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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9a001fc1 VW |
2 | /* |
3 | * z3fold.c | |
4 | * | |
5 | * Author: Vitaly Wool <vitaly.wool@konsulko.com> | |
6 | * Copyright (C) 2016, Sony Mobile Communications Inc. | |
7 | * | |
8 | * This implementation is based on zbud written by Seth Jennings. | |
9 | * | |
10 | * z3fold is an special purpose allocator for storing compressed pages. It | |
11 | * can store up to three compressed pages per page which improves the | |
12 | * compression ratio of zbud while retaining its main concepts (e. g. always | |
13 | * storing an integral number of objects per page) and simplicity. | |
14 | * It still has simple and deterministic reclaim properties that make it | |
15 | * preferable to a higher density approach (with no requirement on integral | |
16 | * number of object per page) when reclaim is used. | |
17 | * | |
18 | * As in zbud, pages are divided into "chunks". The size of the chunks is | |
19 | * fixed at compile time and is determined by NCHUNKS_ORDER below. | |
20 | * | |
21 | * z3fold doesn't export any API and is meant to be used via zpool API. | |
22 | */ | |
23 | ||
24 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
25 | ||
26 | #include <linux/atomic.h> | |
d30561c5 | 27 | #include <linux/sched.h> |
1f862989 | 28 | #include <linux/cpumask.h> |
9a001fc1 VW |
29 | #include <linux/list.h> |
30 | #include <linux/mm.h> | |
31 | #include <linux/module.h> | |
1f862989 VW |
32 | #include <linux/page-flags.h> |
33 | #include <linux/migrate.h> | |
34 | #include <linux/node.h> | |
35 | #include <linux/compaction.h> | |
d30561c5 | 36 | #include <linux/percpu.h> |
1f862989 | 37 | #include <linux/mount.h> |
ea8157ab | 38 | #include <linux/pseudo_fs.h> |
1f862989 | 39 | #include <linux/fs.h> |
9a001fc1 | 40 | #include <linux/preempt.h> |
d30561c5 | 41 | #include <linux/workqueue.h> |
9a001fc1 VW |
42 | #include <linux/slab.h> |
43 | #include <linux/spinlock.h> | |
44 | #include <linux/zpool.h> | |
ea8157ab | 45 | #include <linux/magic.h> |
9a001fc1 | 46 | |
7c2b8baa VW |
47 | /* |
48 | * NCHUNKS_ORDER determines the internal allocation granularity, effectively | |
49 | * adjusting internal fragmentation. It also determines the number of | |
50 | * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the | |
51 | * allocation granularity will be in chunks of size PAGE_SIZE/64. Some chunks | |
52 | * in the beginning of an allocated page are occupied by z3fold header, so | |
53 | * NCHUNKS will be calculated to 63 (or 62 in case CONFIG_DEBUG_SPINLOCK=y), | |
54 | * which shows the max number of free chunks in z3fold page, also there will | |
55 | * be 63, or 62, respectively, freelists per pool. | |
56 | */ | |
57 | #define NCHUNKS_ORDER 6 | |
58 | ||
59 | #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER) | |
60 | #define CHUNK_SIZE (1 << CHUNK_SHIFT) | |
61 | #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE) | |
62 | #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT) | |
63 | #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SHIFT) | |
64 | #define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT) | |
65 | ||
66 | #define BUDDY_MASK (0x3) | |
67 | #define BUDDY_SHIFT 2 | |
68 | #define SLOTS_ALIGN (0x40) | |
69 | ||
9a001fc1 VW |
70 | /***************** |
71 | * Structures | |
72 | *****************/ | |
ede93213 VW |
73 | struct z3fold_pool; |
74 | struct z3fold_ops { | |
75 | int (*evict)(struct z3fold_pool *pool, unsigned long handle); | |
76 | }; | |
77 | ||
78 | enum buddy { | |
79 | HEADLESS = 0, | |
80 | FIRST, | |
81 | MIDDLE, | |
82 | LAST, | |
7c2b8baa VW |
83 | BUDDIES_MAX = LAST |
84 | }; | |
85 | ||
86 | struct z3fold_buddy_slots { | |
87 | /* | |
88 | * we are using BUDDY_MASK in handle_to_buddy etc. so there should | |
89 | * be enough slots to hold all possible variants | |
90 | */ | |
91 | unsigned long slot[BUDDY_MASK + 1]; | |
92 | unsigned long pool; /* back link + flags */ | |
ede93213 | 93 | }; |
7c2b8baa | 94 | #define HANDLE_FLAG_MASK (0x03) |
ede93213 VW |
95 | |
96 | /* | |
d30561c5 | 97 | * struct z3fold_header - z3fold page metadata occupying first chunks of each |
ede93213 | 98 | * z3fold page, except for HEADLESS pages |
d30561c5 VW |
99 | * @buddy: links the z3fold page into the relevant list in the |
100 | * pool | |
2f1e5e4d | 101 | * @page_lock: per-page lock |
d30561c5 VW |
102 | * @refcount: reference count for the z3fold page |
103 | * @work: work_struct for page layout optimization | |
7c2b8baa | 104 | * @slots: pointer to the structure holding buddy slots |
bb9a374d | 105 | * @pool: pointer to the containing pool |
d30561c5 | 106 | * @cpu: CPU which this page "belongs" to |
ede93213 VW |
107 | * @first_chunks: the size of the first buddy in chunks, 0 if free |
108 | * @middle_chunks: the size of the middle buddy in chunks, 0 if free | |
109 | * @last_chunks: the size of the last buddy in chunks, 0 if free | |
110 | * @first_num: the starting number (for the first handle) | |
1f862989 | 111 | * @mapped_count: the number of objects currently mapped |
ede93213 VW |
112 | */ |
113 | struct z3fold_header { | |
114 | struct list_head buddy; | |
2f1e5e4d | 115 | spinlock_t page_lock; |
5a27aa82 | 116 | struct kref refcount; |
d30561c5 | 117 | struct work_struct work; |
7c2b8baa | 118 | struct z3fold_buddy_slots *slots; |
bb9a374d | 119 | struct z3fold_pool *pool; |
d30561c5 | 120 | short cpu; |
ede93213 VW |
121 | unsigned short first_chunks; |
122 | unsigned short middle_chunks; | |
123 | unsigned short last_chunks; | |
124 | unsigned short start_middle; | |
125 | unsigned short first_num:2; | |
1f862989 | 126 | unsigned short mapped_count:2; |
ede93213 VW |
127 | }; |
128 | ||
9a001fc1 VW |
129 | /** |
130 | * struct z3fold_pool - stores metadata for each z3fold pool | |
d30561c5 VW |
131 | * @name: pool name |
132 | * @lock: protects pool unbuddied/lru lists | |
133 | * @stale_lock: protects pool stale page list | |
134 | * @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2- | |
135 | * buddies; the list each z3fold page is added to depends on | |
136 | * the size of its free region. | |
9a001fc1 VW |
137 | * @lru: list tracking the z3fold pages in LRU order by most recently |
138 | * added buddy. | |
d30561c5 | 139 | * @stale: list of pages marked for freeing |
9a001fc1 | 140 | * @pages_nr: number of z3fold pages in the pool. |
7c2b8baa | 141 | * @c_handle: cache for z3fold_buddy_slots allocation |
9a001fc1 VW |
142 | * @ops: pointer to a structure of user defined operations specified at |
143 | * pool creation time. | |
d30561c5 VW |
144 | * @compact_wq: workqueue for page layout background optimization |
145 | * @release_wq: workqueue for safe page release | |
146 | * @work: work_struct for safe page release | |
1f862989 | 147 | * @inode: inode for z3fold pseudo filesystem |
9a001fc1 VW |
148 | * |
149 | * This structure is allocated at pool creation time and maintains metadata | |
150 | * pertaining to a particular z3fold pool. | |
151 | */ | |
152 | struct z3fold_pool { | |
d30561c5 | 153 | const char *name; |
9a001fc1 | 154 | spinlock_t lock; |
d30561c5 VW |
155 | spinlock_t stale_lock; |
