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1// SPDX-License-Identifier: GPL-2.0-or-later
2
3/*
4 * zsmalloc memory allocator
5 *
6 * Copyright (C) 2011 Nitin Gupta
7 * Copyright (C) 2012, 2013 Minchan Kim
8 *
9 * This code is released using a dual license strategy: BSD/GPL
10 * You can choose the license that better fits your requirements.
11 *
12 * Released under the terms of 3-clause BSD License
13 * Released under the terms of GNU General Public License Version 2.0
14 */
15
16/*
17 * Following is how we use various fields and flags of underlying
18 * struct page(s) to form a zspage.
19 *
20 * Usage of struct page fields:
21 * page->private: points to zspage
22 * page->index: links together all component pages of a zspage
23 * For the huge page, this is always 0, so we use this field
24 * to store handle.
25 * page->page_type: PGTY_zsmalloc, lower 24 bits locate the first object
26 * offset in a subpage of a zspage
27 *
28 * Usage of struct page flags:
29 * PG_private: identifies the first component page
30 * PG_owner_priv_1: identifies the huge component page
31 *
32 */
33
34#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
36/*
37 * lock ordering:
38 * page_lock
39 * pool->migrate_lock
40 * class->lock
41 * zspage->lock
42 */
43
44#include <linux/module.h>
45#include <linux/kernel.h>
46#include <linux/sched.h>
47#include <linux/bitops.h>
48#include <linux/errno.h>
49#include <linux/highmem.h>
50#include <linux/string.h>
51#include <linux/slab.h>
52#include <linux/pgtable.h>
53#include <asm/tlbflush.h>
54#include <linux/cpumask.h>
55#include <linux/cpu.h>
56#include <linux/vmalloc.h>
57#include <linux/preempt.h>
58#include <linux/spinlock.h>
59#include <linux/sprintf.h>
60#include <linux/shrinker.h>
61#include <linux/types.h>
62#include <linux/debugfs.h>
63#include <linux/zsmalloc.h>
64#include <linux/zpool.h>
65#include <linux/migrate.h>
66#include <linux/wait.h>
67#include <linux/pagemap.h>
68#include <linux/fs.h>
69#include <linux/local_lock.h>
70
71#define ZSPAGE_MAGIC 0x58
72
73/*
74 * This must be power of 2 and greater than or equal to sizeof(link_free).
75 * These two conditions ensure that any 'struct link_free' itself doesn't
76 * span more than 1 page which avoids complex case of mapping 2 pages simply
77 * to restore link_free pointer values.
78 */
79#define ZS_ALIGN 8
80
81#define ZS_HANDLE_SIZE (sizeof(unsigned long))
82
83/*
84 * Object location (<PFN>, <obj_idx>) is encoded as
85 * a single (unsigned long) handle value.
86 *
87 * Note that object index <obj_idx> starts from 0.
88 *
89 * This is made more complicated by various memory models and PAE.
90 */
91
92#ifndef MAX_POSSIBLE_PHYSMEM_BITS
93#ifdef MAX_PHYSMEM_BITS
94#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
95#else
96/*
97 * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
98 * be PAGE_SHIFT
99 */
100#define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
101#endif
102#endif
103
104#define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
105
106/*
107 * Head in allocated object should have OBJ_ALLOCATED_TAG
108 * to identify the object was allocated or not.
109 * It's okay to add the status bit in the least bit because
110 * header keeps handle which is 4byte-aligned address so we
111 * have room for two bit at least.
112 */
113#define OBJ_ALLOCATED_TAG 1
114
115#define OBJ_TAG_BITS 1
116#define OBJ_TAG_MASK OBJ_ALLOCATED_TAG
117
118#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS)
119#define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
120
121#define HUGE_BITS 1
122#define FULLNESS_BITS 4
123#define CLASS_BITS 8
124#define MAGIC_VAL_BITS 8
125
126#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(CONFIG_ZSMALLOC_CHAIN_SIZE, UL))
127
128/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
129#define ZS_MIN_ALLOC_SIZE \
130 MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
131/* each chunk includes extra space to keep handle */
132#define ZS_MAX_ALLOC_SIZE PAGE_SIZE
133
134/*
135 * On systems with 4K page size, this gives 255 size classes! There is a
136 * trader-off here:
137 * - Large number of size classes is potentially wasteful as free page are
138 * spread across these classes
139 * - Small number of size classes causes large internal fragmentation
140 * - Probably its better to use specific size classes (empirically
141 * determined). NOTE: all those class sizes must be set as multiple of
142 * ZS_ALIGN to make sure link_free itself never has to span 2 pages.
143 *
144 * ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
145 * (reason above)
146 */
147#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS)
148#define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \
149 ZS_SIZE_CLASS_DELTA) + 1)
150
151/*
152 * Pages are distinguished by the ratio of used memory (that is the ratio
153 * of ->inuse objects to all objects that page can store). For example,
154 * INUSE_RATIO_10 means that the ratio of used objects is > 0% and <= 10%.
155 *
156 * The number of fullness groups is not random. It allows us to keep
157 * difference between the least busy page in the group (minimum permitted
158 * number of ->inuse objects) and the most busy page (maximum permitted
159 * number of ->inuse objects) at a reasonable value.
160 */
161enum fullness_group {
162 ZS_INUSE_RATIO_0,
163 ZS_INUSE_RATIO_10,
164 /* NOTE: 8 more fullness groups here */
165 ZS_INUSE_RATIO_99 = 10,
166 ZS_INUSE_RATIO_100,
167 NR_FULLNESS_GROUPS,
168};
169
170enum class_stat_type {
171 /* NOTE: stats for 12 fullness groups here: from inuse 0 to 100 */
172 ZS_OBJS_ALLOCATED = NR_FULLNESS_GROUPS,
173 ZS_OBJS_INUSE,
174 NR_CLASS_STAT_TYPES,
175};
176
177struct zs_size_stat {
178 unsigned long objs[NR_CLASS_STAT_TYPES];
179};
180
181#ifdef CONFIG_ZSMALLOC_STAT
182static struct dentry *zs_stat_root;
183#endif
184
185static size_t huge_class_size;
186
187struct size_class {
188 spinlock_t lock;
189 struct list_head fullness_list[NR_FULLNESS_GROUPS];
190 /*
191 * Size of objects stored in this class. Must be multiple
192 * of ZS_ALIGN.
193 */
194 int size;
195 int objs_per_zspage;
196 /* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
197 int pages_per_zspage;
198
199 unsigned int index;
200 struct zs_size_stat stats;
201};
202
203/*
204 * Placed within free objects to form a singly linked list.
205 * For every zspage, zspage->freeobj gives head of this list.
206 *
207 * This must be power of 2 and less than or equal to ZS_ALIGN
208 */
209struct link_free {
210 union {
211 /*
212 * Free object index;
213 * It's valid for non-allocated object
214 */
215 unsigned long next;
216 /*
217 * Handle of allocated object.
218 */
219 unsigned long handle;
220 };
221};
222
223struct zs_pool {
224 const char *name;
225
226 struct size_class *size_class[ZS_SIZE_CLASSES];
227 struct kmem_cache *handle_cachep;
228 struct kmem_cache *zspage_cachep;
229
230 atomic_long_t pages_allocated;
231
232 struct zs_pool_stats stats;
233
234 /* Compact classes */
235 struct shrinker *shrinker;
236
237#ifdef CONFIG_ZSMALLOC_STAT
238 struct dentry *stat_dentry;
239#endif
240#ifdef CONFIG_COMPACTION
241 struct work_struct free_work;
242#endif
243 /* protect page/zspage migration */
244 rwlock_t migrate_lock;
245 atomic_t compaction_in_progress;
246};
247
248struct zspage {
249 struct {
250 unsigned int huge:HUGE_BITS;
251 unsigned int fullness:FULLNESS_BITS;
252 unsigned int class:CLASS_BITS + 1;
253 unsigned int magic:MAGIC_VAL_BITS;
254 };
255 unsigned int inuse;
256 unsigned int freeobj;
257 struct page *first_page;
258 struct list_head list; /* fullness list */
259 struct zs_pool *pool;
260 rwlock_t lock;
261};
262
263struct mapping_area {
264 local_lock_t lock;
265 char *vm_buf; /* copy buffer for objects that span pages */
266 char *vm_addr; /* address of kmap_local_page()'ed pages */
267 enum zs_mapmode vm_mm; /* mapping mode */
268};
269
270/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
271static void SetZsHugePage(struct zspage *zspage)
272{
273 zspage->huge = 1;
274}
275
276static bool ZsHugePage(struct zspage *zspage)
277{
278 return zspage->huge;
279}
280
281static void migrate_lock_init(struct zspage *zspage);
282static void migrate_read_lock(struct zspage *zspage);
283static void migrate_read_unlock(struct zspage *zspage);
284static void migrate_write_lock(struct zspage *zspage);
285static void migrate_write_unlock(struct zspage *zspage);
286
287#ifdef CONFIG_COMPACTION
288static void kick_deferred_free(struct zs_pool *pool);
289static void init_deferred_free(struct zs_pool *pool);
290static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
291#else
292static void kick_deferred_free(struct zs_pool *pool) {}
293static void init_deferred_free(struct zs_pool *pool) {}
294static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
295#endif
296
297static int create_cache(struct zs_pool *pool)
298{
299 char *name;
300
301 name = kasprintf(GFP_KERNEL, "zs_handle-%s", pool->name);
302 if (!name)
303 return -ENOMEM;
304 pool->handle_cachep = kmem_cache_create(name, ZS_HANDLE_SIZE,
305 0, 0, NULL);
306 kfree(name);
307 if (!pool->handle_cachep)
308 return -EINVAL;
309
310 name = kasprintf(GFP_KERNEL, "zspage-%s", pool->name);
311 if (!name)
312 return -ENOMEM;
313 pool->zspage_cachep = kmem_cache_create(name, sizeof(struct zspage),
314 0, 0, NULL);
315 kfree(name);
316 if (!pool->zspage_cachep) {
317 kmem_cache_destroy(pool->handle_cachep);
318 pool->handle_cachep = NULL;
319 return -EINVAL;
320 }
321
322 return 0;
323}
324
325static void destroy_cache(struct zs_pool *pool)
326{
327 kmem_cache_destroy(pool->handle_cachep);
328 kmem_cache_destroy(pool->zspage_cachep);
329}
330
331static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
332{
333 return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
334 gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
335}
336
337static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
338{
339 kmem_cache_free(pool->handle_cachep, (void *)handle);
340}
341
342static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags)
343{
344 return kmem_cache_zalloc(pool->zspage_cachep,
345 flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
346}
347
348static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
349{
350 kmem_cache_free(pool->zspage_cachep, zspage);
351}
352
353/* class->lock(which owns the handle) synchronizes races */
354static void record_obj(unsigned long handle, unsigned long obj)
355{
356 *(unsigned long *)handle = obj;
357}
358
359/* zpool driver */
360
361#ifdef CONFIG_ZPOOL
362
363static void *zs_zpool_create(const char *name, gfp_t gfp)
364{
365 /*
366 * Ignore global gfp flags: zs_malloc() may be invoked from
367 * different contexts and its caller must provide a valid
368 * gfp mask.
