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) |
ca0246bb | 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, |
6098d7e1 | 148 | PAGE_STALE, |
ca0246bb | 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); | |
ca0246bb | 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; | |
ca0246bb 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 | ||
ca0246bb 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 | ||
9050cce1 VW |
258 | static inline struct z3fold_pool *zhdr_to_pool(struct z3fold_header *zhdr) |
259 | { | |
260 | return zhdr->pool; | |
261 | } | |
262 | ||
d30561c5 VW |
263 | static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) |
264 | { | |
265 | struct page *page = virt_to_page(zhdr); | |
9050cce1 | 266 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 VW |
267 | |
268 | WARN_ON(!list_empty(&zhdr->buddy)); | |
269 | set_bit(PAGE_STALE, &page->private); | |
35529357 | 270 | clear_bit(NEEDS_COMPACTING, &page->private); |
d30561c5 VW |
271 | spin_lock(&pool->lock); |
272 | if (!list_empty(&page->lru)) | |
273 | list_del(&page->lru); | |
274 | spin_unlock(&pool->lock); | |
275 | if (locked) | |
276 | z3fold_page_unlock(zhdr); | |
277 | spin_lock(&pool->stale_lock); | |
278 | list_add(&zhdr->buddy, &pool->stale); | |
279 | queue_work(pool->release_wq, &pool->work); | |
280 | spin_unlock(&pool->stale_lock); | |
281 | } | |
282 | ||
283 | static void __attribute__((__unused__)) | |
284 | release_z3fold_page(struct kref *ref) | |
285 | { | |
286 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
287 | refcount); | |
288 | __release_z3fold_page(zhdr, false); | |
289 | } | |
290 | ||
291 | static void release_z3fold_page_locked(struct kref *ref) | |
292 | { | |
293 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
294 | refcount); | |
295 | WARN_ON(z3fold_page_trylock(zhdr)); | |
296 | __release_z3fold_page(zhdr, true); | |
297 | } | |
298 | ||
299 | static void release_z3fold_page_locked_list(struct kref *ref) | |
300 | { | |
301 | struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, | |
302 | refcount); | |
9050cce1 VW |
303 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
304 | spin_lock(&pool->lock); | |
d30561c5 | 305 | list_del_init(&zhdr->buddy); |
9050cce1 | 306 | spin_unlock(&pool->lock); |
d30561c5 VW |
307 | |
308 | WARN_ON(z3fold_page_trylock(zhdr)); | |
309 | __release_z3fold_page(zhdr, true); | |
310 | } | |
311 | ||
312 | static void free_pages_work(struct work_struct *w) | |
313 | { | |
314 | struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); | |
315 | ||
316 | spin_lock(&pool->stale_lock); | |
317 | while (!list_empty(&pool->stale)) { | |
318 | struct z3fold_header *zhdr = list_first_entry(&pool->stale, | |
319 | struct z3fold_header, buddy); | |
320 | struct page *page = virt_to_page(zhdr); | |
321 | ||
322 | list_del(&zhdr->buddy); | |
323 | if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) | |
324 | continue; | |
d30561c5 VW |
325 | spin_unlock(&pool->stale_lock); |
326 | cancel_work_sync(&zhdr->work); | |
327 | free_z3fold_page(page); | |
328 | cond_resched(); | |
329 | spin_lock(&pool->stale_lock); | |
330 | } | |
331 | spin_unlock(&pool->stale_lock); | |
332 | } | |
333 | ||
9a001fc1 VW |
334 | /* |
335 | * Returns the number of free chunks in a z3fold page. | |
336 | * NB: can't be used with HEADLESS pages. | |
337 | */ | |
338 | static int num_free_chunks(struct z3fold_header *zhdr) | |
339 | { | |
340 | int nfree; | |
341 | /* | |
342 | * If there is a middle object, pick up the bigger free space | |
343 | * either before or after it. Otherwise just subtract the number | |
344 | * of chunks occupied by the first and the last objects. | |
345 | */ | |
346 | if (zhdr->middle_chunks != 0) { | |
347 | int nfree_before = zhdr->first_chunks ? | |
ede93213 | 348 | 0 : zhdr->start_middle - ZHDR_CHUNKS; |
9a001fc1 | 349 | int nfree_after = zhdr->last_chunks ? |
ede93213 VW |
350 | 0 : TOTAL_CHUNKS - |
351 | (zhdr->start_middle + zhdr->middle_chunks); | |
9a001fc1 VW |
352 | nfree = max(nfree_before, nfree_after); |
353 | } else | |
354 | nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; | |
355 | return nfree; | |
356 | } | |
357 | ||
9050cce1 VW |
358 | /* Add to the appropriate unbuddied list */ |
359 | static inline void add_to_unbuddied(struct z3fold_pool *pool, | |