156 | struct list_head *unbuddied; | |
9a001fc1 | 157 | struct list_head lru; |
d30561c5 | 158 | struct list_head stale; |
12d59ae6 | 159 | atomic64_t pages_nr; |
7c2b8baa | 160 | struct kmem_cache *c_handle; |
9a001fc1 VW |
161 | const struct z3fold_ops *ops; |
162 | struct zpool *zpool; | |
163 | const struct zpool_ops *zpool_ops; | |
d30561c5 VW |
164 | struct workqueue_struct *compact_wq; |
165 | struct workqueue_struct *release_wq; | |
166 | struct work_struct work; | |
1f862989 | 167 | struct inode *inode; |
9a001fc1 VW |
168 | }; |
169 | ||
9a001fc1 VW |
170 | /* |
171 | * Internal z3fold page flags | |
172 | */ | |
173 | enum z3fold_page_flags { | |
5a27aa82 | 174 | PAGE_HEADLESS = 0, |
9a001fc1 | 175 | MIDDLE_CHUNK_MAPPED, |
d30561c5 | 176 | NEEDS_COMPACTING, |
6098d7e1 | 177 | PAGE_STALE, |
ca0246bb | 178 | PAGE_CLAIMED, /* by either reclaim or free */ |
9a001fc1 VW |
179 | }; |
180 | ||
181 | /***************** | |
182 | * Helpers | |
183 | *****************/ | |
184 | ||
185 | /* Converts an allocation size in bytes to size in z3fold chunks */ | |
186 | static int size_to_chunks(size_t size) | |
187 | { | |
188 | return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; | |
189 | } | |
190 | ||
191 | #define for_each_unbuddied_list(_iter, _begin) \ | |
192 | for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) | |
193 | ||
d30561c5 VW |
194 | static void compact_page_work(struct work_struct *w); |
195 | ||
bb9f6f63 VW |
196 | static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool, |
197 | gfp_t gfp) | |
7c2b8baa | 198 | { |
f1549cb5 HB |
199 | struct z3fold_buddy_slots *slots; |
200 | ||
201 | slots = kmem_cache_alloc(pool->c_handle, | |
202 | (gfp & ~(__GFP_HIGHMEM | __GFP_MOVABLE))); | |
7c2b8baa VW |
203 | |
204 | if (slots) { | |
205 | memset(slots->slot, 0, sizeof(slots->slot)); | |
206 | slots->pool = (unsigned long)pool; | |
207 | } | |
208 | ||
209 | return slots; | |
210 | } | |
211 | ||
212 | static inline struct z3fold_pool *slots_to_pool(struct z3fold_buddy_slots *s) | |
213 | { | |
214 | return (struct z3fold_pool *)(s->pool & ~HANDLE_FLAG_MASK); | |
215 | } | |
216 | ||
217 | static inline struct z3fold_buddy_slots *handle_to_slots(unsigned long handle) | |
218 | { | |
219 | return (struct z3fold_buddy_slots *)(handle & ~(SLOTS_ALIGN - 1)); | |
220 | } | |
221 | ||
222 | static inline void free_handle(unsigned long handle) | |
223 | { | |
224 | struct z3fold_buddy_slots *slots; | |
225 | int i; | |
226 | bool is_free; | |
227 | ||
228 | if (handle & (1 << PAGE_HEADLESS)) | |
229 | return; | |
230 | ||
231 | WARN_ON(*(unsigned long *)handle == 0); | |
232 | *(unsigned long *)handle = 0; | |
233 | slots = handle_to_slots(handle); | |
234 | is_free = true; | |
235 | for (i = 0; i <= BUDDY_MASK; i++) { | |
236 | if (slots->slot[i]) { | |
237 | is_free = false; | |
238 | break; | |
239 | } | |
240 | } | |
241 | ||
242 | if (is_free) { | |
243 | struct z3fold_pool *pool = slots_to_pool(slots); | |
244 | ||
245 | kmem_cache_free(pool->c_handle, slots); | |
246 | } | |
247 | } | |
248 | ||
ea8157ab | 249 | static int z3fold_init_fs_context(struct fs_context *fc) |
1f862989 | 250 | { |
ea8157ab | 251 | return init_pseudo(fc, Z3FOLD_MAGIC) ? 0 : -ENOMEM; |
1f862989 VW |
252 | } |
253 | ||
254 | static struct file_system_type z3fold_fs = { | |
255 | .name = "z3fold", | |
ea8157ab | 256 | .init_fs_context = z3fold_init_fs_context, |
1f862989 VW |
257 | .kill_sb = kill_anon_super, |
258 | }; | |
259 | ||
260 | static struct vfsmount *z3fold_mnt; | |
261 | static int z3fold_mount(void) | |
262 | { | |
263 | int ret = 0; | |
264 | ||
265 | z3fold_mnt = kern_mount(&z3fold_fs); | |
266 | if (IS_ERR(z3fold_mnt)) | |
267 | ret = PTR_ERR(z3fold_mnt); | |
268 | ||
269 | return ret; | |
270 | } | |
271 | ||
272 | static void z3fold_unmount(void) | |
273 | { | |
274 | kern_unmount(z3fold_mnt); | |
275 | } | |
276 | ||
277 | static const struct address_space_operations z3fold_aops; | |
278 | static int z3fold_register_migration(struct z3fold_pool *pool) | |
279 | { | |
280 | pool->inode = alloc_anon_inode(z3fold_mnt->mnt_sb); | |
281 | if (IS_ERR(pool->inode)) { | |
282 | pool->inode = NULL; | |
283 | return 1; | |
284 | } | |
285 | ||
286 | pool->inode->i_mapping->private_data = pool; | |
287 | pool->inode->i_mapping->a_ops = &z3fold_aops; | |
288 | return 0; | |
289 | } | |
290 | ||
291 | static void z3fold_unregister_migration(struct z3fold_pool *pool) | |
292 | { | |
293 | if (pool->inode) | |
294 | iput(pool->inode); | |
295 | } | |
296 | ||
9a001fc1 | 297 | /* Initializes the z3fold header of a newly allocated z3fold page */ |
d30561c5 | 298 | static struct z3fold_header *init_z3fold_page(struct page *page, |
bb9f6f63 | 299 | struct z3fold_pool *pool, gfp_t gfp) |
9a001fc1 VW |
300 | { |
301 | struct z3fold_header *zhdr = page_address(page); | |
bb9f6f63 | 302 | struct z3fold_buddy_slots *slots = alloc_slots(pool, gfp); |
7c2b8baa VW |
303 | |
304 | if (!slots) | |
305 | return NULL; | |
9a001fc1 VW |
306 | |
307 | INIT_LIST_HEAD(&page->lru); | |
9a001fc1 VW |
308 | clear_bit(PAGE_HEADLESS, &page->private); |
309 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
d30561c5 VW |
310 | clear_bit(NEEDS_COMPACTING, &page->private); |
311 | clear_bit(PAGE_STALE, &page->private); | |
ca0246bb | 312 | clear_bit(PAGE_CLAIMED, &page->private); |
9a001fc1 | 313 | |
2f1e5e4d | 314 | spin_lock_init(&zhdr->page_lock); |
5a27aa82 | 315 | kref_init(&zhdr->refcount); |
9a001fc1 VW |
316 | zhdr->first_chunks = 0; |
317 | zhdr->middle_chunks = 0; | |
318 | zhdr->last_chunks = 0; | |
319 | zhdr->first_num = 0; | |
320 | zhdr->start_middle = 0; | |
d30561c5 | 321 | zhdr->cpu = -1; |
7c2b8baa | 322 | zhdr->slots = slots; |
bb9a374d | 323 | zhdr->pool = pool; |
9a001fc1 | 324 | INIT_LIST_HEAD(&zhdr->buddy); |
d30561c5 | 325 | INIT_WORK(&zhdr->work, compact_page_work); |
9a001fc1 VW |
326 | return zhdr; |
327 | } | |
328 | ||
329 | /* Resets the struct page fields and frees the page */ | |
1f862989 | 330 | static void free_z3fold_page(struct page *page, bool headless) |
9a001fc1 | 331 | { |
1f862989 VW |
332 | if (!headless) { |
333 | lock_page(page); | |
334 | __ClearPageMovable(page); | |
335 | unlock_page(page); | |
336 | } | |
337 | ClearPagePrivate(page); | |
5a27aa82 VW |
338 | __free_page(page); |
339 | } | |
340 | ||
2f1e5e4d VW |
341 | /* Lock a z3fold page */ |
342 | static inline void z3fold_page_lock(struct z3fold_header *zhdr) | |
343 | { | |
344 | spin_lock(&zhdr->page_lock); | |
345 | } | |
346 | ||
76e32a2a VW |
347 | /* Try to lock a z3fold page */ |
348 | static inline int z3fold_page_trylock(struct z3fold_header *zhdr) | |
349 | { | |
350 | return spin_trylock(&zhdr->page_lock); | |
351 | } | |
352 | ||
2f1e5e4d VW |
353 | /* Unlock a z3fold page */ |
354 | static inline void z3fold_page_unlock(struct z3fold_header *zhdr) | |
355 | { | |
356 | spin_unlock(&zhdr->page_lock); | |
357 | } | |
358 | ||
7c2b8baa VW |
359 | /* Helper function to build the index */ |
360 | static inline int __idx(struct z3fold_header *zhdr, enum buddy bud) | |
361 | { | |
362 | return (bud + zhdr->first_num) & BUDDY_MASK; | |
363 | } | |
364 | ||
9a001fc1 VW |
365 | /* |
