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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 | */ | |
3f9d2b57 VW |
369 | static unsigned long __encode_handle(struct z3fold_header *zhdr, |
370 | struct z3fold_buddy_slots *slots, | |
371 | enum buddy bud) | |
9a001fc1 | 372 | { |
7c2b8baa VW |
373 | unsigned long h = (unsigned long)zhdr; |
374 | int idx = 0; | |
9a001fc1 | 375 | |
7c2b8baa VW |
376 | /* |
377 | * For a headless page, its handle is its pointer with the extra | |
378 | * PAGE_HEADLESS bit set | |
379 | */ | |
380 | if (bud == HEADLESS) | |
381 | return h | (1 << PAGE_HEADLESS); | |
382 | ||
383 | /* otherwise, return pointer to encoded handle */ | |
384 | idx = __idx(zhdr, bud); | |
385 | h += idx; | |
386 | if (bud == LAST) | |
387 | h |= (zhdr->last_chunks << BUDDY_SHIFT); | |
388 | ||
7c2b8baa VW |
389 | slots->slot[idx] = h; |
390 | return (unsigned long)&slots->slot[idx]; | |
9a001fc1 VW |
391 | } |
392 | ||
3f9d2b57 VW |
393 | static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) |
394 | { | |
395 | return __encode_handle(zhdr, zhdr->slots, bud); | |
396 | } | |
397 | ||
9a001fc1 | 398 | /* Returns the z3fold page where a given handle is stored */ |
1f862989 | 399 | static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h) |
9a001fc1 | 400 | { |
1f862989 | 401 | unsigned long addr = h; |
7c2b8baa VW |
402 | |
403 | if (!(addr & (1 << PAGE_HEADLESS))) | |
1f862989 | 404 | addr = *(unsigned long *)h; |
7c2b8baa VW |
405 | |
406 | return (struct z3fold_header *)(addr & PAGE_MASK); | |
9a001fc1 VW |
407 | } |
408 | ||
ca0246bb VW |
409 | /* only for LAST bud, returns zero otherwise */ |
410 | static unsigned short handle_to_chunks(unsigned long handle) | |
411 | { | |
7c2b8baa VW |
412 | unsigned long addr = *(unsigned long *)handle; |
413 | ||
414 | return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; | |
ca0246bb VW |
415 | } |
416 | ||
f201ebd8 | 417 | /* |
418 | * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle | |
419 | * but that doesn't matter. because the masking will result in the | |
420 | * correct buddy number. | |
421 | */ | |
9a001fc1 VW |
422 | static enum buddy handle_to_buddy(unsigned long handle) |
423 | { | |
7c2b8baa VW |
424 | struct z3fold_header *zhdr; |
425 | unsigned long addr; | |
426 | ||
427 | WARN_ON(handle & (1 << PAGE_HEADLESS)); | |
428 | addr = *(unsigned long *)handle; | |
429 | zhdr = (struct z3fold_header *)(addr & PAGE_MASK); | |
430 | return (addr - zhdr->first_num) & BUDDY_MASK; | |
9a001fc1 VW |
431 | } |
432 | ||
9050cce1 VW |
433 | static inline struct z3fold_pool *zhdr_to_pool(struct z3fold_header *zhdr) |
434 | { | |
bb9a374d | 435 | return zhdr->pool; |
9050cce1 VW |
436 | } |
437 | ||
d30561c5 VW |
438 | static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) |
439 | { | |
440 | struct page *page = virt_to_page(zhdr); | |
9050cce1 | 441 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 VW |
442 | |
443 | WARN_ON(!list_empty(&zhdr->buddy)); | |
444 | set_bit(PAGE_STALE, &page->private); | |
35529357 | 445 | clear_bit(NEEDS_COMPACTING, &page->private); |
d30561c5 VW |
446 | spin_lock(&pool->lock); |
447 | if (!list_empty(&page->lru)) | |
1f862989 | 448 | list_del_init(&page->lru); |
d30561c5 VW |
449 | spin_unlock(&pool->lock); |
450 | if (locked) | |
451 | z3fold_page_unlock(zhdr); | |
452 | spin_lock(&pool->stale_lock); | |
453 | list_add(&zhdr->buddy, &pool->stale); | |
454 | queue_work(pool->release_wq, &pool->work); | |
455 | spin_unlock(&pool->stale_lock); | |
456 | } | |
457 | ||
458 | static void __attribute__((__unused__)) | |
459 | release_z3fold_page(struct kref *ref) | |
460 | { | |
461 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
462 | refcount); | |
463 | __release_z3fold_page(zhdr, false); | |
464 | } | |
465 | ||
466 | static void release_z3fold_page_locked(struct kref *ref) | |
467 | { | |
468 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
469 | refcount); | |
470 | WARN_ON(z3fold_page_trylock(zhdr)); | |
471 | __release_z3fold_page(zhdr, true); | |
472 | } | |
473 | ||
474 | static void release_z3fold_page_locked_list(struct kref *ref) | |
475 | { | |
476 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
477 | refcount); | |
9050cce1 VW |
478 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
479 | spin_lock(&pool->lock); | |
d30561c5 | 480 | list_del_init(&zhdr->buddy); |
9050cce1 | 481 | spin_unlock(&pool->lock); |
d30561c5 VW |
482 | |
483 | WARN_ON(z3fold_page_trylock(zhdr)); | |
484 | __release_z3fold_page(zhdr, true); | |
485 | } | |
486 | ||
487 | static void free_pages_work(struct work_struct *w) | |
488 | { | |
489 | struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); | |
490 | ||
491 | spin_lock(&pool->stale_lock); | |
492 | while (!list_empty(&pool->stale)) { | |
493 | struct z3fold_header *zhdr = list_first_entry(&pool->stale, | |
494 | struct z3fold_header, buddy); | |
495 | struct page *page = virt_to_page(zhdr); | |
496 | ||
497 | list_del(&zhdr->buddy); | |
498 | if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) | |
499 | continue; | |
d30561c5 VW |
500 | spin_unlock(&pool->stale_lock); |
501 | cancel_work_sync(&zhdr->work); | |
1f862989 | 502 | free_z3fold_page(page, false); |
d30561c5 VW |
503 | cond_resched(); |
504 | spin_lock(&pool->stale_lock); | |
505 | } | |
506 | spin_unlock(&pool->stale_lock); | |
507 | } | |
508 | ||
9a001fc1 VW |
509 | /* |
510 | * Returns the number of free chunks in a z3fold page. | |
511 | * NB: can't be used with HEADLESS pages. | |
512 | */ | |
