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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 | static int zswap_enabled_param_set(const char *, | |
82 | const struct kernel_param *); | |
83 | static struct kernel_param_ops zswap_enabled_param_ops = { | |
84 | .set = zswap_enabled_param_set, | |
85 | .get = param_get_bool, | |
86 | }; | |
87 | module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644); | |
88 | ||
89 | /* Crypto compressor to use */ | |
90 | #define ZSWAP_COMPRESSOR_DEFAULT "lzo" | |
91 | static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
92 | static int zswap_compressor_param_set(const char *, | |
93 | const struct kernel_param *); | |
94 | static struct kernel_param_ops zswap_compressor_param_ops = { | |
95 | .set = zswap_compressor_param_set, | |
96 | .get = param_get_charp, | |
97 | .free = param_free_charp, | |
98 | }; | |
99 | module_param_cb(compressor, &zswap_compressor_param_ops, | |
100 | &zswap_compressor, 0644); | |
101 | ||
102 | /* Compressed storage zpool to use */ | |
103 | #define ZSWAP_ZPOOL_DEFAULT "zbud" | |
104 | static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
105 | static int zswap_zpool_param_set(const char *, const struct kernel_param *); | |
106 | static struct kernel_param_ops zswap_zpool_param_ops = { | |
107 | .set = zswap_zpool_param_set, | |
108 | .get = param_get_charp, | |
109 | .free = param_free_charp, | |
110 | }; | |
111 | module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); | |
112 | ||
113 | /* The maximum percentage of memory that the compressed pool can occupy */ | |
114 | static unsigned int zswap_max_pool_percent = 20; | |
115 | module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); | |
116 | ||
117 | /********************************* | |
118 | * data structures | |
119 | **********************************/ | |
120 | ||
121 | struct zswap_pool { | |
122 | struct zpool *zpool; | |
123 | struct crypto_comp * __percpu *tfm; | |
124 | struct kref kref; | |
125 | struct list_head list; | |
126 | struct work_struct work; | |
127 | struct hlist_node node; | |
128 | char tfm_name[CRYPTO_MAX_ALG_NAME]; | |
129 | }; | |
130 | ||
131 | /* | |
132 | * struct zswap_entry | |
133 | * | |
134 | * This structure contains the metadata for tracking a single compressed | |
135 | * page within zswap. | |
136 | * | |
137 | * rbnode - links the entry into red-black tree for the appropriate swap type | |
138 | * offset - the swap offset for the entry. Index into the red-black tree. | |
139 | * refcount - the number of outstanding reference to the entry. This is needed | |
140 | * to protect against premature freeing of the entry by code | |
141 | * concurrent calls to load, invalidate, and writeback. The lock | |
142 | * for the zswap_tree structure that contains the entry must | |
143 | * be held while changing the refcount. Since the lock must | |
144 | * be held, there is no reason to also make refcount atomic. | |
145 | * length - the length in bytes of the compressed page data. Needed during | |
146 | * decompression | |
147 | * pool - the zswap_pool the entry's data is in | |
148 | * handle - zpool allocation handle that stores the compressed page data | |
149 | */ | |
150 | struct zswap_entry { | |
151 | struct rb_node rbnode; | |
152 | pgoff_t offset; | |
153 | int refcount; | |
154 | unsigned int length; | |
155 | struct zswap_pool *pool; | |
156 | unsigned long handle; | |
157 | }; | |
158 | ||
159 | struct zswap_header { | |
160 | swp_entry_t swpentry; | |
161 | }; | |
162 | ||
163 | /* | |
164 | * The tree lock in the zswap_tree struct protects a few things: | |
165 | * - the rbtree | |
166 | * - the refcount field of each entry in the tree | |
167 | */ | |
168 | struct zswap_tree { | |
169 | struct rb_root rbroot; | |
170 | spinlock_t lock; | |
171 | }; | |
172 | ||
173 | static struct zswap_tree *zswap_trees[MAX_SWAPFILES]; | |
174 | ||
175 | /* RCU-protected iteration */ | |
176 | static LIST_HEAD(zswap_pools); | |
177 | /* protects zswap_pools list modification */ | |
178 | static DEFINE_SPINLOCK(zswap_pools_lock); | |
179 | /* pool counter to provide unique names to zpool */ | |
180 | static atomic_t zswap_pools_count = ATOMIC_INIT(0); | |
181 | ||
182 | /* used by param callback function */ | |
183 | static bool zswap_init_started; | |
184 | ||
185 | /* fatal error during init */ | |
186 | static bool zswap_init_failed; | |
187 | ||
188 | /********************************* | |
189 | * helpers and fwd declarations | |
190 | **********************************/ | |
191 | ||
192 | #define zswap_pool_debug(msg, p) \ | |
193 | pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \ | |
194 | zpool_get_type((p)->zpool)) | |
195 | ||
196 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle); | |
197 | static int zswap_pool_get(struct zswap_pool *pool); | |
198 | static void zswap_pool_put(struct zswap_pool *pool); | |
199 | ||