366 | * Encodes the handle of a particular buddy within a z3fold page | |
367 | * Pool lock should be held as this function accesses first_num | |
368 | */ | |
369 | static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) | |
370 | { | |
7c2b8baa VW |
371 | struct z3fold_buddy_slots *slots; |
372 | unsigned long h = (unsigned long)zhdr; | |
373 | int idx = 0; | |
9a001fc1 | 374 | |
7c2b8baa VW |
375 | /* |
376 | * For a headless page, its handle is its pointer with the extra | |
377 | * PAGE_HEADLESS bit set | |
378 | */ | |
379 | if (bud == HEADLESS) | |
380 | return h | (1 << PAGE_HEADLESS); | |
381 | ||
382 | /* otherwise, return pointer to encoded handle */ | |
383 | idx = __idx(zhdr, bud); | |
384 | h += idx; | |
385 | if (bud == LAST) | |
386 | h |= (zhdr->last_chunks << BUDDY_SHIFT); | |
387 | ||
388 | slots = zhdr->slots; | |
389 | slots->slot[idx] = h; | |
390 | return (unsigned long)&slots->slot[idx]; | |
9a001fc1 VW |
391 | } |
392 | ||
393 | /* Returns the z3fold page where a given handle is stored */ | |
1f862989 | 394 | static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h) |
9a001fc1 | 395 | { |
1f862989 | 396 | unsigned long addr = h; |
7c2b8baa VW |
397 | |
398 | if (!(addr & (1 << PAGE_HEADLESS))) | |
1f862989 | 399 | addr = *(unsigned long *)h; |
7c2b8baa VW |
400 | |
401 | return (struct z3fold_header *)(addr & PAGE_MASK); | |
9a001fc1 VW |
402 | } |
403 | ||
ca0246bb VW |
404 | /* only for LAST bud, returns zero otherwise */ |
405 | static unsigned short handle_to_chunks(unsigned long handle) | |
406 | { | |
7c2b8baa VW |
407 | unsigned long addr = *(unsigned long *)handle; |
408 | ||
409 | return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; | |
ca0246bb VW |
410 | } |
411 | ||
f201ebd8 | 412 | /* |
413 | * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle | |
414 | * but that doesn't matter. because the masking will result in the | |
415 | * correct buddy number. | |
416 | */ | |
9a001fc1 VW |
417 | static enum buddy handle_to_buddy(unsigned long handle) |
418 | { | |
7c2b8baa VW |
419 | struct z3fold_header *zhdr; |
420 | unsigned long addr; | |
421 | ||
422 | WARN_ON(handle & (1 << PAGE_HEADLESS)); | |
423 | addr = *(unsigned long *)handle; | |
424 | zhdr = (struct z3fold_header *)(addr & PAGE_MASK); | |
425 | return (addr - zhdr->first_num) & BUDDY_MASK; | |
9a001fc1 VW |
426 | } |
427 | ||
9050cce1 VW |
428 | static inline struct z3fold_pool *zhdr_to_pool(struct z3fold_header *zhdr) |
429 | { | |
bb9a374d | 430 | return zhdr->pool; |
9050cce1 VW |
431 | } |
432 | ||
d30561c5 VW |
433 | static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) |
434 | { | |
435 | struct page *page = virt_to_page(zhdr); | |
9050cce1 | 436 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 VW |
437 | |
438 | WARN_ON(!list_empty(&zhdr->buddy)); | |
439 | set_bit(PAGE_STALE, &page->private); | |
35529357 | 440 | clear_bit(NEEDS_COMPACTING, &page->private); |
d30561c5 VW |
441 | spin_lock(&pool->lock); |
442 | if (!list_empty(&page->lru)) | |
1f862989 | 443 | list_del_init(&page->lru); |
d30561c5 VW |
444 | spin_unlock(&pool->lock); |
445 | if (locked) | |
446 | z3fold_page_unlock(zhdr); | |
447 | spin_lock(&pool->stale_lock); | |
448 | list_add(&zhdr->buddy, &pool->stale); | |
449 | queue_work(pool->release_wq, &pool->work); | |
450 | spin_unlock(&pool->stale_lock); | |
451 | } | |
452 | ||
453 | static void __attribute__((__unused__)) | |
454 | release_z3fold_page(struct kref *ref) | |
455 | { | |
456 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
457 | refcount); | |
458 | __release_z3fold_page(zhdr, false); | |
459 | } | |
460 | ||
461 | static void release_z3fold_page_locked(struct kref *ref) | |
462 | { | |
463 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
464 | refcount); | |
465 | WARN_ON(z3fold_page_trylock(zhdr)); | |
466 | __release_z3fold_page(zhdr, true); | |
467 | } | |
468 | ||
469 | static void release_z3fold_page_locked_list(struct kref *ref) | |
470 | { | |
471 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
472 | refcount); | |
9050cce1 VW |
473 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
474 | spin_lock(&pool->lock); | |
d30561c5 | 475 | list_del_init(&zhdr->buddy); |
9050cce1 | 476 | spin_unlock(&pool->lock); |
d30561c5 VW |
477 | |
478 | WARN_ON(z3fold_page_trylock(zhdr)); | |
479 | __release_z3fold_page(zhdr, true); | |
480 | } | |
481 | ||
482 | static void free_pages_work(struct work_struct *w) | |
483 | { | |
484 | struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); | |
485 | ||
486 | spin_lock(&pool->stale_lock); | |
487 | while (!list_empty(&pool->stale)) { | |
488 | struct z3fold_header *zhdr = list_first_entry(&pool->stale, | |
489 | struct z3fold_header, buddy); | |
490 | struct page *page = virt_to_page(zhdr); | |
491 | ||
492 | list_del(&zhdr->buddy); | |
493 | if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) | |
494 | continue; | |
d30561c5 VW |
495 | spin_unlock(&pool->stale_lock); |
496 | cancel_work_sync(&zhdr->work); | |
1f862989 | 497 | free_z3fold_page(page, false); |
d30561c5 VW |
498 | cond_resched(); |
499 | spin_lock(&pool->stale_lock); | |
500 | } | |
501 | spin_unlock(&pool->stale_lock); | |
502 | } | |
503 | ||
9a001fc1 VW |
504 | /* |
505 | * Returns the number of free chunks in a z3fold page. | |
506 | * NB: can't be used with HEADLESS pages. | |
507 | */ | |
508 | static int num_free_chunks(struct z3fold_header *zhdr) | |
509 | { | |
510 | int nfree; | |
511 | /* | |
512 | * If there is a middle object, pick up the bigger free space | |
513 | * either before or after it. Otherwise just subtract the number | |
514 | * of chunks occupied by the first and the last objects. | |
515 | */ | |
516 | if (zhdr->middle_chunks != 0) { | |
517 | int nfree_before = zhdr->first_chunks ? | |
ede93213 | 518 | 0 : zhdr->start_middle - ZHDR_CHUNKS; |
9a001fc1 | 519 | int nfree_after = zhdr->last_chunks ? |
ede93213 VW |
520 | 0 : TOTAL_CHUNKS - |
521 | (zhdr->start_middle + zhdr->middle_chunks); | |
9a001fc1 VW |
522 | nfree = max(nfree_before, nfree_after); |
523 | } else | |
524 | nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; | |
525 | return nfree; | |
526 | } | |
527 | ||
9050cce1 VW |
528 | /* Add to the appropriate unbuddied list */ |
529 | static inline void add_to_unbuddied(struct z3fold_pool *pool, | |
530 | struct z3fold_header *zhdr) | |
531 | { | |
532 | if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || | |
533 | zhdr->middle_chunks == 0) { | |
534 | struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied); | |
535 | ||
536 | int freechunks = num_free_chunks(zhdr); | |
537 | spin_lock(&pool->lock); | |
538 | list_add(&zhdr->buddy, &unbuddied[freechunks]); | |
539 | spin_unlock(&pool->lock); | |
540 | zhdr->cpu = smp_processor_id(); | |
541 | put_cpu_ptr(pool->unbuddied); | |
542 | } | |
543 | } | |
544 | ||
ede93213 VW |
545 | static inline void *mchunk_memmove(struct z3fold_header *zhdr, |
546 | unsigned short dst_chunk) | |
547 | { | |
548 | void *beg = zhdr; | |
549 | return memmove(beg + (dst_chunk << CHUNK_SHIFT), | |
550 | beg + (zhdr->start_middle << CHUNK_SHIFT), | |
551 | zhdr->middle_chunks << CHUNK_SHIFT); | |
552 | } | |
553 | ||
1b096e5a | 554 | #define BIG_CHUNK_GAP 3 |
9a001fc1 VW |
555 | /* Has to be called with lock held */ |
556 | static int z3fold_compact_page(struct z3fold_header *zhdr) | |
557 | { | |
558 | struct page *page = virt_to_page(zhdr); | |
9a001fc1 | 559 | |
ede93213 VW |
560 | if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) |
561 | return 0; /* can't move middle chunk, it's used */ | |
9a001fc1 | 562 | |
1f862989 VW |
563 | if (unlikely(PageIsolated(page))) |
564 | return 0; | |
565 | ||
ede93213 VW |
566 | if (zhdr->middle_chunks == 0) |
567 | return 0; /* nothing to compact */ | |
568 | ||
569 | if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { | |
570 | /* move to the beginning */ | |
571 | mchunk_memmove(zhdr, ZHDR_CHUNKS); | |
9a001fc1 VW |
572 | zhdr->first_chunks = zhdr->middle_chunks; |
573 | zhdr->middle_chunks = 0; | |
574 | zhdr->start_middle = 0; | |
575 | zhdr->first_num++; | |
1b096e5a | 576 | return 1; |
9a001fc1 | 577 | } |
1b096e5a VW |
578 | |
579 | /* | |
580 | * moving data is expensive, so let's only do that if | |
581 | * there's substantial gain (at least BIG_CHUNK_GAP chunks) | |
582 | */ | |
583 | if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && | |
584 | zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= | |
585 | BIG_CHUNK_GAP) { | |
586 | mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); | |
587 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; | |
588 | return 1; | |
589 | } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && | |
590 | TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle | |
591 | + zhdr->middle_chunks) >= | |
592 | BIG_CHUNK_GAP) { | |
593 | unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - | |
594 | zhdr->middle_chunks; | |
595 | mchunk_memmove(zhdr, new_start); | |
596 | zhdr->start_middle = new_start; | |
597 | return 1; | |
598 | } | |
599 | ||
600 | return 0; | |
9a001fc1 VW |
601 | } |
602 | ||
d30561c5 VW |
603 | static void do_compact_page(struct z3fold_header *zhdr, bool locked) |
604 | { | |
9050cce1 | 605 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 | 606 | struct page *page; |
d30561c5 VW |
607 | |
608 | page = virt_to_page(zhdr); | |
609 | if (locked) | |
610 | WARN_ON(z3fold_page_trylock(zhdr)); | |
611 | else | |
612 | z3fold_page_lock(zhdr); | |
5d03a661 | 613 | if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { |
d30561c5 VW |
614 | z3fold_page_unlock(zhdr); |
615 | return; | |
616 | } | |
617 | spin_lock(&pool->lock); | |
618 | list_del_init(&zhdr->buddy); | |
619 | spin_unlock(&pool->lock); | |
620 | ||
5d03a661 VW |
621 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { |
622 | atomic64_dec(&pool->pages_nr); | |
623 | return; | |
624 | } | |
625 | ||
1f862989 VW |
626 | if (unlikely(PageIsolated(page) || |
627 | test_bit(PAGE_STALE, &page->private))) { | |
628 | z3fold_page_unlock(zhdr); | |
629 | return; | |
630 | } | |
631 | ||
d30561c5 | 632 | z3fold_compact_page(zhdr); |
9050cce1 | 633 | add_to_unbuddied(pool, zhdr); |
d30561c5 VW |
634 | z3fold_page_unlock(zhdr); |
635 | } | |
636 | ||
637 | static void compact_page_work(struct work_struct *w) | |
638 | { | |
639 | struct z3fold_header *zhdr = container_of(w, struct z3fold_header, | |
640 | work); | |
641 | ||
642 | do_compact_page(zhdr, false); | |
643 | } | |
644 | ||
9050cce1 VW |
645 | /* returns _locked_ z3fold page header or NULL */ |
646 | static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, | |
647 | size_t size, bool can_sleep) | |
648 | { | |
649 | struct z3fold_header *zhdr = NULL; | |
650 | struct page *page; | |
651 | struct list_head *unbuddied; | |
652 | int chunks = size_to_chunks(size), i; | |
653 | ||
654 | lookup: | |
655 | /* First, try to find an unbuddied z3fold page. */ | |
656 | unbuddied = get_cpu_ptr(pool->unbuddied); | |
657 | for_each_unbuddied_list(i, chunks) { | |
658 | struct list_head *l = &unbuddied[i]; | |
659 | ||
660 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
661 | struct z3fold_header, buddy); | |
662 | ||
663 | if (!zhdr) | |
664 | continue; | |
665 | ||
666 | /* Re-check under lock. */ | |
667 | spin_lock(&pool->lock); | |
668 | l = &unbuddied[i]; | |
669 | if (unlikely(zhdr != list_first_entry(READ_ONCE(l), | |
670 | struct z3fold_header, buddy)) || | |
671 | !z3fold_page_trylock(zhdr)) { | |
672 | spin_unlock(&pool->lock); | |
673 | zhdr = NULL; | |
674 | put_cpu_ptr(pool->unbuddied); | |
675 | if (can_sleep) | |
676 | cond_resched(); | |
677 | goto lookup; | |
678 | } | |
679 | list_del_init(&zhdr->buddy); | |
680 | zhdr->cpu = -1; | |
681 | spin_unlock(&pool->lock); | |
682 | ||
683 | page = virt_to_page(zhdr); | |
684 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
685 | z3fold_page_unlock(zhdr); | |
686 | zhdr = NULL; | |
687 | put_cpu_ptr(pool->unbuddied); | |
688 | if (can_sleep) | |
689 | cond_resched(); | |
690 | goto lookup; | |
691 | } | |
692 | ||
693 | /* | |
694 | * this page could not be removed from its unbuddied | |
695 | * list while pool lock was held, and then we've taken | |
696 | * page lock so kref_put could not be called before | |
697 | * we got here, so it's safe to just call kref_get() | |
698 | */ | |
699 | kref_get(&zhdr->refcount); | |
700 | break; | |
701 | } | |
702 | put_cpu_ptr(pool->unbuddied); | |
703 | ||
351618b2 VW |
704 | if (!zhdr) { |
705 | int cpu; | |
706 | ||
707 | /* look for _exact_ match on other cpus' lists */ | |
708 | for_each_online_cpu(cpu) { | |
709 | struct list_head *l; | |
710 | ||
711 | unbuddied = per_cpu_ptr(pool->unbuddied, cpu); | |
712 | spin_lock(&pool->lock); | |
713 | l = &unbuddied[chunks]; | |
714 | ||
715 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
716 | struct z3fold_header, buddy); | |
717 | ||
718 | if (!zhdr || !z3fold_page_trylock(zhdr)) { | |
719 | spin_unlock(&pool->lock); | |
720 | zhdr = NULL; | |
721 | continue; | |
722 | } | |
723 | list_del_init(&zhdr->buddy); | |
724 | zhdr->cpu = -1; | |
725 | spin_unlock(&pool->lock); | |
726 | ||
727 | page = virt_to_page(zhdr); | |
728 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
729 | z3fold_page_unlock(zhdr); | |
730 | zhdr = NULL; | |
731 | if (can_sleep) | |
732 | cond_resched(); | |
733 | continue; | |
734 | } | |
735 | kref_get(&zhdr->refcount); | |
736 | break; | |
737 | } | |
738 | } | |
739 | ||
9050cce1 VW |
740 | return zhdr; |
741 | } | |
d30561c5 VW |
742 | |
743 | /* | |
744 | * API Functions | |
745 | */ | |
746 | ||
747 | /** | |
748 | * z3fold_create_pool() - create a new z3fold pool | |
749 | * @name: pool name | |
750 | * @gfp: gfp flags when allocating the z3fold pool structure | |
751 | * @ops: user-defined operations for the z3fold pool | |
752 | * | |
753 | * Return: pointer to the new z3fold pool or NULL if the metadata allocation | |
754 | * failed. | |
755 | */ | |
756 | static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, | |
757 | const struct z3fold_ops *ops) | |
758 | { | |
759 | struct z3fold_pool *pool = NULL; | |
760 | int i, cpu; | |
761 | ||
762 | pool = kzalloc(sizeof(struct z3fold_pool), gfp); | |
763 | if (!pool) | |
764 | goto out; | |
7c2b8baa VW |
765 | pool->c_handle = kmem_cache_create("z3fold_handle", |
766 | sizeof(struct z3fold_buddy_slots), | |