369 */
370 return zs_create_pool(name);
371}
372
373static void zs_zpool_destroy(void *pool)
374{
375 zs_destroy_pool(pool);
376}
377
378static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp,
379 unsigned long *handle)
380{
381 *handle = zs_malloc(pool, size, gfp);
382
383 if (IS_ERR_VALUE(*handle))
384 return PTR_ERR((void *)*handle);
385 return 0;
386}
387static void zs_zpool_free(void *pool, unsigned long handle)
388{
389 zs_free(pool, handle);
390}
391
392static void *zs_zpool_map(void *pool, unsigned long handle,
393 enum zpool_mapmode mm)
394{
395 enum zs_mapmode zs_mm;
396
397 switch (mm) {
398 case ZPOOL_MM_RO:
399 zs_mm = ZS_MM_RO;
400 break;
401 case ZPOOL_MM_WO:
402 zs_mm = ZS_MM_WO;
403 break;
404 case ZPOOL_MM_RW:
405 default:
406 zs_mm = ZS_MM_RW;
407 break;
408 }
409
410 return zs_map_object(pool, handle, zs_mm);
411}
412static void zs_zpool_unmap(void *pool, unsigned long handle)
413{
414 zs_unmap_object(pool, handle);
415}
416
417static u64 zs_zpool_total_pages(void *pool)
418{
419 return zs_get_total_pages(pool);
420}
421
422static struct zpool_driver zs_zpool_driver = {
423 .type = "zsmalloc",
424 .owner = THIS_MODULE,
425 .create = zs_zpool_create,
426 .destroy = zs_zpool_destroy,
427 .malloc_support_movable = true,
428 .malloc = zs_zpool_malloc,
429 .free = zs_zpool_free,
430 .map = zs_zpool_map,
431 .unmap = zs_zpool_unmap,
432 .total_pages = zs_zpool_total_pages,
433};
434
435MODULE_ALIAS("zpool-zsmalloc");
436#endif /* CONFIG_ZPOOL */
437
438/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
439static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = {
440 .lock = INIT_LOCAL_LOCK(lock),
441};
442
443static __maybe_unused int is_first_page(struct page *page)
444{
445 return PagePrivate(page);
446}
447
448/* Protected by class->lock */
449static inline int get_zspage_inuse(struct zspage *zspage)
450{
451 return zspage->inuse;
452}
453
454
455static inline void mod_zspage_inuse(struct zspage *zspage, int val)
456{
457 zspage->inuse += val;
458}
459
460static inline struct page *get_first_page(struct zspage *zspage)
461{
462 struct page *first_page = zspage->first_page;
463
464 VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
465 return first_page;
466}
467
468#define FIRST_OBJ_PAGE_TYPE_MASK 0xffffff
469
470static inline unsigned int get_first_obj_offset(struct page *page)
471{
472 VM_WARN_ON_ONCE(!PageZsmalloc(page));
473 return page->page_type & FIRST_OBJ_PAGE_TYPE_MASK;
474}
475
476static inline void set_first_obj_offset(struct page *page, unsigned int offset)
477{
478 /* With 24 bits available, we can support offsets into 16 MiB pages. */
479 BUILD_BUG_ON(PAGE_SIZE > SZ_16M);
480 VM_WARN_ON_ONCE(!PageZsmalloc(page));
481 VM_WARN_ON_ONCE(offset & ~FIRST_OBJ_PAGE_TYPE_MASK);
482 page->page_type &= ~FIRST_OBJ_PAGE_TYPE_MASK;
483 page->page_type |= offset & FIRST_OBJ_PAGE_TYPE_MASK;
484}
485
486static inline unsigned int get_freeobj(struct zspage *zspage)
487{
488 return zspage->freeobj;
489}
490
491static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
492{
493 zspage->freeobj = obj;
494}
495
496static struct size_class *zspage_class(struct zs_pool *pool,
497 struct zspage *zspage)
498{
499 return pool->size_class[zspage->class];
500}
501
502/*
503 * zsmalloc divides the pool into various size classes where each
504 * class maintains a list of zspages where each zspage is divided
505 * into equal sized chunks. Each allocation falls into one of these
506 * classes depending on its size. This function returns index of the
507 * size class which has chunk size big enough to hold the given size.
508 */
509static int get_size_class_index(int size)
510{
511 int idx = 0;
512
513 if (likely(size > ZS_MIN_ALLOC_SIZE))
514 idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE,
515 ZS_SIZE_CLASS_DELTA);
516
517 return min_t(int, ZS_SIZE_CLASSES - 1, idx);
518}
519
520static inline void class_stat_add(struct size_class *class, int type,
521 unsigned long cnt)
522{
523 class->stats.objs[type] += cnt;
524}
525
526static inline void class_stat_sub(struct size_class *class, int type,
527 unsigned long cnt)
528{
529 class->stats.objs[type] -= cnt;
530}
531
532static inline unsigned long class_stat_read(struct size_class *class, int type)
533{
534 return class->stats.objs[type];
535}
536
537#ifdef CONFIG_ZSMALLOC_STAT
538
539static void __init zs_stat_init(void)
540{
541 if (!debugfs_initialized()) {
542 pr_warn("debugfs not available, stat dir not created\n");
543 return;
544 }
545
546 zs_stat_root = debugfs_create_dir("zsmalloc", NULL);
547}
548
549static void __exit zs_stat_exit(void)
550{
551 debugfs_remove_recursive(zs_stat_root);
552}
553
554static unsigned long zs_can_compact(struct size_class *class);
555
556static int zs_stats_size_show(struct seq_file *s, void *v)
557{
558 int i, fg;
559 struct zs_pool *pool = s->private;
560 struct size_class *class;
561 int objs_per_zspage;
562 unsigned long obj_allocated, obj_used, pages_used, freeable;
563 unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0;
564 unsigned long total_freeable = 0;
565 unsigned long inuse_totals[NR_FULLNESS_GROUPS] = {0, };
566
567 seq_printf(s, " %5s %5s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %13s %10s %10s %16s %8s\n",
568 "class", "size", "10%", "20%", "30%", "40%",
569 "50%", "60%", "70%", "80%", "90%", "99%", "100%",
570 "obj_allocated", "obj_used", "pages_used",
571 "pages_per_zspage", "freeable");
572
573 for (i = 0; i < ZS_SIZE_CLASSES; i++) {
574
575 class = pool->size_class[i];
576
577 if (class->index != i)
578 continue;
579
580 spin_lock(&class->lock);
581
582 seq_printf(s, " %5u %5u ", i, class->size);
583 for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++) {
584 inuse_totals[fg] += class_stat_read(class, fg);
585 seq_printf(s, "%9lu ", class_stat_read(class, fg));
586 }
587
588 obj_allocated = class_stat_read(class, ZS_OBJS_ALLOCATED);
589 obj_used = class_stat_read(class, ZS_OBJS_INUSE);
590 freeable = zs_can_compact(class);
591 spin_unlock(&class->lock);
592
593 objs_per_zspage = class->objs_per_zspage;
594 pages_used = obj_allocated / objs_per_zspage *
595 class->pages_per_zspage;
596
597 seq_printf(s, "%13lu %10lu %10lu %16d %8lu\n",
598 obj_allocated, obj_used, pages_used,
599 class->pages_per_zspage, freeable);
600
601 total_objs += obj_allocated;
602 total_used_objs += obj_used;
603 total_pages += pages_used;
604 total_freeable += freeable;
605 }
606
607 seq_puts(s, "\n");
608 seq_printf(s, " %5s %5s ", "Total", "");
609
610 for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++)
611 seq_printf(s, "%9lu ", inuse_totals[fg]);
612
613 seq_printf(s, "%13lu %10lu %10lu %16s %8lu\n",
614 total_objs, total_used_objs, total_pages, "",
615 total_freeable);
616
617 return 0;
618}
619DEFINE_SHOW_ATTRIBUTE(zs_stats_size);
620
621static void zs_pool_stat_create(struct zs_pool *pool, const char *name)
622{
623 if (!zs_stat_root) {
624 pr_warn("no root stat dir, not creating <%s> stat dir\n", name);
625 return;
626 }
627
628 pool->stat_dentry = debugfs_create_dir(name, zs_stat_root);
629
630 debugfs_create_file("classes", S_IFREG | 0444, pool->stat_dentry, pool,
631 &zs_stats_size_fops);
632}
633
634static void zs_pool_stat_destroy(struct zs_pool *pool)
635{
636 debugfs_remove_recursive(pool->stat_dentry);
637}
638
639#else /* CONFIG_ZSMALLOC_STAT */
640static void __init zs_stat_init(void)
641{
642}
643
644static void __exit zs_stat_exit(void)
645{
646}
647
648static inline void zs_pool_stat_create(struct zs_pool *pool, const char *name)
649{
650}
651
652static inline void zs_pool_stat_destroy(struct zs_pool *pool)
653{
654}
655#endif
656
657
658/*
659 * For each size class, zspages are divided into different groups
660 * depending on their usage ratio. This function returns fullness
661 * status of the given page.