513 | static int num_free_chunks(struct z3fold_header *zhdr) | |
514 | { | |
515 | int nfree; | |
516 | /* | |
517 | * If there is a middle object, pick up the bigger free space | |
518 | * either before or after it. Otherwise just subtract the number | |
519 | * of chunks occupied by the first and the last objects. | |
520 | */ | |
521 | if (zhdr->middle_chunks != 0) { | |
522 | int nfree_before = zhdr->first_chunks ? | |
ede93213 | 523 | 0 : zhdr->start_middle - ZHDR_CHUNKS; |
9a001fc1 | 524 | int nfree_after = zhdr->last_chunks ? |
ede93213 VW |
525 | 0 : TOTAL_CHUNKS - |
526 | (zhdr->start_middle + zhdr->middle_chunks); | |
9a001fc1 VW |
527 | nfree = max(nfree_before, nfree_after); |
528 | } else | |
529 | nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; | |
530 | return nfree; | |
531 | } | |
532 | ||
9050cce1 VW |
533 | /* Add to the appropriate unbuddied list */ |
534 | static inline void add_to_unbuddied(struct z3fold_pool *pool, | |
535 | struct z3fold_header *zhdr) | |
536 | { | |
537 | if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || | |
538 | zhdr->middle_chunks == 0) { | |
539 | struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied); | |
540 | ||
541 | int freechunks = num_free_chunks(zhdr); | |
542 | spin_lock(&pool->lock); | |
543 | list_add(&zhdr->buddy, &unbuddied[freechunks]); | |
544 | spin_unlock(&pool->lock); | |
545 | zhdr->cpu = smp_processor_id(); | |
546 | put_cpu_ptr(pool->unbuddied); | |
547 | } | |
548 | } | |
549 | ||
ede93213 VW |
550 | static inline void *mchunk_memmove(struct z3fold_header *zhdr, |
551 | unsigned short dst_chunk) | |
552 | { | |
553 | void *beg = zhdr; | |
554 | return memmove(beg + (dst_chunk << CHUNK_SHIFT), | |
555 | beg + (zhdr->start_middle << CHUNK_SHIFT), | |
556 | zhdr->middle_chunks << CHUNK_SHIFT); | |
557 | } | |
558 | ||
1b096e5a | 559 | #define BIG_CHUNK_GAP 3 |
9a001fc1 VW |
560 | /* Has to be called with lock held */ |
561 | static int z3fold_compact_page(struct z3fold_header *zhdr) | |
562 | { | |
563 | struct page *page = virt_to_page(zhdr); | |
9a001fc1 | 564 | |
ede93213 VW |
565 | if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) |
566 | return 0; /* can't move middle chunk, it's used */ | |
9a001fc1 | 567 | |
1f862989 VW |
568 | if (unlikely(PageIsolated(page))) |
569 | return 0; | |
570 | ||
ede93213 VW |
571 | if (zhdr->middle_chunks == 0) |
572 | return 0; /* nothing to compact */ | |
573 | ||
574 | if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { | |
575 | /* move to the beginning */ | |
576 | mchunk_memmove(zhdr, ZHDR_CHUNKS); | |
9a001fc1 VW |
577 | zhdr->first_chunks = zhdr->middle_chunks; |
578 | zhdr->middle_chunks = 0; | |
579 | zhdr->start_middle = 0; | |
580 | zhdr->first_num++; | |
1b096e5a | 581 | return 1; |
9a001fc1 | 582 | } |
1b096e5a VW |
583 | |
584 | /* | |
585 | * moving data is expensive, so let's only do that if | |
586 | * there's substantial gain (at least BIG_CHUNK_GAP chunks) | |
587 | */ | |
588 | if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && | |
589 | zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= | |
590 | BIG_CHUNK_GAP) { | |
591 | mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); | |
592 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; | |
593 | return 1; | |
594 | } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && | |
595 | TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle | |
596 | + zhdr->middle_chunks) >= | |
597 | BIG_CHUNK_GAP) { | |
598 | unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - | |
599 | zhdr->middle_chunks; | |
600 | mchunk_memmove(zhdr, new_start); | |
601 | zhdr->start_middle = new_start; | |
602 | return 1; | |
603 | } | |
604 | ||
605 | return 0; | |
9a001fc1 VW |
606 | } |
607 | ||
d30561c5 VW |
608 | static void do_compact_page(struct z3fold_header *zhdr, bool locked) |
609 | { | |
9050cce1 | 610 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 | 611 | struct page *page; |
d30561c5 VW |
612 | |
613 | page = virt_to_page(zhdr); | |
614 | if (locked) | |
615 | WARN_ON(z3fold_page_trylock(zhdr)); | |
616 | else | |
617 | z3fold_page_lock(zhdr); | |
5d03a661 | 618 | if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { |
d30561c5 VW |
619 | z3fold_page_unlock(zhdr); |
620 | return; | |
621 | } | |
622 | spin_lock(&pool->lock); | |
623 | list_del_init(&zhdr->buddy); | |
624 | spin_unlock(&pool->lock); | |
625 | ||
5d03a661 VW |
626 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { |
627 | atomic64_dec(&pool->pages_nr); | |
628 | return; | |
629 | } | |
630 | ||
1f862989 | 631 | if (unlikely(PageIsolated(page) || |
3f9d2b57 | 632 | test_bit(PAGE_CLAIMED, &page->private) || |
1f862989 VW |
633 | test_bit(PAGE_STALE, &page->private))) { |
634 | z3fold_page_unlock(zhdr); | |
635 | return; | |
636 | } | |
637 | ||
d30561c5 | 638 | z3fold_compact_page(zhdr); |
9050cce1 | 639 | add_to_unbuddied(pool, zhdr); |
d30561c5 VW |
640 | z3fold_page_unlock(zhdr); |
641 | } | |
642 | ||
643 | static void compact_page_work(struct work_struct *w) | |
644 | { | |
645 | struct z3fold_header *zhdr = container_of(w, struct z3fold_header, | |
646 | work); | |
647 | ||
648 | do_compact_page(zhdr, false); | |
649 | } | |
650 | ||
9050cce1 VW |
651 | /* returns _locked_ z3fold page header or NULL */ |
652 | static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, | |
653 | size_t size, bool can_sleep) | |
654 | { | |
655 | struct z3fold_header *zhdr = NULL; | |
656 | struct page *page; | |
657 | struct list_head *unbuddied; | |
658 | int chunks = size_to_chunks(size), i; | |
659 | ||
660 | lookup: | |