767 | SLOTS_ALIGN, 0, NULL); | |
768 | if (!pool->c_handle) | |
769 | goto out_c; | |
d30561c5 VW |
770 | spin_lock_init(&pool->lock); |
771 | spin_lock_init(&pool->stale_lock); | |
772 | pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2); | |
1ec6995d XW |
773 | if (!pool->unbuddied) |
774 | goto out_pool; | |
d30561c5 VW |
775 | for_each_possible_cpu(cpu) { |
776 | struct list_head *unbuddied = | |
777 | per_cpu_ptr(pool->unbuddied, cpu); | |
778 | for_each_unbuddied_list(i, 0) | |
779 | INIT_LIST_HEAD(&unbuddied[i]); | |
780 | } | |
781 | INIT_LIST_HEAD(&pool->lru); | |
782 | INIT_LIST_HEAD(&pool->stale); | |
783 | atomic64_set(&pool->pages_nr, 0); | |
784 | pool->name = name; | |
785 | pool->compact_wq = create_singlethread_workqueue(pool->name); | |
786 | if (!pool->compact_wq) | |
1ec6995d | 787 | goto out_unbuddied; |
d30561c5 VW |
788 | pool->release_wq = create_singlethread_workqueue(pool->name); |
789 | if (!pool->release_wq) | |
790 | goto out_wq; | |
1f862989 VW |
791 | if (z3fold_register_migration(pool)) |
792 | goto out_rwq; | |
d30561c5 VW |
793 | INIT_WORK(&pool->work, free_pages_work); |
794 | pool->ops = ops; | |
795 | return pool; | |
796 | ||
1f862989 VW |
797 | out_rwq: |
798 | destroy_workqueue(pool->release_wq); | |
d30561c5 VW |
799 | out_wq: |
800 | destroy_workqueue(pool->compact_wq); | |
1ec6995d XW |
801 | out_unbuddied: |
802 | free_percpu(pool->unbuddied); | |
803 | out_pool: | |
7c2b8baa VW |
804 | kmem_cache_destroy(pool->c_handle); |
805 | out_c: | |
d30561c5 | 806 | kfree(pool); |
1ec6995d | 807 | out: |
d30561c5 VW |
808 | return NULL; |
809 | } | |
810 | ||
811 | /** | |
812 | * z3fold_destroy_pool() - destroys an existing z3fold pool | |
813 | * @pool: the z3fold pool to be destroyed | |
814 | * | |
815 | * The pool should be emptied before this function is called. | |
816 | */ | |
817 | static void z3fold_destroy_pool(struct z3fold_pool *pool) | |
818 | { | |
7c2b8baa | 819 | kmem_cache_destroy(pool->c_handle); |
1f862989 | 820 | z3fold_unregister_migration(pool); |
d30561c5 VW |
821 | destroy_workqueue(pool->release_wq); |
822 | destroy_workqueue(pool->compact_wq); | |
823 | kfree(pool); | |
824 | } | |
825 | ||
9a001fc1 VW |
826 | /** |
827 | * z3fold_alloc() - allocates a region of a given size | |
828 | * @pool: z3fold pool from which to allocate | |
829 | * @size: size in bytes of the desired allocation | |
830 | * @gfp: gfp flags used if the pool needs to grow | |
831 | * @handle: handle of the new allocation | |
832 | * | |
833 | * This function will attempt to find a free region in the pool large enough to | |
834 | * satisfy the allocation request. A search of the unbuddied lists is | |
835 | * performed first. If no suitable free region is found, then a new page is | |
836 | * allocated and added to the pool to satisfy the request. | |
837 | * | |
838 | * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used | |
839 | * as z3fold pool pages. | |
840 | * | |
841 | * Return: 0 if success and handle is set, otherwise -EINVAL if the size or | |
842 | * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate | |
843 | * a new page. | |
844 | */ | |
845 | static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, | |
846 | unsigned long *handle) | |
847 | { | |
9050cce1 | 848 | int chunks = size_to_chunks(size); |
9a001fc1 | 849 | struct z3fold_header *zhdr = NULL; |
d30561c5 | 850 | struct page *page = NULL; |
9a001fc1 | 851 | enum buddy bud; |
8a97ea54 | 852 | bool can_sleep = gfpflags_allow_blocking(gfp); |
9a001fc1 | 853 | |
f1549cb5 | 854 | if (!size) |
9a001fc1 VW |
855 | return -EINVAL; |
856 | ||
857 | if (size > PAGE_SIZE) | |
858 | return -ENOSPC; | |
859 | ||
860 | if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) | |
861 | bud = HEADLESS; | |
862 | else { | |
9050cce1 VW |
863 | retry: |
864 | zhdr = __z3fold_alloc(pool, size, can_sleep); | |
d30561c5 | 865 | if (zhdr) { |
2f1e5e4d VW |
866 | if (zhdr->first_chunks == 0) { |
867 | if (zhdr->middle_chunks != 0 && | |
868 | chunks >= zhdr->start_middle) | |
9a001fc1 | 869 | bud = LAST; |
2f1e5e4d VW |
870 | else |
871 | bud = FIRST; | |
872 | } else if (zhdr->last_chunks == 0) | |
873 | bud = LAST; | |
874 | else if (zhdr->middle_chunks == 0) | |
875 | bud = MIDDLE; | |
876 | else { | |
5a27aa82 | 877 | if (kref_put(&zhdr->refcount, |
d30561c5 | 878 | release_z3fold_page_locked)) |
5a27aa82 | 879 | atomic64_dec(&pool->pages_nr); |
d30561c5 VW |
880 | else |
881 | z3fold_page_unlock(zhdr); | |
2f1e5e4d VW |
882 | pr_err("No free chunks in unbuddied\n"); |
883 | WARN_ON(1); | |
9050cce1 | 884 | goto retry; |
9a001fc1 | 885 | } |
9050cce1 | 886 | page = virt_to_page(zhdr); |
2f1e5e4d | 887 | goto found; |
9a001fc1 VW |
888 | } |
889 | bud = FIRST; | |
9a001fc1 VW |
890 | } |
891 | ||
5c9bab59 VW |
892 | page = NULL; |
893 | if (can_sleep) { | |
894 | spin_lock(&pool->stale_lock); | |
895 | zhdr = list_first_entry_or_null(&pool->stale, | |
896 | struct z3fold_header, buddy); | |
897 | /* | |
898 | * Before allocating a page, let's see if we can take one from | |
899 | * the stale pages list. cancel_work_sync() can sleep so we | |
900 | * limit this case to the contexts where we can sleep | |
901 | */ | |
902 | if (zhdr) { | |
903 | list_del(&zhdr->buddy); | |
904 | spin_unlock(&pool->stale_lock); | |
d30561c5 | 905 | cancel_work_sync(&zhdr->work); |
5c9bab59 VW |
906 | page = virt_to_page(zhdr); |
907 | } else { | |
908 | spin_unlock(&pool->stale_lock); | |
909 | } | |
d30561c5 | 910 | } |
5c9bab59 VW |
911 | if (!page) |
912 | page = alloc_page(gfp); | |
d30561c5 | 913 | |
9a001fc1 VW |
914 | if (!page) |
915 | return -ENOMEM; | |
2f1e5e4d | 916 | |
bb9f6f63 | 917 | zhdr = init_z3fold_page(page, pool, gfp); |
9050cce1 VW |
918 | if (!zhdr) { |
919 | __free_page(page); | |
920 | return -ENOMEM; | |
921 | } | |
922 | atomic64_inc(&pool->pages_nr); | |
9a001fc1 VW |
923 | |
924 | if (bud == HEADLESS) { | |
925 | set_bit(PAGE_HEADLESS, &page->private); | |
926 | goto headless; | |
927 | } | |
810481a2 HB |
928 | if (can_sleep) { |
929 | lock_page(page); | |
930 | __SetPageMovable(page, pool->inode->i_mapping); | |
931 | unlock_page(page); | |
932 | } else { | |
933 | if (trylock_page(page)) { | |
934 | __SetPageMovable(page, pool->inode->i_mapping); | |
935 | unlock_page(page); | |
936 | } | |
937 | } | |
2f1e5e4d | 938 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
939 | |
940 | found: | |
941 | if (bud == FIRST) | |
942 | zhdr->first_chunks = chunks; | |
943 | else if (bud == LAST) | |
944 | zhdr->last_chunks = chunks; | |
945 | else { | |
946 | zhdr->middle_chunks = chunks; | |
ede93213 | 947 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
9a001fc1 | 948 | } |
9050cce1 | 949 | add_to_unbuddied(pool, zhdr); |
9a001fc1 VW |
950 | |
951 | headless: | |
d30561c5 | 952 | spin_lock(&pool->lock); |
9a001fc1 VW |
953 | /* Add/move z3fold page to beginning of LRU */ |
954 | if (!list_empty(&page->lru)) | |
955 | list_del(&page->lru); | |
956 | ||
957 | list_add(&page->lru, &pool->lru); | |
958 | ||
959 | *handle = encode_handle(zhdr, bud); | |
960 | spin_unlock(&pool->lock); | |
2f1e5e4d VW |
961 | if (bud != HEADLESS) |
962 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
