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Vitaly Wool9a001fc2016-05-20 16:58:30 -07001/*
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>
Vitaly Woold30561c2017-09-06 16:24:47 -070026#include <linux/sched.h>
Vitaly Wool9a001fc2016-05-20 16:58:30 -070027#include <linux/list.h>
28#include <linux/mm.h>
29#include <linux/module.h>
Vitaly Woold30561c2017-09-06 16:24:47 -070030#include <linux/percpu.h>
Vitaly Wool9a001fc2016-05-20 16:58:30 -070031#include <linux/preempt.h>
Vitaly Woold30561c2017-09-06 16:24:47 -070032#include <linux/workqueue.h>
Vitaly Wool9a001fc2016-05-20 16:58:30 -070033#include <linux/slab.h>
34#include <linux/spinlock.h>
35#include <linux/zpool.h>
36
37/*****************
38 * Structures
39*****************/
Vitaly Woolede93212017-02-24 14:57:17 -080040struct z3fold_pool;
41struct z3fold_ops {
42 int (*evict)(struct z3fold_pool *pool, unsigned long handle);
43};
44
45enum buddy {
46 HEADLESS = 0,
47 FIRST,
48 MIDDLE,
49 LAST,
50 BUDDIES_MAX
51};
52
53/*
Vitaly Woold30561c2017-09-06 16:24:47 -070054 * struct z3fold_header - z3fold page metadata occupying first chunks of each
Vitaly Woolede93212017-02-24 14:57:17 -080055 * z3fold page, except for HEADLESS pages
Vitaly Woold30561c2017-09-06 16:24:47 -070056 * @buddy: links the z3fold page into the relevant list in the
57 * pool
Vitaly Wool2f1e5e42017-02-24 14:57:23 -080058 * @page_lock: per-page lock
Vitaly Woold30561c2017-09-06 16:24:47 -070059 * @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
Vitaly Woolede93212017-02-24 14:57:17 -080063 * @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 */
68struct z3fold_header {
69 struct list_head buddy;
Vitaly Wool2f1e5e42017-02-24 14:57:23 -080070 spinlock_t page_lock;
Vitaly Wool5a27aa82017-02-24 14:57:26 -080071 struct kref refcount;
Vitaly Woold30561c2017-09-06 16:24:47 -070072 struct work_struct work;
73 struct z3fold_pool *pool;
74 short cpu;
Vitaly Woolede93212017-02-24 14:57:17 -080075 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
Vitaly Wool9a001fc2016-05-20 16:58:30 -070082/*
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
Vitaly Woolede93212017-02-24 14:57:17 -080086 * 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.
Vitaly Wool9a001fc2016-05-20 16:58:30 -070091 */
92#define NCHUNKS_ORDER 6
93
94#define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER)
95#define CHUNK_SIZE (1 << CHUNK_SHIFT)
Vitaly Woolede93212017-02-24 14:57:17 -080096#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)
Vitaly Wool9a001fc2016-05-20 16:58:30 -070099#define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT)
100
zhong jiangf201ebd2017-02-22 15:46:51 -0800101#define BUDDY_MASK (0x3)
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700102
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700103/**
104 * struct z3fold_pool - stores metadata for each z3fold pool
Vitaly Woold30561c2017-09-06 16:24:47 -0700105 * @name: pool name
106 * @lock: protects pool unbuddied/lru lists
107 * @stale_lock: protects pool stale page list
108 * @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2-
109 * buddies; the list each z3fold page is added to depends on
110 * the size of its free region.
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700111 * @lru: list tracking the z3fold pages in LRU order by most recently
112 * added buddy.
Vitaly Woold30561c2017-09-06 16:24:47 -0700113 * @stale: list of pages marked for freeing
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700114 * @pages_nr: number of z3fold pages in the pool.
115 * @ops: pointer to a structure of user defined operations specified at
116 * pool creation time.
Vitaly Woold30561c2017-09-06 16:24:47 -0700117 * @compact_wq: workqueue for page layout background optimization
118 * @release_wq: workqueue for safe page release
119 * @work: work_struct for safe page release
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700120 *
121 * This structure is allocated at pool creation time and maintains metadata
122 * pertaining to a particular z3fold pool.