661 | /* First, try to find an unbuddied z3fold page. */ | |
662 | unbuddied = get_cpu_ptr(pool->unbuddied); | |
663 | for_each_unbuddied_list(i, chunks) { | |
664 | struct list_head *l = &unbuddied[i]; | |
665 | ||
666 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
667 | struct z3fold_header, buddy); | |
668 | ||
669 | if (!zhdr) | |
670 | continue; | |
671 | ||
672 | /* Re-check under lock. */ | |
673 | spin_lock(&pool->lock); | |
674 | l = &unbuddied[i]; | |
675 | if (unlikely(zhdr != list_first_entry(READ_ONCE(l), | |
676 | struct z3fold_header, buddy)) || | |
677 | !z3fold_page_trylock(zhdr)) { | |
678 | spin_unlock(&pool->lock); | |
679 | zhdr = NULL; | |
680 | put_cpu_ptr(pool->unbuddied); | |
681 | if (can_sleep) | |
682 | cond_resched(); | |
683 | goto lookup; | |
684 | } | |
685 | list_del_init(&zhdr->buddy); | |
686 | zhdr->cpu = -1; | |
687 | spin_unlock(&pool->lock); | |
688 | ||
689 | page = virt_to_page(zhdr); | |
690 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
691 | z3fold_page_unlock(zhdr); | |
692 | zhdr = NULL; | |
693 | put_cpu_ptr(pool->unbuddied); | |
694 | if (can_sleep) | |
695 | cond_resched(); | |
696 | goto lookup; | |
697 | } | |
698 | ||
699 | /* | |
700 | * this page could not be removed from its unbuddied | |
701 | * list while pool lock was held, and then we've taken | |
702 | * page lock so kref_put could not be called before | |
703 | * we got here, so it's safe to just call kref_get() | |
704 | */ | |
705 | kref_get(&zhdr->refcount); | |
706 | break; | |
707 | } | |
708 | put_cpu_ptr(pool->unbuddied); | |
709 | ||
351618b2 VW |
710 | if (!zhdr) { |
711 | int cpu; | |
712 | ||
713 | /* look for _exact_ match on other cpus' lists */ | |
714 | for_each_online_cpu(cpu) { | |
715 | struct list_head *l; | |
716 | ||
717 | unbuddied = per_cpu_ptr(pool->unbuddied, cpu); | |
718 | spin_lock(&pool->lock); | |
719 | l = &unbuddied[chunks]; | |
720 | ||
721 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
722 | struct z3fold_header, buddy); | |
723 | ||
724 | if (!zhdr || !z3fold_page_trylock(zhdr)) { | |
725 | spin_unlock(&pool->lock); | |
726 | zhdr = NULL; | |
727 | continue; | |
728 | } | |
729 | list_del_init(&zhdr->buddy); | |
730 | zhdr->cpu = -1; | |
731 | spin_unlock(&pool->lock); | |
732 | ||
733 | page = virt_to_page(zhdr); | |
734 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
735 | z3fold_page_unlock(zhdr); | |
736 | zhdr = NULL; | |
737 | if (can_sleep) | |
738 | cond_resched(); | |
739 | continue; | |
740 | } | |
741 | kref_get(&zhdr->refcount); | |
742 | break; | |
743 | } | |
744 | } | |
745 | ||
9050cce1 VW |
746 | return zhdr; |
747 | } | |
d30561c5 VW |
748 | |
749 | /* | |
750 | * API Functions | |
751 | */ | |
752 | ||
753 | /** | |
754 | * z3fold_create_pool() - create a new z3fold pool | |
755 | * @name: pool name | |
756 | * @gfp: gfp flags when allocating the z3fold pool structure | |
757 | * @ops: user-defined operations for the z3fold pool | |
758 | * | |
759 | * Return: pointer to the new z3fold pool or NULL if the metadata allocation | |
760 | * failed. | |
761 | */ | |
762 | static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, | |
763 | const struct z3fold_ops *ops) | |
764 | { | |
765 | struct z3fold_pool *pool = NULL; | |
766 | int i, cpu; | |
767 | ||
768 | pool = kzalloc(sizeof(struct z3fold_pool), gfp); | |
769 | if (!pool) | |
770 | goto out; | |
7c2b8baa VW |
771 | pool->c_handle = kmem_cache_create("z3fold_handle", |
772 | sizeof(struct z3fold_buddy_slots), | |
773 | SLOTS_ALIGN, 0, NULL); | |
774 | if (!pool->c_handle) | |
775 | goto out_c; | |
d30561c5 VW |
776 | spin_lock_init(&pool->lock); |
777 | spin_lock_init(&pool->stale_lock); | |
778 | pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2); | |
1ec6995d XW |
779 | if (!pool->unbuddied) |
780 | goto out_pool; | |
d30561c5 VW |
781 | for_each_possible_cpu(cpu) { |
782 | struct list_head *unbuddied = | |
783 | per_cpu_ptr(pool->unbuddied, cpu); | |
784 | for_each_unbuddied_list(i, 0) | |
785 | INIT_LIST_HEAD(&unbuddied[i]); | |
786 | } | |
787 | INIT_LIST_HEAD(&pool->lru); | |
788 | INIT_LIST_HEAD(&pool->stale); | |
789 | atomic64_set(&pool->pages_nr, 0); | |
790 | pool->name = name; | |
791 | pool->compact_wq = create_singlethread_workqueue(pool->name); | |
792 | if (!pool->compact_wq) | |
1ec6995d | 793 | goto out_unbuddied; |
d30561c5 VW |
794 | pool->release_wq = create_singlethread_workqueue(pool->name); |
795 | if (!pool->release_wq) | |
796 | goto out_wq; | |
1f862989 VW |
797 | if (z3fold_register_migration(pool)) |
798 | goto out_rwq; | |
d30561c5 VW |
799 | INIT_WORK(&pool->work, free_pages_work); |
800 | pool->ops = ops; | |
801 | return pool; | |
802 | ||
1f862989 VW |
803 | out_rwq: |
804 | destroy_workqueue(pool->release_wq); | |
d30561c5 VW |
805 | out_wq: |
806 | destroy_workqueue(pool->compact_wq); | |
1ec6995d XW |
807 | out_unbuddied: |
808 | free_percpu(pool->unbuddied); | |
809 | out_pool: | |
7c2b8baa VW |
810 | kmem_cache_destroy(pool->c_handle); |
811 | out_c: | |
d30561c5 | 812 | kfree(pool); |
1ec6995d | 813 | out: |
d30561c5 VW |
814 | return NULL; |
815 | } | |
816 | ||
817 | /** | |
818 | * z3fold_destroy_pool() - destroys an existing z3fold pool | |
819 | * @pool: the z3fold pool to be destroyed | |
820 | * | |
821 | * The pool should be emptied before this function is called. | |
822 | */ | |
823 | static void z3fold_destroy_pool(struct z3fold_pool *pool) | |
824 | { | |
7c2b8baa | 825 | kmem_cache_destroy(pool->c_handle); |
6051d3bd HB |
826 | |
827 | /* | |
828 | * We need to destroy pool->compact_wq before pool->release_wq, | |
