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Commit | Line | Data |
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9a001fc1 VW |
1 | /* |
2 | * z3fold.c | |
3 | * | |
4 | * Author: Vitaly Wool <vitaly.wool@konsulko.com> | |
5 | * Copyright (C) 2016, Sony Mobile Communications Inc. | |
6 | * | |
7 | * This implementation is based on zbud written by Seth Jennings. | |
8 | * | |
9 | * z3fold is an special purpose allocator for storing compressed pages. It | |
10 | * can store up to three compressed pages per page which improves the | |
11 | * compression ratio of zbud while retaining its main concepts (e. g. always | |
12 | * storing an integral number of objects per page) and simplicity. | |
13 | * It still has simple and deterministic reclaim properties that make it | |
14 | * preferable to a higher density approach (with no requirement on integral | |
15 | * number of object per page) when reclaim is used. | |
16 | * | |
17 | * As in zbud, pages are divided into "chunks". The size of the chunks is | |
18 | * fixed at compile time and is determined by NCHUNKS_ORDER below. | |
19 | * | |
20 | * z3fold doesn't export any API and is meant to be used via zpool API. | |
21 | */ | |
22 | ||
23 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
24 | ||
25 | #include <linux/atomic.h> | |
d30561c5 | 26 | #include <linux/sched.h> |
9a001fc1 VW |
27 | #include <linux/list.h> |
28 | #include <linux/mm.h> | |
29 | #include <linux/module.h> | |
d30561c5 | 30 | #include <linux/percpu.h> |
9a001fc1 | 31 | #include <linux/preempt.h> |
d30561c5 | 32 | #include <linux/workqueue.h> |
9a001fc1 VW |
33 | #include <linux/slab.h> |
34 | #include <linux/spinlock.h> | |
35 | #include <linux/zpool.h> | |
36 | ||
37 | /***************** | |
38 | * Structures | |
39 | *****************/ | |
ede93213 VW |
40 | struct z3fold_pool; |
41 | struct z3fold_ops { | |
42 | int (*evict)(struct z3fold_pool *pool, unsigned long handle); | |
43 | }; | |
44 | ||
45 | enum buddy { | |
46 | HEADLESS = 0, | |
47 | FIRST, | |
48 | MIDDLE, | |
49 | LAST, | |
50 | BUDDIES_MAX | |
51 | }; | |
52 | ||
53 | /* | |
d30561c5 | 54 | * struct z3fold_header - z3fold page metadata occupying first chunks of each |
ede93213 | 55 | * z3fold page, except for HEADLESS pages |
d30561c5 VW |
56 | * @buddy: links the z3fold page into the relevant list in the |
57 | * pool | |
2f1e5e4d | 58 | * @page_lock: per-page lock |
d30561c5 VW |
59 | * @refcount: reference count for the z3fold page |
60 | * @work: work_struct for page layout optimization | |
61 | * @pool: pointer to the pool which this page belongs to | |
62 | * @cpu: CPU which this page "belongs" to | |
ede93213 VW |
63 | * @first_chunks: the size of the first buddy in chunks, 0 if free |
64 | * @middle_chunks: the size of the middle buddy in chunks, 0 if free | |
65 | * @last_chunks: the size of the last buddy in chunks, 0 if free | |
66 | * @first_num: the starting number (for the first handle) | |
67 | */ | |
68 | struct z3fold_header { | |
69 | struct list_head buddy; | |
2f1e5e4d | 70 | spinlock_t page_lock; |
5a27aa82 | 71 | struct kref refcount; |
d30561c5 VW |
72 | struct work_struct work; |
73 | struct z3fold_pool *pool; | |
74 | short cpu; | |
ede93213 VW |
75 | unsigned short first_chunks; |
76 | unsigned short middle_chunks; | |
77 | unsigned short last_chunks; | |
78 | unsigned short start_middle; | |
79 | unsigned short first_num:2; | |
80 | }; | |
81 | ||
9a001fc1 VW |
82 | /* |
83 | * NCHUNKS_ORDER determines the internal allocation granularity, effectively | |
84 | * adjusting internal fragmentation. It also determines the number of | |
85 | * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the | |
ede93213 VW |
86 | * allocation granularity will be in chunks of size PAGE_SIZE/64. Some chunks |
87 | * in the beginning of an allocated page are occupied by z3fold header, so | |
88 | * NCHUNKS will be calculated to 63 (or 62 in case CONFIG_DEBUG_SPINLOCK=y), | |
89 | * which shows the max number of free chunks in z3fold page, also there will | |
90 | * be 63, or 62, respectively, freelists per pool. | |
9a001fc1 VW |
91 | */ |
92 | #define NCHUNKS_ORDER 6 | |
93 | ||
94 | #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER) | |
95 | #define CHUNK_SIZE (1 << CHUNK_SHIFT) | |
ede93213 VW |
96 | #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE) |
97 | #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT) | |
98 | #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SHIFT) | |
9a001fc1 VW |
99 | #define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT) |
100 | ||
f201ebd8 | 101 | #define BUDDY_MASK (0x3) |
e28ae7aa | 102 | #define BUDDY_SHIFT 2 |
9a001fc1 | 103 | |
9a001fc1 VW |
104 | /** |
105 | * struct z3fold_pool - stores metadata for each z3fold pool | |
d30561c5 VW |
106 | * @name: pool name |
107 | * @lock: protects pool unbuddied/lru lists | |
108 | * @stale_lock: protects pool stale page list | |
109 | * @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2- | |
110 | * buddies; the list each z3fold page is added to depends on | |
111 | * the size of its free region. | |
9a001fc1 VW |
112 | * @lru: list tracking the z3fold pages in LRU order by most recently |
113 | * added buddy. | |
d30561c5 | 114 | * @stale: list of pages marked for freeing |
9a001fc1 VW |
115 | * @pages_nr: number of z3fold pages in the pool. |
116 | * @ops: pointer to a structure of user defined operations specified at | |
