blob: 275b22cc8df4352c8210948e4381aa4bce83dc08 [file] [log] [blame]
Seth Jennings2b281112013-07-10 16:05:03 -07001/*
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>
Dan Streetman12d79d62014-08-06 16:08:40 -070037#include <linux/zpool.h>
Seth Jennings2b281112013-07-10 16:05:03 -070038
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**********************************/
Dan Streetman12d79d62014-08-06 16:08:40 -070048/* Total bytes used by the compressed storage */
49static u64 zswap_pool_total_size;
Seth Jennings2b281112013-07-10 16:05:03 -070050/* The number of compressed pages currently stored in zswap */
51static 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) */
61static u64 zswap_pool_limit_hit;
62/* Pages written back when pool limit was reached */
63static u64 zswap_written_back_pages;
64/* Store failed due to a reclaim failure after pool limit was reached */
65static u64 zswap_reject_reclaim_fail;
66/* Compressed page was too big for the allocator to (optimally) store */
67static u64 zswap_reject_compress_poor;
68/* Store failed because underlying allocator could not get memory */
69static u64 zswap_reject_alloc_fail;
70/* Store failed because the entry metadata could not be allocated (rare) */
71static u64 zswap_reject_kmemcache_fail;
72/* Duplicate store was encountered (rare) */
73static u64 zswap_duplicate_entry;
74
75/*********************************
76* tunables
77**********************************/
Dan Streetmanc00ed162015-06-25 15:00:35 -070078
79/* Enable/disable zswap (disabled by default) */
80static bool zswap_enabled;
81module_param_named(enabled, zswap_enabled, bool, 0644);
Seth Jennings2b281112013-07-10 16:05:03 -070082
Dan Streetman90b0fc22015-09-09 15:35:21 -070083/* Crypto compressor to use */
Seth Jennings2b281112013-07-10 16:05:03 -070084#define ZSWAP_COMPRESSOR_DEFAULT "lzo"
Dan Streetmanc99b42c2015-11-06 16:29:15 -080085static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
Dan Streetman90b0fc22015-09-09 15:35:21 -070086static int zswap_compressor_param_set(const char *,
87 const struct kernel_param *);
88static struct kernel_param_ops zswap_compressor_param_ops = {
89 .set = zswap_compressor_param_set,
Dan Streetmanc99b42c2015-11-06 16:29:15 -080090 .get = param_get_charp,
91 .free = param_free_charp,
Dan Streetman90b0fc22015-09-09 15:35:21 -070092};
93module_param_cb(compressor, &zswap_compressor_param_ops,
Dan Streetmanc99b42c2015-11-06 16:29:15 -080094 &zswap_compressor, 0644);
Dan Streetman90b0fc22015-09-09 15:35:21 -070095
96/* Compressed storage zpool to use */
97#define ZSWAP_ZPOOL_DEFAULT "zbud"
Dan Streetmanc99b42c2015-11-06 16:29:15 -080098static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
Dan Streetman90b0fc22015-09-09 15:35:21 -070099static int zswap_zpool_param_set(const char *, const struct kernel_param *);
100static struct kernel_param_ops zswap_zpool_param_ops = {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800101 .set = zswap_zpool_param_set,
102 .get = param_get_charp,
103 .free = param_free_charp,
Dan Streetman90b0fc22015-09-09 15:35:21 -0700104};
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800105module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644);
Seth Jennings2b281112013-07-10 16:05:03 -0700106
107/* The maximum percentage of memory that the compressed pool can occupy */
108static unsigned int zswap_max_pool_percent = 20;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700109module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644);
Minchan Kim60105e12014-04-07 15:38:27 -0700110
Seth Jennings2b281112013-07-10 16:05:03 -0700111/*********************************
Seth Jennings2b281112013-07-10 16:05:03 -0700112* data structures
113**********************************/
Dan Streetmanf1c54842015-09-09 15:35:19 -0700114
115struct zswap_pool {
116 struct zpool *zpool;
117 struct crypto_comp * __percpu *tfm;
118 struct kref kref;
119 struct list_head list;
Dan Streetman200867a2016-05-20 16:59:54 -0700120 struct work_struct work;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700121 struct notifier_block notifier;
122 char tfm_name[CRYPTO_MAX_ALG_NAME];
123};
124
Seth Jennings2b281112013-07-10 16:05:03 -0700125/*
126 * struct zswap_entry
127 *
128 * This structure contains the metadata for tracking a single compressed
129 * page within zswap.
