Commit | Line | Data |
---|---|---|
2b281117 SJ |
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> | |
12d79d64 | 37 | #include <linux/zpool.h> |
2b281117 SJ |
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 | **********************************/ | |
12d79d64 DS |
48 | /* Total bytes used by the compressed storage */ |
49 | static u64 zswap_pool_total_size; | |
2b281117 SJ |
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 | **********************************/ | |
c00ed16a DS |
78 | |
79 | /* Enable/disable zswap (disabled by default) */ | |
80 | static bool zswap_enabled; | |
81 | module_param_named(enabled, zswap_enabled, bool, 0644); | |
2b281117 SJ |
82 | |
83 | /* Compressor to be used by zswap (fixed at boot for now) */ | |
84 | #define ZSWAP_COMPRESSOR_DEFAULT "lzo" | |
85 | static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
12ab028b | 86 | module_param_named(compressor, zswap_compressor, charp, 0444); |
2b281117 SJ |
87 | |
88 | /* The maximum percentage of memory that the compressed pool can occupy */ | |
89 | static unsigned int zswap_max_pool_percent = 20; | |
90 | module_param_named(max_pool_percent, | |
91 | zswap_max_pool_percent, uint, 0644); | |
92 | ||
12d79d64 DS |
93 | /* Compressed storage to use */ |
94 | #define ZSWAP_ZPOOL_DEFAULT "zbud" | |
95 | static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
96 | module_param_named(zpool, zswap_zpool_type, charp, 0444); | |
97 | ||
98 | /* zpool is shared by all of zswap backend */ | |
99 | static struct zpool *zswap_pool; | |
60105e12 | 100 | |
2b281117 | 101 | /********************************* |
f1c54846 | 102 | * data structures |
2b281117 | 103 | **********************************/ |
2b281117 | 104 | |
f1c54846 DS |
105 | struct zswap_pool { |
106 | struct zpool *zpool; | |
107 | struct crypto_comp * __percpu *tfm; | |
108 | struct kref kref; | |
109 | struct list_head list; | |
110 | struct rcu_head rcu_head; | |
111 | struct notifier_block notifier; | |
112 | char tfm_name[CRYPTO_MAX_ALG_NAME]; | |
2b281117 SJ |
113 | }; |
114 | ||
2b281117 SJ |
115 | /* |
116 | * struct zswap_entry | |
117 | * | |
118 | * This structure contains the metadata for tracking a single compressed | |
119 | * page within zswap. | |
120 | * | |
121 | * rbnode - links the entry into red-black tree for the appropriate swap type | |
f1c54846 | 122 | * offset - the swap offset for the entry. Index into the red-black tree. |
2b281117 SJ |
123 | * refcount - the number of outstanding reference to the entry. This is needed |
124 | * to protect against premature freeing of the entry by code | |
6b452516 | 125 | * concurrent calls to load, invalidate, and writeback. The lock |
2b281117 SJ |
126 | * for the zswap_tree structure that contains the entry must |
127 | * be held while changing the refcount. Since the lock must | |
128 | * be held, there is no reason to also make refcount atomic. | |
2b281117 | 129 | * length - the length in bytes of the compressed page data. Needed during |
6b452516 | 130 | * decompression |
f1c54846 DS |
131 | * pool - the zswap_pool the entry's data is in |
132 | * handle - zpool allocation handle that stores the compressed page data | |
2b281117 SJ |
133 | */ |
134 | struct zswap_entry { | |
135 | struct rb_node rbnode; | |
136 | pgoff_t offset; | |
137 | int refcount; | |
138 | unsigned int length; | |
f1c54846 | 139 | struct zswap_pool *pool; |
2b281117 SJ |
140 | unsigned long handle; |
141 | }; | |
142 | ||
143 | struct zswap_header { | |
144 | swp_entry_t swpentry; | |
145 | }; | |
146 | ||
147 | /* | |
148 | * The tree lock in the zswap_tree struct protects a few things: | |
149 | * - the rbtree | |
150 | * - the refcount field of each entry in the tree | |
151 | */ | |
152 | struct zswap_tree { | |
153 | struct rb_root rbroot; | |
154 | spinlock_t lock; | |
2b281117 SJ |
155 | }; |
156 | ||
157 | static struct zswap_tree *zswap_trees[MAX_SWAPFILES]; | |
158 | ||
f1c54846 DS |
159 | /* RCU-protected iteration */ |
160 | static LIST_HEAD(zswap_pools); | |
161 | /* protects zswap_pools list modification */ | |
162 | static DEFINE_SPINLOCK(zswap_pools_lock); | |
163 | ||
164 | /********************************* | |
165 | * helpers and fwd declarations | |
166 | **********************************/ | |
167 | ||
168 | #define zswap_pool_debug(msg, p) \ | |
169 | pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \ | |
170 | zpool_get_type((p)->zpool)) | |
171 | ||
172 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle); | |
173 | static int zswap_pool_get(struct zswap_pool *pool); | |
174 | static void zswap_pool_put(struct zswap_pool *pool); | |
175 | ||
176 | static const struct zpool_ops zswap_zpool_ops = { | |
177 | .evict = zswap_writeback_entry | |
178 | }; | |
179 | ||
180 | static bool zswap_is_full(void) | |
181 | { | |
182 | return totalram_pages * zswap_max_pool_percent / 100 < | |
183 | DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); | |
184 | } | |
185 | ||
186 | static void zswap_update_total_size(void) | |
187 | { | |
188 | struct zswap_pool *pool; | |
189 | u64 total = 0; | |
190 | ||
191 | rcu_read_lock(); | |
192 | ||
193 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
194 | total += zpool_get_total_size(pool->zpool); | |
195 | ||
196 | rcu_read_unlock(); | |
197 | ||
198 | zswap_pool_total_size = total; | |
199 | } | |
200 | ||
2b281117 SJ |
201 | /********************************* |
202 | * zswap entry functions | |
203 | **********************************/ | |
204 | static struct kmem_cache *zswap_entry_cache; | |
205 | ||
dd01d7d8 | 206 | static int __init zswap_entry_cache_create(void) |
2b281117 SJ |
207 | { |
208 | zswap_entry_cache = KMEM_CACHE(zswap_entry, 0); | |
5d2d42de | 209 | return zswap_entry_cache == NULL; |
2b281117 SJ |
210 | } |
211 | ||
c119239b | 212 | static void __init zswap_entry_cache_destroy(void) |
2b281117 SJ |
213 | { |
214 | kmem_cache_destroy(zswap_entry_cache); | |
215 | } | |
216 | ||
217 | static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp) | |
218 | { | |
219 | struct zswap_entry *entry; | |
220 | entry = kmem_cache_alloc(zswap_entry_cache, gfp); | |
221 | if (!entry) | |
222 | return NULL; | |
223 | entry->refcount = 1; | |
0ab0abcf | 224 | RB_CLEAR_NODE(&entry->rbnode); |
2b281117 SJ |
225 | return entry; |
226 | } | |
227 | ||
228 | static void zswap_entry_cache_free(struct zswap_entry *entry) | |
229 | { | |
230 | kmem_cache_free(zswap_entry_cache, entry); | |
231 | } | |
232 | ||
2b281117 SJ |
233 | /********************************* |
234 | * rbtree functions | |
235 | **********************************/ | |
236 | static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset) | |
237 | { | |
238 | struct rb_node *node = root->rb_node; | |
239 | struct zswap_entry *entry; | |
240 | ||
241 | while (node) { | |
242 | entry = rb_entry(node, struct zswap_entry, rbnode); | |
243 | if (entry->offset > offset) | |
244 | node = node->rb_left; | |
245 | else if (entry->offset < offset) | |
246 | node = node->rb_right; | |
247 | else | |
248 | return entry; | |
249 | } | |
250 | return NULL; | |
251 | } | |
252 | ||
253 | /* | |
254 | * In the case that a entry with the same offset is found, a pointer to | |
255 | * the existing entry is stored in dupentry and the function returns -EEXIST | |
256 | */ | |
257 | static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry, | |
258 | struct zswap_entry **dupentry) | |
259 | { | |
260 | struct rb_node **link = &root->rb_node, *parent = NULL; | |
261 | struct zswap_entry *myentry; | |
262 | ||
263 | while (*link) { | |
264 | parent = *link; | |
265 | myentry = rb_entry(parent, struct zswap_entry, rbnode); | |
266 | if (myentry->offset > entry->offset) | |
267 | link = &(*link)->rb_left; | |
268 | else if (myentry->offset < entry->offset) | |
269 | link = &(*link)->rb_right; | |
270 | else { | |
271 | *dupentry = myentry; | |
272 | return -EEXIST; | |
273 | } | |
274 | } | |
275 | rb_link_node(&entry->rbnode, parent, link); | |
276 | rb_insert_color(&entry->rbnode, root); | |
277 | return 0; | |
278 | } | |
279 | ||
0ab0abcf WY |
280 | static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry) |
281 | { | |
282 | if (!RB_EMPTY_NODE(&entry->rbnode)) { | |
283 | rb_erase(&entry->rbnode, root); | |
284 | RB_CLEAR_NODE(&entry->rbnode); | |
285 | } | |
286 | } | |
287 | ||
288 | /* | |
12d79d64 | 289 | * Carries out the common pattern of freeing and entry's zpool allocation, |
0ab0abcf WY |
290 | * freeing the entry itself, and decrementing the number of stored pages. |
291 | */ | |
60105e12 | 292 | static void zswap_free_entry(struct zswap_entry *entry) |
0ab0abcf | 293 | { |
f1c54846 DS |
294 | zpool_free(entry->pool->zpool, entry->handle); |
295 | zswap_pool_put(entry->pool); | |
0ab0abcf WY |
296 | zswap_entry_cache_free(entry); |
297 | atomic_dec(&zswap_stored_pages); | |
f1c54846 | 298 | zswap_update_total_size(); |
0ab0abcf WY |
299 | } |
300 | ||
301 | /* caller must hold the tree lock */ | |
302 | static void zswap_entry_get(struct zswap_entry *entry) | |
303 | { | |
304 | entry->refcount++; | |
305 | } | |
306 | ||
307 | /* caller must hold the tree lock | |
308 | * remove from the tree and free it, if nobody reference the entry | |
309 | */ | |
310 | static void zswap_entry_put(struct zswap_tree *tree, | |
311 | struct zswap_entry *entry) | |
312 | { | |
313 | int refcount = --entry->refcount; | |
314 | ||
315 | BUG_ON(refcount < 0); | |
316 | if (refcount == 0) { | |
317 | zswap_rb_erase(&tree->rbroot, entry); | |
60105e12 | 318 | zswap_free_entry(entry); |
0ab0abcf WY |
319 | } |
320 | } | |
321 | ||
322 | /* caller must hold the tree lock */ | |
323 | static struct zswap_entry *zswap_entry_find_get(struct rb_root *root, | |
324 | pgoff_t offset) | |
325 | { | |