117 | * pool creation time. | |
d30561c5 VW |
118 | * @compact_wq: workqueue for page layout background optimization |
119 | * @release_wq: workqueue for safe page release | |
120 | * @work: work_struct for safe page release | |
9a001fc1 VW |
121 | * |
122 | * This structure is allocated at pool creation time and maintains metadata | |
123 | * pertaining to a particular z3fold pool. | |
124 | */ | |
125 | struct z3fold_pool { | |
d30561c5 | 126 | const char *name; |
9a001fc1 | 127 | spinlock_t lock; |
d30561c5 VW |
128 | spinlock_t stale_lock; |
129 | struct list_head *unbuddied; | |
9a001fc1 | 130 | struct list_head lru; |
d30561c5 | 131 | struct list_head stale; |
12d59ae6 | 132 | atomic64_t pages_nr; |
9a001fc1 VW |
133 | const struct z3fold_ops *ops; |
134 | struct zpool *zpool; | |
135 | const struct zpool_ops *zpool_ops; | |
d30561c5 VW |
136 | struct workqueue_struct *compact_wq; |
137 | struct workqueue_struct *release_wq; | |
138 | struct work_struct work; | |
9a001fc1 VW |
139 | }; |
140 | ||
9a001fc1 VW |
141 | /* |
142 | * Internal z3fold page flags | |
143 | */ | |
144 | enum z3fold_page_flags { | |
5a27aa82 | 145 | PAGE_HEADLESS = 0, |
9a001fc1 | 146 | MIDDLE_CHUNK_MAPPED, |
d30561c5 | 147 | NEEDS_COMPACTING, |
21fb6d8b | 148 | PAGE_STALE, |
e28ae7aa | 149 | PAGE_CLAIMED, /* by either reclaim or free */ |
9a001fc1 VW |
150 | }; |
151 | ||
152 | /***************** | |
153 | * Helpers | |
154 | *****************/ | |
155 | ||
156 | /* Converts an allocation size in bytes to size in z3fold chunks */ | |
157 | static int size_to_chunks(size_t size) | |
158 | { | |
159 | return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; | |
160 | } | |
161 | ||
162 | #define for_each_unbuddied_list(_iter, _begin) \ | |
163 | for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) | |
164 | ||
d30561c5 VW |
165 | static void compact_page_work(struct work_struct *w); |
166 | ||
9a001fc1 | 167 | /* Initializes the z3fold header of a newly allocated z3fold page */ |
d30561c5 VW |
168 | static struct z3fold_header *init_z3fold_page(struct page *page, |
169 | struct z3fold_pool *pool) | |
9a001fc1 VW |
170 | { |
171 | struct z3fold_header *zhdr = page_address(page); | |
172 | ||
173 | INIT_LIST_HEAD(&page->lru); | |
9a001fc1 VW |
174 | clear_bit(PAGE_HEADLESS, &page->private); |
175 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
d30561c5 VW |
176 | clear_bit(NEEDS_COMPACTING, &page->private); |
177 | clear_bit(PAGE_STALE, &page->private); | |
e28ae7aa | 178 | clear_bit(PAGE_CLAIMED, &page->private); |
9a001fc1 | 179 | |
2f1e5e4d | 180 | spin_lock_init(&zhdr->page_lock); |
5a27aa82 | 181 | kref_init(&zhdr->refcount); |
9a001fc1 VW |
182 | zhdr->first_chunks = 0; |
183 | zhdr->middle_chunks = 0; | |
184 | zhdr->last_chunks = 0; | |
185 | zhdr->first_num = 0; | |
186 | zhdr->start_middle = 0; | |
d30561c5 VW |
187 | zhdr->cpu = -1; |
188 | zhdr->pool = pool; | |
9a001fc1 | 189 | INIT_LIST_HEAD(&zhdr->buddy); |
d30561c5 | 190 | INIT_WORK(&zhdr->work, compact_page_work); |
9a001fc1 VW |
191 | return zhdr; |
192 | } | |
193 | ||
194 | /* Resets the struct page fields and frees the page */ | |
5a27aa82 | 195 | static void free_z3fold_page(struct page *page) |
9a001fc1 | 196 | { |
5a27aa82 VW |
197 | __free_page(page); |
198 | } | |
199 | ||
2f1e5e4d VW |
200 | /* Lock a z3fold page */ |
201 | static inline void z3fold_page_lock(struct z3fold_header *zhdr) | |
202 | { | |
203 | spin_lock(&zhdr->page_lock); | |
204 | } | |
205 | ||
76e32a2a VW |
206 | /* Try to lock a z3fold page */ |
207 | static inline int z3fold_page_trylock(struct z3fold_header *zhdr) | |
208 | { | |
209 | return spin_trylock(&zhdr->page_lock); | |
210 | } | |
211 | ||
2f1e5e4d VW |
212 | /* Unlock a z3fold page */ |
213 | static inline void z3fold_page_unlock(struct z3fold_header *zhdr) | |
214 | { | |
215 | spin_unlock(&zhdr->page_lock); | |
216 | } | |
217 | ||
9a001fc1 VW |
218 | /* |
219 | * Encodes the handle of a particular buddy within a z3fold page | |
220 | * Pool lock should be held as this function accesses first_num | |
221 | */ | |
222 | static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) | |
223 | { | |
224 | unsigned long handle; | |
225 | ||
226 | handle = (unsigned long)zhdr; | |
e28ae7aa VW |
227 | if (bud != HEADLESS) { |
228 | handle |= (bud + zhdr->first_num) & BUDDY_MASK; | |
229 | if (bud == LAST) | |
230 | handle |= (zhdr->last_chunks << BUDDY_SHIFT); | |
231 | } | |
9a001fc1 VW |
232 | return handle; |
233 | } | |
234 | ||
235 | /* Returns the z3fold page where a given handle is stored */ | |
236 | static struct z3fold_header *handle_to_z3fold_header(unsigned long handle) | |
237 | { | |
238 | return (struct z3fold_header *)(handle & PAGE_MASK); | |
239 | } | |
240 | ||
e28ae7aa VW |
241 | /* only for LAST bud, returns zero otherwise */ |
242 | static unsigned short handle_to_chunks(unsigned long handle) | |
243 | { | |
244 | return (handle & ~PAGE_MASK) >> BUDDY_SHIFT; | |
245 | } | |
246 | ||
f201ebd8 | 247 | /* |
248 | * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle | |
249 | * but that doesn't matter. because the masking will result in the | |
250 | * correct buddy number. | |
251 | */ | |
9a001fc1 VW |
252 | static enum buddy handle_to_buddy(unsigned long handle) |
253 | { | |
254 | struct z3fold_header *zhdr = handle_to_z3fold_header(handle); | |
255 | return (handle - zhdr->first_num) & BUDDY_MASK; | |
256 | } | |
257 | ||
d30561c5 VW |