123 */
124struct z3fold_pool {
Vitaly Woold30561c2017-09-06 16:24:47 -0700125 const char *name;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700126 spinlock_t lock;
Vitaly Woold30561c2017-09-06 16:24:47 -0700127 spinlock_t stale_lock;
128 struct list_head *unbuddied;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700129 struct list_head lru;
Vitaly Woold30561c2017-09-06 16:24:47 -0700130 struct list_head stale;
Vitaly Wool12d59ae2017-02-24 14:57:15 -0800131 atomic64_t pages_nr;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700132 const struct z3fold_ops *ops;
133 struct zpool *zpool;
134 const struct zpool_ops *zpool_ops;
Vitaly Woold30561c2017-09-06 16:24:47 -0700135 struct workqueue_struct *compact_wq;
136 struct workqueue_struct *release_wq;
137 struct work_struct work;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700138};
139
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700140/*
141 * Internal z3fold page flags
142 */
143enum z3fold_page_flags {
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800144 PAGE_HEADLESS = 0,
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700145 MIDDLE_CHUNK_MAPPED,
Vitaly Woold30561c2017-09-06 16:24:47 -0700146 NEEDS_COMPACTING,
147 PAGE_STALE
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700148};
149
150/*****************
151 * Helpers
152*****************/
153
154/* Converts an allocation size in bytes to size in z3fold chunks */
155static int size_to_chunks(size_t size)
156{
157 return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
158}
159
160#define for_each_unbuddied_list(_iter, _begin) \
161 for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++)
162
Vitaly Woold30561c2017-09-06 16:24:47 -0700163static void compact_page_work(struct work_struct *w);
164
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700165/* Initializes the z3fold header of a newly allocated z3fold page */
Vitaly Woold30561c2017-09-06 16:24:47 -0700166static struct z3fold_header *init_z3fold_page(struct page *page,
167 struct z3fold_pool *pool)
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700168{
169 struct z3fold_header *zhdr = page_address(page);
170
171 INIT_LIST_HEAD(&page->lru);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700172 clear_bit(PAGE_HEADLESS, &page->private);
173 clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
Vitaly Woold30561c2017-09-06 16:24:47 -0700174 clear_bit(NEEDS_COMPACTING, &page->private);
175 clear_bit(PAGE_STALE, &page->private);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700176
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800177 spin_lock_init(&zhdr->page_lock);
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800178 kref_init(&zhdr->refcount);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700179 zhdr->first_chunks = 0;
180 zhdr->middle_chunks = 0;
181 zhdr->last_chunks = 0;
182 zhdr->first_num = 0;
183 zhdr->start_middle = 0;
Vitaly Woold30561c2017-09-06 16:24:47 -0700184 zhdr->cpu = -1;
185 zhdr->pool = pool;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700186 INIT_LIST_HEAD(&zhdr->buddy);
Vitaly Woold30561c2017-09-06 16:24:47 -0700187 INIT_WORK(&zhdr->work, compact_page_work);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700188 return zhdr;
189}
190
191/* Resets the struct page fields and frees the page */
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800192static void free_z3fold_page(struct page *page)
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700193{
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800194 __free_page(page);
195}
196
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800197/* Lock a z3fold page */
198static inline void z3fold_page_lock(struct z3fold_header *zhdr)
199{
200 spin_lock(&zhdr->page_lock);
201}
202
Vitaly Wool76e32a22017-04-13 14:56:14 -0700203/* Try to lock a z3fold page */
204static inline int z3fold_page_trylock(struct z3fold_header *zhdr)
205{
206 return spin_trylock(&zhdr->page_lock);
207}
208
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800209/* Unlock a z3fold page */
210static inline void z3fold_page_unlock(struct z3fold_header *zhdr)
211{
212 spin_unlock(&zhdr->page_lock);
213}
214
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700215/*
216 * Encodes the handle of a particular buddy within a z3fold page
217 * Pool lock should be held as this function accesses first_num
218 */
219static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud)
220{
221 unsigned long handle;
222
223 handle = (unsigned long)zhdr;
224 if (bud != HEADLESS)
225 handle += (bud + zhdr->first_num) & BUDDY_MASK;
226 return handle;
227}
228
229/* Returns the z3fold page where a given handle is stored */
230static struct z3fold_header *handle_to_z3fold_header(unsigned long handle)
231{
232 return (struct z3fold_header *)(handle & PAGE_MASK);
233}
234
zhong jiangf201ebd2017-02-22 15:46:51 -0800235/*
236 * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle
237 * but that doesn't matter. because the masking will result in the
238 * correct buddy number.
239 */
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700240static enum buddy handle_to_buddy(unsigned long handle)
241{
242 struct z3fold_header *zhdr = handle_to_z3fold_header(handle);
243 return (handle - zhdr->first_num) & BUDDY_MASK;
244}
245
Vitaly Woold30561c2017-09-06 16:24:47 -0700246static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked)
247{
248 struct page *page = virt_to_page(zhdr);
249 struct z3fold_pool *pool = zhdr->pool;
250
251 WARN_ON(!list_empty(&zhdr->buddy));
252 set_bit(PAGE_STALE, &page->private);
Vitaly Wool35529352017-10-03 16:15:06 -0700253 clear_bit(NEEDS_COMPACTING, &page->private);
Vitaly Woold30561c2017-09-06 16:24:47 -0700254 spin_lock(&pool->lock);
255 if (!list_empty(&page->lru))
256 list_del(&page->lru);
257 spin_unlock(&pool->lock);
258 if (locked)
259 z3fold_page_unlock(zhdr);
260 spin_lock(&pool->stale_lock);
261 list_add(&zhdr->buddy, &pool->stale);
262 queue_work(pool->release_wq, &pool->work);
263 spin_unlock(&pool->stale_lock);
264}
265
266static void __attribute__((__unused__))
267 release_z3fold_page(struct kref *ref)
268{
269 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
270 refcount);
271 __release_z3fold_page(zhdr, false);
272}
273
274static void release_z3fold_page_locked(struct kref *ref)
275{
276 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
277 refcount);
278 WARN_ON(z3fold_page_trylock(zhdr));
279 __release_z3fold_page(zhdr, true);
280}
281
282static void release_z3fold_page_locked_list(struct kref *ref)
283{
284 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
285 refcount);
286 spin_lock(&zhdr->pool->lock);
287 list_del_init(&zhdr->buddy);
288 spin_unlock(&zhdr->pool->lock);
289
290 WARN_ON(z3fold_page_trylock(zhdr));
291 __release_z3fold_page(zhdr, true);
292}
293
294static void free_pages_work(struct work_struct *w)
295{
296 struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work);
297
298 spin_lock(&pool->stale_lock);
299 while (!list_empty(&pool->stale)) {
300 struct z3fold_header *zhdr = list_first_entry(&pool->stale,
301 struct z3fold_header, buddy);
302 struct page *page = virt_to_page(zhdr);
303
304 list_del(&zhdr->buddy);
305 if (WARN_ON(!test_bit(PAGE_STALE, &page->private)))
306 continue;
Vitaly Woold30561c2017-09-06 16:24:47 -0700307 spin_unlock(&pool->stale_lock);
308 cancel_work_sync(&zhdr->work);
309 free_z3fold_page(page);
310 cond_resched();
311 spin_lock(&pool->stale_lock);
312 }
313 spin_unlock(&pool->stale_lock);
314}
315
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700316/*
317 * Returns the number of free chunks in a z3fold page.