360 | struct z3fold_header *zhdr) | |
361 | { | |
362 | if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || | |
363 | zhdr->middle_chunks == 0) { | |
364 | struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied); | |
365 | ||
366 | int freechunks = num_free_chunks(zhdr); | |
367 | spin_lock(&pool->lock); | |
368 | list_add(&zhdr->buddy, &unbuddied[freechunks]); | |
369 | spin_unlock(&pool->lock); | |
370 | zhdr->cpu = smp_processor_id(); | |
371 | put_cpu_ptr(pool->unbuddied); | |
372 | } | |
373 | } | |
374 | ||
ede93213 VW |
375 | static inline void *mchunk_memmove(struct z3fold_header *zhdr, |
376 | unsigned short dst_chunk) | |
377 | { | |
378 | void *beg = zhdr; | |
379 | return memmove(beg + (dst_chunk << CHUNK_SHIFT), | |
380 | beg + (zhdr->start_middle << CHUNK_SHIFT), | |
381 | zhdr->middle_chunks << CHUNK_SHIFT); | |
382 | } | |
383 | ||
1b096e5a | 384 | #define BIG_CHUNK_GAP 3 |
9a001fc1 VW |
385 | /* Has to be called with lock held */ |
386 | static int z3fold_compact_page(struct z3fold_header *zhdr) | |
387 | { | |
388 | struct page *page = virt_to_page(zhdr); | |
9a001fc1 | 389 | |
ede93213 VW |
390 | if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) |
391 | return 0; /* can't move middle chunk, it's used */ | |
9a001fc1 | 392 | |
ede93213 VW |
393 | if (zhdr->middle_chunks == 0) |
394 | return 0; /* nothing to compact */ | |
395 | ||
396 | if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { | |
397 | /* move to the beginning */ | |
398 | mchunk_memmove(zhdr, ZHDR_CHUNKS); | |
9a001fc1 VW |
399 | zhdr->first_chunks = zhdr->middle_chunks; |
400 | zhdr->middle_chunks = 0; | |
401 | zhdr->start_middle = 0; | |
402 | zhdr->first_num++; | |
1b096e5a | 403 | return 1; |
9a001fc1 | 404 | } |
1b096e5a VW |
405 | |
406 | /* | |
407 | * moving data is expensive, so let's only do that if | |
408 | * there's substantial gain (at least BIG_CHUNK_GAP chunks) | |
409 | */ | |
410 | if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && | |
411 | zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= | |
412 | BIG_CHUNK_GAP) { | |
413 | mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); | |
414 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; | |
415 | return 1; | |
416 | } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && | |
417 | TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle | |
418 | + zhdr->middle_chunks) >= | |
419 | BIG_CHUNK_GAP) { | |
420 | unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - | |
421 | zhdr->middle_chunks; | |
422 | mchunk_memmove(zhdr, new_start); | |
423 | zhdr->start_middle = new_start; | |
424 | return 1; | |
425 | } | |
426 | ||
427 | return 0; | |
9a001fc1 VW |
428 | } |
429 | ||
d30561c5 VW |
430 | static void do_compact_page(struct z3fold_header *zhdr, bool locked) |
431 | { | |
9050cce1 | 432 | struct z3fold_pool *pool = zhdr_to_pool(zhdr); |
d30561c5 | 433 | struct page *page; |
d30561c5 VW |
434 | |
435 | page = virt_to_page(zhdr); | |
436 | if (locked) | |
437 | WARN_ON(z3fold_page_trylock(zhdr)); | |
438 | else | |
439 | z3fold_page_lock(zhdr); | |
5d03a661 | 440 | if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { |
d30561c5 VW |
441 | z3fold_page_unlock(zhdr); |
442 | return; | |
443 | } | |
444 | spin_lock(&pool->lock); | |
445 | list_del_init(&zhdr->buddy); | |
446 | spin_unlock(&pool->lock); | |
447 | ||
5d03a661 VW |
448 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { |
449 | atomic64_dec(&pool->pages_nr); | |
450 | return; | |
451 | } | |
452 | ||
d30561c5 | 453 | z3fold_compact_page(zhdr); |
9050cce1 | 454 | add_to_unbuddied(pool, zhdr); |
d30561c5 VW |
455 | z3fold_page_unlock(zhdr); |
456 | } | |
457 | ||
458 | static void compact_page_work(struct work_struct *w) | |
459 | { | |
460 | struct z3fold_header *zhdr = container_of(w, struct z3fold_header, | |
461 | work); | |
462 | ||
463 | do_compact_page(zhdr, false); | |
464 | } | |
465 | ||
9050cce1 VW |
466 | /* returns _locked_ z3fold page header or NULL */ |
467 | static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, | |
468 | size_t size, bool can_sleep) | |
469 | { | |
470 | struct z3fold_header *zhdr = NULL; | |
471 | struct page *page; | |
472 | struct list_head *unbuddied; | |
473 | int chunks = size_to_chunks(size), i; | |
474 | ||
475 | lookup: | |
476 | /* First, try to find an unbuddied z3fold page. */ | |