258 | static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) |
259 | { | |
260 | struct page *page = virt_to_page(zhdr); | |
261 | struct z3fold_pool *pool = zhdr->pool; | |
262 | ||
263 | WARN_ON(!list_empty(&zhdr->buddy)); | |
264 | set_bit(PAGE_STALE, &page->private); | |
35529357 | 265 | clear_bit(NEEDS_COMPACTING, &page->private); |
d30561c5 VW |
266 | spin_lock(&pool->lock); |
267 | if (!list_empty(&page->lru)) | |
268 | list_del(&page->lru); | |
269 | spin_unlock(&pool->lock); | |
270 | if (locked) | |
271 | z3fold_page_unlock(zhdr); | |
272 | spin_lock(&pool->stale_lock); | |
273 | list_add(&zhdr->buddy, &pool->stale); | |
274 | queue_work(pool->release_wq, &pool->work); | |
275 | spin_unlock(&pool->stale_lock); | |
276 | } | |
277 | ||
278 | static void __attribute__((__unused__)) | |
279 | release_z3fold_page(struct kref *ref) | |
280 | { | |
281 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
282 | refcount); | |
283 | __release_z3fold_page(zhdr, false); | |
284 | } | |
285 | ||
286 | static void release_z3fold_page_locked(struct kref *ref) | |
287 | { | |
288 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
289 | refcount); | |
290 | WARN_ON(z3fold_page_trylock(zhdr)); | |
291 | __release_z3fold_page(zhdr, true); | |
292 | } | |
293 | ||
294 | static void release_z3fold_page_locked_list(struct kref *ref) | |
295 | { | |
296 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
297 | refcount); | |
298 | spin_lock(&zhdr->pool->lock); | |
299 | list_del_init(&zhdr->buddy); | |
300 | spin_unlock(&zhdr->pool->lock); | |
301 | ||
302 | WARN_ON(z3fold_page_trylock(zhdr)); | |
303 | __release_z3fold_page(zhdr, true); | |
304 | } | |
305 | ||
306 | static void free_pages_work(struct work_struct *w) | |
307 | { | |
308 | struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); | |
309 | ||
310 | spin_lock(&pool->stale_lock); | |
311 | while (!list_empty(&pool->stale)) { | |
312 | struct z3fold_header *zhdr = list_first_entry(&pool->stale, | |
313 | struct z3fold_header, buddy); | |
314 | struct page *page = virt_to_page(zhdr); | |
315 | ||
316 | list_del(&zhdr->buddy); | |
317 | if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) | |
318 | continue; | |
d30561c5 VW |
319 | spin_unlock(&pool->stale_lock); |
320 | cancel_work_sync(&zhdr->work); | |
321 | free_z3fold_page(page); | |
322 | cond_resched(); | |
323 | spin_lock(&pool->stale_lock); | |
324 | } | |
325 | spin_unlock(&pool->stale_lock); | |
326 | } | |
327 | ||
9a001fc1 VW |
328 | /* |
329 | * Returns the number of free chunks in a z3fold page. | |
330 | * NB: can't be used with HEADLESS pages. | |
331 | */ | |
332 | static int num_free_chunks(struct z3fold_header *zhdr) | |
333 | { | |
334 | int nfree; | |
335 | /* | |
336 | * If there is a middle object, pick up the bigger free space | |
337 | * either before or after it. Otherwise just subtract the number | |
338 | * of chunks occupied by the first and the last objects. | |
339 | */ | |
340 | if (zhdr->middle_chunks != 0) { | |
341 | int nfree_before = zhdr->first_chunks ? | |
ede93213 | 342 | 0 : zhdr->start_middle - ZHDR_CHUNKS; |
9a001fc1 | 343 | int nfree_after = zhdr->last_chunks ? |
ede93213 VW |
344 | 0 : TOTAL_CHUNKS - |
345 | (zhdr->start_middle + zhdr->middle_chunks); | |
9a001fc1 VW |
346 | nfree = max(nfree_before, nfree_after); |
347 | } else | |
348 | nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; | |
349 | return nfree; | |
350 | } | |
351 | ||
ede93213 VW |
352 | static inline void *mchunk_memmove(struct z3fold_header *zhdr, |
353 | unsigned short dst_chunk) | |
354 | { | |
355 | void *beg = zhdr; | |
356 | return memmove(beg + (dst_chunk << CHUNK_SHIFT), | |
357 | beg + (zhdr->start_middle << CHUNK_SHIFT), | |
358 | zhdr->middle_chunks << CHUNK_SHIFT); | |
359 | } | |
360 | ||
1b096e5a | 361 | #define BIG_CHUNK_GAP 3 |
9a001fc1 VW |
362 | /* Has to be called with lock held */ |
363 | static int z3fold_compact_page(struct z3fold_header *zhdr) | |
364 | { | |
365 | struct page *page = virt_to_page(zhdr); | |
9a001fc1 | 366 | |
ede93213 VW |
367 | if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) |
368 | return 0; /* can't move middle chunk, it's used */ | |
9a001fc1 | 369 | |
ede93213 VW |
370 | if (zhdr->middle_chunks == 0) |
371 | return 0; /* nothing to compact */ | |
372 | ||
373 | if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { | |
374 | /* move to the beginning */ | |
375 | mchunk_memmove(zhdr, ZHDR_CHUNKS); | |
9a001fc1 VW |
376 | zhdr->first_chunks = zhdr->middle_chunks; |
377 | zhdr->middle_chunks = 0; | |
378 | zhdr->start_middle = 0; | |
379 | zhdr->first_num++; | |
1b096e5a | 380 | return 1; |
9a001fc1 | 381 | } |
1b096e5a VW |
382 | |
383 | /* | |
384 | * moving data is expensive, so let's only do that if | |
385 | * there's substantial gain (at least BIG_CHUNK_GAP chunks) | |
386 | */ | |
387 | if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && | |
388 | zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= | |
389 | BIG_CHUNK_GAP) { | |
390 | mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); | |
391 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; | |
392 | return 1; | |
393 | } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && | |
394 | TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle | |
395 | + zhdr->middle_chunks) >= | |
396 | BIG_CHUNK_GAP) { | |
397 | unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - | |
398 | zhdr->middle_chunks; | |
