_INUSE); |
1977 | |
1978 | if (obj_allocated <= obj_used) |
1979 | return 0; |
1980 | |
1981 | obj_wasted = obj_allocated - obj_used; |
1982 | obj_wasted /= class->objs_per_zspage; |
1983 | |
1984 | return obj_wasted * class->pages_per_zspage; |
1985 | } |
1986 | |
1987 | static unsigned long __zs_compact(struct zs_pool *pool, |
1988 | struct size_class *class) |
1989 | { |
1990 | struct zspage *src_zspage = NULL; |
1991 | struct zspage *dst_zspage = NULL; |
1992 | unsigned long pages_freed = 0; |
1993 | |
1994 | /* |
1995 | * protect the race between zpage migration and zs_free |
1996 | * as well as zpage allocation/free |
1997 | */ |
1998 | spin_lock(lock: &pool->lock); |
1999 | while (zs_can_compact(class)) { |
2000 | int fg; |
2001 | |
2002 | if (!dst_zspage) { |
2003 | dst_zspage = isolate_dst_zspage(class); |
2004 | if (!dst_zspage) |
2005 | break; |
2006 | migrate_write_lock(zspage: dst_zspage); |
2007 | } |
2008 | |
2009 | src_zspage = isolate_src_zspage(class); |
2010 | if (!src_zspage) |
2011 | break; |
2012 | |
2013 | migrate_write_lock_nested(zspage: src_zspage); |
2014 | |
2015 | migrate_zspage(pool, src_zspage, dst_zspage); |
2016 | fg = putback_zspage(class, zspage: src_zspage); |
2017 | migrate_write_unlock(zspage: src_zspage); |
2018 | |
2019 | if (fg == ZS_INUSE_RATIO_0) { |
2020 | free_zspage(pool, class, zspage: src_zspage); |
2021 | pages_freed += class->pages_per_zspage; |
2022 | } |
2023 | src_zspage = NULL; |
2024 | |
2025 | if (get_fullness_group(class, zspage: dst_zspage) == ZS_INUSE_RATIO_100 |
2026 | || spin_is_contended(lock: &pool->lock)) { |
2027 | putback_zspage(class, zspage: dst_zspage); |
2028 | migrate_write_unlock(zspage: dst_zspage); |
2029 | dst_zspage = NULL; |
2030 | |
2031 | spin_unlock(lock: &pool->lock); |
2032 | cond_resched(); |
2033 | spin_lock(lock: &pool->lock); |
2034 | } |
2035 | } |
2036 | |
2037 | if (src_zspage) { |
2038 | putback_zspage(class, zspage: src_zspage); |
2039 | migrate_write_unlock(zspage: src_zspage); |
2040 | } |
2041 | |
2042 | if (dst_zspage) { |
2043 | putback_zspage(class, zspage: dst_zspage); |
2044 | migrate_write_unlock(zspage: dst_zspage); |
2045 | } |
2046 | spin_unlock(lock: &pool->lock); |
2047 | |
2048 | return pages_freed; |
2049 | } |
2050 | |
2051 | unsigned long zs_compact(struct zs_pool *pool) |
2052 | { |
2053 | int i; |
2054 | struct size_class *class; |
2055 | unsigned long pages_freed = 0; |
2056 | |
2057 | /* |
2058 | * Pool compaction is performed under pool->lock so it is basically |
2059 | * single-threaded. Having more than one thread in __zs_compact() |
2060 | * will increase pool->lock contention, which will impact other |
2061 | * zsmalloc operations that need pool->lock. |
2062 | */ |
2063 | if (atomic_xchg(v: &pool->compaction_in_progress, new: 1)) |
2064 | return 0; |
2065 | |
2066 | for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { |
2067 | class = pool->size_class[i]; |
2068 | if (class->index != i) |
2069 | continue; |
2070 | pages_freed += __zs_compact(pool, class); |
2071 | } |
2072 | atomic_long_add(i: pages_freed, v: &pool->stats.pages_compacted); |
2073 | atomic_set(v: &pool->compaction_in_progress, i: 0); |
2074 | |
2075 | return pages_freed; |
2076 | } |
2077 | EXPORT_SYMBOL_GPL(zs_compact); |
2078 | |
2079 | void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats) |
2080 | { |
2081 | memcpy(stats, &pool->stats, sizeof(struct zs_pool_stats)); |
2082 | } |
2083 | EXPORT_SYMBOL_GPL(zs_pool_stats); |
2084 | |
2085 | static unsigned long zs_shrinker_scan(struct shrinker *shrinker, |
2086 | struct shrink_control *sc) |
2087 | { |
2088 | unsigned long pages_freed; |
2089 | struct zs_pool *pool = shrinker->private_data; |
2090 | |
2091 | /* |
2092 | * Compact classes and calculate compaction delta. |
2093 | * Can run concurrently with a manually triggered |
2094 | * (by user) compaction. |
2095 | */ |
2096 | pages_freed = zs_compact(pool); |
2097 | |
2098 | return pages_freed ? pages_freed : SHRINK_STOP; |
2099 | } |
2100 | |