130 *
131 * rbnode - links the entry into red-black tree for the appropriate swap type
Dan Streetmanf1c54842015-09-09 15:35:19 -0700132 * offset - the swap offset for the entry. Index into the red-black tree.
Seth Jennings2b281112013-07-10 16:05:03 -0700133 * refcount - the number of outstanding reference to the entry. This is needed
134 * to protect against premature freeing of the entry by code
SeongJae Park6b452512014-04-07 15:38:25 -0700135 * concurrent calls to load, invalidate, and writeback. The lock
Seth Jennings2b281112013-07-10 16:05:03 -0700136 * for the zswap_tree structure that contains the entry must
137 * be held while changing the refcount. Since the lock must
138 * be held, there is no reason to also make refcount atomic.
Seth Jennings2b281112013-07-10 16:05:03 -0700139 * length - the length in bytes of the compressed page data. Needed during
SeongJae Park6b452512014-04-07 15:38:25 -0700140 * decompression
Dan Streetmanf1c54842015-09-09 15:35:19 -0700141 * pool - the zswap_pool the entry's data is in
142 * handle - zpool allocation handle that stores the compressed page data
Seth Jennings2b281112013-07-10 16:05:03 -0700143 */
144struct zswap_entry {
145 struct rb_node rbnode;
146 pgoff_t offset;
147 int refcount;
148 unsigned int length;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700149 struct zswap_pool *pool;
Seth Jennings2b281112013-07-10 16:05:03 -0700150 unsigned long handle;
151};
152
153struct zswap_header {
154 swp_entry_t swpentry;
155};
156
157/*
158 * The tree lock in the zswap_tree struct protects a few things:
159 * - the rbtree
160 * - the refcount field of each entry in the tree
161 */
162struct zswap_tree {
163 struct rb_root rbroot;
164 spinlock_t lock;
Seth Jennings2b281112013-07-10 16:05:03 -0700165};
166
167static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
168
Dan Streetmanf1c54842015-09-09 15:35:19 -0700169/* RCU-protected iteration */
170static LIST_HEAD(zswap_pools);
171/* protects zswap_pools list modification */
172static DEFINE_SPINLOCK(zswap_pools_lock);
Dan Streetman32a4e1692016-05-05 16:22:23 -0700173/* pool counter to provide unique names to zpool */
174static atomic_t zswap_pools_count = ATOMIC_INIT(0);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700175
Dan Streetman90b0fc22015-09-09 15:35:21 -0700176/* used by param callback function */
177static bool zswap_init_started;
178
Dan Streetmanf1c54842015-09-09 15:35:19 -0700179/*********************************
180* helpers and fwd declarations
181**********************************/
182
183#define zswap_pool_debug(msg, p) \
184 pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
185 zpool_get_type((p)->zpool))
186
187static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
188static int zswap_pool_get(struct zswap_pool *pool);
189static void zswap_pool_put(struct zswap_pool *pool);
190
191static const struct zpool_ops zswap_zpool_ops = {
192 .evict = zswap_writeback_entry
193};
194
195static bool zswap_is_full(void)
196{
197 return totalram_pages * zswap_max_pool_percent / 100 <
198 DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
199}
200
201static void zswap_update_total_size(void)
202{
203 struct zswap_pool *pool;
204 u64 total = 0;
205
206 rcu_read_lock();
207
208 list_for_each_entry_rcu(pool, &zswap_pools, list)
209 total += zpool_get_total_size(pool->zpool);
210
211 rcu_read_unlock();
212
213 zswap_pool_total_size = total;
214}
215
Seth Jennings2b281112013-07-10 16:05:03 -0700216/*********************************
217* zswap entry functions
218**********************************/
219static struct kmem_cache *zswap_entry_cache;
220
Mahendran Ganeshdd01d7d2014-12-12 16:57:15 -0800221static int __init zswap_entry_cache_create(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700222{
223 zswap_entry_cache = KMEM_CACHE(zswap_entry, 0);
SeongJae Park5d2d42d2014-04-07 15:38:28 -0700224 return zswap_entry_cache == NULL;
Seth Jennings2b281112013-07-10 16:05:03 -0700225}
226
Fabian Frederickc1192392014-08-08 14:19:35 -0700227static void __init zswap_entry_cache_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700228{
229 kmem_cache_destroy(zswap_entry_cache);
230}
231
232static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp)
233{
234 struct zswap_entry *entry;
235 entry = kmem_cache_alloc(zswap_entry_cache, gfp);
236 if (!entry)
237 return NULL;
238 entry->refcount = 1;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800239 RB_CLEAR_NODE(&entry->rbnode);