662 */
663static int get_fullness_group(struct size_class *class, struct zspage *zspage)
664{
665 int inuse, objs_per_zspage, ratio;
666
667 inuse = get_zspage_inuse(zspage);
668 objs_per_zspage = class->objs_per_zspage;
669
670 if (inuse == 0)
671 return ZS_INUSE_RATIO_0;
672 if (inuse == objs_per_zspage)
673 return ZS_INUSE_RATIO_100;
674
675 ratio = 100 * inuse / objs_per_zspage;
676 /*
677 * Take integer division into consideration: a page with one inuse
678 * object out of 127 possible, will end up having 0 usage ratio,
679 * which is wrong as it belongs in ZS_INUSE_RATIO_10 fullness group.
680 */
681 return ratio / 10 + 1;
682}
683
684/*
685 * Each size class maintains various freelists and zspages are assigned
686 * to one of these freelists based on the number of live objects they
687 * have. This functions inserts the given zspage into the freelist
688 * identified by <class, fullness_group>.
689 */
690static void insert_zspage(struct size_class *class,
691 struct zspage *zspage,
692 int fullness)
693{
694 class_stat_add(class, fullness, 1);
695 list_add(&zspage->list, &class->fullness_list[fullness]);
696 zspage->fullness = fullness;
697}
698
699/*
700 * This function removes the given zspage from the freelist identified
701 * by <class, fullness_group>.
702 */
703static void remove_zspage(struct size_class *class, struct zspage *zspage)
704{
705 int fullness = zspage->fullness;
706
707 VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
708
709 list_del_init(&zspage->list);
710 class_stat_sub(class, fullness, 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 */
722static int fix_fullness_group(struct size_class *class, struct zspage *zspage)
723{
724 int newfg;
725
726 newfg = get_fullness_group(class, zspage);
727 if (newfg == zspage->fullness)
728 goto out;
729
730 remove_zspage(class, zspage);
731 insert_zspage(class, zspage, newfg);
732out:
733 return newfg;
734}
735
736static struct zspage *get_zspage(struct page *page)
737{
738 struct zspage *zspage = (struct zspage *)page_private(page);
739
740 BUG_ON(zspage->magic != ZSPAGE_MAGIC);
741 return zspage;
742}
743
744static struct page *get_next_page(struct page *page)
745{
746 struct zspage *zspage = get_zspage(page);
747
748 if (unlikely(ZsHugePage(zspage)))
749 return NULL;
750
751 return (struct page *)page->index;
752}
753
754/**
755 * obj_to_location - get (<page>, <obj_idx>) from encoded object value
756 * @obj: the encoded object value
757 * @page: page object resides in zspage
758 * @obj_idx: object index
759 */
760static void obj_to_location(unsigned long obj, struct page **page,
761 unsigned int *obj_idx)
762{
763 *page = pfn_to_page(obj >> OBJ_INDEX_BITS);
764 *obj_idx = (obj & OBJ_INDEX_MASK);
765}
766
767static void obj_to_page(unsigned long obj, struct page **page)
768{
769 *page = pfn_to_page(obj >> OBJ_INDEX_BITS);
770}
771
772/**
773 * location_to_obj - get obj value encoded from (<page>, <obj_idx>)
774 * @page: page object resides in zspage
775 * @obj_idx: object index
776 */
777static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
778{
779 unsigned long obj;
780
781 obj = page_to_pfn(page) << OBJ_INDEX_BITS;
782 obj |= obj_idx & OBJ_INDEX_MASK;
783
784 return obj;
785}
786
787static unsigned long handle_to_obj(unsigned long handle)
788{
789 return *(unsigned long *)handle;
790}
791
792static inline bool obj_allocated(struct page *page, void *obj,
793 unsigned long *phandle)
794{
795 unsigned long handle;
796 struct zspage *zspage = get_zspage(page);
797
798 if (unlikely(ZsHugePage(zspage))) {
799 VM_BUG_ON_PAGE(!is_first_page(page), page);
800 handle = page->index;
801 } else
802 handle = *(unsigned long *)obj;
803
804 if (!(handle & OBJ_ALLOCATED_TAG))
805 return false;
806
807 /* Clear all tags before returning the handle */
808 *phandle = handle & ~OBJ_TAG_MASK;
809 return true;
810}
811
812static void reset_page(struct page *page)
813{
814 __ClearPageMovable(page);
815 ClearPagePrivate(page);
816 set_page_private(page, 0);
817 page->index = 0;
818 __ClearPageZsmalloc(page);
819}
820
821static int trylock_zspage(struct zspage *zspage)
822{
823 struct page *cursor, *fail;
824
825 for (cursor = get_first_page(zspage); cursor != NULL; cursor =
826 get_next_page(cursor)) {
827 if (!trylock_page(cursor)) {
828 fail = cursor;
829 goto unlock;
830 }
831 }
832
833 return 1;
834unlock:
835 for (cursor = get_first_page(zspage); cursor != fail; cursor =
836 get_next_page(cursor))
837 unlock_page(cursor);
838
839 return 0;
840}
841
842static void __free_zspage(struct zs_pool *pool, struct size_class *class,
843 struct zspage *zspage)
844{
845 struct page *page, *next;
846
847 assert_spin_locked(&class->lock);
848
849 VM_BUG_ON(get_zspage_inuse(zspage));
850 VM_BUG_ON(zspage->fullness != ZS_INUSE_RATIO_0);
851
852 next = page = get_first_page(zspage);
853 do {
854 VM_BUG_ON_PAGE(!PageLocked(page), page);
855 next = get_next_page(page);
856 reset_page(page);
857 unlock_page(page);
858 dec_zone_page_state(page, NR_ZSPAGES);
859 put_page(page);
860 page = next;
861 } while (page != NULL);
862
863 cache_free_zspage(pool, zspage);
864
865 class_stat_sub(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
866 atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated);
867}
868
869static void free_zspage(struct zs_pool *pool, struct size_class *class,
870 struct zspage *zspage)
871{
872 VM_BUG_ON(get_zspage_inuse(zspage));
873 VM_BUG_ON(list_empty(&zspage->list));
874
875 /*
876 * Since zs_free couldn't be sleepable, this function cannot call
877 * lock_page. The page locks trylock_zspage got will be released
878 * by __free_zspage.
879 */
880 if (!trylock_zspage(zspage)) {
881 kick_deferred_free(pool);
882 return;
883 }
884
885 remove_zspage(class, zspage);
886 __free_zspage(pool, class, zspage);
887}
888
889/* Initialize a newly allocated zspage */
890static void init_zspage(struct size_class *class, struct zspage *zspage)
891{
892 unsigned int freeobj = 1;
893 unsigned long off = 0;
894 struct page *page = get_first_page(zspage);
895
896 while (page) {
897 struct page *next_page;
898 struct link_free *link;
899 void *vaddr;
900
901 set_first_obj_offset(page, off);
902
903 vaddr = kmap_local_page(page);
904 link = (struct link_free *)vaddr + off / sizeof(*link);
905
906 while ((off += class->size) < PAGE_SIZE) {
907 link->next = freeobj++ << OBJ_TAG_BITS;
908 link += class->size / sizeof(*link);
909 }
910
911 /*
912 * We now come to the last (full or partial) object on this
913 * page, which must point to the first object on the next
914 * page (if present)
915 */
916 next_page = get_next_page(page);
917 if (next_page) {
918 link->next = freeobj++ << OBJ_TAG_BITS;
919 } else {
920 /*
921 * Reset OBJ_TAG_BITS bit to last link to tell
922 * whether it's allocated object or not.