829 | * as any pending work on pool->compact_wq will call | |
830 | * queue_work(pool->release_wq, &pool->work). | |
b997052b HB |
831 | * |
832 | * There are still outstanding pages until both workqueues are drained, | |
833 | * so we cannot unregister migration until then. | |
6051d3bd HB |
834 | */ |
835 | ||
d30561c5 | 836 | destroy_workqueue(pool->compact_wq); |
6051d3bd | 837 | destroy_workqueue(pool->release_wq); |
b997052b | 838 | z3fold_unregister_migration(pool); |
d30561c5 VW |
839 | kfree(pool); |
840 | } | |
841 | ||
9a001fc1 VW |
842 | /** |
843 | * z3fold_alloc() - allocates a region of a given size | |
844 | * @pool: z3fold pool from which to allocate | |
845 | * @size: size in bytes of the desired allocation | |
846 | * @gfp: gfp flags used if the pool needs to grow | |
847 | * @handle: handle of the new allocation | |
848 | * | |
849 | * This function will attempt to find a free region in the pool large enough to | |
850 | * satisfy the allocation request. A search of the unbuddied lists is | |
851 | * performed first. If no suitable free region is found, then a new page is | |
852 | * allocated and added to the pool to satisfy the request. | |
853 | * | |
854 | * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used | |
855 | * as z3fold pool pages. | |
856 | * | |
857 | * Return: 0 if success and handle is set, otherwise -EINVAL if the size or | |
858 | * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate | |
859 | * a new page. | |
860 | */ | |
861 | static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, | |
862 | unsigned long *handle) | |
863 | { | |
9050cce1 | 864 | int chunks = size_to_chunks(size); |
9a001fc1 | 865 | struct z3fold_header *zhdr = NULL; |
d30561c5 | 866 | struct page *page = NULL; |
9a001fc1 | 867 | enum buddy bud; |
8a97ea54 | 868 | bool can_sleep = gfpflags_allow_blocking(gfp); |
9a001fc1 | 869 | |
f1549cb5 | 870 | if (!size) |
9a001fc1 VW |
871 | return -EINVAL; |
872 | ||
873 | if (size > PAGE_SIZE) | |
874 | return -ENOSPC; | |
875 | ||
876 | if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) | |
877 | bud = HEADLESS; | |
878 | else { | |
9050cce1 VW |
879 | retry: |
880 | zhdr = __z3fold_alloc(pool, size, can_sleep); | |
d30561c5 | 881 | if (zhdr) { |
2f1e5e4d VW |
882 | if (zhdr->first_chunks == 0) { |
883 | if (zhdr->middle_chunks != 0 && | |
884 | chunks >= zhdr->start_middle) | |
9a001fc1 | 885 | bud = LAST; |
2f1e5e4d VW |
886 | else |
887 | bud = FIRST; | |
888 | } else if (zhdr->last_chunks == 0) | |
889 | bud = LAST; | |
890 | else if (zhdr->middle_chunks == 0) | |
891 | bud = MIDDLE; | |
892 | else { | |
5a27aa82 | 893 | if (kref_put(&zhdr->refcount, |
d30561c5 | 894 | release_z3fold_page_locked)) |
5a27aa82 | 895 | atomic64_dec(&pool->pages_nr); |
d30561c5 VW |
896 | else |
897 | z3fold_page_unlock(zhdr); | |
2f1e5e4d VW |
898 | pr_err("No free chunks in unbuddied\n"); |
899 | WARN_ON(1); | |
9050cce1 | 900 | goto retry; |
9a001fc1 | 901 | } |
9050cce1 | 902 | page = virt_to_page(zhdr); |
2f1e5e4d | 903 | goto found; |
9a001fc1 VW |
904 | } |
905 | bud = FIRST; | |
9a001fc1 VW |
906 | } |
907 | ||
5c9bab59 VW |
908 | page = NULL; |
909 | if (can_sleep) { | |
910 | spin_lock(&pool->stale_lock); | |
911 | zhdr = list_first_entry_or_null(&pool->stale, | |
912 | struct z3fold_header, buddy); | |
913 | /* | |
914 | * Before allocating a page, let's see if we can take one from | |
915 | * the stale pages list. cancel_work_sync() can sleep so we | |
916 | * limit this case to the contexts where we can sleep | |
917 | */ | |
918 | if (zhdr) { | |
919 | list_del(&zhdr->buddy); | |
920 | spin_unlock(&pool->stale_lock); | |
d30561c5 | 921 | cancel_work_sync(&zhdr->work); |
5c9bab59 VW |
922 | page = virt_to_page(zhdr); |
923 | } else { | |
924 | spin_unlock(&pool->stale_lock); | |
925 | } | |
d30561c5 | 926 | } |
5c9bab59 VW |
927 | if (!page) |
928 | page = alloc_page(gfp); | |
d30561c5 | 929 | |
9a001fc1 VW |
930 | if (!page) |
931 | return -ENOMEM; | |
2f1e5e4d | 932 | |
bb9f6f63 | 933 | zhdr = init_z3fold_page(page, pool, gfp); |
9050cce1 VW |
934 | if (!zhdr) { |
935 | __free_page(page); | |
936 | return -ENOMEM; | |
937 | } | |
938 | atomic64_inc(&pool->pages_nr); | |
9a001fc1 VW |
939 | |
940 | if (bud == HEADLESS) { | |
941 | set_bit(PAGE_HEADLESS, &page->private); | |
942 | goto headless; | |
943 | } | |
810481a2 HB |
944 | if (can_sleep) { |
945 | lock_page(page); | |
946 | __SetPageMovable(page, pool->inode->i_mapping); | |
947 | unlock_page(page); | |
948 | } else { | |
949 | if (trylock_page(page)) { | |
950 | __SetPageMovable(page, pool->inode->i_mapping); | |
951 | unlock_page(page); | |
952 | } | |
953 | } | |
2f1e5e4d | 954 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
955 | |
956 | found: | |
957 | if (bud == FIRST) | |
958 | zhdr->first_chunks = chunks; | |
959 | else if (bud == LAST) | |
960 | zhdr->last_chunks = chunks; | |
961 | else { | |
962 | zhdr->middle_chunks = chunks; | |
ede93213 | 963 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
9a001fc1 | 964 | } |
9050cce1 | 965 | add_to_unbuddied(pool, zhdr); |
9a001fc1 VW |
966 | |
967 | headless: | |
d30561c5 | 968 | spin_lock(&pool->lock); |
9a001fc1 VW |
969 | /* Add/move z3fold page to beginning of LRU */ |
970 | if (!list_empty(&page->lru)) | |
971 | list_del(&page->lru); | |
972 | ||
973 | list_add(&page->lru, &pool->lru); | |
974 | ||
975 | *handle = encode_handle(zhdr, bud); | |
976 | spin_unlock(&pool->lock); | |
2f1e5e4d VW |
977 | if (bud != HEADLESS) |
978 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