399 | mchunk_memmove(zhdr, new_start); | |
400 | zhdr->start_middle = new_start; | |
401 | return 1; | |
402 | } | |
403 | ||
404 | return 0; | |
9a001fc1 VW |
405 | } |
406 | ||
d30561c5 VW |
407 | static void do_compact_page(struct z3fold_header *zhdr, bool locked) |
408 | { | |
409 | struct z3fold_pool *pool = zhdr->pool; | |
410 | struct page *page; | |
411 | struct list_head *unbuddied; | |
412 | int fchunks; | |
413 | ||
414 | page = virt_to_page(zhdr); | |
415 | if (locked) | |
416 | WARN_ON(z3fold_page_trylock(zhdr)); | |
417 | else | |
418 | z3fold_page_lock(zhdr); | |
c1a14af3 | 419 | if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { |
d30561c5 VW |
420 | z3fold_page_unlock(zhdr); |
421 | return; | |
422 | } | |
423 | spin_lock(&pool->lock); | |
424 | list_del_init(&zhdr->buddy); | |
425 | spin_unlock(&pool->lock); | |
426 | ||
c1a14af3 VW |
427 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { |
428 | atomic64_dec(&pool->pages_nr); | |
429 | return; | |
430 | } | |
431 | ||
d30561c5 VW |
432 | z3fold_compact_page(zhdr); |
433 | unbuddied = get_cpu_ptr(pool->unbuddied); | |
434 | fchunks = num_free_chunks(zhdr); | |
435 | if (fchunks < NCHUNKS && | |
436 | (!zhdr->first_chunks || !zhdr->middle_chunks || | |
437 | !zhdr->last_chunks)) { | |
438 | /* the page's not completely free and it's unbuddied */ | |
439 | spin_lock(&pool->lock); | |
440 | list_add(&zhdr->buddy, &unbuddied[fchunks]); | |
441 | spin_unlock(&pool->lock); | |
442 | zhdr->cpu = smp_processor_id(); | |
443 | } | |
444 | put_cpu_ptr(pool->unbuddied); | |
445 | z3fold_page_unlock(zhdr); | |
446 | } | |
447 | ||
448 | static void compact_page_work(struct work_struct *w) | |
449 | { | |
450 | struct z3fold_header *zhdr = container_of(w, struct z3fold_header, | |
451 | work); | |
452 | ||
453 | do_compact_page(zhdr, false); | |
454 | } | |
455 | ||
456 | ||
457 | /* | |
458 | * API Functions | |
459 | */ | |
460 | ||
461 | /** | |
462 | * z3fold_create_pool() - create a new z3fold pool | |
463 | * @name: pool name | |
464 | * @gfp: gfp flags when allocating the z3fold pool structure | |
465 | * @ops: user-defined operations for the z3fold pool | |
466 | * | |
467 | * Return: pointer to the new z3fold pool or NULL if the metadata allocation | |
468 | * failed. | |
469 | */ | |
470 | static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, | |
471 | const struct z3fold_ops *ops) | |
472 | { | |
473 | struct z3fold_pool *pool = NULL; | |
474 | int i, cpu; | |
475 | ||
476 | pool = kzalloc(sizeof(struct z3fold_pool), gfp); | |
477 | if (!pool) | |
478 | goto out; | |
479 | spin_lock_init(&pool->lock); | |
480 | spin_lock_init(&pool->stale_lock); | |
481 | pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2); | |
3a0de65a XW |
482 | if (!pool->unbuddied) |
483 | goto out_pool; | |
d30561c5 VW |
484 | for_each_possible_cpu(cpu) { |
485 | struct list_head *unbuddied = | |
486 | per_cpu_ptr(pool->unbuddied, cpu); | |
487 | for_each_unbuddied_list(i, 0) | |
488 | INIT_LIST_HEAD(&unbuddied[i]); | |
489 | } | |
490 | INIT_LIST_HEAD(&pool->lru); | |
491 | INIT_LIST_HEAD(&pool->stale); | |
492 | atomic64_set(&pool->pages_nr, 0); | |
493 | pool->name = name; | |
494 | pool->compact_wq = create_singlethread_workqueue(pool->name); | |
495 | if (!pool->compact_wq) | |
3a0de65a | 496 | goto out_unbuddied; |
d30561c5 VW |
497 | pool->release_wq = create_singlethread_workqueue(pool->name); |
498 | if (!pool->release_wq) | |
499 | goto out_wq; | |
500 | INIT_WORK(&pool->work, free_pages_work); | |
501 | pool->ops = ops; | |
502 | return pool; | |
503 | ||
504 | out_wq: | |
505 | destroy_workqueue(pool->compact_wq); | |
3a0de65a XW |
506 | out_unbuddied: |
507 | free_percpu(pool->unbuddied); | |
508 | out_pool: | |
d30561c5 | 509 | kfree(pool); |
3a0de65a | 510 | out: |
d30561c5 VW |
511 | return NULL; |
512 | } | |
513 | ||
514 | /** | |
515 | * z3fold_destroy_pool() - destroys an existing z3fold pool | |
516 | * @pool: the z3fold pool to be destroyed | |
517 | * | |
518 | * The pool should be emptied before this function is called. | |
519 | */ | |
520 | static void z3fold_destroy_pool(struct z3fold_pool *pool) | |
521 | { | |
522 | destroy_workqueue(pool->release_wq); | |
523 | destroy_workqueue(pool->compact_wq); | |
524 | kfree(pool); | |
525 | } | |
526 | ||
9a001fc1 VW |
527 | /** |
528 | * z3fold_alloc() - allocates a region of a given size | |
529 | * @pool: z3fold pool from which to allocate | |
530 | * @size: size in bytes of the desired allocation | |
531 | * @gfp: gfp flags used if the pool needs to grow | |
532 | * @handle: handle of the new allocation | |
533 | * | |
534 | * This function will attempt to find a free region in the pool large enough to | |
535 | * satisfy the allocation request. A search of the unbuddied lists is | |
536 | * performed first. If no suitable free region is found, then a new page is | |
537 | * allocated and added to the pool to satisfy the request. | |
538 | * | |
539 | * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used | |
540 | * as z3fold pool pages. | |
541 | * | |
542 | * Return: 0 if success and handle is set, otherwise -EINVAL if the size or | |
543 | * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate | |
544 | * a new page. | |
545 | */ | |
546 | static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, | |
547 | unsigned long *handle) | |
548 | { | |
549 | int chunks = 0, i, freechunks; | |