Seth Jennings2b281112013-07-10 16:05:03 -0700240 return entry;
241}
242
243static void zswap_entry_cache_free(struct zswap_entry *entry)
244{
245 kmem_cache_free(zswap_entry_cache, entry);
246}
247
Seth Jennings2b281112013-07-10 16:05:03 -0700248/*********************************
249* rbtree functions
250**********************************/
251static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset)
252{
253 struct rb_node *node = root->rb_node;
254 struct zswap_entry *entry;
255
256 while (node) {
257 entry = rb_entry(node, struct zswap_entry, rbnode);
258 if (entry->offset > offset)
259 node = node->rb_left;
260 else if (entry->offset < offset)
261 node = node->rb_right;
262 else
263 return entry;
264 }
265 return NULL;
266}
267
268/*
269 * In the case that a entry with the same offset is found, a pointer to
270 * the existing entry is stored in dupentry and the function returns -EEXIST
271 */
272static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry,
273 struct zswap_entry **dupentry)
274{
275 struct rb_node **link = &root->rb_node, *parent = NULL;
276 struct zswap_entry *myentry;
277
278 while (*link) {
279 parent = *link;
280 myentry = rb_entry(parent, struct zswap_entry, rbnode);
281 if (myentry->offset > entry->offset)
282 link = &(*link)->rb_left;
283 else if (myentry->offset < entry->offset)
284 link = &(*link)->rb_right;
285 else {
286 *dupentry = myentry;
287 return -EEXIST;
288 }
289 }
290 rb_link_node(&entry->rbnode, parent, link);
291 rb_insert_color(&entry->rbnode, root);
292 return 0;
293}
294
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800295static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
296{
297 if (!RB_EMPTY_NODE(&entry->rbnode)) {
298 rb_erase(&entry->rbnode, root);
299 RB_CLEAR_NODE(&entry->rbnode);
300 }
301}
302
303/*
Dan Streetman12d79d62014-08-06 16:08:40 -0700304 * Carries out the common pattern of freeing and entry's zpool allocation,
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800305 * freeing the entry itself, and decrementing the number of stored pages.
306 */
Minchan Kim60105e12014-04-07 15:38:27 -0700307static void zswap_free_entry(struct zswap_entry *entry)
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800308{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700309 zpool_free(entry->pool->zpool, entry->handle);
310 zswap_pool_put(entry->pool);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800311 zswap_entry_cache_free(entry);
312 atomic_dec(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700313 zswap_update_total_size();
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800314}
315
316/* caller must hold the tree lock */
317static void zswap_entry_get(struct zswap_entry *entry)
318{
319 entry->refcount++;
320}
321
322/* caller must hold the tree lock
323* remove from the tree and free it, if nobody reference the entry
324*/
325static void zswap_entry_put(struct zswap_tree *tree,
326 struct zswap_entry *entry)
327{
328 int refcount = --entry->refcount;
329
330 BUG_ON(refcount < 0);
331 if (refcount == 0) {
332 zswap_rb_erase(&tree->rbroot, entry);
Minchan Kim60105e12014-04-07 15:38:27 -0700333 zswap_free_entry(entry);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800334 }
335}
336
337/* caller must hold the tree lock */
338static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
339 pgoff_t offset)
340{
Alexey Klimovb0c98652015-11-06 16:29:09 -0800341 struct zswap_entry *entry;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800342
343 entry = zswap_rb_search(root, offset);
344 if (entry)
345 zswap_entry_get(entry);
346
347 return entry;
348}
349
Seth Jennings2b281112013-07-10 16:05:03 -0700350/*********************************
351* per-cpu code
352**********************************/
353static DEFINE_PER_CPU(u8 *, zswap_dstmem);
354
Dan Streetmanf1c54842015-09-09 15:35:19 -0700355static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700356{
Seth Jennings2b281112013-07-10 16:05:03 -0700357 u8 *dst;
358
359 switch (action) {
360 case CPU_UP_PREPARE:
Eric Dumazet72d09632014-06-04 16:11:11 -0700361 dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
Seth Jennings2b281112013-07-10 16:05:03 -0700362 if (!dst) {
363 pr_err("can't allocate compressor buffer\n");
Seth Jennings2b281112013-07-10 16:05:03 -0700364 return NOTIFY_BAD;
365 }
366 per_cpu(zswap_dstmem, cpu) = dst;
367 break;