200 | static const struct zpool_ops zswap_zpool_ops = { | |
201 | .evict = zswap_writeback_entry | |
202 | }; | |
203 | ||
204 | static bool zswap_is_full(void) | |
205 | { | |
206 | return totalram_pages * zswap_max_pool_percent / 100 < | |
207 | DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); | |
208 | } | |
209 | ||
210 | static void zswap_update_total_size(void) | |
211 | { | |
212 | struct zswap_pool *pool; | |
213 | u64 total = 0; | |
214 | ||
215 | rcu_read_lock(); | |
216 | ||
217 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
218 | total += zpool_get_total_size(pool->zpool); | |
219 | ||
220 | rcu_read_unlock(); | |
221 | ||
222 | zswap_pool_total_size = total; | |
223 | } | |
224 | ||
225 | /********************************* | |
226 | * zswap entry functions | |
227 | **********************************/ | |
228 | static struct kmem_cache *zswap_entry_cache; | |
229 | ||
230 | static int __init zswap_entry_cache_create(void) | |
231 | { | |
232 | zswap_entry_cache = KMEM_CACHE(zswap_entry, 0); | |
233 | return zswap_entry_cache == NULL; | |
234 | } | |
235 | ||
236 | static void __init zswap_entry_cache_destroy(void) | |
237 | { | |
238 | kmem_cache_destroy(zswap_entry_cache); | |
239 | } | |
240 | ||
241 | static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp) | |
242 | { | |
243 | struct zswap_entry *entry; | |
244 | entry = kmem_cache_alloc(zswap_entry_cache, gfp); | |
245 | if (!entry) | |
246 | return NULL; | |
247 | entry->refcount = 1; | |
248 | RB_CLEAR_NODE(&entry->rbnode); | |
249 | return entry; | |
250 | } | |
251 | ||
252 | static void zswap_entry_cache_free(struct zswap_entry *entry) | |
253 | { | |
254 | kmem_cache_free(zswap_entry_cache, entry); | |
255 | } | |
256 | ||
257 | /********************************* | |
258 | * rbtree functions | |
259 | **********************************/ | |
260 | static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset) | |
261 | { | |
262 | struct rb_node *node = root->rb_node; | |
263 | struct zswap_entry *entry; | |
264 | ||
265 | while (node) { | |
266 | entry = rb_entry(node, struct zswap_entry, rbnode); | |
267 | if (entry->offset > offset) | |
268 | node = node->rb_left; | |
269 | else if (entry->offset < offset) | |
270 | node = node->rb_right; | |
271 | else | |
272 | return entry; | |
273 | } | |
274 | return NULL; | |
275 | } | |
276 | ||
277 | /* | |
278 | * In the case that a entry with the same offset is found, a pointer to | |
279 | * the existing entry is stored in dupentry and the function returns -EEXIST | |
280 | */ | |
281 | static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry, | |
282 | struct zswap_entry **dupentry) | |
283 | { | |
284 | struct rb_node **link = &root->rb_node, *parent = NULL; | |
285 | struct zswap_entry *myentry; | |
286 | ||
287 | while (*link) { | |
288 | parent = *link; | |
289 | myentry = rb_entry(parent, struct zswap_entry, rbnode); | |
290 | if (myentry->offset > entry->offset) | |
291 | link = &(*link)->rb_left; | |
292 | else if (myentry->offset < entry->offset) | |
293 | link = &(*link)->rb_right; | |
294 | else { | |
295 | *dupentry = myentry; | |
296 | return -EEXIST; | |
297 | } | |
298 | } | |
299 | rb_link_node(&entry->rbnode, parent, link); | |
300 | rb_insert_color(&entry->rbnode, root); | |
301 | return 0; | |
302 | } | |
303 | ||
304 | static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry) | |
305 | { | |
306 | if (!RB_EMPTY_NODE(&entry->rbnode)) { | |
307 | rb_erase(&entry->rbnode, root); | |
308 | RB_CLEAR_NODE(&entry->rbnode); | |
309 | } | |
310 | } | |
311 | ||
312 | /* | |
313 | * Carries out the common pattern of freeing and entry's zpool allocation, | |
314 | * freeing the entry itself, and decrementing the number of stored pages. | |
315 | */ | |
316 | static void zswap_free_entry(struct zswap_entry *entry) | |
317 | { | |
318 | zpool_free(entry->pool->zpool, entry->handle); | |
319 | zswap_pool_put(entry->pool); | |
320 | zswap_entry_cache_free(entry); | |
321 | atomic_dec(&zswap_stored_pages); | |
322 | zswap_update_total_size(); | |
323 | } | |
324 | ||
325 | /* caller must hold the tree lock */ | |
326 | static void zswap_entry_get(struct zswap_entry *entry) | |
327 | { | |
328 | entry->refcount++; | |
329 | } | |
330 | ||
331 | /* caller must hold the tree lock | |
332 | * remove from the tree and free it, if nobody reference the entry | |
333 | */ | |
334 | static void zswap_entry_put(struct zswap_tree *tree, | |
335 | struct zswap_entry *entry) | |
336 | { | |
337 | int refcount = --entry->refcount; | |
338 | ||
339 | BUG_ON(refcount < 0); | |
340 | if (refcount == 0) { | |
341 | zswap_rb_erase(&tree->rbroot, entry); | |
342 | zswap_free_entry(entry); | |
343 | } | |
344 | } | |
345 | ||
346 | /* caller must hold the tree lock */ | |
347 | static struct zswap_entry *zswap_entry_find_get(struct rb_root *root, | |
348 | pgoff_t offset) | |
349 | { | |