550 | struct z3fold_header *zhdr = NULL; | |
d30561c5 | 551 | struct page *page = NULL; |
9a001fc1 | 552 | enum buddy bud; |
d30561c5 | 553 | bool can_sleep = (gfp & __GFP_RECLAIM) == __GFP_RECLAIM; |
9a001fc1 VW |
554 | |
555 | if (!size || (gfp & __GFP_HIGHMEM)) | |
556 | return -EINVAL; | |
557 | ||
558 | if (size > PAGE_SIZE) | |
559 | return -ENOSPC; | |
560 | ||
561 | if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) | |
562 | bud = HEADLESS; | |
563 | else { | |
d30561c5 | 564 | struct list_head *unbuddied; |
9a001fc1 | 565 | chunks = size_to_chunks(size); |
9a001fc1 | 566 | |
d30561c5 | 567 | lookup: |
9a001fc1 | 568 | /* First, try to find an unbuddied z3fold page. */ |
d30561c5 | 569 | unbuddied = get_cpu_ptr(pool->unbuddied); |
9a001fc1 | 570 | for_each_unbuddied_list(i, chunks) { |
d30561c5 VW |
571 | struct list_head *l = &unbuddied[i]; |
572 | ||
573 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
9a001fc1 | 574 | struct z3fold_header, buddy); |
d30561c5 VW |
575 | |
576 | if (!zhdr) | |
2f1e5e4d | 577 | continue; |
d30561c5 VW |
578 | |
579 | /* Re-check under lock. */ | |
580 | spin_lock(&pool->lock); | |
581 | l = &unbuddied[i]; | |
582 | if (unlikely(zhdr != list_first_entry(READ_ONCE(l), | |
583 | struct z3fold_header, buddy)) || | |
584 | !z3fold_page_trylock(zhdr)) { | |
585 | spin_unlock(&pool->lock); | |
586 | put_cpu_ptr(pool->unbuddied); | |
587 | goto lookup; | |
2f1e5e4d VW |
588 | } |
589 | list_del_init(&zhdr->buddy); | |
d30561c5 | 590 | zhdr->cpu = -1; |
2f1e5e4d VW |
591 | spin_unlock(&pool->lock); |
592 | ||
593 | page = virt_to_page(zhdr); | |
d30561c5 VW |
594 | if (test_bit(NEEDS_COMPACTING, &page->private)) { |
595 | z3fold_page_unlock(zhdr); | |
596 | zhdr = NULL; | |
597 | put_cpu_ptr(pool->unbuddied); | |
598 | if (can_sleep) | |
599 | cond_resched(); | |
600 | goto lookup; | |
601 | } | |
602 | ||
603 | /* | |
604 | * this page could not be removed from its unbuddied | |
605 | * list while pool lock was held, and then we've taken | |
606 | * page lock so kref_put could not be called before | |
607 | * we got here, so it's safe to just call kref_get() | |
608 | */ | |
609 | kref_get(&zhdr->refcount); | |
610 | break; | |
611 | } | |
612 | put_cpu_ptr(pool->unbuddied); | |
613 | ||
614 | if (zhdr) { | |
2f1e5e4d VW |
615 | if (zhdr->first_chunks == 0) { |
616 | if (zhdr->middle_chunks != 0 && | |
617 | chunks >= zhdr->start_middle) | |
9a001fc1 | 618 | bud = LAST; |
2f1e5e4d VW |
619 | else |
620 | bud = FIRST; | |
621 | } else if (zhdr->last_chunks == 0) | |
622 | bud = LAST; | |
623 | else if (zhdr->middle_chunks == 0) | |
624 | bud = MIDDLE; | |
625 | else { | |
5a27aa82 | 626 | if (kref_put(&zhdr->refcount, |
d30561c5 | 627 | release_z3fold_page_locked)) |
5a27aa82 | 628 | atomic64_dec(&pool->pages_nr); |
d30561c5 VW |
629 | else |
630 | z3fold_page_unlock(zhdr); | |
2f1e5e4d VW |
631 | pr_err("No free chunks in unbuddied\n"); |
632 | WARN_ON(1); | |
d30561c5 | 633 | goto lookup; |
9a001fc1 | 634 | } |
2f1e5e4d | 635 | goto found; |
9a001fc1 VW |
636 | } |
637 | bud = FIRST; | |
9a001fc1 VW |
638 | } |
639 | ||
d30561c5 VW |
640 | spin_lock(&pool->stale_lock); |
641 | zhdr = list_first_entry_or_null(&pool->stale, | |
642 | struct z3fold_header, buddy); | |
643 | /* | |
644 | * Before allocating a page, let's see if we can take one from the | |
645 | * stale pages list. cancel_work_sync() can sleep so we must make | |
646 | * sure it won't be called in case we're in atomic context. | |
647 | */ | |
35529357 | 648 | if (zhdr && (can_sleep || !work_pending(&zhdr->work))) { |
d30561c5 | 649 | list_del(&zhdr->buddy); |
d30561c5 VW |
650 | spin_unlock(&pool->stale_lock); |
651 | if (can_sleep) | |
652 | cancel_work_sync(&zhdr->work); | |
653 | page = virt_to_page(zhdr); | |
654 | } else { | |
655 | spin_unlock(&pool->stale_lock); | |
656 | page = alloc_page(gfp); | |
657 | } | |
658 | ||
9a001fc1 VW |
659 | if (!page) |
660 | return -ENOMEM; | |
2f1e5e4d | 661 | |
12d59ae6 | 662 | atomic64_inc(&pool->pages_nr); |
d30561c5 | 663 | zhdr = init_z3fold_page(page, pool); |
9a001fc1 VW |
664 | |
665 | if (bud == HEADLESS) { | |
666 | set_bit(PAGE_HEADLESS, &page->private); | |
667 | goto headless; | |
668 | } | |
2f1e5e4d | 669 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
670 | |
671 | found: | |
672 | if (bud == FIRST) | |
673 | zhdr->first_chunks = chunks; | |
674 | else if (bud == LAST) | |
675 | zhdr->last_chunks = chunks; | |
676 | else { | |
677 | zhdr->middle_chunks = chunks; | |
ede93213 | 678 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
9a001fc1 VW |
679 | } |
680 | ||
681 | if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || | |
682 | zhdr->middle_chunks == 0) { | |
d30561c5 VW |
683 | struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied); |
684 | ||
9a001fc1 VW |
685 | /* Add to unbuddied list */ |
686 | freechunks = num_free_chunks(zhdr); | |
d30561c5 VW |
687 | spin_lock(&pool->lock); |
688 | list_add(&zhdr->buddy, &unbuddied[freechunks]); | |
689 | spin_unlock(&pool->lock); | |
690 | zhdr->cpu = smp_processor_id(); | |
691 | put_cpu_ptr(pool->unbuddied); | |
9a001fc1 VW |
692 | } |
693 | ||
694 | headless: | |
d30561c5 | 695 | spin_lock(&pool->lock); |
9a001fc1 VW |
696 | /* Add/move z3fold page to beginning of LRU */ |
697 | if (!list_empty(&page->lru)) | |
698 | list_del(&page->lru); | |
699 | ||
700 | list_add(&page->lru, &pool->lru); | |
701 | ||
702 | *handle = encode_handle(zhdr, bud); | |