923 */
924 link->next = -1UL << OBJ_TAG_BITS;
925 }
926 kunmap_local(vaddr);
927 page = next_page;
928 off %= PAGE_SIZE;
929 }
930
931 set_freeobj(zspage, 0);
932}
933
934static void create_page_chain(struct size_class *class, struct zspage *zspage,
935 struct page *pages[])
936{
937 int i;
938 struct page *page;
939 struct page *prev_page = NULL;
940 int nr_pages = class->pages_per_zspage;
941
942 /*
943 * Allocate individual pages and link them together as:
944 * 1. all pages are linked together using page->index
945 * 2. each sub-page point to zspage using page->private
946 *
947 * we set PG_private to identify the first page (i.e. no other sub-page
948 * has this flag set).
949 */
950 for (i = 0; i < nr_pages; i++) {
951 page = pages[i];
952 set_page_private(page, (unsigned long)zspage);
953 page->index = 0;
954 if (i == 0) {
955 zspage->first_page = page;
956 SetPagePrivate(page);
957 if (unlikely(class->objs_per_zspage == 1 &&
958 class->pages_per_zspage == 1))
959 SetZsHugePage(zspage);
960 } else {
961 prev_page->index = (unsigned long)page;
962 }
963 prev_page = page;
964 }
965}
966
967/*
968 * Allocate a zspage for the given size class
969 */
970static struct zspage *alloc_zspage(struct zs_pool *pool,
971 struct size_class *class,
972 gfp_t gfp)
973{
974 int i;
975 struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
976 struct zspage *zspage = cache_alloc_zspage(pool, gfp);
977
978 if (!zspage)
979 return NULL;
980
981 zspage->magic = ZSPAGE_MAGIC;
982 migrate_lock_init(zspage);
983
984 for (i = 0; i < class->pages_per_zspage; i++) {
985 struct page *page;
986
987 page = alloc_page(gfp);
988 if (!page) {
989 while (--i >= 0) {
990 dec_zone_page_state(pages[i], NR_ZSPAGES);
991 __ClearPageZsmalloc(pages[i]);
992 __free_page(pages[i]);
993 }
994 cache_free_zspage(pool, zspage);
995 return NULL;
996 }
997 __SetPageZsmalloc(page);
998
999 inc_zone_page_state(page, NR_ZSPAGES);
1000 pages[i] = page;
1001 }
1002
1003 create_page_chain(class, zspage, pages);
1004 init_zspage(class, zspage);
1005 zspage->pool = pool;
1006 zspage->class = class->index;
1007
1008 return zspage;
1009}
1010
1011static struct zspage *find_get_zspage(struct size_class *class)
1012{
1013 int i;
1014 struct zspage *zspage;
1015
1016 for (i = ZS_INUSE_RATIO_99; i >= ZS_INUSE_RATIO_0; i--) {
1017 zspage = list_first_entry_or_null(&class->fullness_list[i],
1018 struct zspage, list);
1019 if (zspage)
1020 break;
1021 }
1022
1023 return zspage;
1024}
1025
1026static inline int __zs_cpu_up(struct mapping_area *area)
1027{
1028 /*
1029 * Make sure we don't leak memory if a cpu UP notification
1030 * and zs_init() race and both call zs_cpu_up() on the same cpu
1031 */
1032 if (area->vm_buf)
1033 return 0;
1034 area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL);
1035 if (!area->vm_buf)
1036 return -ENOMEM;
1037 return 0;
1038}
1039
1040static inline void __zs_cpu_down(struct mapping_area *area)
1041{
1042 kfree(area->vm_buf);
1043 area->vm_buf = NULL;
1044}
1045
1046static void *__zs_map_object(struct mapping_area *area,
1047 struct page *pages[2], int off, int size)
1048{
1049 size_t sizes[2];
1050 char *buf = area->vm_buf;
1051
1052 /* disable page faults to match kmap_local_page() return conditions */
1053 pagefault_disable();
1054
1055 /* no read fastpath */
1056 if (area->vm_mm == ZS_MM_WO)
1057 goto out;
1058
1059 sizes[0] = PAGE_SIZE - off;
1060 sizes[1] = size - sizes[0];
1061
1062 /* copy object to per-cpu buffer */
1063 memcpy_from_page(buf, pages[0], off, sizes[0]);
1064 memcpy_from_page(buf + sizes[0], pages[1], 0, sizes[1]);
1065out:
1066 return area->vm_buf;
1067}
1068
1069static void __zs_unmap_object(struct mapping_area *area,
1070 struct page *pages[2], int off, int size)
1071{
1072 size_t sizes[2];
1073 char *buf;
1074
1075 /* no write fastpath */
1076 if (area->vm_mm == ZS_MM_RO)
1077 goto out;
1078
1079 buf = area->vm_buf;
1080 buf = buf + ZS_HANDLE_SIZE;
1081 size -= ZS_HANDLE_SIZE;
1082 off += ZS_HANDLE_SIZE;
1083
1084 sizes[0] = PAGE_SIZE - off;
1085 sizes[1] = size - sizes[0];
1086
1087 /* copy per-cpu buffer to object */
1088 memcpy_to_page(pages[0], off, buf, sizes[0]);
1089 memcpy_to_page(pages[1], 0, buf + sizes[0], sizes[1]);
1090
1091out:
1092 /* enable page faults to match kunmap_local() return conditions */
1093 pagefault_enable();
1094}
1095
1096static int zs_cpu_prepare(unsigned int cpu)
1097{
1098 struct mapping_area *area;
1099
1100 area = &per_cpu(zs_map_area, cpu);
1101 return __zs_cpu_up(area);
1102}
1103
1104static int zs_cpu_dead(unsigned int cpu)
1105{
1106 struct mapping_area *area;
1107
1108 area = &per_cpu(zs_map_area, cpu);
1109 __zs_cpu_down(area);
1110 return 0;
1111}
1112
1113static bool can_merge(struct size_class *prev, int pages_per_zspage,
1114 int objs_per_zspage)
1115{
1116 if (prev->pages_per_zspage == pages_per_zspage &&
1117 prev->objs_per_zspage == objs_per_zspage)
1118 return true;
1119
1120 return false;
1121}
1122
1123static bool zspage_full(struct size_class *class, struct zspage *zspage)
1124{
1125 return get_zspage_inuse(zspage) == class->objs_per_zspage;
1126}
1127
1128static bool zspage_empty(struct zspage *zspage)
1129{
1130 return get_zspage_inuse(zspage) == 0;
1131}
1132
1133/**
1134 * zs_lookup_class_index() - Returns index of the zsmalloc &size_class
1135 * that hold objects of the provided size.
1136 * @pool: zsmalloc pool to use
1137 * @size: object size
1138 *
1139 * Context: Any context.
1140 *
1141 * Return: the index of the zsmalloc &size_class that hold objects of the
1142 * provided size.
1143 */
1144unsigned int zs_lookup_class_index(struct zs_pool *pool, unsigned int size)
1145{
1146 struct size_class *class;
1147
1148 class = pool->size_class[get_size_class_index(size)];
1149
1150 return class->index;
1151}
1152EXPORT_SYMBOL_GPL(zs_lookup_class_index);
1153
1154unsigned long zs_get_total_pages(struct zs_pool *pool)
1155{
1156 return atomic_long_read(&pool->pages_allocated);
1157}
1158EXPORT_SYMBOL_GPL(zs_get_total_pages);
1159
1160/**
1161 * zs_map_object - get address of allocated object from handle.
1162 * @pool: pool from which the object was allocated
1163 * @handle: handle returned from zs_malloc
1164 * @mm: mapping mode to use
1165 *
1166 * Before using an object allocated from zs_malloc, it must be mapped using
1167 * this function. When done with the object, it must be unmapped using
1168 * zs_unmap_object.
1169 *
1170 * Only one object can be mapped per cpu at a time. There is no protection
1171 * against nested mappings.
1172 *
1173 * This function returns with preemption and page faults disabled.
1174 */
1175void *zs_map_object(struct zs_pool *pool, unsigned long handle,
1176 enum zs_mapmode mm)
1177{
1178 struct zspage *zspage;
1179 struct page *page;
1180 unsigned long obj, off;
1181 unsigned int obj_idx;
1182
1183 struct size_class *class;
1184 struct mapping_area *area;
1185 struct page *pages[2];
1186 void *ret;
1187
1188 /*
1189 * Because we use per-cpu mapping areas shared among the
1190 * pools/users, we can't allow mapping in interrupt context
1191 * because it can corrupt another users mappings.