350 | struct zswap_entry *entry; | |
351 | ||
352 | entry = zswap_rb_search(root, offset); | |
353 | if (entry) | |
354 | zswap_entry_get(entry); | |
355 | ||
356 | return entry; | |
357 | } | |
358 | ||
359 | /********************************* | |
360 | * per-cpu code | |
361 | **********************************/ | |
362 | static DEFINE_PER_CPU(u8 *, zswap_dstmem); | |
363 | ||
364 | static int zswap_dstmem_prepare(unsigned int cpu) | |
365 | { | |
366 | u8 *dst; | |
367 | ||
368 | dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); | |
369 | if (!dst) { | |
370 | pr_err("can't allocate compressor buffer\n"); | |
371 | return -ENOMEM; | |
372 | } | |
373 | per_cpu(zswap_dstmem, cpu) = dst; | |
374 | return 0; | |
375 | } | |
376 | ||
377 | static int zswap_dstmem_dead(unsigned int cpu) | |
378 | { | |
379 | u8 *dst; | |
380 | ||
381 | dst = per_cpu(zswap_dstmem, cpu); | |
382 | kfree(dst); | |
383 | per_cpu(zswap_dstmem, cpu) = NULL; | |
384 | ||
385 | return 0; | |
386 | } | |
387 | ||
388 | static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) | |
389 | { | |
390 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); | |
391 | struct crypto_comp *tfm; | |
392 | ||
393 | if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu))) | |
394 | return 0; | |
395 | ||
396 | tfm = crypto_alloc_comp(pool->tfm_name, 0, 0); | |
397 | if (IS_ERR_OR_NULL(tfm)) { | |
398 | pr_err("could not alloc crypto comp %s : %ld\n", | |
399 | pool->tfm_name, PTR_ERR(tfm)); | |
400 | return -ENOMEM; | |
401 | } | |
402 | *per_cpu_ptr(pool->tfm, cpu) = tfm; | |
403 | return 0; | |
404 | } | |
405 | ||
406 | static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) | |
407 | { | |
408 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); | |
409 | struct crypto_comp *tfm; | |
410 | ||
411 | tfm = *per_cpu_ptr(pool->tfm, cpu); | |
412 | if (!IS_ERR_OR_NULL(tfm)) | |
413 | crypto_free_comp(tfm); | |
414 | *per_cpu_ptr(pool->tfm, cpu) = NULL; | |
415 | return 0; | |
416 | } | |
417 | ||
418 | /********************************* | |
419 | * pool functions | |
420 | **********************************/ | |
421 | ||
422 | static struct zswap_pool *__zswap_pool_current(void) | |
423 | { | |
424 | struct zswap_pool *pool; | |
425 | ||
426 | pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list); | |
427 | WARN_ON(!pool); | |
428 | ||
429 | return pool; | |
430 | } | |
431 | ||
432 | static struct zswap_pool *zswap_pool_current(void) | |
433 | { | |
434 | assert_spin_locked(&zswap_pools_lock); | |
435 | ||
436 | return __zswap_pool_current(); | |
437 | } | |
438 | ||
439 | static struct zswap_pool *zswap_pool_current_get(void) | |
440 | { | |
441 | struct zswap_pool *pool; | |
442 | ||
443 | rcu_read_lock(); | |
444 | ||
445 | pool = __zswap_pool_current(); | |
446 | if (!pool || !zswap_pool_get(pool)) | |
447 | pool = NULL; | |
448 | ||
449 | rcu_read_unlock(); | |
450 | ||
451 | return pool; | |
452 | } | |
453 | ||
454 | static struct zswap_pool *zswap_pool_last_get(void) | |
455 | { | |
456 | struct zswap_pool *pool, *last = NULL; | |
457 | ||
458 | rcu_read_lock(); | |
459 | ||
460 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
461 | last = pool; | |
462 | if (!WARN_ON(!last) && !zswap_pool_get(last)) | |
463 | last = NULL; | |
464 | ||
465 | rcu_read_unlock(); | |
466 | ||
467 | return last; | |
468 | } | |
469 | ||
470 | /* type and compressor must be null-terminated */ | |
471 | static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) | |
472 | { | |
473 | struct zswap_pool *pool; | |
474 | ||
475 | assert_spin_locked(&zswap_pools_lock); | |
476 | ||
477 | list_for_each_entry_rcu(pool, &zswap_pools, list) { | |
478 | if (strcmp(pool->tfm_name, compressor)) | |
479 | continue; | |
480 | if (strcmp(zpool_get_type(pool->zpool), type)) | |
481 | continue; | |
482 | /* if we can't get it, it's about to be destroyed */ | |
483 | if (!zswap_pool_get(pool)) | |
484 | continue; | |
485 | return pool; | |
486 | } | |
487 | ||
488 | return NULL; | |
489 | } | |
490 | ||
491 | static struct zswap_pool *zswap_pool_create(char *type, char *compressor) | |
492 | { | |
493 | struct zswap_pool *pool; | |
494 | char name[38]; /* 'zswap' + 32 char (max) num + \0 */ | |
495 | gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; | |
496 | int ret; | |
497 | ||
498 | pool = kzalloc(sizeof(*pool), GFP_KERNEL); | |
499 | if (!pool) { | |
500 | pr_err("pool alloc failed\n"); | |
501 | return NULL; | |
502 | } | |
503 | ||
504 | /* unique name for each pool specifically required by zsmalloc */ | |
505 | snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count)); | |
506 | ||
507 | pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops); | |
508 | if (!pool->zpool) { | |
509 | pr_err("%s zpool not available\n", type); | |
510 | goto error; | |
511 | } | |
512 | pr_debug("using %s zpool\n", zpool_get_type(pool->zpool)); | |
513 | ||