326 | struct zswap_entry *entry = NULL; | |
327 | ||
328 | entry = zswap_rb_search(root, offset); | |
329 | if (entry) | |
330 | zswap_entry_get(entry); | |
331 | ||
332 | return entry; | |
333 | } | |
334 | ||
2b281117 SJ |
335 | /********************************* |
336 | * per-cpu code | |
337 | **********************************/ | |
338 | static DEFINE_PER_CPU(u8 *, zswap_dstmem); | |
339 | ||
f1c54846 | 340 | static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu) |
2b281117 | 341 | { |
2b281117 SJ |
342 | u8 *dst; |
343 | ||
344 | switch (action) { | |
345 | case CPU_UP_PREPARE: | |
72d09633 | 346 | dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); |
2b281117 SJ |
347 | if (!dst) { |
348 | pr_err("can't allocate compressor buffer\n"); | |
2b281117 SJ |
349 | return NOTIFY_BAD; |
350 | } | |
351 | per_cpu(zswap_dstmem, cpu) = dst; | |
352 | break; | |
353 | case CPU_DEAD: | |
354 | case CPU_UP_CANCELED: | |
2b281117 SJ |
355 | dst = per_cpu(zswap_dstmem, cpu); |
356 | kfree(dst); | |
357 | per_cpu(zswap_dstmem, cpu) = NULL; | |
358 | break; | |
359 | default: | |
360 | break; | |
361 | } | |
362 | return NOTIFY_OK; | |
363 | } | |
364 | ||
f1c54846 DS |
365 | static int zswap_cpu_dstmem_notifier(struct notifier_block *nb, |
366 | unsigned long action, void *pcpu) | |
2b281117 | 367 | { |
f1c54846 | 368 | return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu); |
2b281117 SJ |
369 | } |
370 | ||
f1c54846 DS |
371 | static struct notifier_block zswap_dstmem_notifier = { |
372 | .notifier_call = zswap_cpu_dstmem_notifier, | |
2b281117 SJ |
373 | }; |
374 | ||
f1c54846 DS |
375 | static int __init zswap_cpu_dstmem_init(void) |
376 | { | |
377 | unsigned long cpu; | |
378 | ||
379 | cpu_notifier_register_begin(); | |
380 | for_each_online_cpu(cpu) | |
381 | if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) == | |
382 | NOTIFY_BAD) | |
383 | goto cleanup; | |
384 | __register_cpu_notifier(&zswap_dstmem_notifier); | |
385 | cpu_notifier_register_done(); | |
386 | return 0; | |
387 | ||
388 | cleanup: | |
389 | for_each_online_cpu(cpu) | |
390 | __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu); | |
391 | cpu_notifier_register_done(); | |
392 | return -ENOMEM; | |
393 | } | |
394 | ||
395 | static void zswap_cpu_dstmem_destroy(void) | |
396 | { | |
397 | unsigned long cpu; | |
398 | ||
399 | cpu_notifier_register_begin(); | |
400 | for_each_online_cpu(cpu) | |
401 | __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu); | |
402 | __unregister_cpu_notifier(&zswap_dstmem_notifier); | |
403 | cpu_notifier_register_done(); | |
404 | } | |
405 | ||
406 | static int __zswap_cpu_comp_notifier(struct zswap_pool *pool, | |
407 | unsigned long action, unsigned long cpu) | |
408 | { | |
409 | struct crypto_comp *tfm; | |
410 | ||
411 | switch (action) { | |
412 | case CPU_UP_PREPARE: | |
413 | if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu))) | |
414 | break; | |
415 | tfm = crypto_alloc_comp(pool->tfm_name, 0, 0); | |
416 | if (IS_ERR_OR_NULL(tfm)) { | |
417 | pr_err("could not alloc crypto comp %s : %ld\n", | |
418 | pool->tfm_name, PTR_ERR(tfm)); | |
419 | return NOTIFY_BAD; | |
420 | } | |
421 | *per_cpu_ptr(pool->tfm, cpu) = tfm; | |
422 | break; | |
423 | case CPU_DEAD: | |
424 | case CPU_UP_CANCELED: | |
425 | tfm = *per_cpu_ptr(pool->tfm, cpu); | |
426 | if (!IS_ERR_OR_NULL(tfm)) | |
427 | crypto_free_comp(tfm); | |
428 | *per_cpu_ptr(pool->tfm, cpu) = NULL; | |
429 | break; | |
430 | default: | |
431 | break; | |
432 | } | |
433 | return NOTIFY_OK; | |
434 | } | |
435 | ||
436 | static int zswap_cpu_comp_notifier(struct notifier_block *nb, | |
437 | unsigned long action, void *pcpu) | |
438 | { | |
439 | unsigned long cpu = (unsigned long)pcpu; | |
440 | struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier); | |
441 | ||
442 | return __zswap_cpu_comp_notifier(pool, action, cpu); | |
443 | } | |
444 | ||
445 | static int zswap_cpu_comp_init(struct zswap_pool *pool) | |
2b281117 SJ |
446 | { |
447 | unsigned long cpu; | |
448 | ||
f1c54846 DS |
449 | memset(&pool->notifier, 0, sizeof(pool->notifier)); |
450 | pool->notifier.notifier_call = zswap_cpu_comp_notifier; | |
451 | ||
57637824 | 452 | cpu_notifier_register_begin(); |
2b281117 | 453 | for_each_online_cpu(cpu) |
f1c54846 DS |
454 | if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) == |
455 | NOTIFY_BAD) | |
2b281117 | 456 | goto cleanup; |
f1c54846 | 457 | __register_cpu_notifier(&pool->notifier); |
57637824 | 458 | cpu_notifier_register_done(); |
2b281117 SJ |
459 | return 0; |
460 | ||
461 | cleanup: | |
462 | for_each_online_cpu(cpu) | |
f1c54846 | 463 | __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); |
57637824 | 464 | cpu_notifier_register_done(); |
2b281117 SJ |
465 | return -ENOMEM; |
466 | } | |
467 | ||
f1c54846 DS |
468 | static void zswap_cpu_comp_destroy(struct zswap_pool *pool) |
469 | { | |
470 | unsigned long cpu; | |
471 | ||
472 | cpu_notifier_register_begin(); | |
473 | for_each_online_cpu(cpu) | |
474 | __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); | |
475 | __unregister_cpu_notifier(&pool->notifier); | |
476 | cpu_notifier_register_done(); | |
477 | } | |
478 | ||
2b281117 | 479 | /********************************* |
f1c54846 | 480 | * pool functions |
2b281117 | 481 | **********************************/ |
f1c54846 DS |
482 | |
483 | static struct zswap_pool *__zswap_pool_current(void) | |
2b281117 | 484 | { |
f1c54846 DS |
485 | struct zswap_pool *pool; |
486 | ||
487 | pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list); | |
488 | WARN_ON(!pool); | |
489 | ||
490 | return pool; | |
491 | } | |
492 | ||
493 | static struct zswap_pool *zswap_pool_current(void) | |
494 | { | |
495 | assert_spin_locked(&zswap_pools_lock); | |
496 | ||
497 | return __zswap_pool_current(); | |
498 | } | |
499 | ||
500 | static struct zswap_pool *zswap_pool_current_get(void) | |
501 | { | |
502 | struct zswap_pool *pool; | |
503 | ||
504 | rcu_read_lock(); | |
505 | ||
506 | pool = __zswap_pool_current(); | |
507 | if (!pool || !zswap_pool_get(pool)) | |
508 | pool = NULL; | |
509 | ||
510 | rcu_read_unlock(); | |
511 | ||
512 | return pool; | |
513 | } | |
514 | ||
515 | static struct zswap_pool *zswap_pool_last_get(void) | |
516 | { | |
517 | struct zswap_pool *pool, *last = NULL; | |
518 | ||
519 | rcu_read_lock(); | |
520 | ||
521 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
522 | last = pool; | |
523 | if (!WARN_ON(!last) && !zswap_pool_get(last)) | |
524 | last = NULL; | |
525 | ||
526 | rcu_read_unlock(); | |
527 | ||
528 | return last; | |
529 | } | |
530 | ||
531 | static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) | |
532 | { | |
533 | struct zswap_pool *pool; | |
534 | ||
535 | assert_spin_locked(&zswap_pools_lock); | |
536 | ||
537 | list_for_each_entry_rcu(pool, &zswap_pools, list) { | |
538 | if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name))) | |
539 | continue; | |
540 | if (strncmp(zpool_get_type(pool->zpool), type, | |
541 | sizeof(zswap_zpool_type))) | |
542 | continue; | |
543 | /* if we can't get it, it's about to be destroyed */ | |
544 | if (!zswap_pool_get(pool)) | |
545 | continue; | |
546 | return pool; | |
547 | } | |
548 | ||
549 | return NULL; | |
550 | } | |
551 | ||
552 | static struct zswap_pool *zswap_pool_create(char *type, char *compressor) | |
553 | { | |
554 | struct zswap_pool *pool; | |
555 | gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN; | |
556 | ||
557 | pool = kzalloc(sizeof(*pool), GFP_KERNEL); | |
558 | if (!pool) { | |
559 | pr_err("pool alloc failed\n"); | |
560 | return NULL; | |
561 | } | |
562 | ||
563 | pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops); | |
564 | if (!pool->zpool) { | |
565 | pr_err("%s zpool not available\n", type); | |
566 | goto error; | |
567 | } | |
568 | pr_debug("using %s zpool\n", zpool_get_type(pool->zpool)); | |
569 | ||
570 | strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); | |
571 | pool->tfm = alloc_percpu(struct crypto_comp *); | |
572 | if (!pool->tfm) { | |
573 | pr_err("percpu alloc failed\n"); | |
574 | goto error; | |
575 | } | |
576 | ||
577 | if (zswap_cpu_comp_init(pool)) | |
578 | goto error; | |
579 | pr_debug("using %s compressor\n", pool->tfm_name); | |
580 | ||
581 | /* being the current pool takes 1 ref; this func expects the | |
582 | * caller to always add the new pool as the current pool | |
583 | */ | |
584 | kref_init(&pool->kref); | |
585 | INIT_LIST_HEAD(&pool->list); | |
586 | ||
587 | zswap_pool_debug("created", pool); | |
588 | ||
589 | return pool; | |
590 | ||
591 | error: | |
592 | free_percpu(pool->tfm); | |
593 | if (pool->zpool) | |
594 | zpool_destroy_pool(pool->zpool); | |
595 | kfree(pool); | |
596 | return NULL; | |
597 | } | |
598 | ||
599 | static struct zswap_pool *__zswap_pool_create_fallback(void) | |
600 | { | |
601 | if (!crypto_has_comp(zswap_compressor, 0, 0)) { | |
602 | pr_err("compressor %s not available, using default %s\n", | |
603 | zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT); | |
604 | strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT, | |
605 | sizeof(zswap_compressor)); | |
606 | } | |
607 | if (!zpool_has_pool(zswap_zpool_type)) { | |
608 | pr_err("zpool %s not available, using default %s\n", | |
609 | zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT); | |
610 | strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT, | |
611 | sizeof(zswap_zpool_type)); | |
612 | } | |
613 | ||
614 | return zswap_pool_create(zswap_zpool_type, zswap_compressor); | |
615 | } | |
616 | ||
617 | static void zswap_pool_destroy(struct zswap_pool *pool) | |
618 | { | |
619 | zswap_pool_debug("destroying", pool); | |
620 | ||
621 | zswap_cpu_comp_destroy(pool); | |
622 | free_percpu(pool->tfm); | |
623 | zpool_destroy_pool(pool->zpool); | |
624 | kfree(pool); | |
625 | } | |
626 | ||
627 | static int __must_check zswap_pool_get(struct zswap_pool *pool) | |
628 | { | |
629 | return kref_get_unless_zero(&pool->kref); | |
630 | } | |
631 | ||
632 | static void __zswap_pool_release(struct rcu_head *head) | |
633 | { | |
634 | struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head); | |
635 | ||
636 | /* nobody should have been able to get a kref... */ | |
637 | WARN_ON(kref_get_unless_zero(&pool->kref)); | |
638 | ||
639 | /* pool is now off zswap_pools list and has no references. */ | |
640 | zswap_pool_destroy(pool); | |
641 | } | |
642 | ||
643 | static void __zswap_pool_empty(struct kref *kref) | |
644 | { | |
645 | struct zswap_pool *pool; | |
646 | ||
647 | pool = container_of(kref, typeof(*pool), kref); | |
648 | ||
649 | spin_lock(&zswap_pools_lock); | |
650 | ||
651 | WARN_ON(pool == zswap_pool_current()); | |
652 | ||
653 | list_del_rcu(&pool->list); | |
654 | call_rcu(&pool->rcu_head, __zswap_pool_release); | |
655 | ||
656 | spin_unlock(&zswap_pools_lock); | |
657 | } | |
658 | ||
659 | static void zswap_pool_put(struct zswap_pool *pool) | |
660 | { | |
661 | kref_put(&pool->kref, __zswap_pool_empty); | |
2b281117 SJ |
662 | } |
663 | ||
2b281117 SJ |
664 | /********************************* |
665 | * writeback code | |
666 | **********************************/ | |
667 | /* return enum for zswap_get_swap_cache_page */ | |
668 | enum zswap_get_swap_ret { | |
669 | ZSWAP_SWAPCACHE_NEW, | |
670 | ZSWAP_SWAPCACHE_EXIST, | |
67d13fe8 | 671 | ZSWAP_SWAPCACHE_FAIL, |
2b281117 SJ |
672 | }; |
673 | ||
674 | /* | |
675 | * zswap_get_swap_cache_page | |
676 | * | |
677 | * This is an adaption of read_swap_cache_async() | |
678 | * | |
679 | * This function tries to find a page with the given swap entry | |
680 | * in the swapper_space address space (the swap cache). If the page | |
681 | * is found, it is returned in retpage. Otherwise, a page is allocated, | |
682 | * added to the swap cache, and returned in retpage. | |
683 | * | |
684 | * If success, the swap cache page is returned in retpage | |
67d13fe8 WY |
685 | * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache |
686 | * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated, | |
687 | * the new page is added to swapcache and locked | |
688 | * Returns ZSWAP_SWAPCACHE_FAIL on error | |
2b281117 SJ |
689 | */ |
690 | static int zswap_get_swap_cache_page(swp_entry_t entry, | |
691 | struct page **retpage) | |
692 | { | |
5b999aad | 693 | bool page_was_allocated; |
2b281117 | 694 | |
5b999aad DS |
695 | *retpage = __read_swap_cache_async(entry, GFP_KERNEL, |
696 | NULL, 0, &page_was_allocated); | |
697 | if (page_was_allocated) | |
698 | return ZSWAP_SWAPCACHE_NEW; | |
699 | if (!*retpage) | |
67d13fe8 | 700 | return ZSWAP_SWAPCACHE_FAIL; |
2b281117 SJ |
701 | return ZSWAP_SWAPCACHE_EXIST; |
702 | } | |
703 | ||
704 | /* | |
705 | * Attempts to free an entry by adding a page to the swap cache, | |
706 | * decompressing the entry data into the page, and issuing a | |
707 | * bio write to write the page back to the swap device. | |
708 | * | |
709 | * This can be thought of as a "resumed writeback" of the page | |
710 | * to the swap device. We are basically resuming the same swap | |
711 | * writeback path that was intercepted with the frontswap_store() | |
712 | * in the first place. After the page has been decompressed into | |
713 | * the swap cache, the compressed version stored by zswap can be | |
714 | * freed. | |
715 | */ | |
12d79d64 | 716 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) |
2b281117 SJ |
717 | { |
718 | struct zswap_header *zhdr; | |
719 | swp_entry_t swpentry; | |
720 | struct zswap_tree *tree; | |
721 | pgoff_t offset; | |
722 | struct zswap_entry *entry; | |
723 | struct page *page; | |
f1c54846 | 724 | struct crypto_comp *tfm; |
2b281117 SJ |
725 | u8 *src, *dst; |
726 | unsigned int dlen; | |
0ab0abcf | 727 | int ret; |
2b281117 SJ |
728 | struct writeback_control wbc = { |
729 | .sync_mode = WB_SYNC_NONE, | |
730 | }; | |
731 | ||
732 | /* extract swpentry from data */ | |
12d79d64 | 733 | zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); |
2b281117 | 734 | swpentry = zhdr->swpentry; /* here */ |
12d79d64 | 735 | zpool_unmap_handle(pool, handle); |
2b281117 SJ |
736 | tree = zswap_trees[swp_type(swpentry)]; |
737 | offset = swp_offset(swpentry); | |
2b281117 SJ |
738 | |
739 | /* find and ref zswap entry */ | |
740 | spin_lock(&tree->lock); | |
0ab0abcf | 741 | entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b281117 SJ |
742 | if (!entry) { |
743 | /* entry was invalidated */ | |
744 | spin_unlock(&tree->lock); | |
745 | return 0; | |
746 | } | |
2b281117 SJ |
747 | spin_unlock(&tree->lock); |
748 | BUG_ON(offset != entry->offset); | |
749 | ||
750 | /* try to allocate swap cache page */ | |
751 | switch (zswap_get_swap_cache_page(swpentry, &page)) { | |
67d13fe8 | 752 | case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ |
2b281117 SJ |
753 | ret = -ENOMEM; |
754 | goto fail; | |
755 | ||
67d13fe8 | 756 | case ZSWAP_SWAPCACHE_EXIST: |
2b281117 SJ |
757 | /* page is already in the swap cache, ignore for now */ |
758 | page_cache_release(page); | |
759 | ret = -EEXIST; | |
760 | goto fail; | |
761 | ||
762 | case ZSWAP_SWAPCACHE_NEW: /* page is locked */ | |
763 | /* decompress */ | |
764 | dlen = PAGE_SIZE; | |
f1c54846 | 765 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64 | 766 | ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b281117 | 767 | dst = kmap_atomic(page); |
f1c54846 DS |
768 | tfm = *get_cpu_ptr(entry->pool->tfm); |
769 | ret = crypto_comp_decompress(tfm, src, entry->length, | |
770 | dst, &dlen); | |
771 | put_cpu_ptr(entry->pool->tfm); | |
2b281117 | 772 | kunmap_atomic(dst); |
f1c54846 | 773 | zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b281117 SJ |
774 | BUG_ON(ret); |
775 | BUG_ON(dlen != PAGE_SIZE); | |
776 | ||
777 | /* page is up to date */ | |
778 | SetPageUptodate(page); | |
779 | } | |
780 | ||
b349acc7 WY |
781 | /* move it to the tail of the inactive list after end_writeback */ |
782 | SetPageReclaim(page); | |
783 | ||
2b281117 SJ |
784 | /* start writeback */ |
785 | __swap_writepage(page, &wbc, end_swap_bio_write); | |
786 | page_cache_release(page); | |
787 | zswap_written_back_pages++; | |
788 | ||
789 | spin_lock(&tree->lock); | |
2b281117 | 790 | /* drop local reference */ |
0ab0abcf | 791 | zswap_entry_put(tree, entry); |
2b281117 SJ |
792 | |
793 | /* | |
0ab0abcf WY |
794 | * There are two possible situations for entry here: |
795 | * (1) refcount is 1(normal case), entry is valid and on the tree | |
796 | * (2) refcount is 0, entry is freed and not on the tree | |
797 | * because invalidate happened during writeback | |
798 | * search the tree and free the entry if find entry | |
799 | */ | |
800 | if (entry == zswap_rb_search(&tree->rbroot, offset)) | |
801 | zswap_entry_put(tree, entry); | |
2b281117 | 802 | spin_unlock(&tree->lock); |
2b281117 | 803 | |
0ab0abcf WY |
804 | goto end; |
805 | ||
806 | /* | |
807 | * if we get here due to ZSWAP_SWAPCACHE_EXIST | |
808 | * a load may happening concurrently | |
809 | * it is safe and okay to not free the entry | |
810 | * if we free the entry in the following put | |
811 | * it it either okay to return !0 | |
812 | */ | |
2b281117 SJ |
813 | fail: |
814 | spin_lock(&tree->lock); | |
0ab0abcf | 815 | zswap_entry_put(tree, entry); |
2b281117 | 816 | spin_unlock(&tree->lock); |
0ab0abcf WY |
817 | |
818 | end: | |
2b281117 SJ |
819 | return ret; |
820 | } | |
821 | ||
f1c54846 DS |
822 | static int zswap_shrink(void) |
823 | { | |
824 | struct zswap_pool *pool; | |
825 | int ret; | |
826 | ||
827 | pool = zswap_pool_last_get(); | |
828 | if (!pool) | |
829 | return -ENOENT; | |
830 | ||
831 | ret = zpool_shrink(pool->zpool, 1, NULL); | |
832 | ||
833 | zswap_pool_put(pool); | |
834 | ||
835 | return ret; | |
836 | } | |
837 | ||
2b281117 SJ |
838 | /********************************* |
839 | * frontswap hooks | |
840 | **********************************/ | |
841 | /* attempts to compress and store an single page */ | |
842 | static int zswap_frontswap_store(unsigned type, pgoff_t offset, | |
843 | struct page *page) | |
844 | { | |
845 | struct zswap_tree *tree = zswap_trees[type]; | |
846 | struct zswap_entry *entry, *dupentry; | |
f1c54846 | 847 | struct crypto_comp *tfm; |
2b281117 SJ |
848 | int ret; |
849 | unsigned int dlen = PAGE_SIZE, len; | |
850 | unsigned long handle; | |
851 | char *buf; | |
852 | u8 *src, *dst; | |
853 | struct zswap_header *zhdr; | |
854 | ||
c00ed16a | 855 | if (!zswap_enabled || !tree) { |
2b281117 SJ |
856 | ret = -ENODEV; |
857 | goto reject; | |
858 | } | |
859 | ||
860 | /* reclaim space if needed */ | |
861 | if (zswap_is_full()) { | |
862 | zswap_pool_limit_hit++; | |
f1c54846 | 863 | if (zswap_shrink()) { |
2b281117 SJ |
864 | zswap_reject_reclaim_fail++; |
865 | ret = -ENOMEM; | |
866 | goto reject; | |
867 | } | |
868 | } | |
869 | ||
870 | /* allocate entry */ | |
871 | entry = zswap_entry_cache_alloc(GFP_KERNEL); | |
872 | if (!entry) { | |
873 | zswap_reject_kmemcache_fail++; | |
874 | ret = -ENOMEM; | |
875 | goto reject; | |
876 | } | |
877 | ||
f1c54846 DS |
878 | /* if entry is successfully added, it keeps the reference */ |
879 | entry->pool = zswap_pool_current_get(); | |
880 | if (!entry->pool) { | |
881 | ret = -EINVAL; | |
882 | goto freepage; | |
883 | } | |
884 | ||
2b281117 SJ |
885 | /* compress */ |
886 | dst = get_cpu_var(zswap_dstmem); | |
f1c54846 | 887 | tfm = *get_cpu_ptr(entry->pool->tfm); |
2b281117 | 888 | src = kmap_atomic(page); |
f1c54846 | 889 | ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen); |
2b281117 | 890 | kunmap_atomic(src); |
f1c54846 | 891 | put_cpu_ptr(entry->pool->tfm); |
2b281117 SJ |
892 | if (ret) { |
893 | ret = -EINVAL; | |
f1c54846 | 894 | goto put_dstmem; |
2b281117 SJ |
895 | } |
896 | ||
897 | /* store */ | |
898 | len = dlen + sizeof(struct zswap_header); | |
f1c54846 DS |
899 | ret = zpool_malloc(entry->pool->zpool, len, |
900 | __GFP_NORETRY | __GFP_NOWARN, &handle); | |
2b281117 SJ |
901 | if (ret == -ENOSPC) { |
902 | zswap_reject_compress_poor++; | |
f1c54846 | 903 | goto put_dstmem; |
2b281117 SJ |
904 | } |
905 | if (ret) { | |
906 | zswap_reject_alloc_fail++; | |
f1c54846 | 907 | goto put_dstmem; |
2b281117 | 908 | } |
f1c54846 | 909 | zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); |
2b281117 SJ |
910 | zhdr->swpentry = swp_entry(type, offset); |
911 | buf = (u8 *)(zhdr + 1); | |
912 | memcpy(buf, dst, dlen); | |
f1c54846 | 913 | zpool_unmap_handle(entry->pool->zpool, handle); |
2b281117 SJ |
914 | put_cpu_var(zswap_dstmem); |
915 | ||
916 | /* populate entry */ | |
917 | entry->offset = offset; | |
918 | entry->handle = handle; | |
919 | entry->length = dlen; | |
920 | ||
921 | /* map */ | |
922 | spin_lock(&tree->lock); | |
923 | do { | |
924 | ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry); | |
925 | if (ret == -EEXIST) { | |
926 | zswap_duplicate_entry++; | |
927 | /* remove from rbtree */ | |
0ab0abcf WY |
928 | zswap_rb_erase(&tree->rbroot, dupentry); |
929 | zswap_entry_put(tree, dupentry); | |
2b281117 SJ |
930 | } |
931 | } while (ret == -EEXIST); | |
932 | spin_unlock(&tree->lock); | |
933 | ||
934 | /* update stats */ | |
935 | atomic_inc(&zswap_stored_pages); | |
f1c54846 | 936 | zswap_update_total_size(); |
2b281117 SJ |
937 | |
938 | return 0; | |
939 | ||
f1c54846 | 940 | put_dstmem: |
2b281117 | 941 | put_cpu_var(zswap_dstmem); |
f1c54846 DS |
942 | zswap_pool_put(entry->pool); |
943 | freepage: | |
2b281117 SJ |
944 | zswap_entry_cache_free(entry); |
945 | reject: | |
946 | return ret; | |
947 | } | |
948 | ||
949 | /* | |
950 | * returns 0 if the page was successfully decompressed | |
951 | * return -1 on entry not found or error | |
952 | */ | |
953 | static int zswap_frontswap_load(unsigned type, pgoff_t offset, | |
954 | struct page *page) | |
955 | { | |
956 | struct zswap_tree *tree = zswap_trees[type]; | |
957 | struct zswap_entry *entry; | |
f1c54846 | 958 | struct crypto_comp *tfm; |
2b281117 SJ |
959 | u8 *src, *dst; |
960 | unsigned int dlen; | |
0ab0abcf | 961 | int ret; |
2b281117 SJ |
962 | |
963 | /* find */ | |
964 | spin_lock(&tree->lock); | |
0ab0abcf | 965 | entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b281117 SJ |
966 | if (!entry) { |
967 | /* entry was written back */ | |
968 | spin_unlock(&tree->lock); | |
969 | return -1; | |
970 | } | |
2b281117 SJ |
971 | spin_unlock(&tree->lock); |
972 | ||
973 | /* decompress */ | |
974 | dlen = PAGE_SIZE; | |
f1c54846 | 975 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64 | 976 | ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b281117 | 977 | dst = kmap_atomic(page); |
f1c54846 DS |
978 | tfm = *get_cpu_ptr(entry->pool->tfm); |
979 | ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); | |
980 | put_cpu_ptr(entry->pool->tfm); | |
2b281117 | 981 | kunmap_atomic(dst); |
f1c54846 | 982 | zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b281117 SJ |
983 | BUG_ON(ret); |
984 | ||
985 | spin_lock(&tree->lock); | |
0ab0abcf | 986 | zswap_entry_put(tree, entry); |
2b281117 SJ |
987 | spin_unlock(&tree->lock); |
988 | ||
2b281117 SJ |
989 | return 0; |
990 | } | |
991 | ||
992 | /* frees an entry in zswap */ | |
993 | static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) | |
994 | { | |
995 | struct zswap_tree *tree = zswap_trees[type]; | |
996 | struct zswap_entry *entry; | |
2b281117 SJ |
997 | |
998 | /* find */ | |
999 | spin_lock(&tree->lock); | |
1000 | entry = zswap_rb_search(&tree->rbroot, offset); | |
1001 | if (!entry) { | |
1002 | /* entry was written back */ | |
1003 | spin_unlock(&tree->lock); | |
1004 | return; | |
1005 | } | |
1006 | ||
1007 | /* remove from rbtree */ | |
0ab0abcf | 1008 | zswap_rb_erase(&tree->rbroot, entry); |
2b281117 SJ |
1009 | |
1010 | /* drop the initial reference from entry creation */ | |
0ab0abcf | 1011 | zswap_entry_put(tree, entry); |
2b281117 SJ |
1012 | |
1013 | spin_unlock(&tree->lock); | |
2b281117 SJ |
1014 | } |
1015 | ||
1016 | /* frees all zswap entries for the given swap type */ | |
1017 | static void zswap_frontswap_invalidate_area(unsigned type) | |
1018 | { | |
1019 | struct zswap_tree *tree = zswap_trees[type]; | |
0bd42136 | 1020 | struct zswap_entry *entry, *n; |
2b281117 SJ |
1021 | |
1022 | if (!tree) | |
1023 | return; | |
1024 | ||
1025 | /* walk the tree and free everything */ | |
1026 | spin_lock(&tree->lock); | |
0ab0abcf | 1027 | rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode) |
60105e12 | 1028 | zswap_free_entry(entry); |
2b281117 SJ |
1029 | tree->rbroot = RB_ROOT; |
1030 | spin_unlock(&tree->lock); | |
aa9bca05 WY |
1031 | kfree(tree); |
1032 | zswap_trees[type] = NULL; | |
2b281117 SJ |
1033 | } |
1034 | ||
2b281117 SJ |
1035 | static void zswap_frontswap_init(unsigned type) |
1036 | { | |
1037 | struct zswap_tree *tree; | |
1038 | ||
1039 | tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL); | |
60105e12 MK |
1040 | if (!tree) { |
1041 | pr_err("alloc failed, zswap disabled for swap type %d\n", type); | |
1042 | return; | |
1043 | } | |
1044 | ||
2b281117 SJ |
1045 | tree->rbroot = RB_ROOT; |
1046 | spin_lock_init(&tree->lock); | |
1047 | zswap_trees[type] = tree; | |
2b281117 SJ |
1048 | } |
1049 | ||
1050 | static struct frontswap_ops zswap_frontswap_ops = { | |
1051 | .store = zswap_frontswap_store, | |
1052 | .load = zswap_frontswap_load, | |
1053 | .invalidate_page = zswap_frontswap_invalidate_page, | |
1054 | .invalidate_area = zswap_frontswap_invalidate_area, | |
1055 | .init = zswap_frontswap_init | |
1056 | }; | |
1057 | ||
1058 | /********************************* | |
1059 | * debugfs functions | |
1060 | **********************************/ | |
1061 | #ifdef CONFIG_DEBUG_FS | |
1062 | #include <linux/debugfs.h> | |
1063 | ||
1064 | static struct dentry *zswap_debugfs_root; | |
1065 | ||
1066 | static int __init zswap_debugfs_init(void) | |
1067 | { | |
1068 | if (!debugfs_initialized()) | |
1069 | return -ENODEV; | |
1070 | ||
1071 | zswap_debugfs_root = debugfs_create_dir("zswap", NULL); | |
1072 | if (!zswap_debugfs_root) | |
1073 | return -ENOMEM; | |
1074 | ||
1075 | debugfs_create_u64("pool_limit_hit", S_IRUGO, | |
1076 | zswap_debugfs_root, &zswap_pool_limit_hit); | |
1077 | debugfs_create_u64("reject_reclaim_fail", S_IRUGO, | |
1078 | zswap_debugfs_root, &zswap_reject_reclaim_fail); | |
1079 | debugfs_create_u64("reject_alloc_fail", S_IRUGO, | |
1080 | zswap_debugfs_root, &zswap_reject_alloc_fail); | |
1081 | debugfs_create_u64("reject_kmemcache_fail", S_IRUGO, | |
1082 | zswap_debugfs_root, &zswap_reject_kmemcache_fail); | |
1083 | debugfs_create_u64("reject_compress_poor", S_IRUGO, | |
1084 | zswap_debugfs_root, &zswap_reject_compress_poor); | |
1085 | debugfs_create_u64("written_back_pages", S_IRUGO, | |
1086 | zswap_debugfs_root, &zswap_written_back_pages); | |
1087 | debugfs_create_u64("duplicate_entry", S_IRUGO, | |
1088 | zswap_debugfs_root, &zswap_duplicate_entry); | |
12d79d64 DS |
1089 | debugfs_create_u64("pool_total_size", S_IRUGO, |
1090 | zswap_debugfs_root, &zswap_pool_total_size); | |
2b281117 SJ |
1091 | debugfs_create_atomic_t("stored_pages", S_IRUGO, |
1092 | zswap_debugfs_root, &zswap_stored_pages); | |
1093 | ||
1094 | return 0; | |
1095 | } | |
1096 | ||
1097 | static void __exit zswap_debugfs_exit(void) | |
1098 | { | |
1099 | debugfs_remove_recursive(zswap_debugfs_root); | |
1100 | } | |
1101 | #else | |
1102 | static int __init zswap_debugfs_init(void) | |
1103 | { | |
1104 | return 0; | |
1105 | } | |
1106 | ||
1107 | static void __exit zswap_debugfs_exit(void) { } | |
1108 | #endif | |
1109 | ||
1110 | /********************************* | |
1111 | * module init and exit | |
1112 | **********************************/ | |
1113 | static int __init init_zswap(void) | |
1114 | { | |
f1c54846 | 1115 | struct zswap_pool *pool; |
60105e12 | 1116 | |
2b281117 SJ |
1117 | if (zswap_entry_cache_create()) { |
1118 | pr_err("entry cache creation failed\n"); | |
f1c54846 | 1119 | goto cache_fail; |
2b281117 | 1120 | } |
f1c54846 DS |
1121 | |
1122 | if (zswap_cpu_dstmem_init()) { | |
1123 | pr_err("dstmem alloc failed\n"); | |
1124 | goto dstmem_fail; | |
2b281117 | 1125 | } |
f1c54846 DS |
1126 | |
1127 | pool = __zswap_pool_create_fallback(); | |
1128 | if (!pool) { | |
1129 | pr_err("pool creation failed\n"); | |
1130 | goto pool_fail; | |
2b281117 | 1131 | } |
f1c54846 DS |
1132 | pr_info("loaded using pool %s/%s\n", pool->tfm_name, |
1133 | zpool_get_type(pool->zpool)); | |
1134 | ||
1135 | list_add(&pool->list, &zswap_pools); | |
60105e12 | 1136 | |
2b281117 SJ |
1137 | frontswap_register_ops(&zswap_frontswap_ops); |
1138 | if (zswap_debugfs_init()) | |
1139 | pr_warn("debugfs initialization failed\n"); | |
1140 | return 0; | |
f1c54846 DS |
1141 | |
1142 | pool_fail: | |
1143 | zswap_cpu_dstmem_destroy(); | |
1144 | dstmem_fail: | |
c119239b | 1145 | zswap_entry_cache_destroy(); |
f1c54846 | 1146 | cache_fail: |
2b281117 SJ |
1147 | return -ENOMEM; |
1148 | } | |
1149 | /* must be late so crypto has time to come up */ | |
1150 | late_initcall(init_zswap); | |
1151 | ||
1152 | MODULE_LICENSE("GPL"); | |
68386da8 | 1153 | MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>"); |
2b281117 | 1154 | MODULE_DESCRIPTION("Compressed cache for swap pages"); |