318 * NB: can't be used with HEADLESS pages.
319 */
320static int num_free_chunks(struct z3fold_header *zhdr)
321{
322 int nfree;
323 /*
324 * If there is a middle object, pick up the bigger free space
325 * either before or after it. Otherwise just subtract the number
326 * of chunks occupied by the first and the last objects.
327 */
328 if (zhdr->middle_chunks != 0) {
329 int nfree_before = zhdr->first_chunks ?
Vitaly Woolede93212017-02-24 14:57:17 -0800330 0 : zhdr->start_middle - ZHDR_CHUNKS;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700331 int nfree_after = zhdr->last_chunks ?
Vitaly Woolede93212017-02-24 14:57:17 -0800332 0 : TOTAL_CHUNKS -
333 (zhdr->start_middle + zhdr->middle_chunks);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700334 nfree = max(nfree_before, nfree_after);
335 } else
336 nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks;
337 return nfree;
338}
339
Vitaly Woolede93212017-02-24 14:57:17 -0800340static inline void *mchunk_memmove(struct z3fold_header *zhdr,
341 unsigned short dst_chunk)
342{
343 void *beg = zhdr;
344 return memmove(beg + (dst_chunk << CHUNK_SHIFT),
345 beg + (zhdr->start_middle << CHUNK_SHIFT),
346 zhdr->middle_chunks << CHUNK_SHIFT);
347}
348
Vitaly Wool1b096e52017-02-24 14:57:20 -0800349#define BIG_CHUNK_GAP 3
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700350/* Has to be called with lock held */
351static int z3fold_compact_page(struct z3fold_header *zhdr)
352{
353 struct page *page = virt_to_page(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700354
Vitaly Woolede93212017-02-24 14:57:17 -0800355 if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
356 return 0; /* can't move middle chunk, it's used */
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700357
Vitaly Woolede93212017-02-24 14:57:17 -0800358 if (zhdr->middle_chunks == 0)
359 return 0; /* nothing to compact */
360
361 if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
362 /* move to the beginning */
363 mchunk_memmove(zhdr, ZHDR_CHUNKS);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700364 zhdr->first_chunks = zhdr->middle_chunks;
365 zhdr->middle_chunks = 0;
366 zhdr->start_middle = 0;
367 zhdr->first_num++;
Vitaly Wool1b096e52017-02-24 14:57:20 -0800368 return 1;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700369 }
Vitaly Wool1b096e52017-02-24 14:57:20 -0800370
371 /*
372 * moving data is expensive, so let's only do that if
373 * there's substantial gain (at least BIG_CHUNK_GAP chunks)
374 */
375 if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 &&
376 zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >=
377 BIG_CHUNK_GAP) {
378 mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
379 zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
380 return 1;
381 } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
382 TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
383 + zhdr->middle_chunks) >=
384 BIG_CHUNK_GAP) {
385 unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks -
386 zhdr->middle_chunks;
387 mchunk_memmove(zhdr, new_start);
388 zhdr->start_middle = new_start;
389 return 1;
390 }
391
392 return 0;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700393}
394
Vitaly Woold30561c2017-09-06 16:24:47 -0700395static void do_compact_page(struct z3fold_header *zhdr, bool locked)
396{
397 struct z3fold_pool *pool = zhdr->pool;
398 struct page *page;
399 struct list_head *unbuddied;
400 int fchunks;
401
402 page = virt_to_page(zhdr);
403 if (locked)
404 WARN_ON(z3fold_page_trylock(zhdr));
405 else
406 z3fold_page_lock(zhdr);
Vitaly Wool5d03a662017-11-17 15:26:16 -0800407 if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) {
Vitaly Woold30561c2017-09-06 16:24:47 -0700408 z3fold_page_unlock(zhdr);
409 return;
410 }
411 spin_lock(&pool->lock);
412 list_del_init(&zhdr->buddy);
413 spin_unlock(&pool->lock);
414
Vitaly Wool5d03a662017-11-17 15:26:16 -0800415 if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
416 atomic64_dec(&pool->pages_nr);
417 return;
418 }
419
Vitaly Woold30561c2017-09-06 16:24:47 -0700420 z3fold_compact_page(zhdr);
421 unbuddied = get_cpu_ptr(pool->unbuddied);
422 fchunks = num_free_chunks(zhdr);
423 if (fchunks < NCHUNKS &&
424 (!zhdr->first_chunks || !zhdr->middle_chunks ||
425 !zhdr->last_chunks)) {
426 /* the page's not completely free and it's unbuddied */
427 spin_lock(&pool->lock);
428 list_add(&zhdr->buddy, &unbuddied[fchunks]);
429 spin_unlock(&pool->lock);
430 zhdr->cpu = smp_processor_id();
431 }
432 put_cpu_ptr(pool->unbuddied);
433 z3fold_page_unlock(zhdr);
434}
435
436static void compact_page_work(struct work_struct *w)
437{
438 struct z3fold_header *zhdr = container_of(w, struct z3fold_header,
439 work);
440
441 do_compact_page(zhdr, false);
442}
443
444
445/*
446 * API Functions
447 */
448
449/**
450 * z3fold_create_pool() - create a new z3fold pool
451 * @name: pool name
452 * @gfp: gfp flags when allocating the z3fold pool structure
453 * @ops: user-defined operations for the z3fold pool
454 *
455 * Return: pointer to the new z3fold pool or NULL if the metadata allocation
456 * failed.