514 | strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); | |
515 | pool->tfm = alloc_percpu(struct crypto_comp *); | |
516 | if (!pool->tfm) { | |
517 | pr_err("percpu alloc failed\n"); | |
518 | goto error; | |
519 | } | |
520 | ||
521 | ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE, | |
522 | &pool->node); | |
523 | if (ret) | |
524 | goto error; | |
525 | pr_debug("using %s compressor\n", pool->tfm_name); | |
526 | ||
527 | /* being the current pool takes 1 ref; this func expects the | |
528 | * caller to always add the new pool as the current pool | |
529 | */ | |
530 | kref_init(&pool->kref); | |
531 | INIT_LIST_HEAD(&pool->list); | |
532 | ||
533 | zswap_pool_debug("created", pool); | |
534 | ||
535 | return pool; | |
536 | ||
537 | error: | |
538 | free_percpu(pool->tfm); | |
539 | if (pool->zpool) | |
540 | zpool_destroy_pool(pool->zpool); | |
541 | kfree(pool); | |
542 | return NULL; | |
543 | } | |
544 | ||
545 | static __init struct zswap_pool *__zswap_pool_create_fallback(void) | |
546 | { | |
547 | if (!crypto_has_comp(zswap_compressor, 0, 0)) { | |
548 | if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) { | |
549 | pr_err("default compressor %s not available\n", | |
550 | zswap_compressor); | |
551 | return NULL; | |
552 | } | |
553 | pr_err("compressor %s not available, using default %s\n", | |
554 | zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT); | |
555 | param_free_charp(&zswap_compressor); | |
556 | zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
557 | } | |
558 | if (!zpool_has_pool(zswap_zpool_type)) { | |
559 | if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) { | |
560 | pr_err("default zpool %s not available\n", | |
561 | zswap_zpool_type); | |
562 | return NULL; | |
563 | } | |
564 | pr_err("zpool %s not available, using default %s\n", | |
565 | zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT); | |
566 | param_free_charp(&zswap_zpool_type); | |
567 | zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
568 | } | |
569 | ||
570 | return zswap_pool_create(zswap_zpool_type, zswap_compressor); | |
571 | } | |
572 | ||
573 | static void zswap_pool_destroy(struct zswap_pool *pool) | |
574 | { | |
575 | zswap_pool_debug("destroying", pool); | |
576 | ||
577 | cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); | |
578 | free_percpu(pool->tfm); | |
579 | zpool_destroy_pool(pool->zpool); | |
580 | kfree(pool); | |
581 | } | |
582 | ||
583 | static int __must_check zswap_pool_get(struct zswap_pool *pool) | |
584 | { | |
585 | return kref_get_unless_zero(&pool->kref); | |
586 | } | |
587 | ||
588 | static void __zswap_pool_release(struct work_struct *work) | |
589 | { | |
590 | struct zswap_pool *pool = container_of(work, typeof(*pool), work); | |
591 | ||
592 | synchronize_rcu(); | |
593 | ||
594 | /* nobody should have been able to get a kref... */ | |
595 | WARN_ON(kref_get_unless_zero(&pool->kref)); | |
596 | ||
597 | /* pool is now off zswap_pools list and has no references. */ | |
598 | zswap_pool_destroy(pool); | |
599 | } | |
600 | ||
601 | static void __zswap_pool_empty(struct kref *kref) | |
602 | { | |
603 | struct zswap_pool *pool; | |
604 | ||
605 | pool = container_of(kref, typeof(*pool), kref); | |
606 | ||
607 | spin_lock(&zswap_pools_lock); | |
608 | ||
609 | WARN_ON(pool == zswap_pool_current()); | |
610 | ||
611 | list_del_rcu(&pool->list); | |
612 | ||
613 | INIT_WORK(&pool->work, __zswap_pool_release); | |
614 | schedule_work(&pool->work); | |
615 | ||
616 | spin_unlock(&zswap_pools_lock); | |
617 | } | |
618 | ||
619 | static void zswap_pool_put(struct zswap_pool *pool) | |
620 | { | |
621 | kref_put(&pool->kref, __zswap_pool_empty); | |
622 | } | |
623 | ||
624 | /********************************* | |
625 | * param callbacks | |
626 | **********************************/ | |
627 | ||
628 | /* val must be a null-terminated string */ | |
629 | static int __zswap_param_set(const char *val, const struct kernel_param *kp, | |
630 | char *type, char *compressor) | |
631 | { | |
632 | struct zswap_pool *pool, *put_pool = NULL; | |
633 | char *s = strstrip((char *)val); | |
634 | int ret; | |
635 | ||
636 | if (zswap_init_failed) { | |
637 | pr_err("can't set param, initialization failed\n"); | |
638 | return -ENODEV; | |
639 | } | |
640 | ||
641 | /* no change required */ | |
642 | if (!strcmp(s, *(char **)kp->arg)) | |
643 | return 0; | |
644 | ||
645 | /* if this is load-time (pre-init) param setting, | |
646 | * don't create a pool; that's done during init. | |
647 | */ | |
648 | if (!zswap_init_started) | |
649 | return param_set_charp(s, kp); | |
650 | ||
651 | if (!type) { | |
652 | if (!zpool_has_pool(s)) { | |
653 | pr_err("zpool %s not available\n", s); | |
654 | return -ENOENT; | |
655 | } | |
656 | type = s; | |
657 | } else if (!compressor) { | |
658 | if (!crypto_has_comp(s, 0, 0)) { | |
659 | pr_err("compressor %s not available\n", s); | |