979 | |
980 | return 0; | |
981 | } | |
982 | ||
983 | /** | |
984 | * z3fold_free() - frees the allocation associated with the given handle | |
985 | * @pool: pool in which the allocation resided | |
986 | * @handle: handle associated with the allocation returned by z3fold_alloc() | |
987 | * | |
988 | * In the case that the z3fold page in which the allocation resides is under | |
989 | * reclaim, as indicated by the PG_reclaim flag being set, this function | |
990 | * only sets the first|last_chunks to 0. The page is actually freed | |
991 | * once both buddies are evicted (see z3fold_reclaim_page() below). | |
992 | */ | |
993 | static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) | |
994 | { | |
995 | struct z3fold_header *zhdr; | |
9a001fc1 VW |
996 | struct page *page; |
997 | enum buddy bud; | |
998 | ||
9a001fc1 VW |
999 | zhdr = handle_to_z3fold_header(handle); |
1000 | page = virt_to_page(zhdr); | |
1001 | ||
1002 | if (test_bit(PAGE_HEADLESS, &page->private)) { | |
ca0246bb VW |
1003 | /* if a headless page is under reclaim, just leave. |
1004 | * NB: we use test_and_set_bit for a reason: if the bit | |
1005 | * has not been set before, we release this page | |
1006 | * immediately so we don't care about its value any more. | |
1007 | */ | |
1008 | if (!test_and_set_bit(PAGE_CLAIMED, &page->private)) { | |
1009 | spin_lock(&pool->lock); | |
1010 | list_del(&page->lru); | |
1011 | spin_unlock(&pool->lock); | |
1f862989 | 1012 | free_z3fold_page(page, true); |
ca0246bb | 1013 | atomic64_dec(&pool->pages_nr); |
9a001fc1 | 1014 | } |
ca0246bb | 1015 | return; |
9a001fc1 VW |
1016 | } |
1017 | ||
ca0246bb VW |
1018 | /* Non-headless case */ |
1019 | z3fold_page_lock(zhdr); | |
1020 | bud = handle_to_buddy(handle); | |
1021 | ||
1022 | switch (bud) { | |
1023 | case FIRST: | |
1024 | zhdr->first_chunks = 0; | |
1025 | break; | |
1026 | case MIDDLE: | |
1027 | zhdr->middle_chunks = 0; | |
1028 | break; | |
1029 | case LAST: | |
1030 | zhdr->last_chunks = 0; | |
1031 | break; | |
1032 | default: | |
1033 | pr_err("%s: unknown bud %d\n", __func__, bud); | |
1034 | WARN_ON(1); | |
1035 | z3fold_page_unlock(zhdr); | |
d30561c5 VW |
1036 | return; |
1037 | } | |
1038 | ||
7c2b8baa | 1039 | free_handle(handle); |
d30561c5 VW |
1040 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { |
1041 | atomic64_dec(&pool->pages_nr); | |
1042 | return; | |
1043 | } | |
ca0246bb | 1044 | if (test_bit(PAGE_CLAIMED, &page->private)) { |
6098d7e1 VW |
1045 | z3fold_page_unlock(zhdr); |
1046 | return; | |
1047 | } | |
1f862989 VW |
1048 | if (unlikely(PageIsolated(page)) || |
1049 | test_and_set_bit(NEEDS_COMPACTING, &page->private)) { | |
5a27aa82 | 1050 | z3fold_page_unlock(zhdr); |
d30561c5 VW |
1051 | return; |
1052 | } | |
1053 | if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { | |
2f1e5e4d | 1054 | spin_lock(&pool->lock); |
d30561c5 | 1055 | list_del_init(&zhdr->buddy); |
2f1e5e4d | 1056 | spin_unlock(&pool->lock); |
d30561c5 | 1057 | zhdr->cpu = -1; |
5d03a661 | 1058 | kref_get(&zhdr->refcount); |
d30561c5 VW |
1059 | do_compact_page(zhdr, true); |
1060 | return; | |
9a001fc1 | 1061 | } |
5d03a661 | 1062 | kref_get(&zhdr->refcount); |
d30561c5 VW |
1063 | queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); |
1064 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
1065 | } |
1066 | ||
1067 | /** | |
1068 | * z3fold_reclaim_page() - evicts allocations from a pool page and frees it | |
1069 | * @pool: pool from which a page will attempt to be evicted | |
f144c390 | 1070 | * @retries: number of pages on the LRU list for which eviction will |
9a001fc1 VW |
1071 | * be attempted before failing |
1072 | * | |
1073 | * z3fold reclaim is different from normal system reclaim in that it is done | |
1074 | * from the bottom, up. This is because only the bottom layer, z3fold, has | |
1075 | * information on how the allocations are organized within each z3fold page. | |
1076 | * This has the potential to create interesting locking situations between | |
1077 | * z3fold and the user, however. | |
1078 | * | |
1079 | * To avoid these, this is how z3fold_reclaim_page() should be called: | |
f144c390 | 1080 | * |
9a001fc1 VW |
1081 | * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). |
1082 | * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and | |
1083 | * call the user-defined eviction handler with the pool and handle as | |
1084 | * arguments. | |
1085 | * | |
1086 | * If the handle can not be evicted, the eviction handler should return | |
1087 | * non-zero. z3fold_reclaim_page() will add the z3fold page back to the | |
1088 | * appropriate list and try the next z3fold page on the LRU up to | |
1089 | * a user defined number of retries. | |
1090 | * | |
1091 | * If the handle is successfully evicted, the eviction handler should | |
1092 | * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() | |
1093 | * contains logic to delay freeing the page if the page is under reclaim, | |
1094 | * as indicated by the setting of the PG_reclaim flag on the underlying page. | |
1095 | * | |
1096 | * If all buddies in the z3fold page are successfully evicted, then the | |
1097 | * z3fold page can be freed. | |
1098 | * | |
1099 | * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are | |
1100 | * no pages to evict or an eviction handler is not registered, -EAGAIN if | |
1101 | * the retry limit was hit. | |
1102 | */ | |
1103 | static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) | |
1104 | { | |
d30561c5 VW |
1105 | int i, ret = 0; |
