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1 | /* | |
2 | * zswap.c - zswap driver file | |
3 | * | |
4 | * zswap is a backend for frontswap that takes pages that are in the process | |
5 | * of being swapped out and attempts to compress and store them in a | |
6 | * RAM-based memory pool. This can result in a significant I/O reduction on | |
7 | * the swap device and, in the case where decompressing from RAM is faster | |
8 | * than reading from the swap device, can also improve workload performance. | |
9 | * | |
10 | * Copyright (C) 2012 Seth Jennings <sjenning@linux.vnet.ibm.com> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version 2 | |
15 | * of the License, or (at your option) any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | */ | |
22 | ||
23 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/cpu.h> | |
27 | #include <linux/highmem.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/spinlock.h> | |
30 | #include <linux/types.h> | |
31 | #include <linux/atomic.h> | |
32 | #include <linux/frontswap.h> | |
33 | #include <linux/rbtree.h> | |
34 | #include <linux/swap.h> | |
35 | #include <linux/crypto.h> | |
36 | #include <linux/mempool.h> | |
37 | #include <linux/zpool.h> | |
38 | ||
39 | #include <linux/mm_types.h> | |
40 | #include <linux/page-flags.h> | |
41 | #include <linux/swapops.h> | |
42 | #include <linux/writeback.h> | |
43 | #include <linux/pagemap.h> | |
44 | ||
45 | /********************************* | |
46 | * statistics | |
47 | **********************************/ | |
48 | /* Total bytes used by the compressed storage */ | |
49 | static u64 zswap_pool_total_size; | |
50 | /* The number of compressed pages currently stored in zswap */ | |
51 | static atomic_t zswap_stored_pages = ATOMIC_INIT(0); | |
52 | ||
53 | /* | |
54 | * The statistics below are not protected from concurrent access for | |
55 | * performance reasons so they may not be a 100% accurate. However, | |
56 | * they do provide useful information on roughly how many times a | |
57 | * certain event is occurring. | |
58 | */ | |
59 | ||
60 | /* Pool limit was hit (see zswap_max_pool_percent) */ | |
61 | static u64 zswap_pool_limit_hit; | |
62 | /* Pages written back when pool limit was reached */ | |
63 | static u64 zswap_written_back_pages; | |
64 | /* Store failed due to a reclaim failure after pool limit was reached */ | |
65 | static u64 zswap_reject_reclaim_fail; | |
66 | /* Compressed page was too big for the allocator to (optimally) store */ | |
67 | static u64 zswap_reject_compress_poor; | |
68 | /* Store failed because underlying allocator could not get memory */ | |
69 | static u64 zswap_reject_alloc_fail; | |
70 | /* Store failed because the entry metadata could not be allocated (rare) */ | |
71 | static u64 zswap_reject_kmemcache_fail; | |
72 | /* Duplicate store was encountered (rare) */ | |
73 | static u64 zswap_duplicate_entry; | |
74 | ||
75 | /********************************* | |
76 | * tunables | |
77 | **********************************/ | |
78 | ||
79 | /* Enable/disable zswap (disabled by default) */ | |
80 | static bool zswap_enabled; | |
81 | module_param_named(enabled, zswap_enabled, bool, 0644); | |
82 | ||
83 | /* Crypto compressor to use */ | |
84 | #define ZSWAP_COMPRESSOR_DEFAULT "lzo" | |
85 | static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
86 | static int zswap_compressor_param_set(const char *, | |
87 | const struct kernel_param *); | |
88 | static struct kernel_param_ops zswap_compressor_param_ops = { | |
89 | .set = zswap_compressor_param_set, | |
90 | .get = param_get_charp, | |
91 | .free = param_free_charp, | |
92 | }; | |
93 | module_param_cb(compressor, &zswap_compressor_param_ops, | |
94 | &zswap_compressor, 0644); | |
95 | ||
96 | /* Compressed storage zpool to use */ | |
97 | #define ZSWAP_ZPOOL_DEFAULT "zbud" | |
98 | static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
99 | static int zswap_zpool_param_set(const char *, const struct kernel_param *); | |
100 | static struct kernel_param_ops zswap_zpool_param_ops = { | |
101 | .set = zswap_zpool_param_set, | |
102 | .get = param_get_charp, | |
103 | .free = param_free_charp, | |
104 | }; | |
105 | module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); | |
106 | ||
107 | /* The maximum percentage of memory that the compressed pool can occupy */ | |
108 | static unsigned int zswap_max_pool_percent = 20; | |
109 | module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); | |
110 | ||
111 | /********************************* | |
112 | * data structures | |
113 | **********************************/ | |
114 | ||
115 | struct zswap_pool { | |
116 | struct zpool *zpool; | |
117 | struct crypto_comp * __percpu *tfm; | |
118 | struct kref kref; | |
119 | struct list_head list; | |
120 | struct work_struct work; | |
121 | struct hlist_node node; | |
122 | char tfm_name[CRYPTO_MAX_ALG_NAME]; | |
123 | }; | |
124 | ||
125 | /* | |
126 | * struct zswap_entry | |
127 | * | |
128 | * This structure contains the metadata for tracking a single compressed | |
129 | * page within zswap. | |
130 | * | |
131 | * rbnode - links the entry into red-black tree for the appropriate swap type | |