660 | return -ENOENT; | |
661 | } | |
662 | compressor = s; | |
663 | } else { | |
664 | WARN_ON(1); | |
665 | return -EINVAL; | |
666 | } | |
667 | ||
668 | spin_lock(&zswap_pools_lock); | |
669 | ||
670 | pool = zswap_pool_find_get(type, compressor); | |
671 | if (pool) { | |
672 | zswap_pool_debug("using existing", pool); | |
673 | list_del_rcu(&pool->list); | |
674 | } else { | |
675 | spin_unlock(&zswap_pools_lock); | |
676 | pool = zswap_pool_create(type, compressor); | |
677 | spin_lock(&zswap_pools_lock); | |
678 | } | |
679 | ||
680 | if (pool) | |
681 | ret = param_set_charp(s, kp); | |
682 | else | |
683 | ret = -EINVAL; | |
684 | ||
685 | if (!ret) { | |
686 | put_pool = zswap_pool_current(); | |
687 | list_add_rcu(&pool->list, &zswap_pools); | |
688 | } else if (pool) { | |
689 | /* add the possibly pre-existing pool to the end of the pools | |
690 | * list; if it's new (and empty) then it'll be removed and | |
691 | * destroyed by the put after we drop the lock | |
692 | */ | |
693 | list_add_tail_rcu(&pool->list, &zswap_pools); | |
694 | put_pool = pool; | |
695 | } | |
696 | ||
697 | spin_unlock(&zswap_pools_lock); | |
698 | ||
699 | /* drop the ref from either the old current pool, | |
700 | * or the new pool we failed to add | |
701 | */ | |
702 | if (put_pool) | |
703 | zswap_pool_put(put_pool); | |
704 | ||
705 | return ret; | |
706 | } | |
707 | ||
708 | static int zswap_compressor_param_set(const char *val, | |
709 | const struct kernel_param *kp) | |
710 | { | |
711 | return __zswap_param_set(val, kp, zswap_zpool_type, NULL); | |
712 | } | |
713 | ||
714 | static int zswap_zpool_param_set(const char *val, | |
715 | const struct kernel_param *kp) | |
716 | { | |
717 | return __zswap_param_set(val, kp, NULL, zswap_compressor); | |
718 | } | |
719 | ||
720 | static int zswap_enabled_param_set(const char *val, | |
721 | const struct kernel_param *kp) | |
722 | { | |
723 | if (zswap_init_failed) { | |
724 | pr_err("can't enable, initialization failed\n"); | |
725 | return -ENODEV; | |
726 | } | |
727 | ||
728 | return param_set_bool(val, kp); | |
729 | } | |
730 | ||
731 | /********************************* | |
732 | * writeback code | |
733 | **********************************/ | |
734 | /* return enum for zswap_get_swap_cache_page */ | |
735 | enum zswap_get_swap_ret { | |
736 | ZSWAP_SWAPCACHE_NEW, | |
737 | ZSWAP_SWAPCACHE_EXIST, | |
738 | ZSWAP_SWAPCACHE_FAIL, | |
739 | }; | |
740 | ||
741 | /* | |
742 | * zswap_get_swap_cache_page | |
743 | * | |
744 | * This is an adaption of read_swap_cache_async() | |
745 | * | |
746 | * This function tries to find a page with the given swap entry | |
747 | * in the swapper_space address space (the swap cache). If the page | |
748 | * is found, it is returned in retpage. Otherwise, a page is allocated, | |
749 | * added to the swap cache, and returned in retpage. | |
750 | * | |
751 | * If success, the swap cache page is returned in retpage | |
752 | * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache | |
753 | * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated, | |
754 | * the new page is added to swapcache and locked | |
755 | * Returns ZSWAP_SWAPCACHE_FAIL on error | |
756 | */ | |
757 | static int zswap_get_swap_cache_page(swp_entry_t entry, | |
758 | struct page **retpage) | |
759 | { | |
760 | bool page_was_allocated; | |
761 | ||
762 | *retpage = __read_swap_cache_async(entry, GFP_KERNEL, | |
763 | NULL, 0, &page_was_allocated); | |
764 | if (page_was_allocated) | |
765 | return ZSWAP_SWAPCACHE_NEW; | |
766 | if (!*retpage) | |
767 | return ZSWAP_SWAPCACHE_FAIL; | |
768 | return ZSWAP_SWAPCACHE_EXIST; | |
769 | } | |
770 | ||
771 | /* | |
772 | * Attempts to free an entry by adding a page to the swap cache, | |
773 | * decompressing the entry data into the page, and issuing a | |
774 | * bio write to write the page back to the swap device. | |
775 | * | |
776 | * This can be thought of as a "resumed writeback" of the page | |
777 | * to the swap device. We are basically resuming the same swap | |
778 | * writeback path that was intercepted with the frontswap_store() | |
779 | * in the first place. After the page has been decompressed into | |
780 | * the swap cache, the compressed version stored by zswap can be | |
781 | * freed. | |
782 | */ | |
783 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) | |
784 | { | |
785 | struct zswap_header *zhdr; | |
786 | swp_entry_t swpentry; | |
787 | struct zswap_tree *tree; | |
788 | pgoff_t offset; | |
789 | struct zswap_entry *entry; | |
790 | struct page *page; | |
791 | struct crypto_comp *tfm; | |
792 | u8 *src, *dst; | |
793 | unsigned int dlen; | |
794 | int ret; | |
795 | struct writeback_control wbc = { | |
796 | .sync_mode = WB_SYNC_NONE, | |
797 | }; | |
798 | ||
799 | /* extract swpentry from data */ | |
800 | zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); | |
801 | swpentry = zhdr->swpentry; /* here */ | |
802 | zpool_unmap_handle(pool, handle); | |
803 | tree = zswap_trees[swp_type(swpentry)]; | |
804 | offset = swp_offset(swpentry); | |
805 | ||
806 | /* find and ref zswap entry */ | |
807 | spin_lock(&tree->lock); | |
808 | entry = zswap_entry_find_get(&tree->rbroot, offset); | |
809 | if (!entry) { | |
810 | /* entry was invalidated */ | |
811 | spin_unlock(&tree->lock); | |
812 | return 0; | |
813 | } | |
814 | spin_unlock(&tree->lock); | |
815 | BUG_ON(offset != entry->offset); | |
816 | ||
817 | /* try to allocate swap cache page */ | |
818 | switch (zswap_get_swap_cache_page(swpentry, &page)) { | |
819 | case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ | |
820 | ret = -ENOMEM; | |
821 | goto fail; | |
822 | ||
823 | case ZSWAP_SWAPCACHE_EXIST: | |
824 | /* page is already in the swap cache, ignore for now */ | |
825 | put_page(page); | |
826 | ret = -EEXIST; | |
827 | goto fail; | |
828 | ||
829 | case ZSWAP_SWAPCACHE_NEW: /* page is locked */ | |
830 | /* decompress */ | |
831 | dlen = PAGE_SIZE; | |
832 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, | |
833 | ZPOOL_MM_RO) + sizeof(struct zswap_header); | |
834 | dst = kmap_atomic(page); | |
835 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
836 | ret = crypto_comp_decompress(tfm, src, entry->length, | |
837 | dst, &dlen); | |
838 | put_cpu_ptr(entry->pool->tfm); | |
839 | kunmap_atomic(dst); | |
840 | zpool_unmap_handle(entry->pool->zpool, entry->handle); | |
841 | BUG_ON(ret); | |
842 | BUG_ON(dlen != PAGE_SIZE); | |
843 | ||
844 | /* page is up to date */ | |
845 | SetPageUptodate(page); | |
846 | } | |
847 | ||
848 | /* move it to the tail of the inactive list after end_writeback */ | |
849 | SetPageReclaim(page); | |
850 | ||
851 | /* start writeback */ | |
852 | __swap_writepage(page, &wbc, end_swap_bio_write); | |
853 | put_page(page); | |
854 | zswap_written_back_pages++; | |
855 | ||
856 | spin_lock(&tree->lock); | |
857 | /* drop local reference */ | |
858 | zswap_entry_put(tree, entry); | |
859 | ||
860 | /* | |
861 | * There are two possible situations for entry here: | |
862 | * (1) refcount is 1(normal case), entry is valid and on the tree | |
863 | * (2) refcount is 0, entry is freed and not on the tree | |
864 | * because invalidate happened during writeback | |
865 | * search the tree and free the entry if find entry | |
866 | */ | |
867 | if (entry == zswap_rb_search(&tree->rbroot, offset)) | |
868 | zswap_entry_put(tree, entry); | |
869 | spin_unlock(&tree->lock); | |
870 | ||
871 | goto end; | |
872 | ||
873 | /* | |
874 | * if we get here due to ZSWAP_SWAPCACHE_EXIST | |
875 | * a load may happening concurrently | |
876 | * it is safe and okay to not free the entry | |
877 | * if we free the entry in the following put | |
878 | * it it either okay to return !0 | |
879 | */ | |
880 | fail: | |
881 | spin_lock(&tree->lock); | |
882 | zswap_entry_put(tree, entry); | |
883 | spin_unlock(&tree->lock); | |
884 | ||
885 | end: | |
886 | return ret; | |
887 | } | |
888 | ||
889 | static int zswap_shrink(void) | |
890 | { | |
891 | struct zswap_pool *pool; | |
892 | int ret; | |
893 | ||
894 | pool = zswap_pool_last_get(); | |
895 | if (!pool) | |
896 | return -ENOENT; | |
897 | ||
898 | ret = zpool_shrink(pool->zpool, 1, NULL); | |
899 | ||
900 | zswap_pool_put(pool); | |
901 | ||
902 | return ret; | |
903 | } | |
904 | ||
905 | /********************************* | |
906 | * frontswap hooks | |
907 | **********************************/ | |
908 | /* attempts to compress and store an single page */ | |
909 | static int zswap_frontswap_store(unsigned type, pgoff_t offset, | |
910 | struct page *page) | |
911 | { | |
912 | struct zswap_tree *tree = zswap_trees[type]; | |
913 | struct zswap_entry *entry, *dupentry; | |
914 | struct crypto_comp *tfm; | |
915 | int ret; | |
916 | unsigned int dlen = PAGE_SIZE, len; | |
917 | unsigned long handle; | |
918 | char *buf; | |
919 | u8 *src, *dst; | |
920 | struct zswap_header *zhdr; | |
921 | ||
922 | if (!zswap_enabled || !tree) { | |
923 | ret = -ENODEV; | |
924 | goto reject; | |
925 | } | |
926 | ||
927 | /* reclaim space if needed */ | |
928 | if (zswap_is_full()) { | |
929 | zswap_pool_limit_hit++; | |
930 | if (zswap_shrink()) { | |
931 | zswap_reject_reclaim_fail++; | |
932 | ret = -ENOMEM; | |
933 | goto reject; | |
934 | } | |
935 | } | |
936 | ||
937 | /* allocate entry */ | |
938 | entry = zswap_entry_cache_alloc(GFP_KERNEL); | |
939 | if (!entry) { | |
940 | zswap_reject_kmemcache_fail++; | |
941 | ret = -ENOMEM; | |
942 | goto reject; | |
943 | } | |
944 | ||
945 | /* if entry is successfully added, it keeps the reference */ | |
946 | entry->pool = zswap_pool_current_get(); | |
947 | if (!entry->pool) { | |
948 | ret = -EINVAL; | |
949 | goto freepage; | |
950 | } | |
951 | ||
952 | /* compress */ | |
953 | dst = get_cpu_var(zswap_dstmem); | |