703 | spin_unlock(&pool->lock); | |
2f1e5e4d VW |
704 | if (bud != HEADLESS) |
705 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
706 | |
707 | return 0; | |
708 | } | |
709 | ||
710 | /** | |
711 | * z3fold_free() - frees the allocation associated with the given handle | |
712 | * @pool: pool in which the allocation resided | |
713 | * @handle: handle associated with the allocation returned by z3fold_alloc() | |
714 | * | |
715 | * In the case that the z3fold page in which the allocation resides is under | |
716 | * reclaim, as indicated by the PG_reclaim flag being set, this function | |
717 | * only sets the first|last_chunks to 0. The page is actually freed | |
718 | * once both buddies are evicted (see z3fold_reclaim_page() below). | |
719 | */ | |
720 | static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) | |
721 | { | |
722 | struct z3fold_header *zhdr; | |
9a001fc1 VW |
723 | struct page *page; |
724 | enum buddy bud; | |
725 | ||
9a001fc1 VW |
726 | zhdr = handle_to_z3fold_header(handle); |
727 | page = virt_to_page(zhdr); | |
728 | ||
729 | if (test_bit(PAGE_HEADLESS, &page->private)) { | |
e28ae7aa VW |
730 | /* if a headless page is under reclaim, just leave. |
731 | * NB: we use test_and_set_bit for a reason: if the bit | |
732 | * has not been set before, we release this page | |
733 | * immediately so we don't care about its value any more. | |
734 | */ | |
735 | if (!test_and_set_bit(PAGE_CLAIMED, &page->private)) { | |
736 | spin_lock(&pool->lock); | |
737 | list_del(&page->lru); | |
738 | spin_unlock(&pool->lock); | |
739 | free_z3fold_page(page); | |
740 | atomic64_dec(&pool->pages_nr); | |
9a001fc1 | 741 | } |
e28ae7aa | 742 | return; |
9a001fc1 VW |
743 | } |
744 | ||
e28ae7aa VW |
745 | /* Non-headless case */ |
746 | z3fold_page_lock(zhdr); | |
747 | bud = handle_to_buddy(handle); | |
748 | ||
749 | switch (bud) { | |
750 | case FIRST: | |
751 | zhdr->first_chunks = 0; | |
752 | break; | |
753 | case MIDDLE: | |
754 | zhdr->middle_chunks = 0; | |
755 | break; | |
756 | case LAST: | |
757 | zhdr->last_chunks = 0; | |
758 | break; | |
759 | default: | |
760 | pr_err("%s: unknown bud %d\n", __func__, bud); | |
761 | WARN_ON(1); | |
762 | z3fold_page_unlock(zhdr); | |
d30561c5 VW |
763 | return; |
764 | } | |
765 | ||
766 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { | |
767 | atomic64_dec(&pool->pages_nr); | |
768 | return; | |
769 | } | |
e28ae7aa | 770 | if (test_bit(PAGE_CLAIMED, &page->private)) { |
21fb6d8b VW |
771 | z3fold_page_unlock(zhdr); |
772 | return; | |
773 | } | |
d30561c5 | 774 | if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) { |
5a27aa82 | 775 | z3fold_page_unlock(zhdr); |
d30561c5 VW |
776 | return; |
777 | } | |
778 | if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { | |
2f1e5e4d | 779 | spin_lock(&pool->lock); |
d30561c5 | 780 | list_del_init(&zhdr->buddy); |
2f1e5e4d | 781 | spin_unlock(&pool->lock); |
d30561c5 | 782 | zhdr->cpu = -1; |
c1a14af3 | 783 | kref_get(&zhdr->refcount); |
d30561c5 VW |
784 | do_compact_page(zhdr, true); |
785 | return; | |
9a001fc1 | 786 | } |
c1a14af3 | 787 | kref_get(&zhdr->refcount); |
d30561c5 VW |
788 | queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); |
789 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
790 | } |
791 | ||
792 | /** | |
793 | * z3fold_reclaim_page() - evicts allocations from a pool page and frees it | |
794 | * @pool: pool from which a page will attempt to be evicted | |
795 | * @retires: number of pages on the LRU list for which eviction will | |
796 | * be attempted before failing | |
797 | * | |
798 | * z3fold reclaim is different from normal system reclaim in that it is done | |
799 | * from the bottom, up. This is because only the bottom layer, z3fold, has | |
800 | * information on how the allocations are organized within each z3fold page. | |
801 | * This has the potential to create interesting locking situations between | |
802 | * z3fold and the user, however. | |
803 | * | |
804 | * To avoid these, this is how z3fold_reclaim_page() should be called: | |
805 | ||
806 | * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). | |
807 | * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and | |
808 | * call the user-defined eviction handler with the pool and handle as | |
809 | * arguments. | |
810 | * | |
811 | * If the handle can not be evicted, the eviction handler should return | |
812 | * non-zero. z3fold_reclaim_page() will add the z3fold page back to the | |
813 | * appropriate list and try the next z3fold page on the LRU up to | |
814 | * a user defined number of retries. | |
815 | * | |
816 | * If the handle is successfully evicted, the eviction handler should | |
817 | * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() | |
818 | * contains logic to delay freeing the page if the page is under reclaim, | |
819 | * as indicated by the setting of the PG_reclaim flag on the underlying page. | |
820 | * | |
821 | * If all buddies in the z3fold page are successfully evicted, then the | |
822 | * z3fold page can be freed. | |
823 | * | |
824 | * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are | |
825 | * no pages to evict or an eviction handler is not registered, -EAGAIN if | |
826 | * the retry limit was hit. | |
827 | */ | |
828 | static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) | |
829 | { | |
d30561c5 VW |
830 | int i, ret = 0; |
831 | struct z3fold_header *zhdr = NULL; | |