1106 | struct z3fold_header *zhdr = NULL; | |
1107 | struct page *page = NULL; | |
1108 | struct list_head *pos; | |
3f9d2b57 | 1109 | struct z3fold_buddy_slots slots; |
9a001fc1 VW |
1110 | unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; |
1111 | ||
1112 | spin_lock(&pool->lock); | |
2f1e5e4d | 1113 | if (!pool->ops || !pool->ops->evict || retries == 0) { |
9a001fc1 VW |
1114 | spin_unlock(&pool->lock); |
1115 | return -EINVAL; | |
1116 | } | |
1117 | for (i = 0; i < retries; i++) { | |
2f1e5e4d VW |
1118 | if (list_empty(&pool->lru)) { |
1119 | spin_unlock(&pool->lock); | |
1120 | return -EINVAL; | |
1121 | } | |
d30561c5 VW |
1122 | list_for_each_prev(pos, &pool->lru) { |
1123 | page = list_entry(pos, struct page, lru); | |
ca0246bb VW |
1124 | |
1125 | /* this bit could have been set by free, in which case | |
1126 | * we pass over to the next page in the pool. | |
1127 | */ | |
3f9d2b57 VW |
1128 | if (test_and_set_bit(PAGE_CLAIMED, &page->private)) { |
1129 | page = NULL; | |
ca0246bb | 1130 | continue; |
3f9d2b57 | 1131 | } |
ca0246bb | 1132 | |
3f9d2b57 VW |
1133 | if (unlikely(PageIsolated(page))) { |
1134 | clear_bit(PAGE_CLAIMED, &page->private); | |
1135 | page = NULL; | |
1f862989 | 1136 | continue; |
3f9d2b57 VW |
1137 | } |
1138 | zhdr = page_address(page); | |
d30561c5 | 1139 | if (test_bit(PAGE_HEADLESS, &page->private)) |
d30561c5 VW |
1140 | break; |
1141 | ||
ca0246bb | 1142 | if (!z3fold_page_trylock(zhdr)) { |
3f9d2b57 | 1143 | clear_bit(PAGE_CLAIMED, &page->private); |
ca0246bb | 1144 | zhdr = NULL; |
d30561c5 | 1145 | continue; /* can't evict at this point */ |
ca0246bb | 1146 | } |
d30561c5 VW |
1147 | kref_get(&zhdr->refcount); |
1148 | list_del_init(&zhdr->buddy); | |
1149 | zhdr->cpu = -1; | |
6098d7e1 | 1150 | break; |
d30561c5 VW |
1151 | } |
1152 | ||
ca0246bb VW |
1153 | if (!zhdr) |
1154 | break; | |
1155 | ||
5a27aa82 | 1156 | list_del_init(&page->lru); |
d30561c5 | 1157 | spin_unlock(&pool->lock); |
9a001fc1 | 1158 | |
9a001fc1 | 1159 | if (!test_bit(PAGE_HEADLESS, &page->private)) { |
9a001fc1 | 1160 | /* |
3f9d2b57 VW |
1161 | * We need encode the handles before unlocking, and |
1162 | * use our local slots structure because z3fold_free | |
1163 | * can zero out zhdr->slots and we can't do much | |
1164 | * about that | |
9a001fc1 VW |
1165 | */ |
1166 | first_handle = 0; | |
1167 | last_handle = 0; | |
1168 | middle_handle = 0; | |
1169 | if (zhdr->first_chunks) | |
3f9d2b57 VW |
1170 | first_handle = __encode_handle(zhdr, &slots, |
1171 | FIRST); | |
9a001fc1 | 1172 | if (zhdr->middle_chunks) |
3f9d2b57 VW |
1173 | middle_handle = __encode_handle(zhdr, &slots, |
1174 | MIDDLE); | |
9a001fc1 | 1175 | if (zhdr->last_chunks) |
3f9d2b57 VW |
1176 | last_handle = __encode_handle(zhdr, &slots, |
1177 | LAST); | |
d30561c5 VW |
1178 | /* |
1179 | * it's safe to unlock here because we hold a | |
1180 | * reference to this page | |
1181 | */ | |
2f1e5e4d | 1182 | z3fold_page_unlock(zhdr); |
9a001fc1 | 1183 | } else { |
3f9d2b57 | 1184 | first_handle = __encode_handle(zhdr, &slots, HEADLESS); |
9a001fc1 VW |
1185 | last_handle = middle_handle = 0; |
1186 | } | |
1187 | ||
9a001fc1 VW |
1188 | /* Issue the eviction callback(s) */ |
1189 | if (middle_handle) { | |
1190 | ret = pool->ops->evict(pool, middle_handle); | |
1191 | if (ret) | |
1192 | goto next; | |
1193 | } | |
1194 | if (first_handle) { | |
1195 | ret = pool->ops->evict(pool, first_handle); | |
1196 | if (ret) | |
1197 | goto next; | |
1198 | } | |
1199 | if (last_handle) { | |
1200 | ret = pool->ops->evict(pool, last_handle); | |
1201 | if (ret) | |
1202 | goto next; | |
1203 | } | |
1204 | next: | |
5a27aa82 VW |
1205 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
1206 | if (ret == 0) { | |
1f862989 | 1207 | free_z3fold_page(page, true); |
ca0246bb | 1208 | atomic64_dec(&pool->pages_nr); |
5a27aa82 | 1209 | return 0; |
5a27aa82 | 1210 | } |
6098d7e1 VW |
1211 | spin_lock(&pool->lock); |
1212 | list_add(&page->lru, &pool->lru); | |
1213 | spin_unlock(&pool->lock); | |
3f9d2b57 | 1214 | clear_bit(PAGE_CLAIMED, &page->private); |
6098d7e1 VW |
1215 | } else { |
1216 | z3fold_page_lock(zhdr); | |
6098d7e1 VW |
1217 | if (kref_put(&zhdr->refcount, |
1218 | release_z3fold_page_locked)) { | |
1219 | atomic64_dec(&pool->pages_nr); | |
1220 | return 0; | |
1221 | } | |
1222 | /* | |
1223 | * if we are here, the page is still not completely | |
1224 | * free. Take the global pool lock then to be able | |
1225 | * to add it back to the lru list | |
1226 | */ | |
1227 | spin_lock(&pool->lock); | |
1228 | list_add(&page->lru, &pool->lru); | |
d5567c9d | 1229 | spin_unlock(&pool->lock); |
6098d7e1 | 1230 | z3fold_page_unlock(zhdr); |
3f9d2b57 | 1231 | clear_bit(PAGE_CLAIMED, &page->private); |
5a27aa82 | 1232 | } |
2f1e5e4d | 1233 | |
6098d7e1 VW |
1234 | /* We started off locked to we need to lock the pool back */ |
1235 | spin_lock(&pool->lock); | |
9a001fc1 VW |
1236 | } |
1237 | spin_unlock(&pool->lock); | |
1238 | return -EAGAIN; | |
1239 | } | |
1240 | ||
1241 | /** | |
1242 | * z3fold_map() - maps the allocation associated with the given handle | |
1243 | * @pool: pool in which the allocation resides | |
1244 | * @handle: handle associated with the allocation to be mapped | |
1245 | * | |
1246 | * Extracts the buddy number from handle and constructs the pointer to the | |
1247 | * correct starting chunk within the page. | |
1248 | * | |
1249 | * Returns: a pointer to the mapped allocation | |
1250 | */ | |
1251 | static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) | |
1252 | { | |