457 */
458static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
459 const struct z3fold_ops *ops)
460{
461 struct z3fold_pool *pool = NULL;
462 int i, cpu;
463
464 pool = kzalloc(sizeof(struct z3fold_pool), gfp);
465 if (!pool)
466 goto out;
467 spin_lock_init(&pool->lock);
468 spin_lock_init(&pool->stale_lock);
469 pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2);
Xidong Wang1ec69952018-04-10 16:29:34 -0700470 if (!pool->unbuddied)
471 goto out_pool;
Vitaly Woold30561c2017-09-06 16:24:47 -0700472 for_each_possible_cpu(cpu) {
473 struct list_head *unbuddied =
474 per_cpu_ptr(pool->unbuddied, cpu);
475 for_each_unbuddied_list(i, 0)
476 INIT_LIST_HEAD(&unbuddied[i]);
477 }
478 INIT_LIST_HEAD(&pool->lru);
479 INIT_LIST_HEAD(&pool->stale);
480 atomic64_set(&pool->pages_nr, 0);
481 pool->name = name;
482 pool->compact_wq = create_singlethread_workqueue(pool->name);
483 if (!pool->compact_wq)
Xidong Wang1ec69952018-04-10 16:29:34 -0700484 goto out_unbuddied;
Vitaly Woold30561c2017-09-06 16:24:47 -0700485 pool->release_wq = create_singlethread_workqueue(pool->name);
486 if (!pool->release_wq)
487 goto out_wq;
488 INIT_WORK(&pool->work, free_pages_work);
489 pool->ops = ops;
490 return pool;
491
492out_wq:
493 destroy_workqueue(pool->compact_wq);
Xidong Wang1ec69952018-04-10 16:29:34 -0700494out_unbuddied:
495 free_percpu(pool->unbuddied);
496out_pool:
Vitaly Woold30561c2017-09-06 16:24:47 -0700497 kfree(pool);
Xidong Wang1ec69952018-04-10 16:29:34 -0700498out:
Vitaly Woold30561c2017-09-06 16:24:47 -0700499 return NULL;
500}
501
502/**
503 * z3fold_destroy_pool() - destroys an existing z3fold pool
504 * @pool: the z3fold pool to be destroyed
505 *
506 * The pool should be emptied before this function is called.
507 */
508static void z3fold_destroy_pool(struct z3fold_pool *pool)
509{
510 destroy_workqueue(pool->release_wq);
511 destroy_workqueue(pool->compact_wq);
512 kfree(pool);
513}
514
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700515/**
516 * z3fold_alloc() - allocates a region of a given size
517 * @pool: z3fold pool from which to allocate
518 * @size: size in bytes of the desired allocation
519 * @gfp: gfp flags used if the pool needs to grow
520 * @handle: handle of the new allocation
521 *
522 * This function will attempt to find a free region in the pool large enough to
523 * satisfy the allocation request. A search of the unbuddied lists is
524 * performed first. If no suitable free region is found, then a new page is
525 * allocated and added to the pool to satisfy the request.
526 *
527 * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used
528 * as z3fold pool pages.
529 *
530 * Return: 0 if success and handle is set, otherwise -EINVAL if the size or
531 * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate
532 * a new page.