477 | unbuddied = get_cpu_ptr(pool->unbuddied); | |
478 | for_each_unbuddied_list(i, chunks) { | |
479 | struct list_head *l = &unbuddied[i]; | |
480 | ||
481 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
482 | struct z3fold_header, buddy); | |
483 | ||
484 | if (!zhdr) | |
485 | continue; | |
486 | ||
487 | /* Re-check under lock. */ | |
488 | spin_lock(&pool->lock); | |
489 | l = &unbuddied[i]; | |
490 | if (unlikely(zhdr != list_first_entry(READ_ONCE(l), | |
491 | struct z3fold_header, buddy)) || | |
492 | !z3fold_page_trylock(zhdr)) { | |
493 | spin_unlock(&pool->lock); | |
494 | zhdr = NULL; | |
495 | put_cpu_ptr(pool->unbuddied); | |
496 | if (can_sleep) | |
497 | cond_resched(); | |
498 | goto lookup; | |
499 | } | |
500 | list_del_init(&zhdr->buddy); | |
501 | zhdr->cpu = -1; | |
502 | spin_unlock(&pool->lock); | |
503 | ||
504 | page = virt_to_page(zhdr); | |
505 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
506 | z3fold_page_unlock(zhdr); | |
507 | zhdr = NULL; | |
508 | put_cpu_ptr(pool->unbuddied); | |
509 | if (can_sleep) | |
510 | cond_resched(); | |
511 | goto lookup; | |
512 | } | |
513 | ||
514 | /* | |
515 | * this page could not be removed from its unbuddied | |
516 | * list while pool lock was held, and then we've taken | |
517 | * page lock so kref_put could not be called before | |
518 | * we got here, so it's safe to just call kref_get() | |
519 | */ | |
520 | kref_get(&zhdr->refcount); | |
521 | break; | |
522 | } | |
523 | put_cpu_ptr(pool->unbuddied); | |
524 | ||
351618b2 VW |
525 | if (!zhdr) { |
526 | int cpu; | |
527 | ||
528 | /* look for _exact_ match on other cpus' lists */ | |
529 | for_each_online_cpu(cpu) { | |
530 | struct list_head *l; | |
531 | ||
532 | unbuddied = per_cpu_ptr(pool->unbuddied, cpu); | |
533 | spin_lock(&pool->lock); | |
534 | l = &unbuddied[chunks]; | |
535 | ||
536 | zhdr = list_first_entry_or_null(READ_ONCE(l), | |
537 | struct z3fold_header, buddy); | |
538 | ||
539 | if (!zhdr || !z3fold_page_trylock(zhdr)) { | |
540 | spin_unlock(&pool->lock); | |
541 | zhdr = NULL; | |
542 | continue; | |
543 | } | |
544 | list_del_init(&zhdr->buddy); | |
545 | zhdr->cpu = -1; | |
546 | spin_unlock(&pool->lock); | |
547 | ||
548 | page = virt_to_page(zhdr); | |
549 | if (test_bit(NEEDS_COMPACTING, &page->private)) { | |
550 | z3fold_page_unlock(zhdr); | |
551 | zhdr = NULL; | |
552 | if (can_sleep) | |
553 | cond_resched(); | |
554 | continue; | |
555 | } | |
556 | kref_get(&zhdr->refcount); | |
557 | break; | |
558 | } | |
559 | } | |
560 | ||
9050cce1 VW |
561 | return zhdr; |
562 | } | |
d30561c5 VW |
563 | |
564 | /* | |
565 | * API Functions | |
566 | */ | |
567 | ||
568 | /** | |
569 | * z3fold_create_pool() - create a new z3fold pool | |
570 | * @name: pool name | |
571 | * @gfp: gfp flags when allocating the z3fold pool structure | |
572 | * @ops: user-defined operations for the z3fold pool | |
573 | * | |
574 | * Return: pointer to the new z3fold pool or NULL if the metadata allocation | |
575 | * failed. | |
576 | */ | |
577 | static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, | |
578 | const struct z3fold_ops *ops) | |
579 | { | |
580 | struct z3fold_pool *pool = NULL; | |
581 | int i, cpu; | |
582 | ||
583 | pool = kzalloc(sizeof(struct z3fold_pool), gfp); | |
584 | if (!pool) | |
585 | goto out; | |
586 | spin_lock_init(&pool->lock); | |
587 | spin_lock_init(&pool->stale_lock); | |
588 | pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2); | |
1ec6995d XW |
589 | if (!pool->unbuddied) |
590 | goto out_pool; | |
d30561c5 VW |
591 | for_each_possible_cpu(cpu) { |
592 | struct list_head *unbuddied = | |
593 | per_cpu_ptr(pool->unbuddied, cpu); | |
594 | for_each_unbuddied_list(i, 0) | |
595 | INIT_LIST_HEAD(&unbuddied[i]); | |
596 | } | |
597 | INIT_LIST_HEAD(&pool->lru); | |
598 | INIT_LIST_HEAD(&pool->stale); | |
599 | atomic64_set(&pool->pages_nr, 0); | |
600 | pool->name = name; | |
601 | pool->compact_wq = create_singlethread_workqueue(pool->name); | |
602 | if (!pool->compact_wq) | |
1ec6995d | 603 | goto out_unbuddied; |
d30561c5 VW |
604 | pool->release_wq = create_singlethread_workqueue(pool->name); |
605 | if (!pool->release_wq) | |
606 | goto out_wq; | |
607 | INIT_WORK(&pool->work, free_pages_work); | |
608 | pool->ops = ops; | |
609 | return pool; | |
610 | ||