963 | |
964 | return 0; | |
965 | } | |
966 | ||
967 | /** | |
968 | * z3fold_free() - frees the allocation associated with the given handle | |
969 | * @pool: pool in which the allocation resided | |
970 | * @handle: handle associated with the allocation returned by z3fold_alloc() | |
971 | * | |
972 | * In the case that the z3fold page in which the allocation resides is under | |
973 | * reclaim, as indicated by the PG_reclaim flag being set, this function | |
974 | * only sets the first|last_chunks to 0. The page is actually freed | |
975 | * once both buddies are evicted (see z3fold_reclaim_page() below). | |
976 | */ | |
977 | static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) | |
978 | { | |
979 | struct z3fold_header *zhdr; | |
9a001fc1 VW |
980 | struct page *page; |
981 | enum buddy bud; | |
982 | ||
9a001fc1 VW |
983 | zhdr = handle_to_z3fold_header(handle); |
984 | page = virt_to_page(zhdr); | |
985 | ||
986 | if (test_bit(PAGE_HEADLESS, &page->private)) { | |
ca0246bb VW |
987 | /* if a headless page is under reclaim, just leave. |
988 | * NB: we use test_and_set_bit for a reason: if the bit | |
989 | * has not been set before, we release this page | |
990 | * immediately so we don't care about its value any more. | |
991 | */ | |
992 | if (!test_and_set_bit(PAGE_CLAIMED, &page->private)) { | |
993 | spin_lock(&pool->lock); | |
994 | list_del(&page->lru); | |
995 | spin_unlock(&pool->lock); | |
1f862989 | 996 | free_z3fold_page(page, true); |
ca0246bb | 997 | atomic64_dec(&pool->pages_nr); |
9a001fc1 | 998 | } |
ca0246bb | 999 | return; |
9a001fc1 VW |
1000 | } |
1001 | ||
ca0246bb VW |
1002 | /* Non-headless case */ |
1003 | z3fold_page_lock(zhdr); | |
1004 | bud = handle_to_buddy(handle); | |
1005 | ||
1006 | switch (bud) { | |
1007 | case FIRST: | |
1008 | zhdr->first_chunks = 0; | |
1009 | break; | |
1010 | case MIDDLE: | |
1011 | zhdr->middle_chunks = 0; | |
1012 | break; | |
1013 | case LAST: | |
1014 | zhdr->last_chunks = 0; | |
1015 | break; | |
1016 | default: | |
1017 | pr_err("%s: unknown bud %d\n", __func__, bud); | |
1018 | WARN_ON(1); | |
1019 | z3fold_page_unlock(zhdr); | |
d30561c5 VW |
1020 | return; |
1021 | } | |
1022 | ||
7c2b8baa | 1023 | free_handle(handle); |
d30561c5 VW |
1024 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { |
1025 | atomic64_dec(&pool->pages_nr); | |
1026 | return; | |
1027 | } | |
ca0246bb | 1028 | if (test_bit(PAGE_CLAIMED, &page->private)) { |
6098d7e1 VW |
1029 | z3fold_page_unlock(zhdr); |
1030 | return; | |
1031 | } | |
1f862989 VW |
1032 | if (unlikely(PageIsolated(page)) || |
1033 | test_and_set_bit(NEEDS_COMPACTING, &page->private)) { | |
5a27aa82 | 1034 | z3fold_page_unlock(zhdr); |
d30561c5 VW |
1035 | return; |
1036 | } | |
1037 | if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { | |
2f1e5e4d | 1038 | spin_lock(&pool->lock); |
d30561c5 | 1039 | list_del_init(&zhdr->buddy); |
2f1e5e4d | 1040 | spin_unlock(&pool->lock); |
d30561c5 | 1041 | zhdr->cpu = -1; |
5d03a661 | 1042 | kref_get(&zhdr->refcount); |
d30561c5 VW |
1043 | do_compact_page(zhdr, true); |
1044 | return; | |
9a001fc1 | 1045 | } |
5d03a661 | 1046 | kref_get(&zhdr->refcount); |
d30561c5 VW |
1047 | queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); |
1048 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
1049 | } |
1050 | ||
1051 | /** | |
1052 | * z3fold_reclaim_page() - evicts allocations from a pool page and frees it | |
1053 | * @pool: pool from which a page will attempt to be evicted | |
f144c390 | 1054 | * @retries: number of pages on the LRU list for which eviction will |
9a001fc1 VW |
1055 | * be attempted before failing |
1056 | * | |
1057 | * z3fold reclaim is different from normal system reclaim in that it is done | |
1058 | * from the bottom, up. This is because only the bottom layer, z3fold, has | |
1059 | * information on how the allocations are organized within each z3fold page. | |
1060 | * This has the potential to create interesting locking situations between | |
1061 | * z3fold and the user, however. | |
1062 | * | |
1063 | * To avoid these, this is how z3fold_reclaim_page() should be called: | |
f144c390 | 1064 | * |
9a001fc1 VW |
1065 | * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). |
1066 | * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and | |
1067 | * call the user-defined eviction handler with the pool and handle as | |
1068 | * arguments. | |
1069 | * | |
1070 | * If the handle can not be evicted, the eviction handler should return | |
1071 | * non-zero. z3fold_reclaim_page() will add the z3fold page back to the | |
1072 | * appropriate list and try the next z3fold page on the LRU up to | |
1073 | * a user defined number of retries. | |
1074 | * | |
1075 | * If the handle is successfully evicted, the eviction handler should | |
1076 | * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() | |
1077 | * contains logic to delay freeing the page if the page is under reclaim, | |
1078 | * as indicated by the setting of the PG_reclaim flag on the underlying page. | |
1079 | * | |
1080 | * If all buddies in the z3fold page are successfully evicted, then the | |
1081 | * z3fold page can be freed. | |
1082 | * | |
1083 | * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are | |
1084 | * no pages to evict or an eviction handler is not registered, -EAGAIN if | |
1085 | * the retry limit was hit. | |
1086 | */ | |
1087 | static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) | |
1088 | { | |
d30561c5 VW |
1089 | int i, ret = 0; |
1090 | struct z3fold_header *zhdr = NULL; | |
1091 | struct page *page = NULL; | |
1092 | struct list_head *pos; | |
9a001fc1 VW |
1093 | unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; |
1094 | ||
1095 | spin_lock(&pool->lock); | |
2f1e5e4d | 1096 | if (!pool->ops || !pool->ops->evict || retries == 0) { |
9a001fc1 VW |
1097 | spin_unlock(&pool->lock); |
1098 | return -EINVAL; | |
1099 | } | |
1100 | for (i = 0; i < retries; i++) { | |
2f1e5e4d VW |
1101 | if (list_empty(&pool->lru)) { |
1102 | spin_unlock(&pool->lock); | |
1103 | return -EINVAL; | |
1104 | } | |
d30561c5 VW |
1105 | list_for_each_prev(pos, &pool->lru) { |
1106 | page = list_entry(pos, struct page, lru); | |
ca0246bb VW |
1107 | |
1108 | /* this bit could have been set by free, in which case | |
1109 | * we pass over to the next page in the pool. | |
1110 | */ | |
1111 | if (test_and_set_bit(PAGE_CLAIMED, &page->private)) | |
1112 | continue; | |
1113 | ||
1f862989 VW |
1114 | if (unlikely(PageIsolated(page))) |
1115 | continue; | |
d30561c5 | 1116 | if (test_bit(PAGE_HEADLESS, &page->private)) |
d30561c5 VW |
1117 | break; |
1118 | ||
1f862989 | 1119 | zhdr = page_address(page); |
ca0246bb VW |
1120 | if (!z3fold_page_trylock(zhdr)) { |
1121 | zhdr = NULL; | |
d30561c5 | 1122 | continue; /* can't evict at this point */ |
ca0246bb | 1123 | } |
d30561c5 VW |
1124 | kref_get(&zhdr->refcount); |
1125 | list_del_init(&zhdr->buddy); | |
1126 | zhdr->cpu = -1; | |
6098d7e1 | 1127 | break; |
d30561c5 VW |
1128 | } |
1129 | ||
ca0246bb VW |
1130 | if (!zhdr) |
1131 | break; | |
1132 | ||
5a27aa82 | 1133 | list_del_init(&page->lru); |
d30561c5 | 1134 | spin_unlock(&pool->lock); |