533 */
534static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
535 unsigned long *handle)
536{
537 int chunks = 0, i, freechunks;
538 struct z3fold_header *zhdr = NULL;
Vitaly Woold30561c2017-09-06 16:24:47 -0700539 struct page *page = NULL;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700540 enum buddy bud;
Matthew Wilcox8a97ea52018-04-10 16:29:37 -0700541 bool can_sleep = gfpflags_allow_blocking(gfp);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700542
543 if (!size || (gfp & __GFP_HIGHMEM))
544 return -EINVAL;
545
546 if (size > PAGE_SIZE)
547 return -ENOSPC;
548
549 if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE)
550 bud = HEADLESS;
551 else {
Vitaly Woold30561c2017-09-06 16:24:47 -0700552 struct list_head *unbuddied;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700553 chunks = size_to_chunks(size);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700554
Vitaly Woold30561c2017-09-06 16:24:47 -0700555lookup:
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700556 /* First, try to find an unbuddied z3fold page. */
Vitaly Woold30561c2017-09-06 16:24:47 -0700557 unbuddied = get_cpu_ptr(pool->unbuddied);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700558 for_each_unbuddied_list(i, chunks) {
Vitaly Woold30561c2017-09-06 16:24:47 -0700559 struct list_head *l = &unbuddied[i];
560
561 zhdr = list_first_entry_or_null(READ_ONCE(l),
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700562 struct z3fold_header, buddy);
Vitaly Woold30561c2017-09-06 16:24:47 -0700563
564 if (!zhdr)
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800565 continue;
Vitaly Woold30561c2017-09-06 16:24:47 -0700566
567 /* Re-check under lock. */
568 spin_lock(&pool->lock);
569 l = &unbuddied[i];
570 if (unlikely(zhdr != list_first_entry(READ_ONCE(l),
571 struct z3fold_header, buddy)) ||
572 !z3fold_page_trylock(zhdr)) {
573 spin_unlock(&pool->lock);
574 put_cpu_ptr(pool->unbuddied);
575 goto lookup;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700576 }
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800577 list_del_init(&zhdr->buddy);
Vitaly Woold30561c2017-09-06 16:24:47 -0700578 zhdr->cpu = -1;
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800579 spin_unlock(&pool->lock);
580
581 page = virt_to_page(zhdr);
Vitaly Woold30561c2017-09-06 16:24:47 -0700582 if (test_bit(NEEDS_COMPACTING, &page->private)) {
583 z3fold_page_unlock(zhdr);
584 zhdr = NULL;
585 put_cpu_ptr(pool->unbuddied);
586 if (can_sleep)
587 cond_resched();
588 goto lookup;
589 }
590
591 /*
592 * this page could not be removed from its unbuddied
593 * list while pool lock was held, and then we've taken
594 * page lock so kref_put could not be called before
595 * we got here, so it's safe to just call kref_get()
596 */
597 kref_get(&zhdr->refcount);
598 break;
599 }
600 put_cpu_ptr(pool->unbuddied);
601
602 if (zhdr) {
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800603 if (zhdr->first_chunks == 0) {
604 if (zhdr->middle_chunks != 0 &&
605 chunks >= zhdr->start_middle)
606 bud = LAST;
607 else
608 bud = FIRST;
609 } else if (zhdr->last_chunks == 0)
610 bud = LAST;
611 else if (zhdr->middle_chunks == 0)
612 bud = MIDDLE;
613 else {
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800614 if (kref_put(&zhdr->refcount,
Vitaly Woold30561c2017-09-06 16:24:47 -0700615 release_z3fold_page_locked))
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800616 atomic64_dec(&pool->pages_nr);
Vitaly Woold30561c2017-09-06 16:24:47 -0700617 else
618 z3fold_page_unlock(zhdr);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800619 pr_err("No free chunks in unbuddied\n");
620 WARN_ON(1);
Vitaly Woold30561c2017-09-06 16:24:47 -0700621 goto lookup;
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800622 }
623 goto found;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700624 }
625 bud = FIRST;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700626 }
627
Vitaly Wool5c9bab52018-04-05 16:23:32 -0700628 page = NULL;
629 if (can_sleep) {
630 spin_lock(&pool->stale_lock);
631 zhdr = list_first_entry_or_null(&pool->stale,
632 struct z3fold_header, buddy);
633 /*
634 * Before allocating a page, let's see if we can take one from
635 * the stale pages list. cancel_work_sync() can sleep so we
636 * limit this case to the contexts where we can sleep
637 */
638 if (zhdr) {
639 list_del(&zhdr->buddy);
640 spin_unlock(&pool->stale_lock);
Vitaly Woold30561c2017-09-06 16:24:47 -0700641 cancel_work_sync(&zhdr->work);
Vitaly Wool5c9bab52018-04-05 16:23:32 -0700642 page = virt_to_page(zhdr);
643 } else {
644 spin_unlock(&pool->stale_lock);
645 }
Vitaly Woold30561c2017-09-06 16:24:47 -0700646 }
Vitaly Wool5c9bab52018-04-05 16:23:32 -0700647 if (!page)
648 page = alloc_page(gfp);
Vitaly Woold30561c2017-09-06 16:24:47 -0700649
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700650 if (!page)
651 return -ENOMEM;
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800652
Vitaly Wool12d59ae2017-02-24 14:57:15 -0800653 atomic64_inc(&pool->pages_nr);
Vitaly Woold30561c2017-09-06 16:24:47 -0700654 zhdr = init_z3fold_page(page, pool);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700655
656 if (bud == HEADLESS) {
657 set_bit(PAGE_HEADLESS, &page->private);
658 goto headless;
659 }
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800660 z3fold_page_lock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700661
662found:
663 if (bud == FIRST)
664 zhdr->first_chunks = chunks;
665 else if (bud == LAST)
666 zhdr->last_chunks = chunks;
667 else {
668 zhdr->middle_chunks = chunks;
Vitaly Woolede93212017-02-24 14:57:17 -0800669 zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700670 }
671
672 if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 ||
673 zhdr->middle_chunks == 0) {
Vitaly Woold30561c2017-09-06 16:24:47 -0700674 struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied);
675
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700676 /* Add to unbuddied list */
677 freechunks = num_free_chunks(zhdr);
Vitaly Woold30561c2017-09-06 16:24:47 -0700678 spin_lock(&pool->lock);
679 list_add(&zhdr->buddy, &unbuddied[freechunks]);
680 spin_unlock(&pool->lock);
681 zhdr->cpu = smp_processor_id();
682 put_cpu_ptr(pool->unbuddied);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700683 }
684
685headless:
Vitaly Woold30561c2017-09-06 16:24:47 -0700686 spin_lock(&pool->lock);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700687 /* Add/move z3fold page to beginning of LRU */
688 if (!list_empty(&page->lru))
689 list_del(&page->lru);
690
691 list_add(&page->lru, &pool->lru);
692
693 *handle = encode_handle(zhdr, bud);
694 spin_unlock(&pool->lock);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800695 if (bud != HEADLESS)
696 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700697
698 return 0;
699}
700
701/**
702 * z3fold_free() - frees the allocation associated with the given handle
703 * @pool: pool in which the allocation resided
704 * @handle: handle associated with the allocation returned by z3fold_alloc()
705 *
706 * In the case that the z3fold page in which the allocation resides is under
707 * reclaim, as indicated by the PG_reclaim flag being set, this function
708 * only sets the first|last_chunks to 0. The page is actually freed
709 * once both buddies are evicted (see z3fold_reclaim_page() below).