832 | struct page *page = NULL; | |
833 | struct list_head *pos; | |
9a001fc1 VW |
834 | unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; |
835 | ||
836 | spin_lock(&pool->lock); | |
2f1e5e4d | 837 | if (!pool->ops || !pool->ops->evict || retries == 0) { |
9a001fc1 VW |
838 | spin_unlock(&pool->lock); |
839 | return -EINVAL; | |
840 | } | |
841 | for (i = 0; i < retries; i++) { | |
2f1e5e4d VW |
842 | if (list_empty(&pool->lru)) { |
843 | spin_unlock(&pool->lock); | |
844 | return -EINVAL; | |
845 | } | |
d30561c5 VW |
846 | list_for_each_prev(pos, &pool->lru) { |
847 | page = list_entry(pos, struct page, lru); | |
e28ae7aa VW |
848 | |
849 | /* this bit could have been set by free, in which case | |
850 | * we pass over to the next page in the pool. | |
851 | */ | |
852 | if (test_and_set_bit(PAGE_CLAIMED, &page->private)) | |
853 | continue; | |
854 | ||
855 | zhdr = page_address(page); | |
d30561c5 | 856 | if (test_bit(PAGE_HEADLESS, &page->private)) |
d30561c5 VW |
857 | break; |
858 | ||
e28ae7aa VW |
859 | if (!z3fold_page_trylock(zhdr)) { |
860 | zhdr = NULL; | |
d30561c5 | 861 | continue; /* can't evict at this point */ |
e28ae7aa | 862 | } |
d30561c5 VW |
863 | kref_get(&zhdr->refcount); |
864 | list_del_init(&zhdr->buddy); | |
865 | zhdr->cpu = -1; | |
21fb6d8b | 866 | break; |
d30561c5 VW |
867 | } |
868 | ||
e28ae7aa VW |
869 | if (!zhdr) |
870 | break; | |
871 | ||
5a27aa82 | 872 | list_del_init(&page->lru); |
d30561c5 | 873 | spin_unlock(&pool->lock); |
9a001fc1 | 874 | |
9a001fc1 | 875 | if (!test_bit(PAGE_HEADLESS, &page->private)) { |
9a001fc1 VW |
876 | /* |
877 | * We need encode the handles before unlocking, since | |
878 | * we can race with free that will set | |
879 | * (first|last)_chunks to 0 | |
880 | */ | |
881 | first_handle = 0; | |
882 | last_handle = 0; | |
883 | middle_handle = 0; | |
884 | if (zhdr->first_chunks) | |
885 | first_handle = encode_handle(zhdr, FIRST); | |
886 | if (zhdr->middle_chunks) | |
887 | middle_handle = encode_handle(zhdr, MIDDLE); | |
888 | if (zhdr->last_chunks) | |
889 | last_handle = encode_handle(zhdr, LAST); | |
d30561c5 VW |
890 | /* |
891 | * it's safe to unlock here because we hold a | |
892 | * reference to this page | |
893 | */ | |
2f1e5e4d | 894 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
895 | } else { |
896 | first_handle = encode_handle(zhdr, HEADLESS); | |
897 | last_handle = middle_handle = 0; | |
898 | } | |
899 | ||
9a001fc1 VW |
900 | /* Issue the eviction callback(s) */ |
901 | if (middle_handle) { | |
902 | ret = pool->ops->evict(pool, middle_handle); | |
903 | if (ret) | |
904 | goto next; | |
905 | } | |
906 | if (first_handle) { | |
907 | ret = pool->ops->evict(pool, first_handle); | |
908 | if (ret) | |
909 | goto next; | |
910 | } | |
911 | if (last_handle) { | |
912 | ret = pool->ops->evict(pool, last_handle); | |
913 | if (ret) | |
914 | goto next; | |
915 | } | |
916 | next: | |
5a27aa82 VW |
917 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
918 | if (ret == 0) { | |
919 | free_z3fold_page(page); | |
e28ae7aa | 920 | atomic64_dec(&pool->pages_nr); |
5a27aa82 | 921 | return 0; |
5a27aa82 | 922 | } |
21fb6d8b VW |
923 | spin_lock(&pool->lock); |
924 | list_add(&page->lru, &pool->lru); | |
925 | spin_unlock(&pool->lock); | |
926 | } else { | |
927 | z3fold_page_lock(zhdr); | |
e28ae7aa | 928 | clear_bit(PAGE_CLAIMED, &page->private); |
21fb6d8b VW |
929 | if (kref_put(&zhdr->refcount, |
930 | release_z3fold_page_locked)) { | |
931 | atomic64_dec(&pool->pages_nr); | |
932 | return 0; | |
933 | } | |
934 | /* | |
935 | * if we are here, the page is still not completely | |
936 | * free. Take the global pool lock then to be able | |
937 | * to add it back to the lru list | |
938 | */ | |
939 | spin_lock(&pool->lock); | |
940 | list_add(&page->lru, &pool->lru); | |
d5567c9d | 941 | spin_unlock(&pool->lock); |
21fb6d8b | 942 | z3fold_page_unlock(zhdr); |
5a27aa82 | 943 | } |
2f1e5e4d | 944 | |
21fb6d8b VW |
945 | /* We started off locked to we need to lock the pool back */ |
946 | spin_lock(&pool->lock); | |
9a001fc1 VW |
947 | } |
948 | spin_unlock(&pool->lock); | |
949 | return -EAGAIN; | |
950 | } | |
951 | ||
952 | /** | |
953 | * z3fold_map() - maps the allocation associated with the given handle | |
954 | * @pool: pool in which the allocation resides | |
955 | * @handle: handle associated with the allocation to be mapped | |
956 | * | |
957 | * Extracts the buddy number from handle and constructs the pointer to the | |
958 | * correct starting chunk within the page. | |
959 | * | |
960 | * Returns: a pointer to the mapped allocation | |
961 | */ | |
962 | static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) | |
963 | { | |
964 | struct z3fold_header *zhdr; | |
965 | struct page *page; | |
966 | void *addr; | |
967 | enum buddy buddy; | |
968 | ||
9a001fc1 VW |
969 | zhdr = handle_to_z3fold_header(handle); |
970 | addr = zhdr; | |
971 | page = virt_to_page(zhdr); | |
972 | ||
973 | if (test_bit(PAGE_HEADLESS, &page->private)) | |
974 | goto out; | |
975 | ||
2f1e5e4d | 976 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
977 | buddy = handle_to_buddy(handle); |
978 | switch (buddy) { | |
979 | case FIRST: | |
980 | addr += ZHDR_SIZE_ALIGNED; | |
981 | break; | |
982 | case MIDDLE: | |
983 | addr += zhdr->start_middle << CHUNK_SHIFT; | |
984 | set_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
985 | break; | |