132 | * offset - the swap offset for the entry. Index into the red-black tree. | |
133 | * refcount - the number of outstanding reference to the entry. This is needed | |
134 | * to protect against premature freeing of the entry by code | |
135 | * concurrent calls to load, invalidate, and writeback. The lock | |
136 | * for the zswap_tree structure that contains the entry must | |
137 | * be held while changing the refcount. Since the lock must | |
138 | * be held, there is no reason to also make refcount atomic. | |
139 | * length - the length in bytes of the compressed page data. Needed during | |
140 | * decompression | |
141 | * pool - the zswap_pool the entry's data is in | |
142 | * handle - zpool allocation handle that stores the compressed page data | |
143 | */ | |
144 | struct zswap_entry { | |
145 | struct rb_node rbnode; | |
146 | pgoff_t offset; | |
147 | int refcount; | |
148 | unsigned int length; | |
149 | struct zswap_pool *pool; | |
150 | unsigned long handle; | |
151 | }; | |
152 | ||
153 | struct zswap_header { | |
154 | swp_entry_t swpentry; | |
155 | }; | |
156 | ||
157 | /* | |
158 | * The tree lock in the zswap_tree struct protects a few things: | |
159 | * - the rbtree | |
160 | * - the refcount field of each entry in the tree | |
161 | */ | |
162 | struct zswap_tree { | |
163 | struct rb_root rbroot; | |
164 | spinlock_t lock; | |
165 | }; | |
166 | ||
167 | static struct zswap_tree *zswap_trees[MAX_SWAPFILES]; | |
168 | ||
169 | /* RCU-protected iteration */ | |
170 | static LIST_HEAD(zswap_pools); | |
171 | /* protects zswap_pools list modification */ | |
172 | static DEFINE_SPINLOCK(zswap_pools_lock); | |
173 | /* pool counter to provide unique names to zpool */ | |
174 | static atomic_t zswap_pools_count = ATOMIC_INIT(0); | |
175 | ||
176 | /* used by param callback function */ | |
177 | static bool zswap_init_started; | |
178 | ||
179 | /********************************* | |
180 | * helpers and fwd declarations | |
181 | **********************************/ | |
182 | ||
183 | #define zswap_pool_debug(msg, p) \ | |
184 | pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \ | |
185 | zpool_get_type((p)->zpool)) | |
186 | ||
187 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle); | |
188 | static int zswap_pool_get(struct zswap_pool *pool); | |
189 | static void zswap_pool_put(struct zswap_pool *pool); | |
190 | ||
191 | static const struct zpool_ops zswap_zpool_ops = { | |
192 | .evict = zswap_writeback_entry | |
193 | }; | |
194 | ||
195 | static bool zswap_is_full(void) | |
196 | { | |
197 | return totalram_pages * zswap_max_pool_percent / 100 < | |
198 | DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); | |
199 | } | |
200 | ||
201 | static void zswap_update_total_size(void) | |
202 | { | |
203 | struct zswap_pool *pool; | |
204 | u64 total = 0; | |
205 | ||
206 | rcu_read_lock(); | |
207 | ||
208 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
209 | total += zpool_get_total_size(pool->zpool); | |
210 | ||
211 | rcu_read_unlock(); | |
212 | ||
213 | zswap_pool_total_size = total; | |
214 | } | |
215 | ||
216 | /********************************* | |
217 | * zswap entry functions | |
218 | **********************************/ | |
219 | static struct kmem_cache *zswap_entry_cache; | |
220 | ||
221 | static int __init zswap_entry_cache_create(void) | |
222 | { | |
223 | zswap_entry_cache = KMEM_CACHE(zswap_entry, 0); | |
224 | return zswap_entry_cache == NULL; | |
225 | } | |
226 | ||
227 | static void __init zswap_entry_cache_destroy(void) | |
228 | { | |
229 | kmem_cache_destroy(zswap_entry_cache); | |
230 | } | |
231 | ||
232 | static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp) | |
233 | { | |
234 | struct zswap_entry *entry; | |
235 | entry = kmem_cache_alloc(zswap_entry_cache, gfp); | |
236 | if (!entry) | |
237 | return NULL; | |
238 | entry->refcount = 1; | |
239 | RB_CLEAR_NODE(&entry->rbnode); | |
240 | return entry; | |
241 | } | |
242 | ||
243 | static void zswap_entry_cache_free(struct zswap_entry *entry) | |
244 | { | |
245 | kmem_cache_free(zswap_entry_cache, entry); | |
246 | } | |
247 | ||
248 | /********************************* | |
249 | * rbtree functions | |
250 | **********************************/ | |
251 | static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset) | |
252 | { | |
253 | struct rb_node *node = root->rb_node; | |
254 | struct zswap_entry *entry; | |
255 | ||
256 | while (node) { | |
257 | entry = rb_entry(node, struct zswap_entry, rbnode); | |
258 | if (entry->offset > offset) | |
259 | node = node->rb_left; | |
260 | else if (entry->offset < offset) | |
261 | node = node->rb_right; | |
262 | else | |
263 | return entry; | |
264 | } | |
265 | return NULL; | |
266 | } | |
267 | ||
268 | /* | |
269 | * In the case that a entry with the same offset is found, a pointer to | |
270 | * the existing entry is stored in dupentry and the function returns -EEXIST | |
271 | */ | |
272 | static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry, | |
273 | struct zswap_entry **dupentry) | |
274 | { | |
275 | struct rb_node **link = &root->rb_node, *parent = NULL; | |
276 | struct zswap_entry *myentry; | |
277 | ||
278 | while (*link) { | |
279 | parent = *link; | |
280 | myentry = rb_entry(parent, struct zswap_entry, rbnode); | |
281 | if (myentry->offset > entry->offset) | |
282 | link = &(*link)->rb_left; | |
283 | else if (myentry->offset < entry->offset) | |
284 | link = &(*link)->rb_right; | |
285 | else { | |
286 | *dupentry = myentry; | |
287 | return -EEXIST; | |
288 | } | |
289 | } | |
290 | rb_link_node(&entry->rbnode, parent, link); | |
291 | rb_insert_color(&entry->rbnode, root); | |
292 | return 0; | |
293 | } | |
294 | ||
295 | static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry) | |
296 | { | |
297 | if (!RB_EMPTY_NODE(&entry->rbnode)) { | |
298 | rb_erase(&entry->rbnode, root); | |
299 | RB_CLEAR_NODE(&entry->rbnode); | |
300 | } | |
301 | } | |
302 | ||
303 | /* | |
304 | * Carries out the common pattern of freeing and entry's zpool allocation, | |
305 | * freeing the entry itself, and decrementing the number of stored pages. | |
306 | */ | |
307 | static void zswap_free_entry(struct zswap_entry *entry) | |
308 | { | |
309 | zpool_free(entry->pool->zpool, entry->handle); | |
310 | zswap_pool_put(entry->pool); | |
311 | zswap_entry_cache_free(entry); | |
312 | atomic_dec(&zswap_stored_pages); | |
313 | zswap_update_total_size(); | |
314 | } | |
315 | ||
316 | /* caller must hold the tree lock */ | |
317 | static void zswap_entry_get(struct zswap_entry *entry) | |
318 | { | |
319 | entry->refcount++; | |
320 | } | |
321 | ||
322 | /* caller must hold the tree lock | |
323 | * remove from the tree and free it, if nobody reference the entry | |
324 | */ | |
325 | static void zswap_entry_put(struct zswap_tree *tree, | |
326 | struct zswap_entry *entry) | |
327 | { | |
328 | int refcount = --entry->refcount; | |
329 | ||
330 | BUG_ON(refcount < 0); | |
331 | if (refcount == 0) { | |
332 | zswap_rb_erase(&tree->rbroot, entry); | |
333 | zswap_free_entry(entry); | |
334 | } | |
335 | } | |
336 | ||
337 | /* caller must hold the tree lock */ | |
338 | static struct zswap_entry *zswap_entry_find_get(struct rb_root *root, | |
339 | pgoff_t offset) | |
340 | { | |
341 | struct zswap_entry *entry; | |
342 | ||
343 | entry = zswap_rb_search(root, offset); | |
344 | if (entry) | |
345 | zswap_entry_get(entry); | |
346 | ||
347 | return entry; | |
348 | } | |
349 | ||
350 | /********************************* | |
351 | * per-cpu code | |
352 | **********************************/ | |
353 | static DEFINE_PER_CPU(u8 *, zswap_dstmem); | |
354 | ||
355 | static int zswap_dstmem_prepare(unsigned int cpu) | |
356 | { | |
357 | u8 *dst; | |
358 | ||
359 | dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); | |
360 | if (!dst) { | |
361 | pr_err("can't allocate compressor buffer\n"); | |
362 | return -ENOMEM; | |
363 | } | |
364 | per_cpu(zswap_dstmem, cpu) = dst; | |
365 | return 0; | |
366 | } | |
367 | ||
368 | static int zswap_dstmem_dead(unsigned int cpu) | |
369 | { | |
370 | u8 *dst; | |
371 | ||
372 | dst = per_cpu(zswap_dstmem, cpu); | |
373 | kfree(dst); | |
374 | per_cpu(zswap_dstmem, cpu) = NULL; | |
375 | ||
376 | return 0; | |
377 | } | |
378 | ||
379 | static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) | |
380 | { | |
381 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); | |
382 | struct crypto_comp *tfm; | |
383 | ||
384 | if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu))) | |
385 | return 0; | |
386 | ||
387 | tfm = crypto_alloc_comp(pool->tfm_name, 0, 0); | |
388 | if (IS_ERR_OR_NULL(tfm)) { | |
389 | pr_err("could not alloc crypto comp %s : %ld\n", | |
390 | pool->tfm_name, PTR_ERR(tfm)); | |
391 | return -ENOMEM; | |
392 | } | |
393 | *per_cpu_ptr(pool->tfm, cpu) = tfm; | |
394 | return 0; | |
395 | } | |
396 | ||
397 | static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) | |
398 | { | |
399 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); | |
400 | struct crypto_comp *tfm; | |
401 | ||
402 | tfm = *per_cpu_ptr(pool->tfm, cpu); | |
403 | if (!IS_ERR_OR_NULL(tfm)) | |
404 | crypto_free_comp(tfm); | |
405 | *per_cpu_ptr(pool->tfm, cpu) = NULL; | |
406 | return 0; | |
407 | } | |
408 | ||
409 | /********************************* | |
410 | * pool functions | |
411 | **********************************/ | |
412 | ||
413 | static struct zswap_pool *__zswap_pool_current(void) | |
414 | { | |
415 | struct zswap_pool *pool; | |
416 | ||
417 | pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list); | |
418 | WARN_ON(!pool); | |
419 | ||
420 | return pool; | |
421 | } | |
422 | ||
423 | static struct zswap_pool *zswap_pool_current(void) | |
424 | { | |
425 | assert_spin_locked(&zswap_pools_lock); | |
426 | ||
427 | return __zswap_pool_current(); | |
428 | } | |
429 | ||
430 | static struct zswap_pool *zswap_pool_current_get(void) | |
431 | { | |
432 | struct zswap_pool *pool; | |
433 | ||
434 | rcu_read_lock(); | |
435 | ||
436 | pool = __zswap_pool_current(); | |
437 | if (!pool || !zswap_pool_get(pool)) | |
438 | pool = NULL; | |
439 | ||
440 | rcu_read_unlock(); | |
441 | ||
442 | return pool; | |
443 | } | |
444 | ||
445 | static struct zswap_pool *zswap_pool_last_get(void) | |
446 | { | |
447 | struct zswap_pool *pool, *last = NULL; | |
448 | ||
449 | rcu_read_lock(); | |
450 | ||
451 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
452 | last = pool; | |
453 | if (!WARN_ON(!last) && !zswap_pool_get(last)) | |
454 | last = NULL; | |
455 | ||
456 | rcu_read_unlock(); | |
457 | ||
458 | return last; | |
459 | } | |
460 | ||
461 | /* type and compressor must be null-terminated */ | |
462 | static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) | |
463 | { | |
464 | struct zswap_pool *pool; | |
465 | ||
466 | assert_spin_locked(&zswap_pools_lock); | |
467 | ||
468 | list_for_each_entry_rcu(pool, &zswap_pools, list) { | |
469 | if (strcmp(pool->tfm_name, compressor)) | |
470 | continue; | |
471 | if (strcmp(zpool_get_type(pool->zpool), type)) | |
472 | continue; | |
473 | /* if we can't get it, it's about to be destroyed */ | |
474 | if (!zswap_pool_get(pool)) | |
475 | continue; | |
476 | return pool; | |
477 | } | |
478 | ||
479 | return NULL; | |
480 | } | |
481 | ||
482 | static struct zswap_pool *zswap_pool_create(char *type, char *compressor) | |
483 | { | |
484 | struct zswap_pool *pool; | |
485 | char name[38]; /* 'zswap' + 32 char (max) num + \0 */ | |
486 | gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; | |
487 | int ret; | |
488 | ||
489 | pool = kzalloc(sizeof(*pool), GFP_KERNEL); | |
490 | if (!pool) { | |
491 | pr_err("pool alloc failed\n"); | |
492 | return NULL; | |
493 | } | |
494 | ||
495 | /* unique name for each pool specifically required by zsmalloc */ | |
496 | snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count)); | |
497 | ||
498 | pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops); | |
499 | if (!pool->zpool) { | |
500 | pr_err("%s zpool not available\n", type); | |
501 | goto error; | |
502 | } | |
503 | pr_debug("using %s zpool\n", zpool_get_type(pool->zpool)); | |
504 | ||
505 | strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); | |
506 | pool->tfm = alloc_percpu(struct crypto_comp *); | |
507 | if (!pool->tfm) { | |
508 | pr_err("percpu alloc failed\n"); | |
509 | goto error; | |
510 | } | |
511 | ||
512 | ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE, | |
513 | &pool->node); | |
514 | if (ret) | |
515 | goto error; | |
516 | pr_debug("using %s compressor\n", pool->tfm_name); | |
517 | ||
518 | /* being the current pool takes 1 ref; this func expects the | |
519 | * caller to always add the new pool as the current pool | |
520 | */ | |
521 | kref_init(&pool->kref); | |
522 | INIT_LIST_HEAD(&pool->list); | |
523 | ||
524 | zswap_pool_debug("created", pool); | |
525 | ||
526 | return pool; | |
527 | ||
528 | error: | |
529 | free_percpu(pool->tfm); | |
530 | if (pool->zpool) | |
531 | zpool_destroy_pool(pool->zpool); | |
532 | kfree(pool); | |
533 | return NULL; | |
534 | } | |
535 | ||
536 | static __init struct zswap_pool *__zswap_pool_create_fallback(void) | |
537 | { | |
538 | if (!crypto_has_comp(zswap_compressor, 0, 0)) { | |
539 | if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) { | |
540 | pr_err("default compressor %s not available\n", | |
541 | zswap_compressor); | |
542 | return NULL; | |
543 | } | |
544 | pr_err("compressor %s not available, using default %s\n", | |
545 | zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT); | |
546 | param_free_charp(&zswap_compressor); | |
547 | zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
548 | } | |
549 | if (!zpool_has_pool(zswap_zpool_type)) { | |
550 | if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) { | |
551 | pr_err("default zpool %s not available\n", | |
552 | zswap_zpool_type); | |
553 | return NULL; | |
554 | } | |
555 | pr_err("zpool %s not available, using default %s\n", | |
556 | zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT); | |
557 | param_free_charp(&zswap_zpool_type); | |
558 | zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
559 | } | |
560 | ||
561 | return zswap_pool_create(zswap_zpool_type, zswap_compressor); | |
562 | } | |
563 | ||
564 | static void zswap_pool_destroy(struct zswap_pool *pool) | |
565 | { | |
566 | zswap_pool_debug("destroying", pool); | |
567 | ||
568 | cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); | |
569 | free_percpu(pool->tfm); | |
570 | zpool_destroy_pool(pool->zpool); | |
571 | kfree(pool); | |
572 | } | |
573 | ||
574 | static int __must_check zswap_pool_get(struct zswap_pool *pool) | |
575 | { | |
576 | return kref_get_unless_zero(&pool->kref); | |
577 | } | |
578 | ||
579 | static void __zswap_pool_release(struct work_struct *work) | |
580 | { | |
581 | struct zswap_pool *pool = container_of(work, typeof(*pool), work); | |
582 | ||
583 | synchronize_rcu(); | |
584 | ||
585 | /* nobody should have been able to get a kref... */ | |
586 | WARN_ON(kref_get_unless_zero(&pool->kref)); | |
587 | ||
588 | /* pool is now off zswap_pools list and has no references. */ | |
589 | zswap_pool_destroy(pool); | |
590 | } | |
591 | ||
592 | static void __zswap_pool_empty(struct kref *kref) | |
593 | { | |
594 | struct zswap_pool *pool; | |
595 | ||
596 | pool = container_of(kref, typeof(*pool), kref); | |
597 | ||
598 | spin_lock(&zswap_pools_lock); | |
599 | ||
600 | WARN_ON(pool == zswap_pool_current()); | |
601 | ||
602 | list_del_rcu(&pool->list); | |
603 | ||
604 | INIT_WORK(&pool->work, __zswap_pool_release); | |
605 | schedule_work(&pool->work); | |
606 | ||
607 | spin_unlock(&zswap_pools_lock); | |
608 | } | |
609 | ||
610 | static void zswap_pool_put(struct zswap_pool *pool) | |
611 | { | |
612 | kref_put(&pool->kref, __zswap_pool_empty); | |
613 | } | |
614 | ||
615 | /********************************* | |
616 | * param callbacks | |
617 | **********************************/ | |
618 | ||
619 | /* val must be a null-terminated string */ | |
620 | static int __zswap_param_set(const char *val, const struct kernel_param *kp, | |
621 | char *type, char *compressor) | |
622 | { | |
623 | struct zswap_pool *pool, *put_pool = NULL; | |
624 | char *s = strstrip((char *)val); | |
625 | int ret; | |
626 | ||
627 | /* no change required */ | |
628 | if (!strcmp(s, *(char **)kp->arg)) | |
629 | return 0; | |
630 | ||
631 | /* if this is load-time (pre-init) param setting, | |
632 | * don't create a pool; that's done during init. | |
633 | */ | |
634 | if (!zswap_init_started) | |
635 | return param_set_charp(s, kp); | |
636 | ||
637 | if (!type) { | |
638 | if (!zpool_has_pool(s)) { | |
639 | pr_err("zpool %s not available\n", s); | |
640 | return -ENOENT; | |
641 | } | |
642 | type = s; | |
643 | } else if (!compressor) { | |
644 | if (!crypto_has_comp(s, 0, 0)) { | |
645 | pr_err("compressor %s not available\n", s); | |
646 | return -ENOENT; | |
647 | } | |
648 | compressor = s; | |
649 | } else { | |
650 | WARN_ON(1); | |
651 | return -EINVAL; | |
652 | } | |
653 | ||
654 | spin_lock(&zswap_pools_lock); | |
655 | ||
656 | pool = zswap_pool_find_get(type, compressor); | |
657 | if (pool) { | |
658 | zswap_pool_debug("using existing", pool); | |
659 | list_del_rcu(&pool->list); | |
660 | } else { | |
661 | spin_unlock(&zswap_pools_lock); | |
662 | pool = zswap_pool_create(type, compressor); | |
663 | spin_lock(&zswap_pools_lock); | |
664 | } | |
665 | ||
666 | if (pool) | |
667 | ret = param_set_charp(s, kp); | |
668 | else | |
669 | ret = -EINVAL; | |
670 | ||
671 | if (!ret) { | |
672 | put_pool = zswap_pool_current(); | |
673 | list_add_rcu(&pool->list, &zswap_pools); | |
674 | } else if (pool) { | |
675 | /* add the possibly pre-existing pool to the end of the pools | |
676 | * list; if it's new (and empty) then it'll be removed and | |
677 | * destroyed by the put after we drop the lock | |
678 | */ | |
679 | list_add_tail_rcu(&pool->list, &zswap_pools); | |
680 | put_pool = pool; | |
681 | } | |
682 | ||
683 | spin_unlock(&zswap_pools_lock); | |
684 | ||
685 | /* drop the ref from either the old current pool, | |
686 | * or the new pool we failed to add | |
687 | */ | |
688 | if (put_pool) | |
689 | zswap_pool_put(put_pool); | |
690 | ||
691 | return ret; | |
692 | } | |
693 | ||
694 | static int zswap_compressor_param_set(const char *val, | |
695 | const struct kernel_param *kp) | |
696 | { | |
697 | return __zswap_param_set(val, kp, zswap_zpool_type, NULL); | |
698 | } | |
699 | ||
700 | static int zswap_zpool_param_set(const char *val, | |
701 | const struct kernel_param *kp) | |
702 | { | |
703 | return __zswap_param_set(val, kp, NULL, zswap_compressor); | |
704 | } | |
705 | ||
706 | /********************************* | |
707 | * writeback code | |
708 | **********************************/ | |
709 | /* return enum for zswap_get_swap_cache_page */ | |
710 | enum zswap_get_swap_ret { | |
711 | ZSWAP_SWAPCACHE_NEW, | |
712 | ZSWAP_SWAPCACHE_EXIST, | |
713 | ZSWAP_SWAPCACHE_FAIL, | |
714 | }; | |
715 | ||
716 | /* | |
717 | * zswap_get_swap_cache_page | |
718 | * | |
719 | * This is an adaption of read_swap_cache_async() | |
720 | * | |
721 | * This function tries to find a page with the given swap entry | |
722 | * in the swapper_space address space (the swap cache). If the page | |
723 | * is found, it is returned in retpage. Otherwise, a page is allocated, | |
724 | * added to the swap cache, and returned in retpage. | |
725 | * | |
726 | * If success, the swap cache page is returned in retpage | |
727 | * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache | |
728 | * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated, | |
729 | * the new page is added to swapcache and locked | |
730 | * Returns ZSWAP_SWAPCACHE_FAIL on error | |
731 | */ | |
732 | static int zswap_get_swap_cache_page(swp_entry_t entry, | |
733 | struct page **retpage) | |
734 | { | |
735 | bool page_was_allocated; | |
736 | ||
737 | *retpage = __read_swap_cache_async(entry, GFP_KERNEL, | |
738 | NULL, 0, &page_was_allocated); | |
739 | if (page_was_allocated) | |
740 | return ZSWAP_SWAPCACHE_NEW; | |
741 | if (!*retpage) | |
742 | return ZSWAP_SWAPCACHE_FAIL; | |
743 | return ZSWAP_SWAPCACHE_EXIST; | |
744 | } | |
745 | ||
746 | /* | |
747 | * Attempts to free an entry by adding a page to the swap cache, | |
748 | * decompressing the entry data into the page, and issuing a | |
749 | * bio write to write the page back to the swap device. | |
750 | * | |
751 | * This can be thought of as a "resumed writeback" of the page | |
752 | * to the swap device. We are basically resuming the same swap | |
753 | * writeback path that was intercepted with the frontswap_store() | |
754 | * in the first place. After the page has been decompressed into | |
755 | * the swap cache, the compressed version stored by zswap can be | |
756 | * freed. | |
757 | */ | |
758 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) | |
759 | { | |
760 | struct zswap_header *zhdr; | |
761 | swp_entry_t swpentry; | |
762 | struct zswap_tree *tree; | |
763 | pgoff_t offset; | |
764 | struct zswap_entry *entry; | |
765 | struct page *page; | |
766 | struct crypto_comp *tfm; | |
767 | u8 *src, *dst; | |
768 | unsigned int dlen; | |
769 | int ret; | |
770 | struct writeback_control wbc = { | |
771 | .sync_mode = WB_SYNC_NONE, | |
772 | }; | |
773 | ||
774 | /* extract swpentry from data */ | |
775 | zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); | |
776 | swpentry = zhdr->swpentry; /* here */ | |
777 | zpool_unmap_handle(pool, handle); | |
778 | tree = zswap_trees[swp_type(swpentry)]; | |
779 | offset = swp_offset(swpentry); | |
780 | ||
781 | /* find and ref zswap entry */ | |
782 | spin_lock(&tree->lock); | |
783 | entry = zswap_entry_find_get(&tree->rbroot, offset); | |
784 | if (!entry) { | |
785 | /* entry was invalidated */ | |
786 | spin_unlock(&tree->lock); | |
787 | return 0; | |
788 | } | |
789 | spin_unlock(&tree->lock); | |
790 | BUG_ON(offset != entry->offset); | |
791 | ||
792 | /* try to allocate swap cache page */ | |
793 | switch (zswap_get_swap_cache_page(swpentry, &page)) { | |
794 | case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ | |
795 | ret = -ENOMEM; | |
796 | goto fail; | |
797 | ||
798 | case ZSWAP_SWAPCACHE_EXIST: | |
799 | /* page is already in the swap cache, ignore for now */ | |
800 | put_page(page); | |
801 | ret = -EEXIST; | |
802 | goto fail; | |
803 | ||
804 | case ZSWAP_SWAPCACHE_NEW: /* page is locked */ | |
805 | /* decompress */ | |
806 | dlen = PAGE_SIZE; | |
807 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, | |
808 | ZPOOL_MM_RO) + sizeof(struct zswap_header); | |
809 | dst = kmap_atomic(page); | |
810 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
811 | ret = crypto_comp_decompress(tfm, src, entry->length, | |
812 | dst, &dlen); | |
813 | put_cpu_ptr(entry->pool->tfm); | |
814 | kunmap_atomic(dst); | |
815 | zpool_unmap_handle(entry->pool->zpool, entry->handle); | |
816 | BUG_ON(ret); | |
817 | BUG_ON(dlen != PAGE_SIZE); | |
818 | ||
819 | /* page is up to date */ | |
820 | SetPageUptodate(page); | |
821 | } | |
822 | ||
823 | /* move it to the tail of the inactive list after end_writeback */ | |
824 | SetPageReclaim(page); | |
825 | ||
826 | /* start writeback */ | |
827 | __swap_writepage(page, &wbc, end_swap_bio_write); | |
828 | put_page(page); | |
829 | zswap_written_back_pages++; | |
830 | ||
831 | spin_lock(&tree->lock); | |
832 | /* drop local reference */ | |
833 | zswap_entry_put(tree, entry); | |
834 | ||
835 | /* | |
836 | * There are two possible situations for entry here: | |
837 | * (1) refcount is 1(normal case), entry is valid and on the tree | |
838 | * (2) refcount is 0, entry is freed and not on the tree | |
839 | * because invalidate happened during writeback | |
840 | * search the tree and free the entry if find entry | |
841 | */ | |
842 | if (entry == zswap_rb_search(&tree->rbroot, offset)) | |
843 | zswap_entry_put(tree, entry); | |
844 | spin_unlock(&tree->lock); | |
845 | ||
846 | goto end; | |
847 | ||
848 | /* | |
849 | * if we get here due to ZSWAP_SWAPCACHE_EXIST | |
850 | * a load may happening concurrently | |
851 | * it is safe and okay to not free the entry | |
852 | * if we free the entry in the following put | |
853 | * it it either okay to return !0 | |
854 | */ | |
855 | fail: | |
856 | spin_lock(&tree->lock); | |
857 | zswap_entry_put(tree, entry); | |
858 | spin_unlock(&tree->lock); | |
859 | ||
860 | end: | |
861 | return ret; | |
862 | } | |
863 | ||
864 | static int zswap_shrink(void) | |
865 | { | |
866 | struct zswap_pool *pool; | |
867 | int ret; | |
868 | ||
869 | pool = zswap_pool_last_get(); | |
870 | if (!pool) | |
871 | return -ENOENT; | |
872 | ||
873 | ret = zpool_shrink(pool->zpool, 1, NULL); | |
874 | ||
875 | zswap_pool_put(pool); | |
876 | ||
877 | return ret; | |
878 | } | |
879 | ||
880 | /********************************* | |
881 | * frontswap hooks | |
882 | **********************************/ | |
883 | /* attempts to compress and store an single page */ | |
884 | static int zswap_frontswap_store(unsigned type, pgoff_t offset, | |
885 | struct page *page) | |
886 | { | |
887 | struct zswap_tree *tree = zswap_trees[type]; | |
888 | struct zswap_entry *entry, *dupentry; | |
889 | struct crypto_comp *tfm; | |
890 | int ret; | |
891 | unsigned int dlen = PAGE_SIZE, len; | |
892 | unsigned long handle; | |
893 | char *buf; | |
894 | u8 *src, *dst; | |
895 | struct zswap_header *zhdr; | |
896 | ||
897 | if (!zswap_enabled || !tree) { | |
898 | ret = -ENODEV; | |
899 | goto reject; | |
900 | } | |
901 | ||
902 | /* reclaim space if needed */ | |
903 | if (zswap_is_full()) { | |
904 | zswap_pool_limit_hit++; | |
905 | if (zswap_shrink()) { | |
906 | zswap_reject_reclaim_fail++; | |
907 | ret = -ENOMEM; | |
908 | goto reject; | |
909 | } | |
910 | } | |
911 | ||
912 | /* allocate entry */ | |
913 | entry = zswap_entry_cache_alloc(GFP_KERNEL); | |
914 | if (!entry) { | |
915 | zswap_reject_kmemcache_fail++; | |
916 | ret = -ENOMEM; | |
917 | goto reject; | |
918 | } | |
919 | ||
920 | /* if entry is successfully added, it keeps the reference */ | |
921 | entry->pool = zswap_pool_current_get(); | |
922 | if (!entry->pool) { | |
923 | ret = -EINVAL; | |
924 | goto freepage; | |
925 | } | |
926 | ||
927 | /* compress */ | |
928 | dst = get_cpu_var(zswap_dstmem); | |
929 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
930 | src = kmap_atomic(page); | |
931 | ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen); | |
932 | kunmap_atomic(src); | |
933 | put_cpu_ptr(entry->pool->tfm); | |
934 | if (ret) { | |
935 | ret = -EINVAL; | |
936 | goto put_dstmem; | |
937 | } | |
938 | ||
939 | /* store */ | |
940 | len = dlen + sizeof(struct zswap_header); | |
941 | ret = zpool_malloc(entry->pool->zpool, len, | |
942 | __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM, | |
943 | &handle); | |
944 | if (ret == -ENOSPC) { | |
945 | zswap_reject_compress_poor++; | |
946 | goto put_dstmem; | |
947 | } | |
948 | if (ret) { | |
949 | zswap_reject_alloc_fail++; | |
950 | goto put_dstmem; | |
951 | } | |
952 | zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); | |
953 | zhdr->swpentry = swp_entry(type, offset); | |
954 | buf = (u8 *)(zhdr + 1); | |
955 | memcpy(buf, dst, dlen); | |
956 | zpool_unmap_handle(entry->pool->zpool, handle); | |
957 | put_cpu_var(zswap_dstmem); | |
958 | ||
959 | /* populate entry */ | |
960 | entry->offset = offset; | |
961 | entry->handle = handle; | |
962 | entry->length = dlen; | |
963 | ||
964 | /* map */ | |
965 | spin_lock(&tree->lock); | |
966 | do { | |
967 | ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry); | |
968 | if (ret == -EEXIST) { | |
969 | zswap_duplicate_entry++; | |
970 | /* remove from rbtree */ | |
971 | zswap_rb_erase(&tree->rbroot, dupentry); | |
972 | zswap_entry_put(tree, dupentry); | |
973 | } | |
974 | } while (ret == -EEXIST); | |
975 | spin_unlock(&tree->lock); | |
976 | ||
977 | /* update stats */ | |
978 | atomic_inc(&zswap_stored_pages); | |
979 | zswap_update_total_size(); | |
980 | ||
981 | return 0; | |
982 | ||
983 | put_dstmem: | |
984 | put_cpu_var(zswap_dstmem); | |
985 | zswap_pool_put(entry->pool); | |
986 | freepage: | |
987 | zswap_entry_cache_free(entry); | |
988 | reject: | |
989 | return ret; | |
990 | } | |
991 | ||
992 | /* | |
993 | * returns 0 if the page was successfully decompressed | |
994 | * return -1 on entry not found or error | |
995 | */ | |
996 | static int zswap_frontswap_load(unsigned type, pgoff_t offset, | |
997 | struct page *page) | |
998 | { | |
999 | struct zswap_tree *tree = zswap_trees[type]; | |
1000 | struct zswap_entry *entry; | |
1001 | struct crypto_comp *tfm; | |
1002 | u8 *src, *dst; | |
1003 | unsigned int dlen; | |
1004 | int ret; | |
1005 | ||
1006 | /* find */ | |
1007 | spin_lock(&tree->lock); | |
1008 | entry = zswap_entry_find_get(&tree->rbroot, offset); | |
1009 | if (!entry) { | |
1010 | /* entry was written back */ | |
1011 | spin_unlock(&tree->lock); | |
1012 | return -1; | |
1013 | } | |
1014 | spin_unlock(&tree->lock); | |
1015 | ||
1016 | /* decompress */ | |
1017 | dlen = PAGE_SIZE; | |
1018 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, | |
1019 | ZPOOL_MM_RO) + sizeof(struct zswap_header); | |
1020 | dst = kmap_atomic(page); | |
1021 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
1022 | ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); | |
1023 | put_cpu_ptr(entry->pool->tfm); | |
1024 | kunmap_atomic(dst); | |
1025 | zpool_unmap_handle(entry->pool->zpool, entry->handle); | |
1026 | BUG_ON(ret); | |
1027 | ||
1028 | spin_lock(&tree->lock); | |
1029 | zswap_entry_put(tree, entry); | |
1030 | spin_unlock(&tree->lock); | |
1031 | ||
1032 | return 0; | |
1033 | } | |
1034 | ||
1035 | /* frees an entry in zswap */ | |
1036 | static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) | |
1037 | { | |
1038 | struct zswap_tree *tree = zswap_trees[type]; | |
1039 | struct zswap_entry *entry; | |
1040 | ||
1041 | /* find */ | |
1042 | spin_lock(&tree->lock); | |
1043 | entry = zswap_rb_search(&tree->rbroot, offset); | |
1044 | if (!entry) { | |
1045 | /* entry was written back */ | |
1046 | spin_unlock(&tree->lock); | |
1047 | return; | |
1048 | } | |
1049 | ||
1050 | /* remove from rbtree */ | |
1051 | zswap_rb_erase(&tree->rbroot, entry); | |
1052 | ||
1053 | /* drop the initial reference from entry creation */ | |
1054 | zswap_entry_put(tree, entry); | |
1055 | ||
1056 | spin_unlock(&tree->lock); | |
1057 | } | |
1058 | ||
1059 | /* frees all zswap entries for the given swap type */ | |
1060 | static void zswap_frontswap_invalidate_area(unsigned type) | |
1061 | { | |
1062 | struct zswap_tree *tree = zswap_trees[type]; | |
1063 | struct zswap_entry *entry, *n; | |
1064 | ||
1065 | if (!tree) | |
1066 | return; | |
1067 | ||