954 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
955 | src = kmap_atomic(page); | |
956 | ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen); | |
957 | kunmap_atomic(src); | |
958 | put_cpu_ptr(entry->pool->tfm); | |
959 | if (ret) { | |
960 | ret = -EINVAL; | |
961 | goto put_dstmem; | |
962 | } | |
963 | ||
964 | /* store */ | |
965 | len = dlen + sizeof(struct zswap_header); | |
966 | ret = zpool_malloc(entry->pool->zpool, len, | |
967 | __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM, | |
968 | &handle); | |
969 | if (ret == -ENOSPC) { | |
970 | zswap_reject_compress_poor++; | |
971 | goto put_dstmem; | |
972 | } | |
973 | if (ret) { | |
974 | zswap_reject_alloc_fail++; | |
975 | goto put_dstmem; | |
976 | } | |
977 | zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); | |
978 | zhdr->swpentry = swp_entry(type, offset); | |
979 | buf = (u8 *)(zhdr + 1); | |
980 | memcpy(buf, dst, dlen); | |
981 | zpool_unmap_handle(entry->pool->zpool, handle); | |
982 | put_cpu_var(zswap_dstmem); | |
983 | ||
984 | /* populate entry */ | |
985 | entry->offset = offset; | |
986 | entry->handle = handle; | |
987 | entry->length = dlen; | |
988 | ||
989 | /* map */ | |
990 | spin_lock(&tree->lock); | |
991 | do { | |
992 | ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry); | |
993 | if (ret == -EEXIST) { | |
994 | zswap_duplicate_entry++; | |
995 | /* remove from rbtree */ | |
996 | zswap_rb_erase(&tree->rbroot, dupentry); | |
997 | zswap_entry_put(tree, dupentry); | |
998 | } | |
999 | } while (ret == -EEXIST); | |
1000 | spin_unlock(&tree->lock); | |
1001 | ||
1002 | /* update stats */ | |
1003 | atomic_inc(&zswap_stored_pages); | |
1004 | zswap_update_total_size(); | |
1005 | ||
1006 | return 0; | |
1007 | ||
1008 | put_dstmem: | |
1009 | put_cpu_var(zswap_dstmem); | |
1010 | zswap_pool_put(entry->pool); | |
1011 | freepage: | |
1012 | zswap_entry_cache_free(entry); | |
1013 | reject: | |
1014 | return ret; | |
1015 | } | |
1016 | ||
1017 | /* | |
1018 | * returns 0 if the page was successfully decompressed | |
1019 | * return -1 on entry not found or error | |
1020 | */ | |
1021 | static int zswap_frontswap_load(unsigned type, pgoff_t offset, | |
1022 | struct page *page) | |
1023 | { | |
1024 | struct zswap_tree *tree = zswap_trees[type]; | |
1025 | struct zswap_entry *entry; | |
1026 | struct crypto_comp *tfm; | |
1027 | u8 *src, *dst; | |
1028 | unsigned int dlen; | |
1029 | int ret; | |
1030 | ||
1031 | /* find */ | |
1032 | spin_lock(&tree->lock); | |
1033 | entry = zswap_entry_find_get(&tree->rbroot, offset); | |
1034 | if (!entry) { | |
1035 | /* entry was written back */ | |
1036 | spin_unlock(&tree->lock); | |
1037 | return -1; | |
1038 | } | |
1039 | spin_unlock(&tree->lock); | |
1040 | ||
1041 | /* decompress */ | |
1042 | dlen = PAGE_SIZE; | |
1043 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, | |
1044 | ZPOOL_MM_RO) + sizeof(struct zswap_header); | |
1045 | dst = kmap_atomic(page); | |
1046 | tfm = *get_cpu_ptr(entry->pool->tfm); | |
1047 | ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); | |
1048 | put_cpu_ptr(entry->pool->tfm); | |
1049 | kunmap_atomic(dst); | |
1050 | zpool_unmap_handle(entry->pool->zpool, entry->handle); | |
1051 | BUG_ON(ret); | |
1052 | ||
1053 | spin_lock(&tree->lock); | |
1054 | zswap_entry_put(tree, entry); | |
1055 | spin_unlock(&tree->lock); | |
1056 | ||
1057 | return 0; | |
1058 | } | |
1059 | ||
1060 | /* frees an entry in zswap */ | |
1061 | static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) | |
1062 | { | |
1063 | struct zswap_tree *tree = zswap_trees[type]; | |
1064 | struct zswap_entry *entry; | |
1065 | ||
1066 | /* find */ | |
1067 | spin_lock(&tree->lock); | |
1068 | entry = zswap_rb_search(&tree->rbroot, offset); | |
1069 | if (!entry) { | |
1070 | /* entry was written back */ | |
1071 | spin_unlock(&tree->lock); | |
1072 | return; | |
1073 | } | |
1074 | ||
1075 | /* remove from rbtree */ | |
1076 | zswap_rb_erase(&tree->rbroot, entry); | |
1077 | ||
1078 | /* drop the initial reference from entry creation */ | |
1079 | zswap_entry_put(tree, entry); | |
1080 | ||
1081 | spin_unlock(&tree->lock); | |
1082 | } | |
1083 | ||
1084 | /* frees all zswap entries for the given swap type */ | |
1085 | static void zswap_frontswap_invalidate_area(unsigned type) | |
1086 | { | |
1087 | struct zswap_tree *tree = zswap_trees[type]; | |
1088 | struct zswap_entry *entry, *n; | |
1089 | ||
1090 | if (!tree) | |
1091 | return; | |
1092 | ||
1093 | /* walk the tree and free everything */ | |
1094 | spin_lock(&tree->lock); | |
1095 | rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode) | |
1096 | zswap_free_entry(entry); | |
1097 | tree->rbroot = RB_ROOT; | |
1098 | spin_unlock(&tree->lock); | |
1099 | kfree(tree); | |
1100 | zswap_trees[type] = NULL; | |
1101 | } | |
1102 | ||
1103 | static void zswap_frontswap_init(unsigned type) | |