1192 */
1193 BUG_ON(in_interrupt());
1194
1195 /* It guarantees it can get zspage from handle safely */
1196 read_lock(&pool->migrate_lock);
1197 obj = handle_to_obj(handle);
1198 obj_to_location(obj, &page, &obj_idx);
1199 zspage = get_zspage(page);
1200
1201 /*
1202 * migration cannot move any zpages in this zspage. Here, class->lock
1203 * is too heavy since callers would take some time until they calls
1204 * zs_unmap_object API so delegate the locking from class to zspage
1205 * which is smaller granularity.
1206 */
1207 migrate_read_lock(zspage);
1208 read_unlock(&pool->migrate_lock);
1209
1210 class = zspage_class(pool, zspage);
1211 off = offset_in_page(class->size * obj_idx);
1212
1213 local_lock(&zs_map_area.lock);
1214 area = this_cpu_ptr(&zs_map_area);
1215 area->vm_mm = mm;
1216 if (off + class->size <= PAGE_SIZE) {
1217 /* this object is contained entirely within a page */
1218 area->vm_addr = kmap_local_page(page);
1219 ret = area->vm_addr + off;
1220 goto out;
1221 }
1222
1223 /* this object spans two pages */
1224 pages[0] = page;
1225 pages[1] = get_next_page(page);
1226 BUG_ON(!pages[1]);
1227
1228 ret = __zs_map_object(area, pages, off, class->size);
1229out:
1230 if (likely(!ZsHugePage(zspage)))
1231 ret += ZS_HANDLE_SIZE;
1232
1233 return ret;
1234}
1235EXPORT_SYMBOL_GPL(zs_map_object);
1236
1237void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
1238{
1239 struct zspage *zspage;
1240 struct page *page;
1241 unsigned long obj, off;
1242 unsigned int obj_idx;
1243
1244 struct size_class *class;
1245 struct mapping_area *area;
1246
1247 obj = handle_to_obj(handle);
1248 obj_to_location(obj, &page, &obj_idx);
1249 zspage = get_zspage(page);
1250 class = zspage_class(pool, zspage);
1251 off = offset_in_page(class->size * obj_idx);
1252
1253 area = this_cpu_ptr(&zs_map_area);
1254 if (off + class->size <= PAGE_SIZE)
1255 kunmap_local(area->vm_addr);
1256 else {
1257 struct page *pages[2];
1258
1259 pages[0] = page;
1260 pages[1] = get_next_page(page);
1261 BUG_ON(!pages[1]);
1262
1263 __zs_unmap_object(area, pages, off, class->size);
1264 }
1265 local_unlock(&zs_map_area.lock);
1266
1267 migrate_read_unlock(zspage);
1268}
1269EXPORT_SYMBOL_GPL(zs_unmap_object);
1270
1271/**
1272 * zs_huge_class_size() - Returns the size (in bytes) of the first huge
1273 * zsmalloc &size_class.
1274 * @pool: zsmalloc pool to use
1275 *
1276 * The function returns the size of the first huge class - any object of equal
1277 * or bigger size will be stored in zspage consisting of a single physical
1278 * page.
1279 *
1280 * Context: Any context.
1281 *
1282 * Return: the size (in bytes) of the first huge zsmalloc &size_class.
1283 */
1284size_t zs_huge_class_size(struct zs_pool *pool)
1285{
1286 return huge_class_size;
1287}
1288EXPORT_SYMBOL_GPL(zs_huge_class_size);
1289
1290static unsigned long obj_malloc(struct zs_pool *pool,
1291 struct zspage *zspage, unsigned long handle)
1292{
1293 int i, nr_page, offset;
1294 unsigned long obj;
1295 struct link_free *link;
1296 struct size_class *class;
1297
1298 struct page *m_page;
1299 unsigned long m_offset;
1300 void *vaddr;
1301
1302 class = pool->size_class[zspage->class];
1303 obj = get_freeobj(zspage);
1304
1305 offset = obj * class->size;
1306 nr_page = offset >> PAGE_SHIFT;
1307 m_offset = offset_in_page(offset);
1308 m_page = get_first_page(zspage);
1309
1310 for (i = 0; i < nr_page; i++)
1311 m_page = get_next_page(m_page);
1312
1313 vaddr = kmap_local_page(m_page);
1314 link = (struct link_free *)vaddr + m_offset / sizeof(*link);
1315 set_freeobj(zspage, link->next >> OBJ_TAG_BITS);
1316 if (likely(!ZsHugePage(zspage)))
1317 /* record handle in the header of allocated chunk */
1318 link->handle = handle | OBJ_ALLOCATED_TAG;
1319 else
1320 /* record handle to page->index */
1321 zspage->first_page->index = handle | OBJ_ALLOCATED_TAG;
1322
1323 kunmap_local(vaddr);
1324 mod_zspage_inuse(zspage, 1);
1325
1326 obj = location_to_obj(m_page, obj);
1327 record_obj(handle, obj);
1328
1329 return obj;
1330}
1331
1332
1333/**
1334 * zs_malloc - Allocate block of given size from pool.
1335 * @pool: pool to allocate from
1336 * @size: size of block to allocate
1337 * @gfp: gfp flags when allocating object
1338 *
1339 * On success, handle to the allocated object is returned,
1340 * otherwise an ERR_PTR().
1341 * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
1342 */
1343unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
1344{
1345 unsigned long handle;
1346 struct size_class *class;
1347 int newfg;
1348 struct zspage *zspage;
1349
1350 if (unlikely(!size))
1351 return (unsigned long)ERR_PTR(-EINVAL);
1352
1353 if (unlikely(size > ZS_MAX_ALLOC_SIZE))
1354 return (unsigned long)ERR_PTR(-ENOSPC);
1355
1356 handle = cache_alloc_handle(pool, gfp);
1357 if (!handle)
1358 return (unsigned long)ERR_PTR(-ENOMEM);
1359
1360 /* extra space in chunk to keep the handle */
1361 size += ZS_HANDLE_SIZE;
1362 class = pool->size_class[get_size_class_index(size)];
1363
1364 /* class->lock effectively protects the zpage migration */
1365 spin_lock(&class->lock);
1366 zspage = find_get_zspage(class);
1367 if (likely(zspage)) {
1368 obj_malloc(pool, zspage, handle);
1369 /* Now move the zspage to another fullness group, if required */
1370 fix_fullness_group(class, zspage);
1371 class_stat_add(class, ZS_OBJS_INUSE, 1);
1372
1373 goto out;
1374 }
1375
1376 spin_unlock(&class->lock);
1377
1378 zspage = alloc_zspage(pool, class, gfp);
1379 if (!zspage) {
1380 cache_free_handle(pool, handle);
1381 return (unsigned long)ERR_PTR(-ENOMEM);
1382 }
1383
1384 spin_lock(&class->lock);
1385 obj_malloc(pool, zspage, handle);
1386 newfg = get_fullness_group(class, zspage);
1387 insert_zspage(class, zspage, newfg);
1388 atomic_long_add(class->pages_per_zspage, &pool->pages_allocated);
1389 class_stat_add(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
1390 class_stat_add(class, ZS_OBJS_INUSE, 1);
1391
1392 /* We completely set up zspage so mark them as movable */
1393 SetZsPageMovable(pool, zspage);
1394out:
1395 spin_unlock(&class->lock);
1396
1397 return handle;
1398}
1399EXPORT_SYMBOL_GPL(zs_malloc);
1400
1401static void obj_free(int class_size, unsigned long obj)
1402{
1403 struct link_free *link;
1404 struct zspage *zspage;
1405 struct page *f_page;
1406 unsigned long f_offset;
1407 unsigned int f_objidx;
1408 void *vaddr;
1409
1410 obj_to_location(obj, &f_page, &f_objidx);
1411 f_offset = offset_in_page(class_size * f_objidx);
1412 zspage = get_zspage(f_page);
1413
1414 vaddr = kmap_local_page(f_page);
1415 link = (struct link_free *)(vaddr + f_offset);
1416
1417 /* Insert this object in containing zspage's freelist */
1418 if (likely(!ZsHugePage(zspage)))
1419 link->next = get_freeobj(zspage) << OBJ_TAG_BITS;
1420 else
1421 f_page->index = 0;
1422 set_freeobj(zspage, f_objidx);
1423
1424 kunmap_local(vaddr);
1425 mod_zspage_inuse(zspage, -1);
1426}
1427
1428void zs_free(struct zs_pool *pool, unsigned long handle)
1429{
1430 struct zspage *zspage;
1431 struct page *f_page;
1432 unsigned long obj;
1433 struct size_class *class;
1434 int fullness;
1435
1436 if (IS_ERR_OR_NULL((void *)handle))
1437 return;
1438
1439 /*
1440 * The pool->migrate_lock protects the race with zpage's migration
1441 * so it's safe to get the page from handle.
1442 */
1443 read_lock(&pool->migrate_lock);
1444 obj = handle_to_obj(handle);
1445 obj_to_page(obj, &f_page);
1446 zspage = get_zspage(f_page);
1447 class = zspage_class(pool, zspage);
1448 spin_lock(&class->lock);
1449 read_unlock(&pool->migrate_lock);
1450
1451 class_stat_sub(class, ZS_OBJS_INUSE, 1);
1452 obj_free(class->size, obj);
1453
1454 fullness = fix_fullness_group(class, zspage);
1455 if (fullness == ZS_INUSE_RATIO_0)
1456 free_zspage(pool, class, zspage);
1457
1458 spin_unlock(&class->lock);
1459 cache_free_handle(pool, handle);
1460}
1461EXPORT_SYMBOL_GPL(zs_free);
1462
1463static void zs_object_copy(struct size_class *class, unsigned long dst,
1464 unsigned long src)
1465{
1466 struct page *s_page, *d_page;
1467 unsigned int s_objidx, d_objidx;
1468 unsigned long s_off, d_off;
1469 void *s_addr, *d_addr;
1470 int s_size, d_size, size;
1471 int written = 0;
1472
1473 s_size = d_size = class->size;
1474
1475 obj_to_location(src, &s_page, &s_objidx);
1476 obj_to_location(dst, &d_page, &d_objidx);
1477
1478 s_off = offset_in_page(class->size * s_objidx);
1479 d_off = offset_in_page(class->size * d_objidx);
1480
1481 if (s_off + class->size > PAGE_SIZE)
1482 s_size = PAGE_SIZE - s_off;
1483
1484 if (d_off + class->size > PAGE_SIZE)
1485 d_size = PAGE_SIZE - d_off;
1486
1487 s_addr = kmap_local_page(s_page);
1488 d_addr = kmap_local_page(d_page);
1489
1490 while (1) {
1491 size = min(s_size, d_size);
1492 memcpy(d_addr + d_off, s_addr + s_off, size);
1493 written += size;
1494
1495 if (written == class->size)
1496 break;
1497
1498 s_off += size;
1499 s_size -= size;
1500 d_off += size;
1501 d_size -= size;
1502
1503 /*
1504 * Calling kunmap_local(d_addr) is necessary. kunmap_local()
1505 * calls must occurs in reverse order of calls to kmap_local_page().
1506 * So, to call kunmap_local(s_addr) we should first call
1507 * kunmap_local(d_addr). For more details see
1508 * Documentation/mm/highmem.rst.
1509 */
1510 if (s_off >= PAGE_SIZE) {
1511 kunmap_local(d_addr);
1512 kunmap_local(s_addr);
1513 s_page = get_next_page(s_page);
1514 s_addr = kmap_local_page(s_page);
1515 d_addr = kmap_local_page(d_page);
1516 s_size = class->size - written;
1517 s_off = 0;
1518 }
1519
1520 if (d_off >= PAGE_SIZE) {
1521 kunmap_local(d_addr);
1522 d_page = get_next_page(d_page);
1523 d_addr = kmap_local_page(d_page);
1524 d_size = class->size - written;
1525 d_off = 0;
1526 }
1527 }
1528
1529 kunmap_local(d_addr);
1530 kunmap_local(s_addr);
1531}
1532
1533/*
1534 * Find alloced object in zspage from index object and
1535 * return handle.
1536 */
1537static unsigned long find_alloced_obj(struct size_class *class,
1538 struct page *page, int *obj_idx)
1539{
1540 unsigned int offset;
1541 int index = *obj_idx;
1542 unsigned long handle = 0;
1543 void *addr = kmap_local_page(page);
1544
1545 offset = get_first_obj_offset(page);
1546 offset += class->size * index;
1547
1548 while (offset < PAGE_SIZE) {
1549 if (obj_allocated(page, addr + offset, &handle))
1550 break;
1551
1552 offset += class->size;
1553 index++;
1554 }
1555
1556 kunmap_local(addr);
1557
1558 *obj_idx = index;
1559
1560 return handle;
1561}
1562
1563static void migrate_zspage(struct zs_pool *pool, struct zspage *src_zspage,
1564 struct zspage *dst_zspage)
1565{
1566 unsigned long used_obj, free_obj;
1567 unsigned long handle;
1568 int obj_idx = 0;
1569 struct page *s_page = get_first_page(src_zspage);
1570 struct size_class *class = pool->size_class[src_zspage->class];
1571
1572 while (1) {
1573 handle = find_alloced_obj(class, s_page, &obj_idx);
1574 if (!handle) {
1575 s_page = get_next_page(s_page);
1576 if (!s_page)
1577 break;
1578 obj_idx = 0;
1579 continue;
1580 }
1581
1582 used_obj = handle_to_obj(handle);
1583 free_obj = obj_malloc(pool, dst_zspage, handle);
1584 zs_object_copy(class, free_obj, used_obj);
1585 obj_idx++;
1586 obj_free(class->size, used_obj);
1587
1588 /* Stop if there is no more space */
1589 if (zspage_full(class, dst_zspage))
1590 break;
1591
1592 /* Stop if there are no more objects to migrate */
1593 if (zspage_empty(src_zspage))
1594 break;
1595 }
1596}
1597
1598static struct zspage *isolate_src_zspage(struct size_class *class)
1599{
1600 struct zspage *zspage;
1601 int fg;
1602
1603 for (fg = ZS_INUSE_RATIO_10; fg <= ZS_INUSE_RATIO_99; fg++) {
1604 zspage = list_first_entry_or_null(&class->fullness_list[fg],
1605 struct zspage, list);
1606 if (zspage) {
1607 remove_zspage(class, zspage);
1608 return zspage;
1609 }
1610 }
1611
1612 return zspage;
1613}
1614
1615static struct zspage *isolate_dst_zspage(struct size_class *class)
1616{
1617 struct zspage *zspage;
1618 int fg;
1619
1620 for (fg = ZS_INUSE_RATIO_99; fg >= ZS_INUSE_RATIO_10; fg--) {
1621 zspage = list_first_entry_or_null(&class->fullness_list[fg],
1622 struct zspage, list);
1623 if (zspage) {
1624 remove_zspage(class, zspage);
1625 return zspage;
1626 }
1627 }
1628
1629 return zspage;
1630}
1631
1632/*
1633 * putback_zspage - add @zspage into right class's fullness list
1634 * @class: destination class
1635 * @zspage: target page
1636 *
1637 * Return @zspage's fullness status
1638 */
1639static int putback_zspage(struct size_class *class, struct zspage *zspage)
1640{
1641 int fullness;
1642
1643 fullness = get_fullness_group(class, zspage);
1644 insert_zspage(class, zspage, fullness);
1645
1646 return fullness;
1647}
1648
1649#ifdef CONFIG_COMPACTION
1650/*
1651 * To prevent zspage destroy during migration, zspage freeing should
1652 * hold locks of all pages in the zspage.
1653 */
1654static void lock_zspage(struct zspage *zspage)
1655{
1656 struct page *curr_page, *page;
1657
1658 /*
1659 * Pages we haven't locked yet can be migrated off the list while we're
1660 * trying to lock them, so we need to be careful and only attempt to
1661 * lock each page under migrate_read_lock(). Otherwise, the page we lock
1662 * may no longer belong to the zspage. This means that we may wait for
1663 * the wrong page to unlock, so we must take a reference to the page
1664 * prior to waiting for it to unlock outside migrate_read_lock().
1665 */
1666 while (1) {
1667 migrate_read_lock(zspage);
1668 page = get_first_page(zspage);
1669 if (trylock_page(page))
1670 break;
1671 get_page(page);
1672 migrate_read_unlock(zspage);
1673 wait_on_page_locked(page);
1674 put_page(page);
1675 }
1676
1677 curr_page = page;
1678 while ((page = get_next_page(curr_page))) {
1679 if (trylock_page(page)) {
1680 curr_page = page;
1681 } else {
1682 get_page(page);
1683 migrate_read_unlock(zspage);
1684 wait_on_page_locked(page);
1685 put_page(page);
1686 migrate_read_lock(zspage);
1687 }
1688 }
1689 migrate_read_unlock(zspage);
1690}
1691#endif /* CONFIG_COMPACTION */
1692
1693static void migrate_lock_init(struct zspage *zspage)
1694{
1695 rwlock_init(&zspage->lock);
1696}
1697
1698static void migrate_read_lock(struct zspage *zspage) __acquires(&zspage->lock)
1699{
1700 read_lock(&zspage->lock);
1701}
1702
1703static void migrate_read_unlock(struct zspage *zspage) __releases(&zspage->lock)
1704{
1705 read_unlock(&zspage->lock);
1706}
1707
1708static void migrate_write_lock(struct zspage *zspage)
1709{
1710 write_lock(&zspage->lock);
1711}
1712
1713static void migrate_write_unlock(struct zspage *zspage)
1714{
1715 write_unlock(&zspage->lock);
1716}
1717
1718#ifdef CONFIG_COMPACTION
1719
1720static const struct movable_operations zsmalloc_mops;
1721
1722static void replace_sub_page(struct size_class *class, struct zspage *zspage,
1723 struct page *newpage, struct page *oldpage)
1724{
1725 struct page *page;
1726 struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
1727 int idx = 0;
1728
1729 page = get_first_page(zspage);
1730 do {
1731 if (page == oldpage)
1732 pages[idx] = newpage;
1733 else
1734 pages[idx] = page;
1735 idx++;
1736 } while ((page = get_next_page(page)) != NULL);
1737
1738 create_page_chain(class, zspage, pages);
1739 set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
1740 if (unlikely(ZsHugePage(zspage)))
1741 newpage->index = oldpage->index;
1742 __SetPageMovable(newpage, &zsmalloc_mops);
1743}
1744
1745static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
1746{
1747 /*
1748 * Page is locked so zspage couldn't be destroyed. For detail, look at
1749 * lock_zspage in free_zspage.
1750 */
1751 VM_BUG_ON_PAGE(PageIsolated(page), page);
1752
1753 return true;
1754}
1755
1756static int zs_page_migrate(struct page *newpage, struct page *page,
1757 enum migrate_mode mode)
1758{
1759 struct zs_pool *pool;
1760 struct size_class *class;
1761 struct zspage *zspage;
1762 struct page *dummy;
1763 void *s_addr, *d_addr, *addr;
1764 unsigned int offset;
1765 unsigned long handle;
1766 unsigned long old_obj, new_obj;
1767 unsigned int obj_idx;
1768
1769 VM_BUG_ON_PAGE(!PageIsolated(page), page);
1770
1771 /* We're committed, tell the world that this is a Zsmalloc page. */
1772 __SetPageZsmalloc(newpage);
1773
1774 /* The page is locked, so this pointer must remain valid */
1775 zspage = get_zspage(page);
1776 pool = zspage->pool;
1777
1778 /*
1779 * The pool migrate_lock protects the race between zpage migration
1780 * and zs_free.
1781 */
1782 write_lock(&pool->migrate_lock);
1783 class = zspage_class(pool, zspage);
1784
1785 /*
1786 * the class lock protects zpage alloc/free in the zspage.
1787 */
1788 spin_lock(&class->lock);
1789 /* the migrate_write_lock protects zpage access via zs_map_object */
1790 migrate_write_lock(zspage);
1791
1792 offset = get_first_obj_offset(page);
1793 s_addr = kmap_local_page(page);
1794
1795 /*
1796 * Here, any user cannot access all objects in the zspage so let's move.
1797 */
1798 d_addr = kmap_local_page(newpage);
1799 copy_page(d_addr, s_addr);
1800 kunmap_local(d_addr);
1801
1802 for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE;
1803 addr += class->size) {
1804 if (obj_allocated(page, addr, &handle)) {
1805
1806 old_obj = handle_to_obj(handle);
1807 obj_to_location(old_obj, &dummy, &obj_idx);
1808 new_obj = (unsigned long)location_to_obj(newpage,
1809 obj_idx);
1810 record_obj(handle, new_obj);
1811 }
1812 }
1813 kunmap_local(s_addr);
1814
1815 replace_sub_page(class, zspage, newpage, page);
1816 /*
1817 * Since we complete the data copy and set up new zspage structure,
1818 * it's okay to release migration_lock.
1819 */
1820 write_unlock(&pool->migrate_lock);
1821 spin_unlock(&class->lock);
1822 migrate_write_unlock(zspage);
1823
1824 get_page(newpage);
1825 if (page_zone(newpage) != page_zone(page)) {
1826 dec_zone_page_state(page, NR_ZSPAGES);
1827 inc_zone_page_state(newpage, NR_ZSPAGES);
1828 }
1829
1830 reset_page(page);
1831 put_page(page);
1832
1833 return MIGRATEPAGE_SUCCESS;
1834}
1835
1836static void zs_page_putback(struct page *page)
1837{
1838 VM_BUG_ON_PAGE(!PageIsolated(page), page);
1839}
1840
1841static const struct movable_operations zsmalloc_mops = {
1842 .isolate_page = zs_page_isolate,
1843 .migrate_page = zs_page_migrate,
1844 .putback_page = zs_page_putback,
1845};
1846
1847/*
1848 * Caller should hold page_lock of all pages in the zspage
1849 * In here, we cannot use zspage meta data.
1850 */
1851static void async_free_zspage(struct work_struct *work)
1852{
1853 int i;
1854 struct size_class *class;
1855 struct zspage *zspage, *tmp;
1856 LIST_HEAD(free_pages);
1857 struct zs_pool *pool = container_of(work, struct zs_pool,
1858 free_work);
1859
1860 for (i = 0; i < ZS_SIZE_CLASSES; i++) {
1861 class = pool->size_class[i];
1862 if (class->index != i)
1863 continue;
1864
1865 spin_lock(&class->lock);
1866 list_splice_init(&class->fullness_list[ZS_INUSE_RATIO_0],
1867 &free_pages);
1868 spin_unlock(&class->lock);
1869 }
1870
1871 list_for_each_entry_safe(zspage, tmp, &free_pages, list) {
1872 list_del(&zspage->list);
1873 lock_zspage(zspage);
1874
1875 class = zspage_class(pool, zspage);
1876 spin_lock(&class->lock);
1877 class_stat_sub(class, ZS_INUSE_RATIO_0, 1);
1878 __free_zspage(pool, class, zspage);
1879 spin_unlock(&class->lock);
1880 }
1881};
1882
1883static void kick_deferred_free(struct zs_pool *pool)
1884{
1885 schedule_work(&pool->free_work);
1886}
1887
1888static void zs_flush_migration(struct zs_pool *pool)
1889{
1890 flush_work(&pool->free_work);
1891}
1892
1893static void init_deferred_free(struct zs_pool *pool)
1894{
1895 INIT_WORK(&pool->free_work, async_free_zspage);
1896}
1897
1898static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
1899{
1900 struct page *page = get_first_page(zspage);
1901
1902 do {
1903 WARN_ON(!trylock_page(page));
1904 __SetPageMovable(page, &zsmalloc_mops);
1905 unlock_page(page);
1906 } while ((page = get_next_page(page)) != NULL);
1907}
1908#else
1909static inline void zs_flush_migration(struct zs_pool *pool) { }
1910#endif
1911
1912/*
1913 *
1914 * Based on the number of unused allocated objects calculate
1915 * and return the number of pages that we can free.
1916 */
1917static unsigned long zs_can_compact(struct size_class *class)
1918{
1919 unsigned long obj_wasted;
1920 unsigned long obj_allocated = class_stat_read(class, ZS_OBJS_ALLOCATED);
1921 unsigned long obj_used = class_stat_read(class, ZS_OBJS_INUSE);
1922
1923 if (obj_allocated <= obj_used)
1924 return 0;
1925
1926 obj_wasted = obj_allocated - obj_used;
1927 obj_wasted /= class->objs_per_zspage;
1928
1929 return obj_wasted * class->pages_per_zspage;
1930}
1931
1932static unsigned long __zs_compact(struct zs_pool *pool,
1933 struct size_class *class)
1934{
1935 struct zspage *src_zspage = NULL;
1936 struct zspage *dst_zspage = NULL;
1937 unsigned long pages_freed = 0;
1938
1939 /*
1940 * protect the race between zpage migration and zs_free
1941 * as well as zpage allocation/free
1942 */
1943 write_lock(&pool->migrate_lock);
1944 spin_lock(&class->lock);
1945 while (zs_can_compact(class)) {
1946 int fg;
1947
1948 if (!dst_zspage) {
1949 dst_zspage = isolate_dst_zspage(class);
1950 if (!dst_zspage)
1951 break;
1952 }
1953
1954 src_zspage = isolate_src_zspage(class);
1955 if (!src_zspage)
1956 break;
1957
1958 migrate_write_lock(src_zspage);
1959 migrate_zspage(pool, src_zspage, dst_zspage);
1960 migrate_write_unlock(src_zspage);
1961
1962 fg = putback_zspage(class, src_zspage);
1963 if (fg == ZS_INUSE_RATIO_0) {
1964 free_zspage(pool, class, src_zspage);
1965 pages_freed += class->pages_per_zspage;
1966 }
1967 src_zspage = NULL;
1968
1969 if (get_fullness_group(class, dst_zspage) == ZS_INUSE_RATIO_100
1970 || rwlock_is_contended(&pool->migrate_lock)) {
1971 putback_zspage(class, dst_zspage);
1972 dst_zspage = NULL;
1973
1974 spin_unlock(&class->lock);
1975 write_unlock(&pool->migrate_lock);
1976 cond_resched();
1977 write_lock(&pool->migrate_lock);
1978 spin_lock(&class->lock);
1979 }
1980 }
1981
1982 if (src_zspage)
1983 putback_zspage(class, src_zspage);
1984
1985 if (dst_zspage)
1986 putback_zspage(class, dst_zspage);
1987
1988 spin_unlock(&class->lock);
1989 write_unlock(&pool->migrate_lock);
1990
1991 return pages_freed;
1992}
1993
1994unsigned long zs_compact(struct zs_pool *pool)
1995{
1996 int i;
1997 struct size_class *class;
1998 unsigned long pages_freed = 0;
1999
2000 /*
2001 * Pool compaction is performed under pool->migrate_lock so it is basically
2002 * single-threaded. Having more than one thread in __zs_compact()
2003 * will increase pool->migrate_lock contention, which will impact other
2004 * zsmalloc operations that need pool->migrate_lock.
2005 */
2006 if (atomic_xchg(&pool->compaction_in_progress, 1))
2007 return 0;
2008
2009 for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
2010 class = pool->size_class[i];
2011 if (class->index != i)
2012 continue;
2013 pages_freed += __zs_compact(pool, class);
2014 }
2015 atomic_long_add(pages_freed, &pool->stats.pages_compacted);
2016 atomic_set(&pool->compaction_in_progress, 0);
2017
2018 return pages_freed;
2019}
2020EXPORT_SYMBOL_GPL(zs_compact);
2021
2022void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats)
2023{
2024 memcpy(stats, &pool->stats, sizeof(struct zs_pool_stats));
2025}
2026EXPORT_SYMBOL_GPL(zs_pool_stats);
2027
2028static unsigned long zs_shrinker_scan(struct shrinker *shrinker,
2029 struct shrink_control *sc)
2030{
2031 unsigned long pages_freed;
2032 struct zs_pool *pool = shrinker->private_data;
2033
2034 /*
2035 * Compact classes and calculate compaction delta.
2036 * Can run concurrently with a manually triggered
2037 * (by user) compaction.
2038 */
2039 pages_freed = zs_compact(pool);
2040
2041 return pages_freed ? pages_freed : SHRINK_STOP;
2042}
2043
2044static unsigned long zs_shrinker_count(struct shrinker *shrinker,
2045 struct shrink_control *sc)
2046{
2047 int i;
2048 struct size_class *class;
2049 unsigned long pages_to_free = 0;
2050 struct zs_pool *pool = shrinker->private_data;
2051
2052 for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
2053 class = pool->size_class[i];
2054 if (class->index != i)
2055 continue;
2056
2057 pages_to_free += zs_can_compact(class);
2058 }
2059
2060 return pages_to_free;
2061}
2062
2063static void zs_unregister_shrinker(struct zs_pool *pool)
2064{
2065 shrinker_free(pool->shrinker);
2066}
2067
2068static int zs_register_shrinker(struct zs_pool *pool)
2069{
2070 pool->shrinker = shrinker_alloc(0, "mm-zspool:%s", pool->name);
2071 if (!pool->shrinker)
2072 return -ENOMEM;
2073
2074 pool->shrinker->scan_objects = zs_shrinker_scan;
2075 pool->shrinker->count_objects = zs_shrinker_count;
2076 pool->shrinker->batch = 0;
2077 pool->shrinker->private_data = pool;
2078
2079 shrinker_register(pool->shrinker);
2080
2081 return 0;
2082}
2083
2084static int calculate_zspage_chain_size(int class_size)
2085{
2086 int i, min_waste = INT_MAX;
2087 int chain_size = 1;
2088
2089 if (is_power_of_2(class_size))
2090 return chain_size;
2091
2092 for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
2093 int waste;
2094
2095 waste = (i * PAGE_SIZE) % class_size;
2096 if (waste < min_waste) {
2097 min_waste = waste;
2098 chain_size = i;
2099 }
2100 }
2101
2102 return chain_size;
2103}
2104
2105/**
2106 * zs_create_pool - Creates an allocation pool to work from.
2107 * @name: pool name to be created
2108 *
2109 * This function must be called before anything when using
2110 * the zsmalloc allocator.
2111 *
2112 * On success, a pointer to the newly created pool is returned,
2113 * otherwise NULL.
2114 */
2115struct zs_pool *zs_create_pool(const char *name)
2116{
2117 int i;
2118 struct zs_pool *pool;
2119 struct size_class *prev_class = NULL;
2120
2121 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2122 if (!pool)
2123 return NULL;
2124
2125 init_deferred_free(pool);
2126 rwlock_init(&pool->migrate_lock);
2127 atomic_set(&pool->compaction_in_progress, 0);
2128
2129 pool->name = kstrdup(name, GFP_KERNEL);
2130 if (!pool->name)
2131 goto err;
2132
2133 if (create_cache(pool))
2134 goto err;
2135
2136 /*
2137 * Iterate reversely, because, size of size_class that we want to use
2138 * for merging should be larger or equal to current size.
2139 */
2140 for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
2141 int size;
2142 int pages_per_zspage;
2143 int objs_per_zspage;
2144 struct size_class *class;
2145 int fullness;
2146
2147 size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
2148 if (size > ZS_MAX_ALLOC_SIZE)
2149 size = ZS_MAX_ALLOC_SIZE;
2150 pages_per_zspage = calculate_zspage_chain_size(size);
2151 objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
2152
2153 /*
2154 * We iterate from biggest down to smallest classes,
2155 * so huge_class_size holds the size of the first huge
2156 * class. Any object bigger than or equal to that will
2157 * endup in the huge class.
2158 */
2159 if (pages_per_zspage != 1 && objs_per_zspage != 1 &&
2160 !huge_class_size) {
2161 huge_class_size = size;
2162 /*
2163 * The object uses ZS_HANDLE_SIZE bytes to store the
2164 * handle. We need to subtract it, because zs_malloc()
2165 * unconditionally adds handle size before it performs
2166 * size class search - so object may be smaller than
2167 * huge class size, yet it still can end up in the huge
2168 * class because it grows by ZS_HANDLE_SIZE extra bytes
2169 * right before class lookup.
2170 */
2171 huge_class_size -= (ZS_HANDLE_SIZE - 1);
2172 }
2173
2174 /*
2175 * size_class is used for normal zsmalloc operation such
2176 * as alloc/free for that size. Although it is natural that we
2177 * have one size_class for each size, there is a chance that we
2178 * can get more memory utilization if we use one size_class for
2179 * many different sizes whose size_class have same
2180 * characteristics. So, we makes size_class point to
2181 * previous size_class if possible.
2182 */
2183 if (prev_class) {
2184 if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
2185 pool->size_class[i] = prev_class;
2186 continue;
2187 }
2188 }
2189
2190 class = kzalloc(sizeof(struct size_class), GFP_KERNEL);
2191 if (!class)
2192 goto err;
2193
2194 class->size = size;
2195 class->index = i;
2196 class->pages_per_zspage = pages_per_zspage;
2197 class->objs_per_zspage = objs_per_zspage;
2198 spin_lock_init(&class->lock);
2199 pool->size_class[i] = class;
2200
2201 fullness = ZS_INUSE_RATIO_0;
2202 while (fullness < NR_FULLNESS_GROUPS) {
2203 INIT_LIST_HEAD(&class->fullness_list[fullness]);
2204 fullness++;
2205 }
2206
2207 prev_class = class;
2208 }
2209
2210 /* debug only, don't abort if it fails */
2211 zs_pool_stat_create(pool, name);
2212
2213 /*
2214 * Not critical since shrinker is only used to trigger internal
2215 * defragmentation of the pool which is pretty optional thing. If
2216 * registration fails we still can use the pool normally and user can
2217 * trigger compaction manually. Thus, ignore return code.
2218 */
2219 zs_register_shrinker(pool);
2220
2221 return pool;
2222
2223err:
2224 zs_destroy_pool(pool);
2225 return NULL;
2226}
2227EXPORT_SYMBOL_GPL(zs_create_pool);
2228
2229void zs_destroy_pool(struct zs_pool *pool)
2230{
2231 int i;
2232
2233 zs_unregister_shrinker(pool);
2234 zs_flush_migration(pool);
2235 zs_pool_stat_destroy(pool);
2236
2237 for (i = 0; i < ZS_SIZE_CLASSES; i++) {
2238 int fg;
2239 struct size_class *class = pool->size_class[i];
2240
2241 if (!class)
2242 continue;
2243
2244 if (class->index != i)
2245 continue;
2246
2247 for (fg = ZS_INUSE_RATIO_0; fg < NR_FULLNESS_GROUPS; fg++) {
2248 if (list_empty(&class->fullness_list[fg]))
2249 continue;
2250
2251 pr_err("Class-%d fullness group %d is not empty\n",
2252 class->size, fg);
2253 }
2254 kfree(class);
2255 }
2256
2257 destroy_cache(pool);
2258 kfree(pool->name);
2259 kfree(pool);
2260}
2261EXPORT_SYMBOL_GPL(zs_destroy_pool);
2262
2263static int __init zs_init(void)
2264{
2265 int ret;
2266
2267 ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare",
2268 zs_cpu_prepare, zs_cpu_dead);
2269 if (ret)
2270 goto out;
2271
2272#ifdef CONFIG_ZPOOL
2273 zpool_register_driver(&zs_zpool_driver);
2274#endif
2275
2276 zs_stat_init();
2277
2278 return 0;
2279
2280out:
2281 return ret;
2282}
2283
2284static void __exit zs_exit(void)
2285{
2286#ifdef CONFIG_ZPOOL
2287 zpool_unregister_driver(&zs_zpool_driver);
2288#endif
2289 cpuhp_remove_state(CPUHP_MM_ZS_PREPARE);
2290
2291 zs_stat_exit();
2292}
2293
2294module_init(zs_init);
2295module_exit(zs_exit);
2296
2297MODULE_LICENSE("Dual BSD/GPL");
2298MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
2299MODULE_DESCRIPTION("zsmalloc memory allocator");