710 */
711static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
712{
713 struct z3fold_header *zhdr;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700714 struct page *page;
715 enum buddy bud;
716
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700717 zhdr = handle_to_z3fold_header(handle);
718 page = virt_to_page(zhdr);
719
720 if (test_bit(PAGE_HEADLESS, &page->private)) {
721 /* HEADLESS page stored */
722 bud = HEADLESS;
723 } else {
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800724 z3fold_page_lock(zhdr);
Vitaly Wool43afc192016-06-03 14:55:47 -0700725 bud = handle_to_buddy(handle);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700726
727 switch (bud) {
728 case FIRST:
729 zhdr->first_chunks = 0;
730 break;
731 case MIDDLE:
732 zhdr->middle_chunks = 0;
733 zhdr->start_middle = 0;
734 break;
735 case LAST:
736 zhdr->last_chunks = 0;
737 break;
738 default:
739 pr_err("%s: unknown bud %d\n", __func__, bud);
740 WARN_ON(1);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800741 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700742 return;
743 }
744 }
745
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800746 if (bud == HEADLESS) {
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800747 spin_lock(&pool->lock);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700748 list_del(&page->lru);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800749 spin_unlock(&pool->lock);
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800750 free_z3fold_page(page);
Vitaly Wool12d59ae2017-02-24 14:57:15 -0800751 atomic64_dec(&pool->pages_nr);
Vitaly Woold30561c2017-09-06 16:24:47 -0700752 return;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700753 }
754
Vitaly Woold30561c2017-09-06 16:24:47 -0700755 if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) {
756 atomic64_dec(&pool->pages_nr);
757 return;
758 }
759 if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) {
760 z3fold_page_unlock(zhdr);
761 return;
762 }
763 if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) {
764 spin_lock(&pool->lock);
765 list_del_init(&zhdr->buddy);
766 spin_unlock(&pool->lock);
767 zhdr->cpu = -1;
Vitaly Wool5d03a662017-11-17 15:26:16 -0800768 kref_get(&zhdr->refcount);
Vitaly Woold30561c2017-09-06 16:24:47 -0700769 do_compact_page(zhdr, true);
770 return;
771 }
Vitaly Wool5d03a662017-11-17 15:26:16 -0800772 kref_get(&zhdr->refcount);
Vitaly Woold30561c2017-09-06 16:24:47 -0700773 queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work);
774 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700775}
776
777/**
778 * z3fold_reclaim_page() - evicts allocations from a pool page and frees it
779 * @pool: pool from which a page will attempt to be evicted
Mike Rapoportf144c392018-02-06 15:42:16 -0800780 * @retries: number of pages on the LRU list for which eviction will
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700781 * be attempted before failing
782 *
783 * z3fold reclaim is different from normal system reclaim in that it is done
784 * from the bottom, up. This is because only the bottom layer, z3fold, has
785 * information on how the allocations are organized within each z3fold page.
786 * This has the potential to create interesting locking situations between
787 * z3fold and the user, however.
788 *
789 * To avoid these, this is how z3fold_reclaim_page() should be called:
Mike Rapoportf144c392018-02-06 15:42:16 -0800790 *
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700791 * The user detects a page should be reclaimed and calls z3fold_reclaim_page().
792 * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and
793 * call the user-defined eviction handler with the pool and handle as
794 * arguments.
795 *
796 * If the handle can not be evicted, the eviction handler should return
797 * non-zero. z3fold_reclaim_page() will add the z3fold page back to the
798 * appropriate list and try the next z3fold page on the LRU up to
799 * a user defined number of retries.
800 *
801 * If the handle is successfully evicted, the eviction handler should
802 * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free()
803 * contains logic to delay freeing the page if the page is under reclaim,
804 * as indicated by the setting of the PG_reclaim flag on the underlying page.
805 *
806 * If all buddies in the z3fold page are successfully evicted, then the
807 * z3fold page can be freed.