1253 | struct z3fold_header *zhdr; | |
1254 | struct page *page; | |
1255 | void *addr; | |
1256 | enum buddy buddy; | |
1257 | ||
9a001fc1 VW |
1258 | zhdr = handle_to_z3fold_header(handle); |
1259 | addr = zhdr; | |
1260 | page = virt_to_page(zhdr); | |
1261 | ||
1262 | if (test_bit(PAGE_HEADLESS, &page->private)) | |
1263 | goto out; | |
1264 | ||
2f1e5e4d | 1265 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1266 | buddy = handle_to_buddy(handle); |
1267 | switch (buddy) { | |
1268 | case FIRST: | |
1269 | addr += ZHDR_SIZE_ALIGNED; | |
1270 | break; | |
1271 | case MIDDLE: | |
1272 | addr += zhdr->start_middle << CHUNK_SHIFT; | |
1273 | set_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
1274 | break; | |
1275 | case LAST: | |
ca0246bb | 1276 | addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); |
9a001fc1 VW |
1277 | break; |
1278 | default: | |
1279 | pr_err("unknown buddy id %d\n", buddy); | |
1280 | WARN_ON(1); | |
1281 | addr = NULL; | |
1282 | break; | |
1283 | } | |
2f1e5e4d | 1284 | |
1f862989 VW |
1285 | if (addr) |
1286 | zhdr->mapped_count++; | |
2f1e5e4d | 1287 | z3fold_page_unlock(zhdr); |
9a001fc1 | 1288 | out: |
9a001fc1 VW |
1289 | return addr; |
1290 | } | |
1291 | ||
1292 | /** | |
1293 | * z3fold_unmap() - unmaps the allocation associated with the given handle | |
1294 | * @pool: pool in which the allocation resides | |
1295 | * @handle: handle associated with the allocation to be unmapped | |
1296 | */ | |
1297 | static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) | |
1298 | { | |
1299 | struct z3fold_header *zhdr; | |
1300 | struct page *page; | |
1301 | enum buddy buddy; | |
1302 | ||
9a001fc1 VW |
1303 | zhdr = handle_to_z3fold_header(handle); |
1304 | page = virt_to_page(zhdr); | |
1305 | ||
2f1e5e4d | 1306 | if (test_bit(PAGE_HEADLESS, &page->private)) |
9a001fc1 | 1307 | return; |
9a001fc1 | 1308 | |
2f1e5e4d | 1309 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1310 | buddy = handle_to_buddy(handle); |
1311 | if (buddy == MIDDLE) | |
1312 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
1f862989 | 1313 | zhdr->mapped_count--; |
2f1e5e4d | 1314 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
1315 | } |
1316 | ||
1317 | /** | |
1318 | * z3fold_get_pool_size() - gets the z3fold pool size in pages | |
1319 | * @pool: pool whose size is being queried | |
1320 | * | |
12d59ae6 | 1321 | * Returns: size in pages of the given pool. |
9a001fc1 VW |
1322 | */ |
1323 | static u64 z3fold_get_pool_size(struct z3fold_pool *pool) | |
1324 | { | |
12d59ae6 | 1325 | return atomic64_read(&pool->pages_nr); |
9a001fc1 VW |
1326 | } |
1327 | ||
1f862989 VW |
1328 | static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode) |
1329 | { | |
1330 | struct z3fold_header *zhdr; | |
1331 | struct z3fold_pool *pool; | |
1332 | ||
1333 | VM_BUG_ON_PAGE(!PageMovable(page), page); | |
1334 | VM_BUG_ON_PAGE(PageIsolated(page), page); | |
1335 | ||
3f9d2b57 VW |
1336 | if (test_bit(PAGE_HEADLESS, &page->private) || |
1337 | test_bit(PAGE_CLAIMED, &page->private)) | |
1f862989 VW |
1338 | return false; |
1339 | ||
1340 | zhdr = page_address(page); | |
1341 | z3fold_page_lock(zhdr); | |
1342 | if (test_bit(NEEDS_COMPACTING, &page->private) || | |
1343 | test_bit(PAGE_STALE, &page->private)) | |
1344 | goto out; | |
1345 | ||
1346 | pool = zhdr_to_pool(zhdr); | |
1347 | ||
1348 | if (zhdr->mapped_count == 0) { | |
1349 | kref_get(&zhdr->refcount); | |
1350 | if (!list_empty(&zhdr->buddy)) | |
1351 | list_del_init(&zhdr->buddy); | |
1352 | spin_lock(&pool->lock); | |
1353 | if (!list_empty(&page->lru)) | |
1354 | list_del(&page->lru); | |
1355 | spin_unlock(&pool->lock); | |
1356 | z3fold_page_unlock(zhdr); | |
1357 | return true; | |
1358 | } | |
1359 | out: | |
1360 | z3fold_page_unlock(zhdr); | |
1361 | return false; | |
1362 | } | |
1363 | ||
1364 | static int z3fold_page_migrate(struct address_space *mapping, struct page *newpage, | |
1365 | struct page *page, enum migrate_mode mode) | |
1366 | { | |
1367 | struct z3fold_header *zhdr, *new_zhdr; | |
1368 | struct z3fold_pool *pool; | |
1369 | struct address_space *new_mapping; | |
1370 | ||
1371 | VM_BUG_ON_PAGE(!PageMovable(page), page); | |
1372 | VM_BUG_ON_PAGE(!PageIsolated(page), page); | |
810481a2 | 1373 | VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); |
1f862989 VW |
1374 | |
1375 | zhdr = page_address(page); | |
1376 | pool = zhdr_to_pool(zhdr); | |
1377 | ||
1f862989 | 1378 | if (!z3fold_page_trylock(zhdr)) { |
1f862989 VW |
1379 | return -EAGAIN; |
1380 | } | |
1381 | if (zhdr->mapped_count != 0) { | |
1382 | z3fold_page_unlock(zhdr); | |
1f862989 VW |
1383 | return -EBUSY; |
1384 | } | |
c92d2f38 HB |
1385 | if (work_pending(&zhdr->work)) { |
1386 | z3fold_page_unlock(zhdr); | |
1387 | return -EAGAIN; | |
1388 | } | |
1f862989 VW |
1389 | new_zhdr = page_address(newpage); |
1390 | memcpy(new_zhdr, zhdr, PAGE_SIZE); | |
1391 | newpage->private = page->private; | |
1392 | page->private = 0; | |
1393 | z3fold_page_unlock(zhdr); | |
1394 | spin_lock_init(&new_zhdr->page_lock); | |
c92d2f38 HB |
1395 | INIT_WORK(&new_zhdr->work, compact_page_work); |
1396 | /* | |
1397 | * z3fold_page_isolate() ensures that new_zhdr->buddy is empty, | |
1398 | * so we only have to reinitialize it. | |
1399 | */ | |
1400 | INIT_LIST_HEAD(&new_zhdr->buddy); | |
1f862989 VW |
1401 | new_mapping = page_mapping(page); |
1402 | __ClearPageMovable(page); | |
1403 | ClearPagePrivate(page); | |
1404 | ||
1405 | get_page(newpage); | |
1406 | z3fold_page_lock(new_zhdr); | |
1407 | if (new_zhdr->first_chunks) | |
1408 | encode_handle(new_zhdr, FIRST); | |
1409 | if (new_zhdr->last_chunks) | |
1410 | encode_handle(new_zhdr, LAST); | |
1411 | if (new_zhdr->middle_chunks) | |
1412 | encode_handle(new_zhdr, MIDDLE); | |
1413 | set_bit(NEEDS_COMPACTING, &newpage->private); | |
1414 | new_zhdr->cpu = smp_processor_id(); | |
1415 | spin_lock(&pool->lock); | |
1416 | list_add(&newpage->lru, &pool->lru); | |
1417 | spin_unlock(&pool->lock); | |
1418 | __SetPageMovable(newpage, new_mapping); | |
1419 | z3fold_page_unlock(new_zhdr); | |
1420 | ||
1421 | queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work); | |
1422 | ||
1423 | page_mapcount_reset(page); | |
1f862989 VW |
1424 | put_page(page); |
1425 | return 0; | |
1426 | } | |
1427 | ||
1428 | static void z3fold_page_putback(struct page *page) | |
1429 | { | |
1430 | struct z3fold_header *zhdr; | |
1431 | struct z3fold_pool *pool; | |
1432 | ||
1433 | zhdr = page_address(page); | |
1434 | pool = zhdr_to_pool(zhdr); | |
1435 | ||
1436 | z3fold_page_lock(zhdr); | |
1437 | if (!list_empty(&zhdr->buddy)) | |
1438 | list_del_init(&zhdr->buddy); | |
1439 | INIT_LIST_HEAD(&page->lru); | |
1440 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { | |
1441 | atomic64_dec(&pool->pages_nr); | |
1442 | return; | |
1443 | } | |
1444 | spin_lock(&pool->lock); | |
1445 | list_add(&page->lru, &pool->lru); | |
1446 | spin_unlock(&pool->lock); | |
1447 | z3fold_page_unlock(zhdr); | |
1448 | } | |
1449 | ||
1450 | static const struct address_space_operations z3fold_aops = { | |
1451 | .isolate_page = z3fold_page_isolate, | |
1452 | .migratepage = z3fold_page_migrate, | |
1453 | .putback_page = z3fold_page_putback, | |
1454 | }; | |
1455 | ||
9a001fc1 VW |
1456 | /***************** |
1457 | * zpool | |
1458 | ****************/ | |
1459 | ||
1460 | static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) | |
1461 | { | |
1462 | if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) | |
1463 | return pool->zpool_ops->evict(pool->zpool, handle); | |
1464 | else | |
1465 | return -ENOENT; | |
1466 | } | |
1467 | ||
1468 | static const struct z3fold_ops z3fold_zpool_ops = { | |
1469 | .evict = z3fold_zpool_evict | |
1470 | }; | |
1471 | ||
1472 | static void *z3fold_zpool_create(const char *name, gfp_t gfp, | |
1473 | const struct zpool_ops *zpool_ops, | |
1474 | struct zpool *zpool) | |
1475 | { | |
1476 | struct z3fold_pool *pool; | |
1477 | ||
d30561c5 VW |
1478 | pool = z3fold_create_pool(name, gfp, |
1479 | zpool_ops ? &z3fold_zpool_ops : NULL); | |
9a001fc1 VW |
1480 | if (pool) { |
1481 | pool->zpool = zpool; | |
1482 | pool->zpool_ops = zpool_ops; | |
1483 | } | |
1484 | return pool; | |
1485 | } | |
1486 | ||
1487 | static void z3fold_zpool_destroy(void *pool) | |
1488 | { | |
1489 | z3fold_destroy_pool(pool); | |
1490 | } | |
1491 | ||
1492 | static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
1493 | unsigned long *handle) | |
1494 | { | |
1495 | return z3fold_alloc(pool, size, gfp, handle); | |
1496 | } | |
1497 | static void z3fold_zpool_free(void *pool, unsigned long handle) | |
1498 | { | |
1499 | z3fold_free(pool, handle); | |
1500 | } | |
1501 | ||
1502 | static int z3fold_zpool_shrink(void *pool, unsigned int pages, | |
1503 | unsigned int *reclaimed) | |
1504 | { | |
1505 | unsigned int total = 0; | |
1506 | int ret = -EINVAL; | |
1507 | ||
1508 | while (total < pages) { | |
1509 | ret = z3fold_reclaim_page(pool, 8); | |
1510 | if (ret < 0) | |
1511 | break; | |
1512 | total++; | |
1513 | } | |
1514 | ||
1515 | if (reclaimed) | |
1516 | *reclaimed = total; | |
1517 | ||
1518 | return ret; | |
1519 | } | |
1520 | ||
1521 | static void *z3fold_zpool_map(void *pool, unsigned long handle, | |
1522 | enum zpool_mapmode mm) | |
1523 | { | |
1524 | return z3fold_map(pool, handle); | |
1525 | } | |
1526 | static void z3fold_zpool_unmap(void *pool, unsigned long handle) | |
1527 | { | |
1528 | z3fold_unmap(pool, handle); | |
1529 | } | |
1530 | ||
1531 | static u64 z3fold_zpool_total_size(void *pool) | |
1532 | { | |
1533 | return z3fold_get_pool_size(pool) * PAGE_SIZE; | |
1534 | } | |
1535 | ||
1536 | static struct zpool_driver z3fold_zpool_driver = { | |
1537 | .type = "z3fold", | |
1538 | .owner = THIS_MODULE, | |
1539 | .create = z3fold_zpool_create, | |
1540 | .destroy = z3fold_zpool_destroy, | |
1541 | .malloc = z3fold_zpool_malloc, | |
1542 | .free = z3fold_zpool_free, | |
1543 | .shrink = z3fold_zpool_shrink, | |
1544 | .map = z3fold_zpool_map, | |
1545 | .unmap = z3fold_zpool_unmap, | |
1546 | .total_size = z3fold_zpool_total_size, | |
1547 | }; | |
1548 | ||
1549 | MODULE_ALIAS("zpool-z3fold"); | |
1550 | ||
1551 | static int __init init_z3fold(void) | |
1552 | { | |
1f862989 VW |
1553 | int ret; |
1554 | ||
ede93213 VW |
1555 | /* Make sure the z3fold header is not larger than the page size */ |
1556 | BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); | |
1f862989 VW |
1557 | ret = z3fold_mount(); |
1558 | if (ret) | |
1559 | return ret; | |
1560 | ||
9a001fc1 VW |
1561 | zpool_register_driver(&z3fold_zpool_driver); |
1562 | ||
1563 | return 0; | |
1564 | } | |
1565 | ||
1566 | static void __exit exit_z3fold(void) | |
1567 | { | |
1f862989 | 1568 | z3fold_unmount(); |
9a001fc1 VW |
1569 | zpool_unregister_driver(&z3fold_zpool_driver); |
1570 | } | |
1571 | ||
1572 | module_init(init_z3fold); | |
1573 | module_exit(exit_z3fold); | |
1574 | ||
1575 | MODULE_LICENSE("GPL"); | |
1576 | MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); | |
1577 | MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); |