611 | out_wq: | |
612 | destroy_workqueue(pool->compact_wq); | |
1ec6995d XW |
613 | out_unbuddied: |
614 | free_percpu(pool->unbuddied); | |
615 | out_pool: | |
d30561c5 | 616 | kfree(pool); |
1ec6995d | 617 | out: |
d30561c5 VW |
618 | return NULL; |
619 | } | |
620 | ||
621 | /** | |
622 | * z3fold_destroy_pool() - destroys an existing z3fold pool | |
623 | * @pool: the z3fold pool to be destroyed | |
624 | * | |
625 | * The pool should be emptied before this function is called. | |
626 | */ | |
627 | static void z3fold_destroy_pool(struct z3fold_pool *pool) | |
628 | { | |
629 | destroy_workqueue(pool->release_wq); | |
630 | destroy_workqueue(pool->compact_wq); | |
631 | kfree(pool); | |
632 | } | |
633 | ||
9a001fc1 VW |
634 | /** |
635 | * z3fold_alloc() - allocates a region of a given size | |
636 | * @pool: z3fold pool from which to allocate | |
637 | * @size: size in bytes of the desired allocation | |
638 | * @gfp: gfp flags used if the pool needs to grow | |
639 | * @handle: handle of the new allocation | |
640 | * | |
641 | * This function will attempt to find a free region in the pool large enough to | |
642 | * satisfy the allocation request. A search of the unbuddied lists is | |
643 | * performed first. If no suitable free region is found, then a new page is | |
644 | * allocated and added to the pool to satisfy the request. | |
645 | * | |
646 | * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used | |
647 | * as z3fold pool pages. | |
648 | * | |
649 | * Return: 0 if success and handle is set, otherwise -EINVAL if the size or | |
650 | * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate | |
651 | * a new page. | |
652 | */ | |
653 | static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, | |
654 | unsigned long *handle) | |
655 | { | |
9050cce1 | 656 | int chunks = size_to_chunks(size); |
9a001fc1 | 657 | struct z3fold_header *zhdr = NULL; |
d30561c5 | 658 | struct page *page = NULL; |
9a001fc1 | 659 | enum buddy bud; |
8a97ea54 | 660 | bool can_sleep = gfpflags_allow_blocking(gfp); |
9a001fc1 VW |
661 | |
662 | if (!size || (gfp & __GFP_HIGHMEM)) | |
663 | return -EINVAL; | |
664 | ||
665 | if (size > PAGE_SIZE) | |
666 | return -ENOSPC; | |
667 | ||
668 | if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) | |
669 | bud = HEADLESS; | |
670 | else { | |
9050cce1 VW |
671 | retry: |
672 | zhdr = __z3fold_alloc(pool, size, can_sleep); | |
d30561c5 | 673 | if (zhdr) { |
2f1e5e4d VW |
674 | if (zhdr->first_chunks == 0) { |
675 | if (zhdr->middle_chunks != 0 && | |
676 | chunks >= zhdr->start_middle) | |
9a001fc1 | 677 | bud = LAST; |
2f1e5e4d VW |
678 | else |
679 | bud = FIRST; | |
680 | } else if (zhdr->last_chunks == 0) | |
681 | bud = LAST; | |
682 | else if (zhdr->middle_chunks == 0) | |
683 | bud = MIDDLE; | |
684 | else { | |
5a27aa82 | 685 | if (kref_put(&zhdr->refcount, |
d30561c5 | 686 | release_z3fold_page_locked)) |
5a27aa82 | 687 | atomic64_dec(&pool->pages_nr); |
d30561c5 VW |
688 | else |
689 | z3fold_page_unlock(zhdr); | |
2f1e5e4d VW |
690 | pr_err("No free chunks in unbuddied\n"); |
691 | WARN_ON(1); | |
9050cce1 | 692 | goto retry; |
9a001fc1 | 693 | } |
9050cce1 | 694 | page = virt_to_page(zhdr); |
2f1e5e4d | 695 | goto found; |
9a001fc1 VW |
696 | } |
697 | bud = FIRST; | |
9a001fc1 VW |
698 | } |
699 | ||
5c9bab59 VW |
700 | page = NULL; |
701 | if (can_sleep) { | |
702 | spin_lock(&pool->stale_lock); | |
703 | zhdr = list_first_entry_or_null(&pool->stale, | |
704 | struct z3fold_header, buddy); | |
705 | /* | |
706 | * Before allocating a page, let's see if we can take one from | |
707 | * the stale pages list. cancel_work_sync() can sleep so we | |
708 | * limit this case to the contexts where we can sleep | |
709 | */ | |
710 | if (zhdr) { | |
711 | list_del(&zhdr->buddy); | |
712 | spin_unlock(&pool->stale_lock); | |
d30561c5 | 713 | cancel_work_sync(&zhdr->work); |
5c9bab59 VW |
714 | page = virt_to_page(zhdr); |
715 | } else { | |
716 | spin_unlock(&pool->stale_lock); | |
717 | } | |
d30561c5 | 718 | } |
5c9bab59 VW |
719 | if (!page) |
720 | page = alloc_page(gfp); | |
d30561c5 | 721 | |
9a001fc1 VW |
722 | if (!page) |
723 | return -ENOMEM; | |
2f1e5e4d | 724 | |
d30561c5 | 725 | zhdr = init_z3fold_page(page, pool); |
9050cce1 VW |
726 | if (!zhdr) { |
727 | __free_page(page); | |
728 | return -ENOMEM; | |
729 | } | |
730 | atomic64_inc(&pool->pages_nr); | |
9a001fc1 VW |
731 | |
732 | if (bud == HEADLESS) { | |
733 | set_bit(PAGE_HEADLESS, &page->private); | |
734 | goto headless; | |
735 | } | |
2f1e5e4d | 736 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
737 | |
738 | found: | |
739 | if (bud == FIRST) | |
740 | zhdr->first_chunks = chunks; | |
741 | else if (bud == LAST) | |
742 | zhdr->last_chunks = chunks; | |
743 | else { | |
744 | zhdr->middle_chunks = chunks; | |
ede93213 | 745 | zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; |
9a001fc1 | 746 | } |
9050cce1 | 747 | add_to_unbuddied(pool, zhdr); |
9a001fc1 VW |
748 | |
749 | headless: | |
d30561c5 | 750 | spin_lock(&pool->lock); |
9a001fc1 VW |
751 | /* Add/move z3fold page to beginning of LRU */ |
752 | if (!list_empty(&page->lru)) | |
753 | list_del(&page->lru); | |
754 | ||
755 | list_add(&page->lru, &pool->lru); | |
756 | ||
757 | *handle = encode_handle(zhdr, bud); | |
758 | spin_unlock(&pool->lock); | |
2f1e5e4d VW |
759 | if (bud != HEADLESS) |
760 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
761 | |
762 | return 0; | |
763 | } | |
764 | ||
765 | /** | |
766 | * z3fold_free() - frees the allocation associated with the given handle | |
767 | * @pool: pool in which the allocation resided | |
768 | * @handle: handle associated with the allocation returned by z3fold_alloc() | |
769 | * | |
770 | * In the case that the z3fold page in which the allocation resides is under | |
771 | * reclaim, as indicated by the PG_reclaim flag being set, this function | |
772 | * only sets the first|last_chunks to 0. The page is actually freed | |
773 | * once both buddies are evicted (see z3fold_reclaim_page() below). | |
774 | */ | |
775 | static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) | |
776 | { | |
777 | struct z3fold_header *zhdr; | |
9a001fc1 VW |
778 | struct page *page; |
779 | enum buddy bud; | |
780 | ||
9a001fc1 VW |
781 | zhdr = handle_to_z3fold_header(handle); |
782 | page = virt_to_page(zhdr); | |
783 | ||
784 | if (test_bit(PAGE_HEADLESS, &page->private)) { | |
ca0246bb VW |
785 | /* if a headless page is under reclaim, just leave. |
786 | * NB: we use test_and_set_bit for a reason: if the bit | |
787 | * has not been set before, we release this page | |
788 | * immediately so we don't care about its value any more. | |
789 | */ | |
790 | if (!test_and_set_bit(PAGE_CLAIMED, &page->private)) { | |
791 | spin_lock(&pool->lock); | |
792 | list_del(&page->lru); | |
793 | spin_unlock(&pool->lock); | |
794 | free_z3fold_page(page); | |
795 | atomic64_dec(&pool->pages_nr); | |
9a001fc1 | 796 | } |
ca0246bb | 797 | return; |
9a001fc1 VW |
798 | } |
799 | ||
ca0246bb VW |
800 | /* Non-headless case */ |
801 | z3fold_page_lock(zhdr); | |
802 | bud = handle_to_buddy(handle); | |
803 | ||
804 | switch (bud) { | |
805 | case FIRST: | |
806 | zhdr->first_chunks = 0; | |
807 | break; | |
808 | case MIDDLE: | |
809 | zhdr->middle_chunks = 0; | |
810 | break; | |
811 | case LAST: | |
812 | zhdr->last_chunks = 0; | |
813 | break; | |
814 | default: | |
815 | pr_err("%s: unknown bud %d\n", __func__, bud); | |
816 | WARN_ON(1); | |
817 | z3fold_page_unlock(zhdr); | |
d30561c5 VW |
818 | return; |
819 | } | |
820 | ||
821 | if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { | |
822 | atomic64_dec(&pool->pages_nr); | |
823 | return; | |
824 | } | |
ca0246bb | 825 | if (test_bit(PAGE_CLAIMED, &page->private)) { |
6098d7e1 VW |
826 | z3fold_page_unlock(zhdr); |
827 | return; | |
828 | } | |
d30561c5 | 829 | if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) { |
5a27aa82 | 830 | z3fold_page_unlock(zhdr); |
d30561c5 VW |
831 | return; |
832 | } | |
833 | if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { | |
2f1e5e4d | 834 | spin_lock(&pool->lock); |
d30561c5 | 835 | list_del_init(&zhdr->buddy); |
2f1e5e4d | 836 | spin_unlock(&pool->lock); |
d30561c5 | 837 | zhdr->cpu = -1; |
5d03a661 | 838 | kref_get(&zhdr->refcount); |
d30561c5 VW |
839 | do_compact_page(zhdr, true); |
840 | return; | |
9a001fc1 | 841 | } |
5d03a661 | 842 | kref_get(&zhdr->refcount); |
d30561c5 VW |
843 | queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); |
844 | z3fold_page_unlock(zhdr); | |
9a001fc1 VW |
845 | } |
846 | ||
847 | /** | |
848 | * z3fold_reclaim_page() - evicts allocations from a pool page and frees it | |
849 | * @pool: pool from which a page will attempt to be evicted | |
f144c390 | 850 | * @retries: number of pages on the LRU list for which eviction will |
9a001fc1 VW |
851 | * be attempted before failing |
852 | * | |
853 | * z3fold reclaim is different from normal system reclaim in that it is done | |
854 | * from the bottom, up. This is because only the bottom layer, z3fold, has | |
855 | * information on how the allocations are organized within each z3fold page. | |
856 | * This has the potential to create interesting locking situations between | |
857 | * z3fold and the user, however. | |
858 | * | |
859 | * To avoid these, this is how z3fold_reclaim_page() should be called: | |
f144c390 | 860 | * |
9a001fc1 VW |
861 | * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). |
862 | * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and | |
863 | * call the user-defined eviction handler with the pool and handle as | |
864 | * arguments. | |
865 | * | |
866 | * If the handle can not be evicted, the eviction handler should return | |
867 | * non-zero. z3fold_reclaim_page() will add the z3fold page back to the | |
868 | * appropriate list and try the next z3fold page on the LRU up to | |
869 | * a user defined number of retries. | |
870 | * | |
871 | * If the handle is successfully evicted, the eviction handler should | |
872 | * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() | |
873 | * contains logic to delay freeing the page if the page is under reclaim, | |
874 | * as indicated by the setting of the PG_reclaim flag on the underlying page. | |
875 | * | |
876 | * If all buddies in the z3fold page are successfully evicted, then the | |
877 | * z3fold page can be freed. | |
878 | * | |
879 | * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are | |
880 | * no pages to evict or an eviction handler is not registered, -EAGAIN if | |
881 | * the retry limit was hit. | |
882 | */ | |
883 | static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) | |
884 | { | |
d30561c5 VW |
885 | int i, ret = 0; |
886 | struct z3fold_header *zhdr = NULL; | |
887 | struct page *page = NULL; | |
888 | struct list_head *pos; | |
9a001fc1 VW |
889 | unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; |
890 | ||
891 | spin_lock(&pool->lock); | |
2f1e5e4d | 892 | if (!pool->ops || !pool->ops->evict || retries == 0) { |
9a001fc1 VW |
893 | spin_unlock(&pool->lock); |
894 | return -EINVAL; | |
895 | } | |
896 | for (i = 0; i < retries; i++) { | |
2f1e5e4d VW |
897 | if (list_empty(&pool->lru)) { |
898 | spin_unlock(&pool->lock); | |
899 | return -EINVAL; | |
900 | } | |
d30561c5 VW |
901 | list_for_each_prev(pos, &pool->lru) { |
902 | page = list_entry(pos, struct page, lru); | |
ca0246bb VW |
903 | |
904 | /* this bit could have been set by free, in which case | |
905 | * we pass over to the next page in the pool. | |
906 | */ | |
907 | if (test_and_set_bit(PAGE_CLAIMED, &page->private)) | |
908 | continue; | |
909 | ||
910 | zhdr = page_address(page); | |
d30561c5 | 911 | if (test_bit(PAGE_HEADLESS, &page->private)) |
d30561c5 VW |
912 | break; |
913 | ||
ca0246bb VW |
914 | if (!z3fold_page_trylock(zhdr)) { |
915 | zhdr = NULL; | |
d30561c5 | 916 | continue; /* can't evict at this point */ |
ca0246bb | 917 | } |
d30561c5 VW |
918 | kref_get(&zhdr->refcount); |
919 | list_del_init(&zhdr->buddy); | |
920 | zhdr->cpu = -1; | |
6098d7e1 | 921 | break; |
d30561c5 VW |
922 | } |
923 | ||
ca0246bb VW |
924 | if (!zhdr) |
925 | break; | |
926 | ||
5a27aa82 | 927 | list_del_init(&page->lru); |
d30561c5 | 928 | spin_unlock(&pool->lock); |
9a001fc1 | 929 | |
9a001fc1 | 930 | if (!test_bit(PAGE_HEADLESS, &page->private)) { |
9a001fc1 VW |
931 | /* |
932 | * We need encode the handles before unlocking, since | |
933 | * we can race with free that will set | |
934 | * (first|last)_chunks to 0 | |
935 | */ | |
936 | first_handle = 0; | |
937 | last_handle = 0; | |
938 | middle_handle = 0; | |
939 | if (zhdr->first_chunks) | |
940 | first_handle = encode_handle(zhdr, FIRST); | |
941 | if (zhdr->middle_chunks) | |
942 | middle_handle = encode_handle(zhdr, MIDDLE); | |
943 | if (zhdr->last_chunks) | |
944 | last_handle = encode_handle(zhdr, LAST); | |
d30561c5 VW |
945 | /* |
946 | * it's safe to unlock here because we hold a | |
947 | * reference to this page | |
948 | */ | |