9a001fc1 | 1135 | |
9a001fc1 | 1136 | if (!test_bit(PAGE_HEADLESS, &page->private)) { |
9a001fc1 VW |
1137 | /* |
1138 | * We need encode the handles before unlocking, since | |
1139 | * we can race with free that will set | |
1140 | * (first|last)_chunks to 0 | |
1141 | */ | |
1142 | first_handle = 0; | |
1143 | last_handle = 0; | |
1144 | middle_handle = 0; | |
1145 | if (zhdr->first_chunks) | |
1146 | first_handle = encode_handle(zhdr, FIRST); | |
1147 | if (zhdr->middle_chunks) | |
1148 | middle_handle = encode_handle(zhdr, MIDDLE); | |
1149 | if (zhdr->last_chunks) | |
1150 | last_handle = encode_handle(zhdr, LAST); | |
d30561c5 VW |
1151 | /* |
1152 | * it's safe to unlock here because we hold a | |
1153 | * reference to this page | |
1154 | */ | |
2f1e5e4d | 1155 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
1156 | } else { |
1157 | first_handle = encode_handle(zhdr, HEADLESS); | |
1158 | last_handle = middle_handle = 0; | |
1159 | } | |
1160 | ||
9a001fc1 VW |
1161 | /* Issue the eviction callback(s) */ |
1162 | if (middle_handle) { | |
1163 | ret = pool->ops->evict(pool, middle_handle); | |
1164 | if (ret) | |
1165 | goto next; | |
1166 | } | |
1167 | if (first_handle) { | |
1168 | ret = pool->ops->evict(pool, first_handle); | |
1169 | if (ret) | |
1170 | goto next; | |
1171 | } | |
1172 | if (last_handle) { | |
1173 | ret = pool->ops->evict(pool, last_handle); | |
1174 | if (ret) | |
1175 | goto next; | |
1176 | } | |
1177 | next: | |
5a27aa82 VW |
1178 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
1179 | if (ret == 0) { | |
1f862989 | 1180 | free_z3fold_page(page, true); |
ca0246bb | 1181 | atomic64_dec(&pool->pages_nr); |
5a27aa82 | 1182 | return 0; |
5a27aa82 | 1183 | } |
6098d7e1 VW |
1184 | spin_lock(&pool->lock); |
1185 | list_add(&page->lru, &pool->lru); | |
1186 | spin_unlock(&pool->lock); | |
1187 | } else { | |
1188 | z3fold_page_lock(zhdr); | |
ca0246bb | 1189 | clear_bit(PAGE_CLAIMED, &page->private); |
6098d7e1 VW |
1190 | if (kref_put(&zhdr->refcount, |
1191 | release_z3fold_page_locked)) { | |
1192 | atomic64_dec(&pool->pages_nr); | |
1193 | return 0; | |
1194 | } | |
1195 | /* | |
1196 | * if we are here, the page is still not completely | |
1197 | * free. Take the global pool lock then to be able | |
1198 | * to add it back to the lru list | |
1199 | */ | |
1200 | spin_lock(&pool->lock); | |
1201 | list_add(&page->lru, &pool->lru); | |
d5567c9d | 1202 | spin_unlock(&pool->lock); |
6098d7e1 | 1203 | z3fold_page_unlock(zhdr); |
5a27aa82 | 1204 | } |
2f1e5e4d | 1205 | |
6098d7e1 VW |
1206 | /* We started off locked to we need to lock the pool back */ |
1207 | spin_lock(&pool->lock); | |
9a001fc1 VW |
1208 | } |
1209 | spin_unlock(&pool->lock); | |
1210 | return -EAGAIN; | |
1211 | } | |
1212 | ||
1213 | /** | |
1214 | * z3fold_map() - maps the allocation associated with the given handle | |
1215 | * @pool: pool in which the allocation resides | |
1216 | * @handle: handle associated with the allocation to be mapped | |
1217 | * | |
1218 | * Extracts the buddy number from handle and constructs the pointer to the | |
1219 | * correct starting chunk within the page. | |
1220 | * | |
1221 | * Returns: a pointer to the mapped allocation | |
1222 | */ | |
1223 | static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) | |
1224 | { | |
1225 | struct z3fold_header *zhdr; | |
1226 | struct page *page; | |
1227 | void *addr; | |
1228 | enum buddy buddy; | |
1229 | ||
9a001fc1 VW |
1230 | zhdr = handle_to_z3fold_header(handle); |
1231 | addr = zhdr; | |
1232 | page = virt_to_page(zhdr); | |
1233 | ||
1234 | if (test_bit(PAGE_HEADLESS, &page->private)) | |
1235 | goto out; | |
1236 | ||
2f1e5e4d | 1237 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1238 | buddy = handle_to_buddy(handle); |
1239 | switch (buddy) { | |
1240 | case FIRST: | |
1241 | addr += ZHDR_SIZE_ALIGNED; | |
1242 | break; | |
1243 | case MIDDLE: | |
1244 | addr += zhdr->start_middle << CHUNK_SHIFT; | |
1245 | set_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
1246 | break; | |
1247 | case LAST: | |
ca0246bb | 1248 | addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); |
9a001fc1 VW |
1249 | break; |
1250 | default: | |
1251 | pr_err("unknown buddy id %d\n", buddy); | |
1252 | WARN_ON(1); | |
1253 | addr = NULL; | |
1254 | break; | |
1255 | } | |
2f1e5e4d | 1256 | |
1f862989 VW |
1257 | if (addr) |
1258 | zhdr->mapped_count++; | |
2f1e5e4d | 1259 | z3fold_page_unlock(zhdr); |
9a001fc1 | 1260 | out: |
9a001fc1 VW |
1261 | return addr; |
1262 | } | |
1263 | ||
1264 | /** | |
1265 | * z3fold_unmap() - unmaps the allocation associated with the given handle | |
1266 | * @pool: pool in which the allocation resides | |
1267 | * @handle: handle associated with the allocation to be unmapped | |
1268 | */ | |
1269 | static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) | |
1270 | { | |
1271 | struct z3fold_header *zhdr; | |
1272 | struct page *page; | |
1273 | enum buddy buddy; | |
1274 | ||
9a001fc1 VW |
1275 | zhdr = handle_to_z3fold_header(handle); |
1276 | page = virt_to_page(zhdr); | |
1277 | ||
2f1e5e4d | 1278 | if (test_bit(PAGE_HEADLESS, &page->private)) |
9a001fc1 | 1279 | return; |
9a001fc1 | 1280 | |
2f1e5e4d | 1281 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1282 | buddy = handle_to_buddy(handle); |
1283 | if (buddy == MIDDLE) | |
1284 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
1f862989 | 1285 | zhdr->mapped_count--; |
2f1e5e4d | 1286 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
1287 | } |
1288 | ||
1289 | /** | |
1290 | * z3fold_get_pool_size() - gets the z3fold pool size in pages | |
1291 | * @pool: pool whose size is being queried | |
1292 | * | |
12d59ae6 | 1293 | * Returns: size in pages of the given pool. |
9a001fc1 VW |
1294 | */ |
1295 | static u64 z3fold_get_pool_size(struct z3fold_pool *pool) | |
1296 | { | |
12d59ae6 | 1297 | return atomic64_read(&pool->pages_nr); |
9a001fc1 VW |
1298 | } |
1299 | ||
1f862989 VW |
1300 | static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode) |
1301 | { | |
1302 | struct z3fold_header *zhdr; | |
1303 | struct z3fold_pool *pool; | |
1304 | ||
1305 | VM_BUG_ON_PAGE(!PageMovable(page), page); | |
1306 | VM_BUG_ON_PAGE(PageIsolated(page), page); | |
1307 | ||
1308 | if (test_bit(PAGE_HEADLESS, &page->private)) | |
1309 | return false; | |
1310 | ||
1311 | zhdr = page_address(page); | |
1312 | z3fold_page_lock(zhdr); | |
1313 | if (test_bit(NEEDS_COMPACTING, &page->private) || | |
1314 | test_bit(PAGE_STALE, &page->private)) | |
1315 | goto out; | |
1316 | ||
1317 | pool = zhdr_to_pool(zhdr); | |
1318 | ||
1319 | if (zhdr->mapped_count == 0) { | |
1320 | kref_get(&zhdr->refcount); | |
1321 | if (!list_empty(&zhdr->buddy)) | |
1322 | list_del_init(&zhdr->buddy); | |
1323 | spin_lock(&pool->lock); | |
1324 | if (!list_empty(&page->lru)) | |
1325 | list_del(&page->lru); | |
1326 | spin_unlock(&pool->lock); | |
1327 | z3fold_page_unlock(zhdr); | |
1328 | return true; | |
1329 | } | |
1330 | out: | |
1331 | z3fold_page_unlock(zhdr); | |
1332 | return false; | |
1333 | } | |
1334 | ||
1335 | static int z3fold_page_migrate(struct address_space *mapping, struct page *newpage, | |
1336 | struct page *page, enum migrate_mode mode) | |
1337 | { | |
1338 | struct z3fold_header *zhdr, *new_zhdr; | |
1339 | struct z3fold_pool *pool; | |
1340 | struct address_space *new_mapping; | |
1341 | ||
1342 | VM_BUG_ON_PAGE(!PageMovable(page), page); | |
1343 | VM_BUG_ON_PAGE(!PageIsolated(page), page); | |
810481a2 | 1344 | VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); |
1f862989 VW |
1345 | |
1346 | zhdr = page_address(page); | |
1347 | pool = zhdr_to_pool(zhdr); | |
1348 | ||
1f862989 | 1349 | if (!z3fold_page_trylock(zhdr)) { |
1f862989 VW |
1350 | return -EAGAIN; |
1351 | } | |
1352 | if (zhdr->mapped_count != 0) { | |
1353 | z3fold_page_unlock(zhdr); | |
1f862989 VW |
1354 | return -EBUSY; |
1355 | } | |
c92d2f38 HB |
1356 | if (work_pending(&zhdr->work)) { |
1357 | z3fold_page_unlock(zhdr); | |
1358 | return -EAGAIN; | |
1359 | } | |
1f862989 VW |
1360 | new_zhdr = page_address(newpage); |
1361 | memcpy(new_zhdr, zhdr, PAGE_SIZE); | |
1362 | newpage->private = page->private; | |
1363 | page->private = 0; | |
1364 | z3fold_page_unlock(zhdr); | |
1365 | spin_lock_init(&new_zhdr->page_lock); | |
c92d2f38 HB |
1366 | INIT_WORK(&new_zhdr->work, compact_page_work); |
1367 | /* | |
1368 | * z3fold_page_isolate() ensures that new_zhdr->buddy is empty, | |
1369 | * so we only have to reinitialize it. | |
1370 | */ | |
1371 | INIT_LIST_HEAD(&new_zhdr->buddy); | |
1f862989 VW |
1372 | new_mapping = page_mapping(page); |
1373 | __ClearPageMovable(page); | |
1374 | ClearPagePrivate(page); | |
1375 | ||
1376 | get_page(newpage); | |
1377 | z3fold_page_lock(new_zhdr); | |
1378 | if (new_zhdr->first_chunks) | |
1379 | encode_handle(new_zhdr, FIRST); | |
1380 | if (new_zhdr->last_chunks) | |
1381 | encode_handle(new_zhdr, LAST); | |
1382 | if (new_zhdr->middle_chunks) | |
1383 | encode_handle(new_zhdr, MIDDLE); | |
1384 | set_bit(NEEDS_COMPACTING, &newpage->private); | |
1385 | new_zhdr->cpu = smp_processor_id(); | |
1386 | spin_lock(&pool->lock); | |
1387 | list_add(&newpage->lru, &pool->lru); | |
1388 | spin_unlock(&pool->lock); | |
1389 | __SetPageMovable(newpage, new_mapping); | |
1390 | z3fold_page_unlock(new_zhdr); | |
1391 | ||
1392 | queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work); | |
1393 | ||
1394 | page_mapcount_reset(page); | |
1f862989 VW |
1395 | put_page(page); |
1396 | return 0; | |
1397 | } | |
1398 | ||
1399 | static void z3fold_page_putback(struct page *page) | |
1400 | { | |
1401 | struct z3fold_header *zhdr; | |
1402 | struct z3fold_pool *pool; | |
1403 | ||
1404 | zhdr = page_address(page); | |
1405 | pool = zhdr_to_pool(zhdr); | |
1406 | ||
1407 | z3fold_page_lock(zhdr); | |
1408 | if (!list_empty(&zhdr->buddy)) | |
1409 | list_del_init(&zhdr->buddy); | |
1410 | INIT_LIST_HEAD(&page->lru); | |
1411 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { | |
1412 | atomic64_dec(&pool->pages_nr); | |
1413 | return; | |
1414 | } | |
1415 | spin_lock(&pool->lock); | |
1416 | list_add(&page->lru, &pool->lru); | |
1417 | spin_unlock(&pool->lock); | |
1418 | z3fold_page_unlock(zhdr); | |
1419 | } | |
1420 | ||
1421 | static const struct address_space_operations z3fold_aops = { | |
1422 | .isolate_page = z3fold_page_isolate, | |
1423 | .migratepage = z3fold_page_migrate, | |
1424 | .putback_page = z3fold_page_putback, | |
1425 | }; | |
1426 | ||
9a001fc1 VW |
1427 | /***************** |
1428 | * zpool | |
1429 | ****************/ | |
1430 | ||
1431 | static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) | |
1432 | { | |
1433 | if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) | |
1434 | return pool->zpool_ops->evict(pool->zpool, handle); | |
1435 | else | |
1436 | return -ENOENT; | |
1437 | } | |
1438 | ||
1439 | static const struct z3fold_ops z3fold_zpool_ops = { | |
1440 | .evict = z3fold_zpool_evict | |
1441 | }; | |
1442 | ||
1443 | static void *z3fold_zpool_create(const char *name, gfp_t gfp, | |
1444 | const struct zpool_ops *zpool_ops, | |
1445 | struct zpool *zpool) | |
1446 | { | |
1447 | struct z3fold_pool *pool; | |
1448 | ||
d30561c5 VW |
1449 | pool = z3fold_create_pool(name, gfp, |
1450 | zpool_ops ? &z3fold_zpool_ops : NULL); | |
9a001fc1 VW |
1451 | if (pool) { |
1452 | pool->zpool = zpool; | |
1453 | pool->zpool_ops = zpool_ops; | |
1454 | } | |
1455 | return pool; | |
1456 | } | |
1457 | ||
1458 | static void z3fold_zpool_destroy(void *pool) | |
1459 | { | |
1460 | z3fold_destroy_pool(pool); | |
1461 | } | |
1462 | ||
1463 | static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
1464 | unsigned long *handle) | |
1465 | { | |
1466 | return z3fold_alloc(pool, size, gfp, handle); | |
1467 | } | |
1468 | static void z3fold_zpool_free(void *pool, unsigned long handle) | |
1469 | { | |
1470 | z3fold_free(pool, handle); | |
1471 | } | |
1472 | ||
1473 | static int z3fold_zpool_shrink(void *pool, unsigned int pages, | |
1474 | unsigned int *reclaimed) | |
1475 | { | |
1476 | unsigned int total = 0; | |
1477 | int ret = -EINVAL; | |
1478 | ||
1479 | while (total < pages) { | |
1480 | ret = z3fold_reclaim_page(pool, 8); | |
1481 | if (ret < 0) | |
1482 | break; | |
1483 | total++; | |
1484 | } | |
1485 | ||
1486 | if (reclaimed) | |
1487 | *reclaimed = total; | |
1488 | ||
1489 | return ret; | |
1490 | } | |
1491 | ||
1492 | static void *z3fold_zpool_map(void *pool, unsigned long handle, | |
1493 | enum zpool_mapmode mm) | |
1494 | { | |
1495 | return z3fold_map(pool, handle); | |
1496 | } | |
1497 | static void z3fold_zpool_unmap(void *pool, unsigned long handle) | |
1498 | { | |
1499 | z3fold_unmap(pool, handle); | |
1500 | } | |
1501 | ||
1502 | static u64 z3fold_zpool_total_size(void *pool) | |
1503 | { | |
1504 | return z3fold_get_pool_size(pool) * PAGE_SIZE; | |
1505 | } | |
1506 | ||
1507 | static struct zpool_driver z3fold_zpool_driver = { | |
1508 | .type = "z3fold", | |
1509 | .owner = THIS_MODULE, | |
1510 | .create = z3fold_zpool_create, | |
1511 | .destroy = z3fold_zpool_destroy, | |
1512 | .malloc = z3fold_zpool_malloc, | |
1513 | .free = z3fold_zpool_free, | |
1514 | .shrink = z3fold_zpool_shrink, | |
1515 | .map = z3fold_zpool_map, | |
1516 | .unmap = z3fold_zpool_unmap, | |
1517 | .total_size = z3fold_zpool_total_size, | |
1518 | }; | |
1519 | ||
1520 | MODULE_ALIAS("zpool-z3fold"); | |
1521 | ||
1522 | static int __init init_z3fold(void) | |
1523 | { | |
1f862989 VW |
1524 | int ret; |
1525 | ||
ede93213 VW |
1526 | /* Make sure the z3fold header is not larger than the page size */ |
1527 | BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); | |
1f862989 VW |
1528 | ret = z3fold_mount(); |
1529 | if (ret) | |
1530 | return ret; | |
1531 | ||
9a001fc1 VW |
1532 | zpool_register_driver(&z3fold_zpool_driver); |
1533 | ||
1534 | return 0; | |
1535 | } | |
1536 | ||
1537 | static void __exit exit_z3fold(void) | |
1538 | { | |
1f862989 | 1539 | z3fold_unmount(); |
9a001fc1 VW |
1540 | zpool_unregister_driver(&z3fold_zpool_driver); |
1541 | } | |
1542 | ||
1543 | module_init(init_z3fold); | |
1544 | module_exit(exit_z3fold); | |
1545 | ||
1546 | MODULE_LICENSE("GPL"); | |
1547 | MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); | |
1548 | MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); |