808 *
809 * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are
810 * no pages to evict or an eviction handler is not registered, -EAGAIN if
811 * the retry limit was hit.
812 */
813static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
814{
Vitaly Woold30561c2017-09-06 16:24:47 -0700815 int i, ret = 0;
816 struct z3fold_header *zhdr = NULL;
817 struct page *page = NULL;
818 struct list_head *pos;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700819 unsigned long first_handle = 0, middle_handle = 0, last_handle = 0;
820
821 spin_lock(&pool->lock);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800822 if (!pool->ops || !pool->ops->evict || retries == 0) {
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700823 spin_unlock(&pool->lock);
824 return -EINVAL;
825 }
826 for (i = 0; i < retries; i++) {
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800827 if (list_empty(&pool->lru)) {
828 spin_unlock(&pool->lock);
829 return -EINVAL;
830 }
Vitaly Woold30561c2017-09-06 16:24:47 -0700831 list_for_each_prev(pos, &pool->lru) {
832 page = list_entry(pos, struct page, lru);
833 if (test_bit(PAGE_HEADLESS, &page->private))
834 /* candidate found */
835 break;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700836
Vitaly Woold30561c2017-09-06 16:24:47 -0700837 zhdr = page_address(page);
838 if (!z3fold_page_trylock(zhdr))
839 continue; /* can't evict at this point */
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800840 kref_get(&zhdr->refcount);
Vitaly Woold30561c2017-09-06 16:24:47 -0700841 list_del_init(&zhdr->buddy);
842 zhdr->cpu = -1;
843 }
844
845 list_del_init(&page->lru);
846 spin_unlock(&pool->lock);
847
848 if (!test_bit(PAGE_HEADLESS, &page->private)) {
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700849 /*
850 * We need encode the handles before unlocking, since
851 * we can race with free that will set
852 * (first|last)_chunks to 0
853 */
854 first_handle = 0;
855 last_handle = 0;
856 middle_handle = 0;
857 if (zhdr->first_chunks)
858 first_handle = encode_handle(zhdr, FIRST);
859 if (zhdr->middle_chunks)
860 middle_handle = encode_handle(zhdr, MIDDLE);
861 if (zhdr->last_chunks)
862 last_handle = encode_handle(zhdr, LAST);
Vitaly Woold30561c2017-09-06 16:24:47 -0700863 /*
864 * it's safe to unlock here because we hold a
865 * reference to this page
866 */
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800867 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700868 } else {
869 first_handle = encode_handle(zhdr, HEADLESS);
870 last_handle = middle_handle = 0;
871 }
872
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700873 /* Issue the eviction callback(s) */
874 if (middle_handle) {
875 ret = pool->ops->evict(pool, middle_handle);
876 if (ret)
877 goto next;
878 }
879 if (first_handle) {
880 ret = pool->ops->evict(pool, first_handle);
881 if (ret)
882 goto next;
883 }
884 if (last_handle) {
885 ret = pool->ops->evict(pool, last_handle);
886 if (ret)
887 goto next;
888 }
889next:
Vitaly Woold5567c92017-10-03 16:14:47 -0700890 spin_lock(&pool->lock);
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800891 if (test_bit(PAGE_HEADLESS, &page->private)) {
892 if (ret == 0) {
Vitaly Woold5567c92017-10-03 16:14:47 -0700893 spin_unlock(&pool->lock);
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800894 free_z3fold_page(page);
895 return 0;
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800896 }
Vitaly Woold30561c2017-09-06 16:24:47 -0700897 } else if (kref_put(&zhdr->refcount, release_z3fold_page)) {
898 atomic64_dec(&pool->pages_nr);
Vitaly Woold5567c92017-10-03 16:14:47 -0700899 spin_unlock(&pool->lock);
Vitaly Woold30561c2017-09-06 16:24:47 -0700900 return 0;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700901 }
902
Vitaly Wool5a27aa82017-02-24 14:57:26 -0800903 /*
904 * Add to the beginning of LRU.
905 * Pool lock has to be kept here to ensure the page has
906 * not already been released
907 */
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700908 list_add(&page->lru, &pool->lru);
909 }
910 spin_unlock(&pool->lock);
911 return -EAGAIN;
912}
913
914/**
915 * z3fold_map() - maps the allocation associated with the given handle
916 * @pool: pool in which the allocation resides
917 * @handle: handle associated with the allocation to be mapped
918 *
919 * Extracts the buddy number from handle and constructs the pointer to the
920 * correct starting chunk within the page.