2f1e5e4d | 949 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
950 | } else { |
951 | first_handle = encode_handle(zhdr, HEADLESS); | |
952 | last_handle = middle_handle = 0; | |
953 | } | |
954 | ||
9a001fc1 VW |
955 | /* Issue the eviction callback(s) */ |
956 | if (middle_handle) { | |
957 | ret = pool->ops->evict(pool, middle_handle); | |
958 | if (ret) | |
959 | goto next; | |
960 | } | |
961 | if (first_handle) { | |
962 | ret = pool->ops->evict(pool, first_handle); | |
963 | if (ret) | |
964 | goto next; | |
965 | } | |
966 | if (last_handle) { | |
967 | ret = pool->ops->evict(pool, last_handle); | |
968 | if (ret) | |
969 | goto next; | |
970 | } | |
971 | next: | |
5a27aa82 VW |
972 | if (test_bit(PAGE_HEADLESS, &page->private)) { |
973 | if (ret == 0) { | |
974 | free_z3fold_page(page); | |
ca0246bb | 975 | atomic64_dec(&pool->pages_nr); |
5a27aa82 | 976 | return 0; |
5a27aa82 | 977 | } |
6098d7e1 VW |
978 | spin_lock(&pool->lock); |
979 | list_add(&page->lru, &pool->lru); | |
980 | spin_unlock(&pool->lock); | |
981 | } else { | |
982 | z3fold_page_lock(zhdr); | |
ca0246bb | 983 | clear_bit(PAGE_CLAIMED, &page->private); |
6098d7e1 VW |
984 | if (kref_put(&zhdr->refcount, |
985 | release_z3fold_page_locked)) { | |
986 | atomic64_dec(&pool->pages_nr); | |
987 | return 0; | |
988 | } | |
989 | /* | |
990 | * if we are here, the page is still not completely | |
991 | * free. Take the global pool lock then to be able | |
992 | * to add it back to the lru list | |
993 | */ | |
994 | spin_lock(&pool->lock); | |
995 | list_add(&page->lru, &pool->lru); | |
d5567c9d | 996 | spin_unlock(&pool->lock); |
6098d7e1 | 997 | z3fold_page_unlock(zhdr); |
5a27aa82 | 998 | } |
2f1e5e4d | 999 | |
6098d7e1 VW |
1000 | /* We started off locked to we need to lock the pool back */ |
1001 | spin_lock(&pool->lock); | |
9a001fc1 VW |
1002 | } |
1003 | spin_unlock(&pool->lock); | |
1004 | return -EAGAIN; | |
1005 | } | |
1006 | ||
1007 | /** | |
1008 | * z3fold_map() - maps the allocation associated with the given handle | |
1009 | * @pool: pool in which the allocation resides | |
1010 | * @handle: handle associated with the allocation to be mapped | |
1011 | * | |
1012 | * Extracts the buddy number from handle and constructs the pointer to the | |
1013 | * correct starting chunk within the page. | |
1014 | * | |
1015 | * Returns: a pointer to the mapped allocation | |
1016 | */ | |
1017 | static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) | |
1018 | { | |
1019 | struct z3fold_header *zhdr; | |
1020 | struct page *page; | |
1021 | void *addr; | |
1022 | enum buddy buddy; | |
1023 | ||
9a001fc1 VW |
1024 | zhdr = handle_to_z3fold_header(handle); |
1025 | addr = zhdr; | |
1026 | page = virt_to_page(zhdr); | |
1027 | ||
1028 | if (test_bit(PAGE_HEADLESS, &page->private)) | |
1029 | goto out; | |
1030 | ||
2f1e5e4d | 1031 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1032 | buddy = handle_to_buddy(handle); |
1033 | switch (buddy) { | |
1034 | case FIRST: | |
1035 | addr += ZHDR_SIZE_ALIGNED; | |
1036 | break; | |
1037 | case MIDDLE: | |
1038 | addr += zhdr->start_middle << CHUNK_SHIFT; | |
1039 | set_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
1040 | break; | |
1041 | case LAST: | |
ca0246bb | 1042 | addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); |
9a001fc1 VW |
1043 | break; |
1044 | default: | |
1045 | pr_err("unknown buddy id %d\n", buddy); | |
1046 | WARN_ON(1); | |
1047 | addr = NULL; | |
1048 | break; | |
1049 | } | |
2f1e5e4d VW |
1050 | |
1051 | z3fold_page_unlock(zhdr); | |
9a001fc1 | 1052 | out: |
9a001fc1 VW |
1053 | return addr; |
1054 | } | |
1055 | ||
1056 | /** | |
1057 | * z3fold_unmap() - unmaps the allocation associated with the given handle | |
1058 | * @pool: pool in which the allocation resides | |
1059 | * @handle: handle associated with the allocation to be unmapped | |
1060 | */ | |
1061 | static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) | |
1062 | { | |
1063 | struct z3fold_header *zhdr; | |
1064 | struct page *page; | |
1065 | enum buddy buddy; | |
1066 | ||
9a001fc1 VW |
1067 | zhdr = handle_to_z3fold_header(handle); |
1068 | page = virt_to_page(zhdr); | |
1069 | ||
2f1e5e4d | 1070 | if (test_bit(PAGE_HEADLESS, &page->private)) |
9a001fc1 | 1071 | return; |
9a001fc1 | 1072 | |
2f1e5e4d | 1073 | z3fold_page_lock(zhdr); |
9a001fc1 VW |
1074 | buddy = handle_to_buddy(handle); |
1075 | if (buddy == MIDDLE) | |
1076 | clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); | |
2f1e5e4d | 1077 | z3fold_page_unlock(zhdr); |
9a001fc1 VW |
1078 | } |
1079 | ||
1080 | /** | |
1081 | * z3fold_get_pool_size() - gets the z3fold pool size in pages | |
1082 | * @pool: pool whose size is being queried | |
1083 | * | |
12d59ae6 | 1084 | * Returns: size in pages of the given pool. |
9a001fc1 VW |
1085 | */ |
1086 | static u64 z3fold_get_pool_size(struct z3fold_pool *pool) | |
1087 | { | |
12d59ae6 | 1088 | return atomic64_read(&pool->pages_nr); |
9a001fc1 VW |
1089 | } |
1090 | ||
1091 | /***************** | |
1092 | * zpool | |
1093 | ****************/ | |
1094 | ||
1095 | static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) | |
1096 | { | |
1097 | if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) | |
1098 | return pool->zpool_ops->evict(pool->zpool, handle); | |
1099 | else | |
1100 | return -ENOENT; | |
1101 | } | |
1102 | ||
1103 | static const struct z3fold_ops z3fold_zpool_ops = { | |
1104 | .evict = z3fold_zpool_evict | |
1105 | }; | |
1106 | ||
1107 | static void *z3fold_zpool_create(const char *name, gfp_t gfp, | |
1108 | const struct zpool_ops *zpool_ops, | |
1109 | struct zpool *zpool) | |
1110 | { | |
1111 | struct z3fold_pool *pool; | |
1112 | ||
d30561c5 VW |
1113 | pool = z3fold_create_pool(name, gfp, |
1114 | zpool_ops ? &z3fold_zpool_ops : NULL); | |
9a001fc1 VW |
1115 | if (pool) { |
1116 | pool->zpool = zpool; | |
1117 | pool->zpool_ops = zpool_ops; | |
1118 | } | |
1119 | return pool; | |
1120 | } | |
1121 | ||
1122 | static void z3fold_zpool_destroy(void *pool) | |
1123 | { | |
1124 | z3fold_destroy_pool(pool); | |
1125 | } | |
1126 | ||
1127 | static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, | |
1128 | unsigned long *handle) | |
1129 | { | |
1130 | return z3fold_alloc(pool, size, gfp, handle); | |
1131 | } | |
1132 | static void z3fold_zpool_free(void *pool, unsigned long handle) | |
1133 | { | |
1134 | z3fold_free(pool, handle); | |
1135 | } | |
1136 | ||
1137 | static int z3fold_zpool_shrink(void *pool, unsigned int pages, | |
1138 | unsigned int *reclaimed) | |
1139 | { | |
1140 | unsigned int total = 0; | |
1141 | int ret = -EINVAL; | |
1142 | ||
1143 | while (total < pages) { | |
1144 | ret = z3fold_reclaim_page(pool, 8); | |
1145 | if (ret < 0) | |
1146 | break; | |
1147 | total++; | |
1148 | } | |
1149 | ||
1150 | if (reclaimed) | |
1151 | *reclaimed = total; | |
1152 | ||
1153 | return ret; | |
1154 | } | |
1155 | ||
1156 | static void *z3fold_zpool_map(void *pool, unsigned long handle, | |
1157 | enum zpool_mapmode mm) | |
1158 | { | |
1159 | return z3fold_map(pool, handle); | |
1160 | } | |
1161 | static void z3fold_zpool_unmap(void *pool, unsigned long handle) | |
1162 | { | |
1163 | z3fold_unmap(pool, handle); | |
1164 | } | |
1165 | ||
1166 | static u64 z3fold_zpool_total_size(void *pool) | |
1167 | { | |
1168 | return z3fold_get_pool_size(pool) * PAGE_SIZE; | |
1169 | } | |
1170 | ||
1171 | static struct zpool_driver z3fold_zpool_driver = { | |
1172 | .type = "z3fold", | |
1173 | .owner = THIS_MODULE, | |
1174 | .create = z3fold_zpool_create, | |
1175 | .destroy = z3fold_zpool_destroy, | |
1176 | .malloc = z3fold_zpool_malloc, | |
1177 | .free = z3fold_zpool_free, | |
1178 | .shrink = z3fold_zpool_shrink, | |
1179 | .map = z3fold_zpool_map, | |
1180 | .unmap = z3fold_zpool_unmap, | |
1181 | .total_size = z3fold_zpool_total_size, | |
1182 | }; | |
1183 | ||
1184 | MODULE_ALIAS("zpool-z3fold"); | |
1185 | ||
1186 | static int __init init_z3fold(void) | |
1187 | { | |
ede93213 VW |
1188 | /* Make sure the z3fold header is not larger than the page size */ |
1189 | BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); | |
9a001fc1 VW |
1190 | zpool_register_driver(&z3fold_zpool_driver); |
1191 | ||
1192 | return 0; | |
1193 | } | |
1194 | ||
1195 | static void __exit exit_z3fold(void) | |
1196 | { | |
1197 | zpool_unregister_driver(&z3fold_zpool_driver); | |
1198 | } | |
1199 | ||
1200 | module_init(init_z3fold); | |
1201 | module_exit(exit_z3fold); | |
1202 | ||
1203 | MODULE_LICENSE("GPL"); | |
1204 | MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); | |
1205 | MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); |