1068 | /* walk the tree and free everything */ | |
1069 | spin_lock(&tree->lock); | |
1070 | rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode) | |
1071 | zswap_free_entry(entry); | |
1072 | tree->rbroot = RB_ROOT; | |
1073 | spin_unlock(&tree->lock); | |
1074 | kfree(tree); | |
1075 | zswap_trees[type] = NULL; | |
1076 | } | |
1077 | ||
1078 | static void zswap_frontswap_init(unsigned type) | |
1079 | { | |
1080 | struct zswap_tree *tree; | |
1081 | ||
1082 | tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL); | |
1083 | if (!tree) { | |
1084 | pr_err("alloc failed, zswap disabled for swap type %d\n", type); | |
1085 | return; | |
1086 | } | |
1087 | ||
1088 | tree->rbroot = RB_ROOT; | |
1089 | spin_lock_init(&tree->lock); | |
1090 | zswap_trees[type] = tree; | |
1091 | } | |
1092 | ||
1093 | static struct frontswap_ops zswap_frontswap_ops = { | |
1094 | .store = zswap_frontswap_store, | |
1095 | .load = zswap_frontswap_load, | |
1096 | .invalidate_page = zswap_frontswap_invalidate_page, | |
1097 | .invalidate_area = zswap_frontswap_invalidate_area, | |
1098 | .init = zswap_frontswap_init | |
1099 | }; | |
1100 | ||
1101 | /********************************* | |
1102 | * debugfs functions | |
1103 | **********************************/ | |
1104 | #ifdef CONFIG_DEBUG_FS | |
1105 | #include <linux/debugfs.h> | |
1106 | ||
1107 | static struct dentry *zswap_debugfs_root; | |
1108 | ||
1109 | static int __init zswap_debugfs_init(void) | |
1110 | { | |
1111 | if (!debugfs_initialized()) | |
1112 | return -ENODEV; | |
1113 | ||
1114 | zswap_debugfs_root = debugfs_create_dir("zswap", NULL); | |
1115 | if (!zswap_debugfs_root) | |
1116 | return -ENOMEM; | |
1117 | ||
1118 | debugfs_create_u64("pool_limit_hit", S_IRUGO, | |
1119 | zswap_debugfs_root, &zswap_pool_limit_hit); | |
1120 | debugfs_create_u64("reject_reclaim_fail", S_IRUGO, | |
1121 | zswap_debugfs_root, &zswap_reject_reclaim_fail); | |
1122 | debugfs_create_u64("reject_alloc_fail", S_IRUGO, | |
1123 | zswap_debugfs_root, &zswap_reject_alloc_fail); | |
1124 | debugfs_create_u64("reject_kmemcache_fail", S_IRUGO, | |
1125 | zswap_debugfs_root, &zswap_reject_kmemcache_fail); | |
1126 | debugfs_create_u64("reject_compress_poor", S_IRUGO, | |
1127 | zswap_debugfs_root, &zswap_reject_compress_poor); | |
1128 | debugfs_create_u64("written_back_pages", S_IRUGO, | |
1129 | zswap_debugfs_root, &zswap_written_back_pages); | |
1130 | debugfs_create_u64("duplicate_entry", S_IRUGO, | |
1131 | zswap_debugfs_root, &zswap_duplicate_entry); | |
1132 | debugfs_create_u64("pool_total_size", S_IRUGO, | |
1133 | zswap_debugfs_root, &zswap_pool_total_size); | |
1134 | debugfs_create_atomic_t("stored_pages", S_IRUGO, | |
1135 | zswap_debugfs_root, &zswap_stored_pages); | |
1136 | ||
1137 | return 0; | |
1138 | } | |
1139 | ||
1140 | static void __exit zswap_debugfs_exit(void) | |
1141 | { | |
1142 | debugfs_remove_recursive(zswap_debugfs_root); | |
1143 | } | |
1144 | #else | |
1145 | static int __init zswap_debugfs_init(void) | |
1146 | { | |
1147 | return 0; | |
1148 | } | |
1149 | ||
1150 | static void __exit zswap_debugfs_exit(void) { } | |
1151 | #endif | |
1152 | ||
1153 | /********************************* | |
1154 | * module init and exit | |
1155 | **********************************/ | |
1156 | static int __init init_zswap(void) | |
1157 | { | |
1158 | struct zswap_pool *pool; | |
1159 | int ret; | |
1160 | ||
1161 | zswap_init_started = true; | |
1162 | ||
1163 | if (zswap_entry_cache_create()) { | |
1164 | pr_err("entry cache creation failed\n"); | |
1165 | goto cache_fail; | |
1166 | } | |
1167 | ||
1168 | ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare", | |
1169 | zswap_dstmem_prepare, zswap_dstmem_dead); | |
1170 | if (ret) { | |
1171 | pr_err("dstmem alloc failed\n"); | |
1172 | goto dstmem_fail; | |
1173 | } | |
1174 | ||
1175 | ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE, | |
1176 | "mm/zswap_pool:prepare", | |
1177 | zswap_cpu_comp_prepare, | |
1178 | zswap_cpu_comp_dead); | |
1179 | if (ret) | |
1180 | goto hp_fail; | |
1181 | ||
1182 | pool = __zswap_pool_create_fallback(); | |
1183 | if (!pool) { | |
1184 | pr_err("pool creation failed\n"); | |
1185 | goto pool_fail; | |
1186 | } | |
1187 | pr_info("loaded using pool %s/%s\n", pool->tfm_name, | |
1188 | zpool_get_type(pool->zpool)); | |
1189 | ||
1190 | list_add(&pool->list, &zswap_pools); | |
1191 | ||
1192 | frontswap_register_ops(&zswap_frontswap_ops); | |
1193 | if (zswap_debugfs_init()) | |
1194 | pr_warn("debugfs initialization failed\n"); | |
1195 | return 0; | |
1196 | ||
1197 | pool_fail: | |
1198 | cpuhp_remove_state_nocalls(CPUHP_MM_ZSWP_POOL_PREPARE); | |
1199 | hp_fail: | |
1200 | cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE); | |
1201 | dstmem_fail: | |
1202 | zswap_entry_cache_destroy(); | |
1203 | cache_fail: | |
1204 | return -ENOMEM; | |
1205 | } | |
1206 | /* must be late so crypto has time to come up */ | |
1207 | late_initcall(init_zswap); | |
1208 | ||
1209 | MODULE_LICENSE("GPL"); | |
1210 | MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>"); | |
1211 | MODULE_DESCRIPTION("Compressed cache for swap pages"); |