921 *
922 * Returns: a pointer to the mapped allocation
923 */
924static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle)
925{
926 struct z3fold_header *zhdr;
927 struct page *page;
928 void *addr;
929 enum buddy buddy;
930
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700931 zhdr = handle_to_z3fold_header(handle);
932 addr = zhdr;
933 page = virt_to_page(zhdr);
934
935 if (test_bit(PAGE_HEADLESS, &page->private))
936 goto out;
937
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800938 z3fold_page_lock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700939 buddy = handle_to_buddy(handle);
940 switch (buddy) {
941 case FIRST:
942 addr += ZHDR_SIZE_ALIGNED;
943 break;
944 case MIDDLE:
945 addr += zhdr->start_middle << CHUNK_SHIFT;
946 set_bit(MIDDLE_CHUNK_MAPPED, &page->private);
947 break;
948 case LAST:
949 addr += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT);
950 break;
951 default:
952 pr_err("unknown buddy id %d\n", buddy);
953 WARN_ON(1);
954 addr = NULL;
955 break;
956 }
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800957
958 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700959out:
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700960 return addr;
961}
962
963/**
964 * z3fold_unmap() - unmaps the allocation associated with the given handle
965 * @pool: pool in which the allocation resides
966 * @handle: handle associated with the allocation to be unmapped
967 */
968static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle)
969{
970 struct z3fold_header *zhdr;
971 struct page *page;
972 enum buddy buddy;
973
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700974 zhdr = handle_to_z3fold_header(handle);
975 page = virt_to_page(zhdr);
976
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800977 if (test_bit(PAGE_HEADLESS, &page->private))
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700978 return;
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700979
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800980 z3fold_page_lock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700981 buddy = handle_to_buddy(handle);
982 if (buddy == MIDDLE)
983 clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
Vitaly Wool2f1e5e42017-02-24 14:57:23 -0800984 z3fold_page_unlock(zhdr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700985}
986
987/**
988 * z3fold_get_pool_size() - gets the z3fold pool size in pages
989 * @pool: pool whose size is being queried
990 *
Vitaly Wool12d59ae2017-02-24 14:57:15 -0800991 * Returns: size in pages of the given pool.
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700992 */
993static u64 z3fold_get_pool_size(struct z3fold_pool *pool)
994{
Vitaly Wool12d59ae2017-02-24 14:57:15 -0800995 return atomic64_read(&pool->pages_nr);
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700996}
997
998/*****************
999 * zpool
1000 ****************/
1001
1002static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle)
1003{
1004 if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
1005 return pool->zpool_ops->evict(pool->zpool, handle);
1006 else
1007 return -ENOENT;
1008}
1009
1010static const struct z3fold_ops z3fold_zpool_ops = {
1011 .evict = z3fold_zpool_evict
1012};
1013
1014static void *z3fold_zpool_create(const char *name, gfp_t gfp,
1015 const struct zpool_ops *zpool_ops,
1016 struct zpool *zpool)
1017{
1018 struct z3fold_pool *pool;
1019
Vitaly Woold30561c2017-09-06 16:24:47 -07001020 pool = z3fold_create_pool(name, gfp,
1021 zpool_ops ? &z3fold_zpool_ops : NULL);
Vitaly Wool9a001fc2016-05-20 16:58:30 -07001022 if (pool) {
1023 pool->zpool = zpool;
1024 pool->zpool_ops = zpool_ops;
1025 }
1026 return pool;
1027}
1028
1029static void z3fold_zpool_destroy(void *pool)
1030{
1031 z3fold_destroy_pool(pool);
1032}
1033
1034static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp,
1035 unsigned long *handle)
1036{
1037 return z3fold_alloc(pool, size, gfp, handle);
1038}
1039static void z3fold_zpool_free(void *pool, unsigned long handle)
1040{
1041 z3fold_free(pool, handle);
1042}
1043
1044static int z3fold_zpool_shrink(void *pool, unsigned int pages,
1045 unsigned int *reclaimed)
1046{
1047 unsigned int total = 0;
1048 int ret = -EINVAL;
1049
1050 while (total < pages) {
1051 ret = z3fold_reclaim_page(pool, 8);
1052 if (ret < 0)
1053 break;
1054 total++;
1055 }
1056
1057 if (reclaimed)
1058 *reclaimed = total;
1059
1060 return ret;
1061}
1062
1063static void *z3fold_zpool_map(void *pool, unsigned long handle,
1064 enum zpool_mapmode mm)
1065{
1066 return z3fold_map(pool, handle);
1067}
1068static void z3fold_zpool_unmap(void *pool, unsigned long handle)
1069{
1070 z3fold_unmap(pool, handle);
1071}
1072
1073static u64 z3fold_zpool_total_size(void *pool)
1074{
1075 return z3fold_get_pool_size(pool) * PAGE_SIZE;
1076}
1077
1078static struct zpool_driver z3fold_zpool_driver = {
1079 .type = "z3fold",
1080 .owner = THIS_MODULE,
1081 .create = z3fold_zpool_create,
1082 .destroy = z3fold_zpool_destroy,
1083 .malloc = z3fold_zpool_malloc,
1084 .free = z3fold_zpool_free,
1085 .shrink = z3fold_zpool_shrink,
1086 .map = z3fold_zpool_map,
1087 .unmap = z3fold_zpool_unmap,
1088 .total_size = z3fold_zpool_total_size,
1089};
1090
1091MODULE_ALIAS("zpool-z3fold");
1092
1093static int __init init_z3fold(void)
1094{
Vitaly Woolede93212017-02-24 14:57:17 -08001095 /* Make sure the z3fold header is not larger than the page size */
1096 BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE);
Vitaly Wool9a001fc2016-05-20 16:58:30 -07001097 zpool_register_driver(&z3fold_zpool_driver);
1098
1099 return 0;
1100}
1101
1102static void __exit exit_z3fold(void)
1103{
1104 zpool_unregister_driver(&z3fold_zpool_driver);
1105}
1106
1107module_init(init_z3fold);
1108module_exit(exit_z3fold);
1109
1110MODULE_LICENSE("GPL");
1111MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>");
1112MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages");