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 | 78 | |
bae21db8 DS |
79 | #define ZSWAP_PARAM_UNSET "" |
80 | ||
c00ed16a DS |
81 | /* Enable/disable zswap (disabled by default) */ |
82 | static bool zswap_enabled; | |
d7b028f5 DS |
83 | static int zswap_enabled_param_set(const char *, |
84 | const struct kernel_param *); | |
85 | static struct kernel_param_ops zswap_enabled_param_ops = { | |
86 | .set = zswap_enabled_param_set, | |
87 | .get = param_get_bool, | |
88 | }; | |
89 | module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644); | |
2b281117 | 90 | |
90b0fc26 | 91 | /* Crypto compressor to use */ |
2b281117 | 92 | #define ZSWAP_COMPRESSOR_DEFAULT "lzo" |
c99b42c3 | 93 | static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; |
90b0fc26 DS |
94 | static int zswap_compressor_param_set(const char *, |
95 | const struct kernel_param *); | |
96 | static struct kernel_param_ops zswap_compressor_param_ops = { | |
97 | .set = zswap_compressor_param_set, | |
c99b42c3 DS |
98 | .get = param_get_charp, |
99 | .free = param_free_charp, | |
90b0fc26 DS |
100 | }; |
101 | module_param_cb(compressor, &zswap_compressor_param_ops, | |
c99b42c3 | 102 | &zswap_compressor, 0644); |
2b281117 | 103 | |
90b0fc26 | 104 | /* Compressed storage zpool to use */ |
12d79d64 | 105 | #define ZSWAP_ZPOOL_DEFAULT "zbud" |
c99b42c3 | 106 | static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; |
90b0fc26 DS |
107 | static int zswap_zpool_param_set(const char *, const struct kernel_param *); |
108 | static struct kernel_param_ops zswap_zpool_param_ops = { | |
c99b42c3 DS |
109 | .set = zswap_zpool_param_set, |
110 | .get = param_get_charp, | |
111 | .free = param_free_charp, | |
90b0fc26 | 112 | }; |
c99b42c3 | 113 | module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); |
12d79d64 | 114 | |
90b0fc26 DS |
115 | /* The maximum percentage of memory that the compressed pool can occupy */ |
116 | static unsigned int zswap_max_pool_percent = 20; | |
117 | module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); | |
60105e12 | 118 | |
2b281117 | 119 | /********************************* |
f1c54846 | 120 | * data structures |
2b281117 | 121 | **********************************/ |
2b281117 | 122 | |
f1c54846 DS |
123 | struct zswap_pool { |
124 | struct zpool *zpool; | |
125 | struct crypto_comp * __percpu *tfm; | |
126 | struct kref kref; | |
127 | struct list_head list; | |
200867af | 128 | struct work_struct work; |
cab7a7e5 | 129 | struct hlist_node node; |
f1c54846 | 130 | char tfm_name[CRYPTO_MAX_ALG_NAME]; |
2b281117 SJ |
131 | }; |
132 | ||
2b281117 SJ |
133 | /* |
134 | * struct zswap_entry | |
135 | * | |
136 | * This structure contains the metadata for tracking a single compressed | |
137 | * page within zswap. | |
138 | * | |
139 | * rbnode - links the entry into red-black tree for the appropriate swap type | |
f1c54846 | 140 | * offset - the swap offset for the entry. Index into the red-black tree. |
2b281117 SJ |
141 | * refcount - the number of outstanding reference to the entry. This is needed |
142 | * to protect against premature freeing of the entry by code | |
6b452516 | 143 | * concurrent calls to load, invalidate, and writeback. The lock |
2b281117 SJ |
144 | * for the zswap_tree structure that contains the entry must |
145 | * be held while changing the refcount. Since the lock must | |
146 | * be held, there is no reason to also make refcount atomic. | |
2b281117 | 147 | * length - the length in bytes of the compressed page data. Needed during |
6b452516 | 148 | * decompression |
f1c54846 DS |
149 | * pool - the zswap_pool the entry's data is in |
150 | * handle - zpool allocation handle that stores the compressed page data | |
2b281117 SJ |
151 | */ |
152 | struct zswap_entry { | |
153 | struct rb_node rbnode; | |
154 | pgoff_t offset; | |
155 | int refcount; | |
156 | unsigned int length; | |
f1c54846 | 157 | struct zswap_pool *pool; |
2b281117 SJ |
158 | unsigned long handle; |
159 | }; | |
160 | ||
161 | struct zswap_header { | |
162 | swp_entry_t swpentry; | |
163 | }; | |
164 | ||
165 | /* | |
166 | * The tree lock in the zswap_tree struct protects a few things: | |
167 | * - the rbtree | |
168 | * - the refcount field of each entry in the tree | |
169 | */ | |
170 | struct zswap_tree { | |
171 | struct rb_root rbroot; | |
172 | spinlock_t lock; | |
2b281117 SJ |
173 | }; |
174 | ||
175 | static struct zswap_tree *zswap_trees[MAX_SWAPFILES]; | |
176 | ||
f1c54846 DS |
177 | /* RCU-protected iteration */ |
178 | static LIST_HEAD(zswap_pools); | |
179 | /* protects zswap_pools list modification */ | |
180 | static DEFINE_SPINLOCK(zswap_pools_lock); | |
32a4e169 DS |
181 | /* pool counter to provide unique names to zpool */ |
182 | static atomic_t zswap_pools_count = ATOMIC_INIT(0); | |
f1c54846 | 183 | |
90b0fc26 DS |
184 | /* used by param callback function */ |
185 | static bool zswap_init_started; | |
186 | ||
d7b028f5 DS |
187 | /* fatal error during init */ |
188 | static bool zswap_init_failed; | |
189 | ||
ae3d89a7 DS |
190 | /* init completed, but couldn't create the initial pool */ |
191 | static bool zswap_has_pool; | |
192 | ||
f1c54846 DS |
193 | /********************************* |
194 | * helpers and fwd declarations | |
195 | **********************************/ | |
196 | ||
197 | #define zswap_pool_debug(msg, p) \ | |
198 | pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \ | |
199 | zpool_get_type((p)->zpool)) | |
200 | ||
201 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle); | |
202 | static int zswap_pool_get(struct zswap_pool *pool); | |
203 | static void zswap_pool_put(struct zswap_pool *pool); | |
204 | ||
205 | static const struct zpool_ops zswap_zpool_ops = { | |
206 | .evict = zswap_writeback_entry | |
207 | }; | |
208 | ||
209 | static bool zswap_is_full(void) | |
210 | { | |
211 | return totalram_pages * zswap_max_pool_percent / 100 < | |
212 | DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); | |
213 | } | |
214 | ||
215 | static void zswap_update_total_size(void) | |
216 | { | |
217 | struct zswap_pool *pool; | |
218 | u64 total = 0; | |
219 | ||
220 | rcu_read_lock(); | |
221 | ||
222 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
223 | total += zpool_get_total_size(pool->zpool); | |
224 | ||
225 | rcu_read_unlock(); | |
226 | ||
227 | zswap_pool_total_size = total; | |
228 | } | |
229 | ||
2b281117 SJ |
230 | /********************************* |
231 | * zswap entry functions | |
232 | **********************************/ | |
233 | static struct kmem_cache *zswap_entry_cache; | |
234 | ||
dd01d7d8 | 235 | static int __init zswap_entry_cache_create(void) |
2b281117 SJ |
236 | { |
237 | zswap_entry_cache = KMEM_CACHE(zswap_entry, 0); | |
5d2d42de | 238 | return zswap_entry_cache == NULL; |
2b281117 SJ |
239 | } |
240 | ||
c119239b | 241 | static void __init zswap_entry_cache_destroy(void) |
2b281117 SJ |
242 | { |
243 | kmem_cache_destroy(zswap_entry_cache); | |
244 | } | |
245 | ||
246 | static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp) | |
247 | { | |
248 | struct zswap_entry *entry; | |
249 | entry = kmem_cache_alloc(zswap_entry_cache, gfp); | |
250 | if (!entry) | |
251 | return NULL; | |
252 | entry->refcount = 1; | |
0ab0abcf | 253 | RB_CLEAR_NODE(&entry->rbnode); |
2b281117 SJ |
254 | return entry; |
255 | } | |
256 | ||
257 | static void zswap_entry_cache_free(struct zswap_entry *entry) | |
258 | { | |
259 | kmem_cache_free(zswap_entry_cache, entry); | |
260 | } | |
261 | ||
2b281117 SJ |
262 | /********************************* |
263 | * rbtree functions | |
264 | **********************************/ | |
265 | static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset) | |
266 | { | |
267 | struct rb_node *node = root->rb_node; | |
268 | struct zswap_entry *entry; | |
269 | ||
270 | while (node) { | |
271 | entry = rb_entry(node, struct zswap_entry, rbnode); | |
272 | if (entry->offset > offset) | |
273 | node = node->rb_left; | |
274 | else if (entry->offset < offset) | |
275 | node = node->rb_right; | |
276 | else | |
277 | return entry; | |
278 | } | |
279 | return NULL; | |
280 | } | |
281 | ||
282 | /* | |
283 | * In the case that a entry with the same offset is found, a pointer to | |
284 | * the existing entry is stored in dupentry and the function returns -EEXIST | |
285 | */ | |
286 | static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry, | |
287 | struct zswap_entry **dupentry) | |
288 | { | |
289 | struct rb_node **link = &root->rb_node, *parent = NULL; | |
290 | struct zswap_entry *myentry; | |
291 | ||
292 | while (*link) { | |
293 | parent = *link; | |
294 | myentry = rb_entry(parent, struct zswap_entry, rbnode); | |
295 | if (myentry->offset > entry->offset) | |
296 | link = &(*link)->rb_left; | |
297 | else if (myentry->offset < entry->offset) | |
298 | link = &(*link)->rb_right; | |
299 | else { | |
300 | *dupentry = myentry; | |
301 | return -EEXIST; | |
302 | } | |
303 | } | |
304 | rb_link_node(&entry->rbnode, parent, link); | |
305 | rb_insert_color(&entry->rbnode, root); | |
306 | return 0; | |
307 | } | |
308 | ||
0ab0abcf WY |
309 | static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry) |
310 | { | |
311 | if (!RB_EMPTY_NODE(&entry->rbnode)) { | |
312 | rb_erase(&entry->rbnode, root); | |
313 | RB_CLEAR_NODE(&entry->rbnode); | |
314 | } | |
315 | } | |
316 | ||
317 | /* | |
12d79d64 | 318 | * Carries out the common pattern of freeing and entry's zpool allocation, |
0ab0abcf WY |
319 | * freeing the entry itself, and decrementing the number of stored pages. |
320 | */ | |
60105e12 | 321 | static void zswap_free_entry(struct zswap_entry *entry) |
0ab0abcf | 322 | { |
f1c54846 DS |
323 | zpool_free(entry->pool->zpool, entry->handle); |
324 | zswap_pool_put(entry->pool); | |
0ab0abcf WY |
325 | zswap_entry_cache_free(entry); |
326 | atomic_dec(&zswap_stored_pages); | |
f1c54846 | 327 | zswap_update_total_size(); |
0ab0abcf WY |
328 | } |
329 | ||
330 | /* caller must hold the tree lock */ | |
331 | static void zswap_entry_get(struct zswap_entry *entry) | |
332 | { | |
333 | entry->refcount++; | |
334 | } | |
335 | ||
336 | /* caller must hold the tree lock | |
337 | * remove from the tree and free it, if nobody reference the entry | |
338 | */ | |
339 | static void zswap_entry_put(struct zswap_tree *tree, | |
340 | struct zswap_entry *entry) | |
341 | { | |
342 | int refcount = --entry->refcount; | |
343 | ||
344 | BUG_ON(refcount < 0); | |
345 | if (refcount == 0) { | |
346 | zswap_rb_erase(&tree->rbroot, entry); | |
60105e12 | 347 | zswap_free_entry(entry); |
0ab0abcf WY |
348 | } |
349 | } | |
350 | ||
351 | /* caller must hold the tree lock */ | |
352 | static struct zswap_entry *zswap_entry_find_get(struct rb_root *root, | |
353 | pgoff_t offset) | |
354 | { | |
b0c9865f | 355 | struct zswap_entry *entry; |
0ab0abcf WY |
356 | |
357 | entry = zswap_rb_search(root, offset); | |
358 | if (entry) | |
359 | zswap_entry_get(entry); | |
360 | ||
361 | return entry; | |
362 | } | |
363 | ||
2b281117 SJ |
364 | /********************************* |
365 | * per-cpu code | |
366 | **********************************/ | |
367 | static DEFINE_PER_CPU(u8 *, zswap_dstmem); | |
368 | ||
ad7ed770 | 369 | static int zswap_dstmem_prepare(unsigned int cpu) |
2b281117 | 370 | { |
2b281117 SJ |
371 | u8 *dst; |
372 | ||
ad7ed770 SAS |
373 | dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); |
374 | if (!dst) { | |
375 | pr_err("can't allocate compressor buffer\n"); | |
376 | return -ENOMEM; | |
2b281117 | 377 | } |
ad7ed770 SAS |
378 | per_cpu(zswap_dstmem, cpu) = dst; |
379 | return 0; | |
2b281117 SJ |
380 | } |
381 | ||
ad7ed770 | 382 | static int zswap_dstmem_dead(unsigned int cpu) |
2b281117 | 383 | { |
ad7ed770 | 384 | u8 *dst; |
2b281117 | 385 | |
ad7ed770 SAS |
386 | dst = per_cpu(zswap_dstmem, cpu); |
387 | kfree(dst); | |
388 | per_cpu(zswap_dstmem, cpu) = NULL; | |
f1c54846 | 389 | |
f1c54846 | 390 | return 0; |
f1c54846 DS |
391 | } |
392 | ||
cab7a7e5 | 393 | static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) |
f1c54846 | 394 | { |
cab7a7e5 | 395 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); |
f1c54846 DS |
396 | struct crypto_comp *tfm; |
397 | ||
cab7a7e5 SAS |
398 | if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu))) |
399 | return 0; | |
f1c54846 | 400 | |
cab7a7e5 SAS |
401 | tfm = crypto_alloc_comp(pool->tfm_name, 0, 0); |
402 | if (IS_ERR_OR_NULL(tfm)) { | |
403 | pr_err("could not alloc crypto comp %s : %ld\n", | |
404 | pool->tfm_name, PTR_ERR(tfm)); | |
405 | return -ENOMEM; | |
406 | } | |
407 | *per_cpu_ptr(pool->tfm, cpu) = tfm; | |
2b281117 | 408 | return 0; |
2b281117 SJ |
409 | } |
410 | ||
cab7a7e5 | 411 | static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) |
f1c54846 | 412 | { |
cab7a7e5 SAS |
413 | struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); |
414 | struct crypto_comp *tfm; | |
f1c54846 | 415 | |
cab7a7e5 SAS |
416 | tfm = *per_cpu_ptr(pool->tfm, cpu); |
417 | if (!IS_ERR_OR_NULL(tfm)) | |
418 | crypto_free_comp(tfm); | |
419 | *per_cpu_ptr(pool->tfm, cpu) = NULL; | |
420 | return 0; | |
f1c54846 DS |
421 | } |
422 | ||
2b281117 | 423 | /********************************* |
f1c54846 | 424 | * pool functions |
2b281117 | 425 | **********************************/ |
f1c54846 DS |
426 | |
427 | static struct zswap_pool *__zswap_pool_current(void) | |
2b281117 | 428 | { |
f1c54846 DS |
429 | struct zswap_pool *pool; |
430 | ||
431 | pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list); | |
ae3d89a7 DS |
432 | WARN_ONCE(!pool && zswap_has_pool, |
433 | "%s: no page storage pool!\n", __func__); | |
f1c54846 DS |
434 | |
435 | return pool; | |
436 | } | |
437 | ||
438 | static struct zswap_pool *zswap_pool_current(void) | |
439 | { | |
440 | assert_spin_locked(&zswap_pools_lock); | |
441 | ||
442 | return __zswap_pool_current(); | |
443 | } | |
444 | ||
445 | static struct zswap_pool *zswap_pool_current_get(void) | |
446 | { | |
447 | struct zswap_pool *pool; | |
448 | ||
449 | rcu_read_lock(); | |
450 | ||
451 | pool = __zswap_pool_current(); | |
ae3d89a7 | 452 | if (!zswap_pool_get(pool)) |
f1c54846 DS |
453 | pool = NULL; |
454 | ||
455 | rcu_read_unlock(); | |
456 | ||
457 | return pool; | |
458 | } | |
459 | ||
460 | static struct zswap_pool *zswap_pool_last_get(void) | |
461 | { | |
462 | struct zswap_pool *pool, *last = NULL; | |
463 | ||
464 | rcu_read_lock(); | |
465 | ||
466 | list_for_each_entry_rcu(pool, &zswap_pools, list) | |
467 | last = pool; | |
ae3d89a7 DS |
468 | WARN_ONCE(!last && zswap_has_pool, |
469 | "%s: no page storage pool!\n", __func__); | |
470 | if (!zswap_pool_get(last)) | |
f1c54846 DS |
471 | last = NULL; |
472 | ||
473 | rcu_read_unlock(); | |
474 | ||
475 | return last; | |
476 | } | |
477 | ||
8bc8b228 | 478 | /* type and compressor must be null-terminated */ |
f1c54846 DS |
479 | static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) |
480 | { | |
481 | struct zswap_pool *pool; | |
482 | ||
483 | assert_spin_locked(&zswap_pools_lock); | |
484 | ||
485 | list_for_each_entry_rcu(pool, &zswap_pools, list) { | |
8bc8b228 | 486 | if (strcmp(pool->tfm_name, compressor)) |
f1c54846 | 487 | continue; |
8bc8b228 | 488 | if (strcmp(zpool_get_type(pool->zpool), type)) |
f1c54846 DS |
489 | continue; |
490 | /* if we can't get it, it's about to be destroyed */ | |
491 | if (!zswap_pool_get(pool)) | |
492 | continue; | |
493 | return pool; | |
494 | } | |
495 | ||
496 | return NULL; | |
497 | } | |
498 | ||
499 | static struct zswap_pool *zswap_pool_create(char *type, char *compressor) | |
500 | { | |
501 | struct zswap_pool *pool; | |
32a4e169 | 502 | char name[38]; /* 'zswap' + 32 char (max) num + \0 */ |
d0164adc | 503 | gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; |
cab7a7e5 | 504 | int ret; |
f1c54846 | 505 | |
bae21db8 DS |
506 | if (!zswap_has_pool) { |
507 | /* if either are unset, pool initialization failed, and we | |
508 | * need both params to be set correctly before trying to | |
509 | * create a pool. | |
510 | */ | |
511 | if (!strcmp(type, ZSWAP_PARAM_UNSET)) | |
512 | return NULL; | |
513 | if (!strcmp(compressor, ZSWAP_PARAM_UNSET)) | |
514 | return NULL; | |
515 | } | |
516 | ||
f1c54846 | 517 | pool = kzalloc(sizeof(*pool), GFP_KERNEL); |
f4ae0ce0 | 518 | if (!pool) |
f1c54846 | 519 | return NULL; |
f1c54846 | 520 | |
32a4e169 DS |
521 | /* unique name for each pool specifically required by zsmalloc */ |
522 | snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count)); | |
523 | ||
524 | pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops); | |
f1c54846 DS |
525 | if (!pool->zpool) { |
526 | pr_err("%s zpool not available\n", type); | |
527 | goto error; | |
528 | } | |
529 | pr_debug("using %s zpool\n", zpool_get_type(pool->zpool)); | |
530 | ||
531 | strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); | |
532 | pool->tfm = alloc_percpu(struct crypto_comp *); | |
533 | if (!pool->tfm) { | |
534 | pr_err("percpu alloc failed\n"); | |
535 | goto error; | |
536 | } | |
537 | ||
cab7a7e5 SAS |
538 | ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE, |
539 | &pool->node); | |
540 | if (ret) | |
f1c54846 DS |
541 | goto error; |
542 | pr_debug("using %s compressor\n", pool->tfm_name); | |
543 | ||
544 | /* being the current pool takes 1 ref; this func expects the | |
545 | * caller to always add the new pool as the current pool | |
546 | */ | |
547 | kref_init(&pool->kref); | |
548 | INIT_LIST_HEAD(&pool->list); | |
549 | ||
550 | zswap_pool_debug("created", pool); | |
551 | ||
552 | return pool; | |
553 | ||
554 | error: | |
555 | free_percpu(pool->tfm); | |
556 | if (pool->zpool) | |
557 | zpool_destroy_pool(pool->zpool); | |
558 | kfree(pool); | |
559 | return NULL; | |
560 | } | |
561 | ||
c99b42c3 | 562 | static __init struct zswap_pool *__zswap_pool_create_fallback(void) |
f1c54846 | 563 | { |
bae21db8 DS |
564 | bool has_comp, has_zpool; |
565 | ||
566 | has_comp = crypto_has_comp(zswap_compressor, 0, 0); | |
567 | if (!has_comp && strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) { | |
f1c54846 DS |
568 | pr_err("compressor %s not available, using default %s\n", |
569 | zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT); | |
c99b42c3 DS |
570 | param_free_charp(&zswap_compressor); |
571 | zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; | |
bae21db8 | 572 | has_comp = crypto_has_comp(zswap_compressor, 0, 0); |
f1c54846 | 573 | } |
bae21db8 DS |
574 | if (!has_comp) { |
575 | pr_err("default compressor %s not available\n", | |
576 | zswap_compressor); | |
577 | param_free_charp(&zswap_compressor); | |
578 | zswap_compressor = ZSWAP_PARAM_UNSET; | |
579 | } | |
580 | ||
581 | has_zpool = zpool_has_pool(zswap_zpool_type); | |
582 | if (!has_zpool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) { | |
f1c54846 DS |
583 | pr_err("zpool %s not available, using default %s\n", |
584 | zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT); | |
c99b42c3 DS |
585 | param_free_charp(&zswap_zpool_type); |
586 | zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; | |
bae21db8 | 587 | has_zpool = zpool_has_pool(zswap_zpool_type); |
f1c54846 | 588 | } |
bae21db8 DS |
589 | if (!has_zpool) { |
590 | pr_err("default zpool %s not available\n", | |
591 | zswap_zpool_type); | |
592 | param_free_charp(&zswap_zpool_type); | |
593 | zswap_zpool_type = ZSWAP_PARAM_UNSET; | |
594 | } | |
595 | ||
596 | if (!has_comp || !has_zpool) | |
597 | return NULL; | |
f1c54846 DS |
598 | |
599 | return zswap_pool_create(zswap_zpool_type, zswap_compressor); | |
600 | } | |
601 | ||
602 | static void zswap_pool_destroy(struct zswap_pool *pool) | |
603 | { | |
604 | zswap_pool_debug("destroying", pool); | |
605 | ||
cab7a7e5 | 606 | cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); |
f1c54846 DS |
607 | free_percpu(pool->tfm); |
608 | zpool_destroy_pool(pool->zpool); | |
609 | kfree(pool); | |
610 | } | |
611 | ||
612 | static int __must_check zswap_pool_get(struct zswap_pool *pool) | |
613 | { | |
ae3d89a7 DS |
614 | if (!pool) |
615 | return 0; | |
616 | ||
f1c54846 DS |
617 | return kref_get_unless_zero(&pool->kref); |
618 | } | |
619 | ||
200867af | 620 | static void __zswap_pool_release(struct work_struct *work) |
f1c54846 | 621 | { |
200867af DS |
622 | struct zswap_pool *pool = container_of(work, typeof(*pool), work); |
623 | ||
624 | synchronize_rcu(); | |
f1c54846 DS |
625 | |
626 | /* nobody should have been able to get a kref... */ | |
627 | WARN_ON(kref_get_unless_zero(&pool->kref)); | |
628 | ||
629 | /* pool is now off zswap_pools list and has no references. */ | |
630 | zswap_pool_destroy(pool); | |
631 | } | |
632 | ||
633 | static void __zswap_pool_empty(struct kref *kref) | |
634 | { | |
635 | struct zswap_pool *pool; | |
636 | ||
637 | pool = container_of(kref, typeof(*pool), kref); | |
638 | ||
639 | spin_lock(&zswap_pools_lock); | |
640 | ||
641 | WARN_ON(pool == zswap_pool_current()); | |
642 | ||
643 | list_del_rcu(&pool->list); | |
200867af DS |
644 | |
645 | INIT_WORK(&pool->work, __zswap_pool_release); | |
646 | schedule_work(&pool->work); | |
f1c54846 DS |
647 | |
648 | spin_unlock(&zswap_pools_lock); | |
649 | } | |
650 | ||
651 | static void zswap_pool_put(struct zswap_pool *pool) | |
652 | { | |
653 | kref_put(&pool->kref, __zswap_pool_empty); | |
2b281117 SJ |
654 | } |
655 | ||
90b0fc26 DS |
656 | /********************************* |
657 | * param callbacks | |
658 | **********************************/ | |
659 | ||
c99b42c3 | 660 | /* val must be a null-terminated string */ |
90b0fc26 DS |
661 | static int __zswap_param_set(const char *val, const struct kernel_param *kp, |
662 | char *type, char *compressor) | |
663 | { | |
664 | struct zswap_pool *pool, *put_pool = NULL; | |
c99b42c3 | 665 | char *s = strstrip((char *)val); |
90b0fc26 DS |
666 | int ret; |
667 | ||
d7b028f5 DS |
668 | if (zswap_init_failed) { |
669 | pr_err("can't set param, initialization failed\n"); | |
670 | return -ENODEV; | |
671 | } | |
672 | ||
c99b42c3 | 673 | /* no change required */ |
ae3d89a7 | 674 | if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool) |
c99b42c3 | 675 | return 0; |
90b0fc26 DS |
676 | |
677 | /* if this is load-time (pre-init) param setting, | |
678 | * don't create a pool; that's done during init. | |
679 | */ | |
680 | if (!zswap_init_started) | |
c99b42c3 | 681 | return param_set_charp(s, kp); |
90b0fc26 DS |
682 | |
683 | if (!type) { | |
c99b42c3 DS |
684 | if (!zpool_has_pool(s)) { |
685 | pr_err("zpool %s not available\n", s); | |
90b0fc26 DS |
686 | return -ENOENT; |
687 | } | |
c99b42c3 | 688 | type = s; |
90b0fc26 | 689 | } else if (!compressor) { |
c99b42c3 DS |
690 | if (!crypto_has_comp(s, 0, 0)) { |
691 | pr_err("compressor %s not available\n", s); | |
90b0fc26 DS |
692 | return -ENOENT; |
693 | } | |
c99b42c3 DS |
694 | compressor = s; |
695 | } else { | |
696 | WARN_ON(1); | |
697 | return -EINVAL; | |
90b0fc26 DS |
698 | } |
699 | ||
700 | spin_lock(&zswap_pools_lock); | |
701 | ||
702 | pool = zswap_pool_find_get(type, compressor); | |
703 | if (pool) { | |
704 | zswap_pool_debug("using existing", pool); | |
fd5bb66c | 705 | WARN_ON(pool == zswap_pool_current()); |
90b0fc26 | 706 | list_del_rcu(&pool->list); |
90b0fc26 DS |
707 | } |
708 | ||
fd5bb66c DS |
709 | spin_unlock(&zswap_pools_lock); |
710 | ||
711 | if (!pool) | |
712 | pool = zswap_pool_create(type, compressor); | |
713 | ||
90b0fc26 | 714 | if (pool) |
c99b42c3 | 715 | ret = param_set_charp(s, kp); |
90b0fc26 DS |
716 | else |
717 | ret = -EINVAL; | |
718 | ||
fd5bb66c DS |
719 | spin_lock(&zswap_pools_lock); |
720 | ||
90b0fc26 DS |
721 | if (!ret) { |
722 | put_pool = zswap_pool_current(); | |
723 | list_add_rcu(&pool->list, &zswap_pools); | |
ae3d89a7 | 724 | zswap_has_pool = true; |
90b0fc26 DS |
725 | } else if (pool) { |
726 | /* add the possibly pre-existing pool to the end of the pools | |
727 | * list; if it's new (and empty) then it'll be removed and | |
728 | * destroyed by the put after we drop the lock | |
729 | */ | |
730 | list_add_tail_rcu(&pool->list, &zswap_pools); | |
731 | put_pool = pool; | |
fd5bb66c DS |
732 | } |
733 | ||
734 | spin_unlock(&zswap_pools_lock); | |
735 | ||
736 | if (!zswap_has_pool && !pool) { | |
ae3d89a7 DS |
737 | /* if initial pool creation failed, and this pool creation also |
738 | * failed, maybe both compressor and zpool params were bad. | |
739 | * Allow changing this param, so pool creation will succeed | |
740 | * when the other param is changed. We already verified this | |
741 | * param is ok in the zpool_has_pool() or crypto_has_comp() | |
742 | * checks above. | |
743 | */ | |
744 | ret = param_set_charp(s, kp); | |
90b0fc26 DS |
745 | } |
746 | ||
90b0fc26 DS |
747 | /* drop the ref from either the old current pool, |
748 | * or the new pool we failed to add | |
749 | */ | |
750 | if (put_pool) | |
751 | zswap_pool_put(put_pool); | |
752 | ||
753 | return ret; | |
754 | } | |
755 | ||
756 | static int zswap_compressor_param_set(const char *val, | |
757 | const struct kernel_param *kp) | |
758 | { | |
759 | return __zswap_param_set(val, kp, zswap_zpool_type, NULL); | |
760 | } | |
761 | ||
762 | static int zswap_zpool_param_set(const char *val, | |
763 | const struct kernel_param *kp) | |
764 | { | |
765 | return __zswap_param_set(val, kp, NULL, zswap_compressor); | |
766 | } | |
767 | ||
d7b028f5 DS |
768 | static int zswap_enabled_param_set(const char *val, |
769 | const struct kernel_param *kp) | |
770 | { | |
771 | if (zswap_init_failed) { | |
772 | pr_err("can't enable, initialization failed\n"); | |
773 | return -ENODEV; | |
774 | } | |
ae3d89a7 DS |
775 | if (!zswap_has_pool && zswap_init_started) { |
776 | pr_err("can't enable, no pool configured\n"); | |
777 | return -ENODEV; | |
778 | } | |
d7b028f5 DS |
779 | |
780 | return param_set_bool(val, kp); | |
781 | } | |
782 | ||
2b281117 SJ |
783 | /********************************* |
784 | * writeback code | |
785 | **********************************/ | |
786 | /* return enum for zswap_get_swap_cache_page */ | |
787 | enum zswap_get_swap_ret { | |
788 | ZSWAP_SWAPCACHE_NEW, | |
789 | ZSWAP_SWAPCACHE_EXIST, | |
67d13fe8 | 790 | ZSWAP_SWAPCACHE_FAIL, |
2b281117 SJ |
791 | }; |
792 | ||
793 | /* | |
794 | * zswap_get_swap_cache_page | |
795 | * | |
796 | * This is an adaption of read_swap_cache_async() | |
797 | * | |
798 | * This function tries to find a page with the given swap entry | |
799 | * in the swapper_space address space (the swap cache). If the page | |
800 | * is found, it is returned in retpage. Otherwise, a page is allocated, | |
801 | * added to the swap cache, and returned in retpage. | |
802 | * | |
803 | * If success, the swap cache page is returned in retpage | |
67d13fe8 WY |
804 | * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache |
805 | * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated, | |
806 | * the new page is added to swapcache and locked | |
807 | * Returns ZSWAP_SWAPCACHE_FAIL on error | |
2b281117 SJ |
808 | */ |
809 | static int zswap_get_swap_cache_page(swp_entry_t entry, | |
810 | struct page **retpage) | |
811 | { | |
5b999aad | 812 | bool page_was_allocated; |
2b281117 | 813 | |
5b999aad DS |
814 | *retpage = __read_swap_cache_async(entry, GFP_KERNEL, |
815 | NULL, 0, &page_was_allocated); | |
816 | if (page_was_allocated) | |
817 | return ZSWAP_SWAPCACHE_NEW; | |
818 | if (!*retpage) | |
67d13fe8 | 819 | return ZSWAP_SWAPCACHE_FAIL; |
2b281117 SJ |
820 | return ZSWAP_SWAPCACHE_EXIST; |
821 | } | |
822 | ||
823 | /* | |
824 | * Attempts to free an entry by adding a page to the swap cache, | |
825 | * decompressing the entry data into the page, and issuing a | |
826 | * bio write to write the page back to the swap device. | |
827 | * | |
828 | * This can be thought of as a "resumed writeback" of the page | |
829 | * to the swap device. We are basically resuming the same swap | |
830 | * writeback path that was intercepted with the frontswap_store() | |
831 | * in the first place. After the page has been decompressed into | |
832 | * the swap cache, the compressed version stored by zswap can be | |
833 | * freed. | |
834 | */ | |
12d79d64 | 835 | static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) |
2b281117 SJ |
836 | { |
837 | struct zswap_header *zhdr; | |
838 | swp_entry_t swpentry; | |
839 | struct zswap_tree *tree; | |
840 | pgoff_t offset; | |
841 | struct zswap_entry *entry; | |
842 | struct page *page; | |
f1c54846 | 843 | struct crypto_comp *tfm; |
2b281117 SJ |
844 | u8 *src, *dst; |
845 | unsigned int dlen; | |
0ab0abcf | 846 | int ret; |
2b281117 SJ |
847 | struct writeback_control wbc = { |
848 | .sync_mode = WB_SYNC_NONE, | |
849 | }; | |
850 | ||
851 | /* extract swpentry from data */ | |
12d79d64 | 852 | zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); |
2b281117 | 853 | swpentry = zhdr->swpentry; /* here */ |
12d79d64 | 854 | zpool_unmap_handle(pool, handle); |
2b281117 SJ |
855 | tree = zswap_trees[swp_type(swpentry)]; |
856 | offset = swp_offset(swpentry); | |
2b281117 SJ |
857 | |
858 | /* find and ref zswap entry */ | |
859 | spin_lock(&tree->lock); | |
0ab0abcf | 860 | entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b281117 SJ |
861 | if (!entry) { |
862 | /* entry was invalidated */ | |
863 | spin_unlock(&tree->lock); | |
864 | return 0; | |
865 | } | |
2b281117 SJ |
866 | spin_unlock(&tree->lock); |
867 | BUG_ON(offset != entry->offset); | |
868 | ||
869 | /* try to allocate swap cache page */ | |
870 | switch (zswap_get_swap_cache_page(swpentry, &page)) { | |
67d13fe8 | 871 | case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ |
2b281117 SJ |
872 | ret = -ENOMEM; |
873 | goto fail; | |
874 | ||
67d13fe8 | 875 | case ZSWAP_SWAPCACHE_EXIST: |
2b281117 | 876 | /* page is already in the swap cache, ignore for now */ |
09cbfeaf | 877 | put_page(page); |
2b281117 SJ |
878 | ret = -EEXIST; |
879 | goto fail; | |
880 | ||
881 | case ZSWAP_SWAPCACHE_NEW: /* page is locked */ | |
882 | /* decompress */ | |
883 | dlen = PAGE_SIZE; | |
f1c54846 | 884 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64 | 885 | ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b281117 | 886 | dst = kmap_atomic(page); |
f1c54846 DS |
887 | tfm = *get_cpu_ptr(entry->pool->tfm); |
888 | ret = crypto_comp_decompress(tfm, src, entry->length, | |
889 | dst, &dlen); | |
890 | put_cpu_ptr(entry->pool->tfm); | |
2b281117 | 891 | kunmap_atomic(dst); |
f1c54846 | 892 | zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b281117 SJ |
893 | BUG_ON(ret); |
894 | BUG_ON(dlen != PAGE_SIZE); | |
895 | ||
896 | /* page is up to date */ | |
897 | SetPageUptodate(page); | |
898 | } | |
899 | ||
b349acc7 WY |
900 | /* move it to the tail of the inactive list after end_writeback */ |
901 | SetPageReclaim(page); | |
902 | ||
2b281117 SJ |
903 | /* start writeback */ |
904 | __swap_writepage(page, &wbc, end_swap_bio_write); | |
09cbfeaf | 905 | put_page(page); |
2b281117 SJ |
906 | zswap_written_back_pages++; |
907 | ||
908 | spin_lock(&tree->lock); | |
2b281117 | 909 | /* drop local reference */ |
0ab0abcf | 910 | zswap_entry_put(tree, entry); |
2b281117 SJ |
911 | |
912 | /* | |
0ab0abcf WY |
913 | * There are two possible situations for entry here: |
914 | * (1) refcount is 1(normal case), entry is valid and on the tree | |
915 | * (2) refcount is 0, entry is freed and not on the tree | |
916 | * because invalidate happened during writeback | |
917 | * search the tree and free the entry if find entry | |
918 | */ | |
919 | if (entry == zswap_rb_search(&tree->rbroot, offset)) | |
920 | zswap_entry_put(tree, entry); | |
2b281117 | 921 | spin_unlock(&tree->lock); |
2b281117 | 922 | |
0ab0abcf WY |
923 | goto end; |
924 | ||
925 | /* | |
926 | * if we get here due to ZSWAP_SWAPCACHE_EXIST | |
927 | * a load may happening concurrently | |
928 | * it is safe and okay to not free the entry | |
929 | * if we free the entry in the following put | |
930 | * it it either okay to return !0 | |
931 | */ | |
2b281117 SJ |
932 | fail: |
933 | spin_lock(&tree->lock); | |
0ab0abcf | 934 | zswap_entry_put(tree, entry); |
2b281117 | 935 | spin_unlock(&tree->lock); |
0ab0abcf WY |
936 | |
937 | end: | |
2b281117 SJ |
938 | return ret; |
939 | } | |
940 | ||
f1c54846 DS |
941 | static int zswap_shrink(void) |
942 | { | |
943 | struct zswap_pool *pool; | |
944 | int ret; | |
945 | ||
946 | pool = zswap_pool_last_get(); | |
947 | if (!pool) | |
948 | return -ENOENT; | |
949 | ||
950 | ret = zpool_shrink(pool->zpool, 1, NULL); | |
951 | ||
952 | zswap_pool_put(pool); | |
953 | ||
954 | return ret; | |
955 | } | |
956 | ||
2b281117 SJ |
957 | /********************************* |
958 | * frontswap hooks | |
959 | **********************************/ | |
960 | /* attempts to compress and store an single page */ | |
961 | static int zswap_frontswap_store(unsigned type, pgoff_t offset, | |
962 | struct page *page) | |
963 | { | |
964 | struct zswap_tree *tree = zswap_trees[type]; | |
965 | struct zswap_entry *entry, *dupentry; | |
f1c54846 | 966 | struct crypto_comp *tfm; |
2b281117 SJ |
967 | int ret; |
968 | unsigned int dlen = PAGE_SIZE, len; | |
969 | unsigned long handle; | |
970 | char *buf; | |
971 | u8 *src, *dst; | |
972 | struct zswap_header *zhdr; | |
973 | ||
c00ed16a | 974 | if (!zswap_enabled || !tree) { |
2b281117 SJ |
975 | ret = -ENODEV; |
976 | goto reject; | |
977 | } | |
978 | ||
979 | /* reclaim space if needed */ | |
980 | if (zswap_is_full()) { | |
981 | zswap_pool_limit_hit++; | |
f1c54846 | 982 | if (zswap_shrink()) { |
2b281117 SJ |
983 | zswap_reject_reclaim_fail++; |
984 | ret = -ENOMEM; | |
985 | goto reject; | |
986 | } | |
987 | } | |
988 | ||
989 | /* allocate entry */ | |
990 | entry = zswap_entry_cache_alloc(GFP_KERNEL); | |
991 | if (!entry) { | |
992 | zswap_reject_kmemcache_fail++; | |
993 | ret = -ENOMEM; | |
994 | goto reject; | |
995 | } | |
996 | ||
f1c54846 DS |
997 | /* if entry is successfully added, it keeps the reference */ |
998 | entry->pool = zswap_pool_current_get(); | |
999 | if (!entry->pool) { | |
1000 | ret = -EINVAL; | |
1001 | goto freepage; | |
1002 | } | |
1003 | ||
2b281117 SJ |
1004 | /* compress */ |
1005 | dst = get_cpu_var(zswap_dstmem); | |
f1c54846 | 1006 | tfm = *get_cpu_ptr(entry->pool->tfm); |
2b281117 | 1007 | src = kmap_atomic(page); |
f1c54846 | 1008 | ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen); |
2b281117 | 1009 | kunmap_atomic(src); |
f1c54846 | 1010 | put_cpu_ptr(entry->pool->tfm); |
2b281117 SJ |
1011 | if (ret) { |
1012 | ret = -EINVAL; | |
f1c54846 | 1013 | goto put_dstmem; |
2b281117 SJ |
1014 | } |
1015 | ||
1016 | /* store */ | |
1017 | len = dlen + sizeof(struct zswap_header); | |
f1c54846 | 1018 | ret = zpool_malloc(entry->pool->zpool, len, |
d0164adc MG |
1019 | __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM, |
1020 | &handle); | |
2b281117 SJ |
1021 | if (ret == -ENOSPC) { |
1022 | zswap_reject_compress_poor++; | |
f1c54846 | 1023 | goto put_dstmem; |
2b281117 SJ |
1024 | } |
1025 | if (ret) { | |
1026 | zswap_reject_alloc_fail++; | |
f1c54846 | 1027 | goto put_dstmem; |
2b281117 | 1028 | } |
f1c54846 | 1029 | zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); |
2b281117 SJ |
1030 | zhdr->swpentry = swp_entry(type, offset); |
1031 | buf = (u8 *)(zhdr + 1); | |
1032 | memcpy(buf, dst, dlen); | |
f1c54846 | 1033 | zpool_unmap_handle(entry->pool->zpool, handle); |
2b281117 SJ |
1034 | put_cpu_var(zswap_dstmem); |
1035 | ||
1036 | /* populate entry */ | |
1037 | entry->offset = offset; | |
1038 | entry->handle = handle; | |
1039 | entry->length = dlen; | |
1040 | ||
1041 | /* map */ | |
1042 | spin_lock(&tree->lock); | |
1043 | do { | |
1044 | ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry); | |
1045 | if (ret == -EEXIST) { | |
1046 | zswap_duplicate_entry++; | |
1047 | /* remove from rbtree */ | |
0ab0abcf WY |
1048 | zswap_rb_erase(&tree->rbroot, dupentry); |
1049 | zswap_entry_put(tree, dupentry); | |
2b281117 SJ |
1050 | } |
1051 | } while (ret == -EEXIST); | |
1052 | spin_unlock(&tree->lock); | |
1053 | ||
1054 | /* update stats */ | |
1055 | atomic_inc(&zswap_stored_pages); | |
f1c54846 | 1056 | zswap_update_total_size(); |
2b281117 SJ |
1057 | |
1058 | return 0; | |
1059 | ||
f1c54846 | 1060 | put_dstmem: |
2b281117 | 1061 | put_cpu_var(zswap_dstmem); |
f1c54846 DS |
1062 | zswap_pool_put(entry->pool); |
1063 | freepage: | |
2b281117 SJ |
1064 | zswap_entry_cache_free(entry); |
1065 | reject: | |
1066 | return ret; | |
1067 | } | |
1068 | ||
1069 | /* | |
1070 | * returns 0 if the page was successfully decompressed | |
1071 | * return -1 on entry not found or error | |
1072 | */ | |
1073 | static int zswap_frontswap_load(unsigned type, pgoff_t offset, | |
1074 | struct page *page) | |
1075 | { | |
1076 | struct zswap_tree *tree = zswap_trees[type]; | |
1077 | struct zswap_entry *entry; | |
f1c54846 | 1078 | struct crypto_comp *tfm; |
2b281117 SJ |
1079 | u8 *src, *dst; |
1080 | unsigned int dlen; | |
0ab0abcf | 1081 | int ret; |
2b281117 SJ |
1082 | |
1083 | /* find */ | |
1084 | spin_lock(&tree->lock); | |
0ab0abcf | 1085 | entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b281117 SJ |
1086 | if (!entry) { |
1087 | /* entry was written back */ | |
1088 | spin_unlock(&tree->lock); | |
1089 | return -1; | |
1090 | } | |
2b281117 SJ |
1091 | spin_unlock(&tree->lock); |
1092 | ||
1093 | /* decompress */ | |
1094 | dlen = PAGE_SIZE; | |
f1c54846 | 1095 | src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64 | 1096 | ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b281117 | 1097 | dst = kmap_atomic(page); |
f1c54846 DS |
1098 | tfm = *get_cpu_ptr(entry->pool->tfm); |
1099 | ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); | |
1100 | put_cpu_ptr(entry->pool->tfm); | |
2b281117 | 1101 | kunmap_atomic(dst); |
f1c54846 | 1102 | zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b281117 SJ |
1103 | BUG_ON(ret); |
1104 | ||
1105 | spin_lock(&tree->lock); | |
0ab0abcf | 1106 | zswap_entry_put(tree, entry); |
2b281117 SJ |
1107 | spin_unlock(&tree->lock); |
1108 | ||
2b281117 SJ |
1109 | return 0; |
1110 | } | |
1111 | ||
1112 | /* frees an entry in zswap */ | |
1113 | static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) | |
1114 | { | |
1115 | struct zswap_tree *tree = zswap_trees[type]; | |
1116 | struct zswap_entry *entry; | |
2b281117 SJ |
1117 | |
1118 | /* find */ | |
1119 | spin_lock(&tree->lock); | |
1120 | entry = zswap_rb_search(&tree->rbroot, offset); | |
1121 | if (!entry) { | |
1122 | /* entry was written back */ | |
1123 | spin_unlock(&tree->lock); | |
1124 | return; | |
1125 | } | |
1126 | ||
1127 | /* remove from rbtree */ | |
0ab0abcf | 1128 | zswap_rb_erase(&tree->rbroot, entry); |
2b281117 SJ |
1129 | |
1130 | /* drop the initial reference from entry creation */ | |
0ab0abcf | 1131 | zswap_entry_put(tree, entry); |
2b281117 SJ |
1132 | |
1133 | spin_unlock(&tree->lock); | |
2b281117 SJ |
1134 | } |
1135 | ||
1136 | /* frees all zswap entries for the given swap type */ | |
1137 | static void zswap_frontswap_invalidate_area(unsigned type) | |
1138 | { | |
1139 | struct zswap_tree *tree = zswap_trees[type]; | |
0bd42136 | 1140 | struct zswap_entry *entry, *n; |
2b281117 SJ |
1141 | |
1142 | if (!tree) | |
1143 | return; | |
1144 | ||
1145 | /* walk the tree and free everything */ | |
1146 | spin_lock(&tree->lock); | |
0ab0abcf | 1147 | rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode) |
60105e12 | 1148 | zswap_free_entry(entry); |
2b281117 SJ |
1149 | tree->rbroot = RB_ROOT; |
1150 | spin_unlock(&tree->lock); | |
aa9bca05 WY |
1151 | kfree(tree); |
1152 | zswap_trees[type] = NULL; | |
2b281117 SJ |
1153 | } |
1154 | ||
2b281117 SJ |
1155 | static void zswap_frontswap_init(unsigned type) |
1156 | { | |
1157 | struct zswap_tree *tree; | |
1158 | ||
1159 | tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL); | |
60105e12 MK |
1160 | if (!tree) { |
1161 | pr_err("alloc failed, zswap disabled for swap type %d\n", type); | |
1162 | return; | |
1163 | } | |
1164 | ||
2b281117 SJ |
1165 | tree->rbroot = RB_ROOT; |
1166 | spin_lock_init(&tree->lock); | |
1167 | zswap_trees[type] = tree; | |
2b281117 SJ |
1168 | } |
1169 | ||
1170 | static struct frontswap_ops zswap_frontswap_ops = { | |
1171 | .store = zswap_frontswap_store, | |
1172 | .load = zswap_frontswap_load, | |
1173 | .invalidate_page = zswap_frontswap_invalidate_page, | |
1174 | .invalidate_area = zswap_frontswap_invalidate_area, | |
1175 | .init = zswap_frontswap_init | |
1176 | }; | |
1177 | ||
1178 | /********************************* | |
1179 | * debugfs functions | |
1180 | **********************************/ | |
1181 | #ifdef CONFIG_DEBUG_FS | |
1182 | #include <linux/debugfs.h> | |
1183 | ||
1184 | static struct dentry *zswap_debugfs_root; | |
1185 | ||
1186 | static int __init zswap_debugfs_init(void) | |
1187 | { | |
1188 | if (!debugfs_initialized()) | |
1189 | return -ENODEV; | |
1190 | ||
1191 | zswap_debugfs_root = debugfs_create_dir("zswap", NULL); | |
1192 | if (!zswap_debugfs_root) | |
1193 | return -ENOMEM; | |
1194 | ||
1195 | debugfs_create_u64("pool_limit_hit", S_IRUGO, | |
1196 | zswap_debugfs_root, &zswap_pool_limit_hit); | |
1197 | debugfs_create_u64("reject_reclaim_fail", S_IRUGO, | |
1198 | zswap_debugfs_root, &zswap_reject_reclaim_fail); | |
1199 | debugfs_create_u64("reject_alloc_fail", S_IRUGO, | |
1200 | zswap_debugfs_root, &zswap_reject_alloc_fail); | |
1201 | debugfs_create_u64("reject_kmemcache_fail", S_IRUGO, | |
1202 | zswap_debugfs_root, &zswap_reject_kmemcache_fail); | |
1203 | debugfs_create_u64("reject_compress_poor", S_IRUGO, | |
1204 | zswap_debugfs_root, &zswap_reject_compress_poor); | |
1205 | debugfs_create_u64("written_back_pages", S_IRUGO, | |
1206 | zswap_debugfs_root, &zswap_written_back_pages); | |
1207 | debugfs_create_u64("duplicate_entry", S_IRUGO, | |
1208 | zswap_debugfs_root, &zswap_duplicate_entry); | |
12d79d64 DS |
1209 | debugfs_create_u64("pool_total_size", S_IRUGO, |
1210 | zswap_debugfs_root, &zswap_pool_total_size); | |
2b281117 SJ |
1211 | debugfs_create_atomic_t("stored_pages", S_IRUGO, |
1212 | zswap_debugfs_root, &zswap_stored_pages); | |
1213 | ||
1214 | return 0; | |
1215 | } | |
1216 | ||
1217 | static void __exit zswap_debugfs_exit(void) | |
1218 | { | |
1219 | debugfs_remove_recursive(zswap_debugfs_root); | |
1220 | } | |
1221 | #else | |
1222 | static int __init zswap_debugfs_init(void) | |
1223 | { | |
1224 | return 0; | |
1225 | } | |
1226 | ||
1227 | static void __exit zswap_debugfs_exit(void) { } | |
1228 | #endif | |
1229 | ||
1230 | /********************************* | |
1231 | * module init and exit | |
1232 | **********************************/ | |
1233 | static int __init init_zswap(void) | |
1234 | { | |
f1c54846 | 1235 | struct zswap_pool *pool; |
ad7ed770 | 1236 | int ret; |
60105e12 | 1237 | |
90b0fc26 DS |
1238 | zswap_init_started = true; |
1239 | ||
2b281117 SJ |
1240 | if (zswap_entry_cache_create()) { |
1241 | pr_err("entry cache creation failed\n"); | |
f1c54846 | 1242 | goto cache_fail; |
2b281117 | 1243 | } |
f1c54846 | 1244 | |
ad7ed770 SAS |
1245 | ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare", |
1246 | zswap_dstmem_prepare, zswap_dstmem_dead); | |
1247 | if (ret) { | |
f1c54846 DS |
1248 | pr_err("dstmem alloc failed\n"); |
1249 | goto dstmem_fail; | |
2b281117 | 1250 | } |
f1c54846 | 1251 | |
cab7a7e5 SAS |
1252 | ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE, |
1253 | "mm/zswap_pool:prepare", | |
1254 | zswap_cpu_comp_prepare, | |
1255 | zswap_cpu_comp_dead); | |
1256 | if (ret) | |
1257 | goto hp_fail; | |
1258 | ||
f1c54846 | 1259 | pool = __zswap_pool_create_fallback(); |
ae3d89a7 DS |
1260 | if (pool) { |
1261 | pr_info("loaded using pool %s/%s\n", pool->tfm_name, | |
1262 | zpool_get_type(pool->zpool)); | |
1263 | list_add(&pool->list, &zswap_pools); | |
1264 | zswap_has_pool = true; | |
1265 | } else { | |
f1c54846 | 1266 | pr_err("pool creation failed\n"); |
ae3d89a7 | 1267 | zswap_enabled = false; |
2b281117 | 1268 | } |
60105e12 | 1269 | |
2b281117 SJ |
1270 | frontswap_register_ops(&zswap_frontswap_ops); |
1271 | if (zswap_debugfs_init()) | |
1272 | pr_warn("debugfs initialization failed\n"); | |
1273 | return 0; | |
f1c54846 | 1274 | |
cab7a7e5 | 1275 | hp_fail: |
ad7ed770 | 1276 | cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE); |
f1c54846 | 1277 | dstmem_fail: |
c119239b | 1278 | zswap_entry_cache_destroy(); |
f1c54846 | 1279 | cache_fail: |
d7b028f5 DS |
1280 | /* if built-in, we aren't unloaded on failure; don't allow use */ |
1281 | zswap_init_failed = true; | |
1282 | zswap_enabled = false; | |
2b281117 SJ |
1283 | return -ENOMEM; |
1284 | } | |
1285 | /* must be late so crypto has time to come up */ | |
1286 | late_initcall(init_zswap); | |
1287 | ||
1288 | MODULE_LICENSE("GPL"); | |
68386da8 | 1289 | MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>"); |
2b281117 | 1290 | MODULE_DESCRIPTION("Compressed cache for swap pages"); |