986 | case LAST: | |
e28ae7aa | 987 | addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); |
9a001fc1 VW |
988 | break; |
989 | default: | |
990 | pr_err("unknown buddy id %d\n", buddy); | |
991 | WARN_ON(1); | |
992 | addr = NULL; | |
993 | break; | |
994 | } | |
2f1e5e4d VW |
995 | |
996 | z3fold_page_unlock(zhdr); | |
9a001fc1 | 997 | out: |
9a001fc1 VW |
998 | return addr; |
999 | } | |
1000 | ||
1001 | /** | |
1002 | * z3fold_unmap() - unmaps the allocation associated with the given handle | |
1003 | * @pool: pool in which the allocation resides | |
1004 | * @handle: handle associated with the allocation to be unmapped | |
1005 | */ | |
1006 | static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) | |
1007 | { | |
1008 | struct z3fold_header *zhdr; | |
1009 | struct page *page; | |
1010 | enum buddy buddy; | |
1011 | ||
9a001fc1 VW |
1012 | zhdr = handle_to_z3fold_header(handle); |
1013 | page = virt_to_page(zhdr); | |
1014 | ||
2f1e5e4d | 1015 | if (test_bit(PAGE_HEADLESS, &page->private)) |
9a001fc1 | 1016 | return; |
9a001fc1 | 1017 | |
2f1e5e4d | 1018 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1019 | buddy = handle_to_buddy(handle); |
1020 | if (buddy == MIDDLE) | |
1021 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
2f1e5e4d | 1022 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
1023 | } |
1024 | ||
1025 | /** | |
1026 | * z3fold_get_pool_size() - gets the z3fold pool size in pages | |
1027 | * @pool: pool whose size is being queried | |
1028 | * | |
12d59ae6 | 1029 | * Returns: size in pages of the given pool. |
9a001fc1 VW |
1030 | */ |
1031 | static u64 z3fold_get_pool_size(struct z3fold_pool *pool) | |
1032 | { | |
12d59ae6 | 1033 | return atomic64_read(&pool->pages_nr); |
9a001fc1 VW |
1034 | } |
1035 | ||
1036 | /***************** | |
1037 | * zpool | |
1038 | ****************/ | |
1039 | ||
1040 | static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) | |
1041 | { | |
1042 | if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) | |
1043 | return pool->zpool_ops->evict(pool->zpool, handle); | |
1044 | else | |
1045 | return -ENOENT; | |
1046 | } | |
1047 | ||
1048 | static const struct z3fold_ops z3fold_zpool_ops = { | |
1049 | .evict = z3fold_zpool_evict | |
1050 | }; | |
1051 | ||
1052 | static void *z3fold_zpool_create(const char *name, gfp_t gfp, | |
1053 | const struct zpool_ops *zpool_ops, | |
1054 | struct zpool *zpool) | |
1055 | { | |
1056 | struct z3fold_pool *pool; | |
1057 | ||
d30561c5 VW |
1058 | pool = z3fold_create_pool(name, gfp, |
1059 | zpool_ops ? &z3fold_zpool_ops : NULL); | |
9a001fc1 VW |
1060 | if (pool) { |
1061 | pool->zpool = zpool; | |
1062 | pool->zpool_ops = zpool_ops; | |
1063 | } | |
1064 | return pool; | |
1065 | } | |
1066 | ||
1067 | static void z3fold_zpool_destroy(void *pool) | |
1068 | { | |
1069 | z3fold_destroy_pool(pool); | |
1070 | } | |
1071 | ||
1072 | static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
1073 | unsigned long *handle) | |
1074 | { | |
1075 | return z3fold_alloc(pool, size, gfp, handle); | |
1076 | } | |
1077 | static void z3fold_zpool_free(void *pool, unsigned long handle) | |
1078 | { | |
1079 | z3fold_free(pool, handle); | |
1080 | } | |
1081 | ||
1082 | static int z3fold_zpool_shrink(void *pool, unsigned int pages, | |
1083 | unsigned int *reclaimed) | |
1084 | { | |
1085 | unsigned int total = 0; | |
1086 | int ret = -EINVAL; | |
1087 | ||
1088 | while (total < pages) { | |
1089 | ret = z3fold_reclaim_page(pool, 8); | |
1090 | if (ret < 0) | |
1091 | break; | |
1092 | total++; | |
1093 | } | |
1094 | ||
1095 | if (reclaimed) | |
1096 | *reclaimed = total; | |
1097 | ||
1098 | return ret; | |
1099 | } | |
1100 | ||
1101 | static void *z3fold_zpool_map(void *pool, unsigned long handle, | |
1102 | enum zpool_mapmode mm) | |
1103 | { | |
1104 | return z3fold_map(pool, handle); | |
1105 | } | |
1106 | static void z3fold_zpool_unmap(void *pool, unsigned long handle) | |
1107 | { | |
1108 | z3fold_unmap(pool, handle); | |
1109 | } | |
1110 | ||
1111 | static u64 z3fold_zpool_total_size(void *pool) | |
1112 | { | |
1113 | return z3fold_get_pool_size(pool) * PAGE_SIZE; | |
1114 | } | |
1115 | ||
1116 | static struct zpool_driver z3fold_zpool_driver = { | |
1117 | .type = "z3fold", | |
1118 | .owner = THIS_MODULE, | |
1119 | .create = z3fold_zpool_create, | |
1120 | .destroy = z3fold_zpool_destroy, | |
1121 | .malloc = z3fold_zpool_malloc, | |
1122 | .free = z3fold_zpool_free, | |
1123 | .shrink = z3fold_zpool_shrink, | |
1124 | .map = z3fold_zpool_map, | |
1125 | .unmap = z3fold_zpool_unmap, | |
1126 | .total_size = z3fold_zpool_total_size, | |
1127 | }; | |
1128 | ||
1129 | MODULE_ALIAS("zpool-z3fold"); | |
1130 | ||
1131 | static int __init init_z3fold(void) | |
1132 | { | |
ede93213 VW |
1133 | /* Make sure the z3fold header is not larger than the page size */ |
1134 | BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); | |
9a001fc1 VW |
1135 | zpool_register_driver(&z3fold_zpool_driver); |
1136 | ||
1137 | return 0; | |
1138 | } | |
1139 | ||
1140 | static void __exit exit_z3fold(void) | |
1141 | { | |
1142 | zpool_unregister_driver(&z3fold_zpool_driver); | |
1143 | } | |
1144 | ||
1145 | module_init(init_z3fold); | |
1146 | module_exit(exit_z3fold); | |
1147 | ||
1148 | MODULE_LICENSE("GPL"); | |
1149 | MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); | |
1150 | MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); |