2101 | static unsigned long zs_shrinker_count(struct shrinker *shrinker, |
2102 | struct shrink_control *sc) |
2103 | { |
2104 | int i; |
2105 | struct size_class *class; |
2106 | unsigned long pages_to_free = 0; |
2107 | struct zs_pool *pool = shrinker->private_data; |
2108 | |
2109 | for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { |
2110 | class = pool->size_class[i]; |
2111 | if (class->index != i) |
2112 | continue; |
2113 | |
2114 | pages_to_free += zs_can_compact(class); |
2115 | } |
2116 | |
2117 | return pages_to_free; |
2118 | } |
2119 | |
2120 | static void zs_unregister_shrinker(struct zs_pool *pool) |
2121 | { |
2122 | shrinker_free(shrinker: pool->shrinker); |
2123 | } |
2124 | |
2125 | static int zs_register_shrinker(struct zs_pool *pool) |
2126 | { |
2127 | pool->shrinker = shrinker_alloc(flags: 0, fmt: "mm-zspool:%s" , pool->name); |
2128 | if (!pool->shrinker) |
2129 | return -ENOMEM; |
2130 | |
2131 | pool->shrinker->scan_objects = zs_shrinker_scan; |
2132 | pool->shrinker->count_objects = zs_shrinker_count; |
2133 | pool->shrinker->batch = 0; |
2134 | pool->shrinker->private_data = pool; |
2135 | |
2136 | shrinker_register(shrinker: pool->shrinker); |
2137 | |
2138 | return 0; |
2139 | } |
2140 | |
2141 | static int calculate_zspage_chain_size(int class_size) |
2142 | { |
2143 | int i, min_waste = INT_MAX; |
2144 | int chain_size = 1; |
2145 | |
2146 | if (is_power_of_2(n: class_size)) |
2147 | return chain_size; |
2148 | |
2149 | for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { |
2150 | int waste; |
2151 | |
2152 | waste = (i * PAGE_SIZE) % class_size; |
2153 | if (waste < min_waste) { |
2154 | min_waste = waste; |
2155 | chain_size = i; |
2156 | } |
2157 | } |
2158 | |
2159 | return chain_size; |
2160 | } |
2161 | |
2162 | /** |
2163 | * zs_create_pool - Creates an allocation pool to work from. |
2164 | * @name: pool name to be created |
2165 | * |
2166 | * This function must be called before anything when using |
2167 | * the zsmalloc allocator. |
2168 | * |
2169 | * On success, a pointer to the newly created pool is returned, |
2170 | * otherwise NULL. |
2171 | */ |
2172 | struct zs_pool *zs_create_pool(const char *name) |
2173 | { |
2174 | int i; |
2175 | struct zs_pool *pool; |
2176 | struct size_class *prev_class = NULL; |
2177 | |
2178 | pool = kzalloc(size: sizeof(*pool), GFP_KERNEL); |
2179 | if (!pool) |
2180 | return NULL; |
2181 | |
2182 | init_deferred_free(pool); |
2183 | spin_lock_init(&pool->lock); |
2184 | atomic_set(v: &pool->compaction_in_progress, i: 0); |
2185 | |
2186 | pool->name = kstrdup(s: name, GFP_KERNEL); |
2187 | if (!pool->name) |
2188 | goto err; |
2189 | |
2190 | if (create_cache(pool)) |
2191 | goto err; |
2192 | |
2193 | /* |
2194 | * Iterate reversely, because, size of size_class that we want to use |
2195 | * for merging should be larger or equal to current size. |
2196 | */ |
2197 | for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { |
2198 | int size; |
2199 | int pages_per_zspage; |
2200 | int objs_per_zspage; |
2201 | struct size_class *class; |
2202 | int fullness; |
2203 | |
2204 | size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA; |
2205 | if (size > ZS_MAX_ALLOC_SIZE) |
2206 | size = ZS_MAX_ALLOC_SIZE; |
2207 | pages_per_zspage = calculate_zspage_chain_size(class_size: size); |
2208 | objs_per_zspage = pages_per_zspage * PAGE_SIZE / size; |
2209 | |
2210 | /* |
2211 | * We iterate from biggest down to smallest classes, |
2212 | * so huge_class_size holds the size of the first huge |
2213 | * class. Any object bigger than or equal to that will |
2214 | * endup in the huge class. |
2215 | */ |
2216 | if (pages_per_zspage != 1 && objs_per_zspage != 1 && |
2217 | !huge_class_size) { |
2218 | huge_class_size = size; |
2219 | /* |
2220 | * The object uses ZS_HANDLE_SIZE bytes to store the |
2221 | * handle. We need to subtract it, because zs_malloc() |
2222 | * unconditionally adds handle size before it performs |
2223 | * size class search - so object may be smaller than |
2224 | * huge class size, yet it still can end up in the huge |
2225 | * class because it grows by ZS_HANDLE_SIZE extra bytes |
2226 | * right before class lookup. |
2227 | */ |
2228 | huge_class_size -= (ZS_HANDLE_SIZE - 1); |
2229 | } |
2230 | |
2231 | /* |
2232 | * size_class is used for normal zsmalloc operation such |
2233 | * as alloc/free for that size. Although it is natural that we |
2234 | * have one size_class for each size, there is a chance that we |
2235 | * can get more memory utilization if we use one size_class for |
2236 | * many different sizes whose size_class have same |
2237 | * characteristics. So, we makes size_class point to |
2238 | * previous size_class if possible. |
2239 | */ |
2240 | if (prev_class) { |
2241 | if (can_merge(prev: prev_class, pages_per_zspage, objs_per_zspage)) { |
2242 | pool->size_class[i] = prev_class; |
2243 | continue; |
2244 | } |
2245 | } |
2246 | |
2247 | class = kzalloc(size: sizeof(struct size_class), GFP_KERNEL); |
2248 | if (!class) |
2249 | goto err; |
2250 | |
2251 | class->size = size; |
2252 | class->index = i; |
2253 | class->pages_per_zspage = pages_per_zspage; |
2254 | class->objs_per_zspage = objs_per_zspage; |
2255 | pool->size_class[i] = class; |
2256 | |
2257 | fullness = ZS_INUSE_RATIO_0; |
2258 | while (fullness < NR_FULLNESS_GROUPS) { |
2259 | INIT_LIST_HEAD(list: &class->fullness_list[fullness]); |
2260 | fullness++; |
2261 | } |
2262 | |
2263 | prev_class = class; |
2264 | } |
2265 | |
2266 | /* debug only, don't abort if it fails */ |
2267 | zs_pool_stat_create(pool, name); |
2268 | |
2269 | /* |
2270 | * Not critical since shrinker is only used to trigger internal |
2271 | * defragmentation of the pool which is pretty optional thing. If |
2272 | * registration fails we still can use the pool normally and user can |
2273 | * trigger compaction manually. Thus, ignore return code. |
2274 | */ |
2275 | zs_register_shrinker(pool); |
2276 | |
2277 | return pool; |
2278 | |
2279 | err: |
2280 | zs_destroy_pool(pool); |
2281 | return NULL; |
2282 | } |
2283 | EXPORT_SYMBOL_GPL(zs_create_pool); |
2284 | |
2285 | void zs_destroy_pool(struct zs_pool *pool) |
2286 | { |
2287 | int i; |
2288 | |
2289 | zs_unregister_shrinker(pool); |
2290 | zs_flush_migration(pool); |
2291 | zs_pool_stat_destroy(pool); |
2292 | |
2293 | for (i = 0; i < ZS_SIZE_CLASSES; i++) { |
2294 | int fg; |
2295 | struct size_class *class = pool->size_class[i]; |
2296 | |
2297 | if (!class) |
2298 | continue; |
2299 | |
2300 | if (class->index != i) |
2301 | continue; |
2302 | |
2303 | for (fg = ZS_INUSE_RATIO_0; fg < NR_FULLNESS_GROUPS; fg++) { |
2304 | if (list_empty(head: &class->fullness_list[fg])) |
2305 | continue; |
2306 | |
2307 | pr_err("Class-%d fullness group %d is not empty\n" , |
2308 | class->size, fg); |
2309 | } |
2310 | kfree(objp: class); |
2311 | } |
2312 | |
2313 | destroy_cache(pool); |
2314 | kfree(objp: pool->name); |
2315 | kfree(objp: pool); |
2316 | } |
2317 | EXPORT_SYMBOL_GPL(zs_destroy_pool); |
2318 | |
2319 | static int __init zs_init(void) |
2320 | { |
2321 | int ret; |
2322 | |
2323 | ret = cpuhp_setup_state(state: CPUHP_MM_ZS_PREPARE, name: "mm/zsmalloc:prepare" , |
2324 | startup: zs_cpu_prepare, teardown: zs_cpu_dead); |
2325 | if (ret) |
2326 | goto out; |
2327 | |
2328 | #ifdef CONFIG_ZPOOL |
2329 | zpool_register_driver(driver: &zs_zpool_driver); |
2330 | #endif |
2331 | |
2332 | zs_stat_init(); |
2333 | |
2334 | return 0; |
2335 | |
2336 | out: |
2337 | return ret; |
2338 | } |
2339 | |
2340 | static void __exit zs_exit(void) |
2341 | { |
2342 | #ifdef CONFIG_ZPOOL |
2343 | zpool_unregister_driver(driver: &zs_zpool_driver); |
2344 | #endif |
2345 | cpuhp_remove_state(state: CPUHP_MM_ZS_PREPARE); |
2346 | |
2347 | zs_stat_exit(); |
2348 | } |
2349 | |
2350 | module_init(zs_init); |
2351 | module_exit(zs_exit); |
2352 | |
2353 | MODULE_LICENSE("Dual BSD/GPL" ); |
2354 | MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>" ); |
2355 | |