1104 | { | |
1105 | struct zswap_tree *tree; | |
1106 | ||
1107 | tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL); | |
1108 | if (!tree) { | |
1109 | pr_err("alloc failed, zswap disabled for swap type %d\n", type); | |
1110 | return; | |
1111 | } | |
1112 | ||
1113 | tree->rbroot = RB_ROOT; | |
1114 | spin_lock_init(&tree->lock); | |
1115 | zswap_trees[type] = tree; | |
1116 | } | |
1117 | ||
1118 | static struct frontswap_ops zswap_frontswap_ops = { | |
1119 | .store = zswap_frontswap_store, | |
1120 | .load = zswap_frontswap_load, | |
1121 | .invalidate_page = zswap_frontswap_invalidate_page, | |
1122 | .invalidate_area = zswap_frontswap_invalidate_area, | |
1123 | .init = zswap_frontswap_init | |
1124 | }; | |
1125 | ||
1126 | /********************************* | |
1127 | * debugfs functions | |
1128 | **********************************/ | |
1129 | #ifdef CONFIG_DEBUG_FS | |
1130 | #include <linux/debugfs.h> | |
1131 | ||
1132 | static struct dentry *zswap_debugfs_root; | |
1133 | ||
1134 | static int __init zswap_debugfs_init(void) | |
1135 | { | |
1136 | if (!debugfs_initialized()) | |
1137 | return -ENODEV; | |
1138 | ||
1139 | zswap_debugfs_root = debugfs_create_dir("zswap", NULL); | |
1140 | if (!zswap_debugfs_root) | |
1141 | return -ENOMEM; | |
1142 | ||
1143 | debugfs_create_u64("pool_limit_hit", S_IRUGO, | |
1144 | zswap_debugfs_root, &zswap_pool_limit_hit); | |
1145 | debugfs_create_u64("reject_reclaim_fail", S_IRUGO, | |
1146 | zswap_debugfs_root, &zswap_reject_reclaim_fail); | |
1147 | debugfs_create_u64("reject_alloc_fail", S_IRUGO, | |
1148 | zswap_debugfs_root, &zswap_reject_alloc_fail); | |
1149 | debugfs_create_u64("reject_kmemcache_fail", S_IRUGO, | |
1150 | zswap_debugfs_root, &zswap_reject_kmemcache_fail); | |
1151 | debugfs_create_u64("reject_compress_poor", S_IRUGO, | |
1152 | zswap_debugfs_root, &zswap_reject_compress_poor); | |
1153 | debugfs_create_u64("written_back_pages", S_IRUGO, | |
1154 | zswap_debugfs_root, &zswap_written_back_pages); | |
1155 | debugfs_create_u64("duplicate_entry", S_IRUGO, | |
1156 | zswap_debugfs_root, &zswap_duplicate_entry); | |
1157 | debugfs_create_u64("pool_total_size", S_IRUGO, | |
1158 | zswap_debugfs_root, &zswap_pool_total_size); | |
1159 | debugfs_create_atomic_t("stored_pages", S_IRUGO, | |
1160 | zswap_debugfs_root, &zswap_stored_pages); | |
1161 | ||
1162 | return 0; | |
1163 | } | |
1164 | ||
1165 | static void __exit zswap_debugfs_exit(void) | |
1166 | { | |
1167 | debugfs_remove_recursive(zswap_debugfs_root); | |
1168 | } | |
1169 | #else | |
1170 | static int __init zswap_debugfs_init(void) | |
1171 | { | |
1172 | return 0; | |
1173 | } | |
1174 | ||
1175 | static void __exit zswap_debugfs_exit(void) { } | |
1176 | #endif | |
1177 | ||
1178 | /********************************* | |
1179 | * module init and exit | |
1180 | **********************************/ | |
1181 | static int __init init_zswap(void) | |
1182 | { | |
1183 | struct zswap_pool *pool; | |
1184 | int ret; | |
1185 | ||
1186 | zswap_init_started = true; | |
1187 | ||
1188 | if (zswap_entry_cache_create()) { | |
1189 | pr_err("entry cache creation failed\n"); | |
1190 | goto cache_fail; | |
1191 | } | |
1192 | ||
1193 | ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare", | |
1194 | zswap_dstmem_prepare, zswap_dstmem_dead); | |
1195 | if (ret) { | |
1196 | pr_err("dstmem alloc failed\n"); | |
1197 | goto dstmem_fail; | |
1198 | } | |
1199 | ||
1200 | ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE, | |
1201 | "mm/zswap_pool:prepare", | |
1202 | zswap_cpu_comp_prepare, | |
1203 | zswap_cpu_comp_dead); | |
1204 | if (ret) | |
1205 | goto hp_fail; | |
1206 | ||
1207 | pool = __zswap_pool_create_fallback(); | |
1208 | if (!pool) { | |
1209 | pr_err("pool creation failed\n"); | |
1210 | goto pool_fail; | |
1211 | } | |
1212 | pr_info("loaded using pool %s/%s\n", pool->tfm_name, | |
1213 | zpool_get_type(pool->zpool)); | |
1214 | ||
1215 | list_add(&pool->list, &zswap_pools); | |
1216 | ||
1217 | frontswap_register_ops(&zswap_frontswap_ops); | |
1218 | if (zswap_debugfs_init()) | |
1219 | pr_warn("debugfs initialization failed\n"); | |
1220 | return 0; | |
1221 | ||
1222 | pool_fail: | |
1223 | cpuhp_remove_state_nocalls(CPUHP_MM_ZSWP_POOL_PREPARE); | |
1224 | hp_fail: | |
1225 | cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE); | |
1226 | dstmem_fail: | |
1227 | zswap_entry_cache_destroy(); | |
1228 | cache_fail: | |
1229 | /* if built-in, we aren't unloaded on failure; don't allow use */ | |
1230 | zswap_init_failed = true; | |
1231 | zswap_enabled = false; | |
1232 | return -ENOMEM; | |
1233 | } | |
1234 | /* must be late so crypto has time to come up */ | |
1235 | late_initcall(init_zswap); | |
1236 | ||
1237 | MODULE_LICENSE("GPL"); | |
1238 | MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>"); | |
1239 | MODULE_DESCRIPTION("Compressed cache for swap pages"); |