368 case CPU_DEAD:
369 case CPU_UP_CANCELED:
Seth Jennings2b281112013-07-10 16:05:03 -0700370 dst = per_cpu(zswap_dstmem, cpu);
371 kfree(dst);
372 per_cpu(zswap_dstmem, cpu) = NULL;
373 break;
374 default:
375 break;
376 }
377 return NOTIFY_OK;
378}
379
Dan Streetmanf1c54842015-09-09 15:35:19 -0700380static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
381 unsigned long action, void *pcpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700382{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700383 return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
Seth Jennings2b281112013-07-10 16:05:03 -0700384}
385
Dan Streetmanf1c54842015-09-09 15:35:19 -0700386static struct notifier_block zswap_dstmem_notifier = {
387 .notifier_call = zswap_cpu_dstmem_notifier,
Seth Jennings2b281112013-07-10 16:05:03 -0700388};
389
Dan Streetmanf1c54842015-09-09 15:35:19 -0700390static int __init zswap_cpu_dstmem_init(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700391{
392 unsigned long cpu;
393
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530394 cpu_notifier_register_begin();
Seth Jennings2b281112013-07-10 16:05:03 -0700395 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700396 if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
397 NOTIFY_BAD)
Seth Jennings2b281112013-07-10 16:05:03 -0700398 goto cleanup;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700399 __register_cpu_notifier(&zswap_dstmem_notifier);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530400 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700401 return 0;
402
403cleanup:
404 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700405 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530406 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700407 return -ENOMEM;
408}
409
Dan Streetmanf1c54842015-09-09 15:35:19 -0700410static void zswap_cpu_dstmem_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700411{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700412 unsigned long cpu;
413
414 cpu_notifier_register_begin();
415 for_each_online_cpu(cpu)
416 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
417 __unregister_cpu_notifier(&zswap_dstmem_notifier);
418 cpu_notifier_register_done();
419}
420
421static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
422 unsigned long action, unsigned long cpu)
423{
424 struct crypto_comp *tfm;
425
426 switch (action) {
427 case CPU_UP_PREPARE:
428 if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
429 break;
430 tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
431 if (IS_ERR_OR_NULL(tfm)) {
432 pr_err("could not alloc crypto comp %s : %ld\n",
433 pool->tfm_name, PTR_ERR(tfm));
434 return NOTIFY_BAD;
435 }
436 *per_cpu_ptr(pool->tfm, cpu) = tfm;
437 break;
438 case CPU_DEAD:
439 case CPU_UP_CANCELED:
440 tfm = *per_cpu_ptr(pool->tfm, cpu);
441 if (!IS_ERR_OR_NULL(tfm))
442 crypto_free_comp(tfm);
443 *per_cpu_ptr(pool->tfm, cpu) = NULL;
444 break;
445 default:
446 break;
447 }
448 return NOTIFY_OK;
449}
450
451static int zswap_cpu_comp_notifier(struct notifier_block *nb,
452 unsigned long action, void *pcpu)
453{
454 unsigned long cpu = (unsigned long)pcpu;
455 struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
456
457 return __zswap_cpu_comp_notifier(pool, action, cpu);
458}
459
460static int zswap_cpu_comp_init(struct zswap_pool *pool)
461{
462 unsigned long cpu;
463
464 memset(&pool->notifier, 0, sizeof(pool->notifier));
465 pool->notifier.notifier_call = zswap_cpu_comp_notifier;
466
467 cpu_notifier_register_begin();
468 for_each_online_cpu(cpu)
469 if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
470 NOTIFY_BAD)
471 goto cleanup;
472 __register_cpu_notifier(&pool->notifier);
473 cpu_notifier_register_done();
474 return 0;
475
476cleanup:
477 for_each_online_cpu(cpu)
478 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
479 cpu_notifier_register_done();
480 return -ENOMEM;
481}
482
483static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
484{
485 unsigned long cpu;
486
487 cpu_notifier_register_begin();
488 for_each_online_cpu(cpu)
489 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
490 __unregister_cpu_notifier(&pool->notifier);
491 cpu_notifier_register_done();
492}
493
494/*********************************
495* pool functions
496**********************************/
497
498static struct zswap_pool *__zswap_pool_current(void)
499{
500 struct zswap_pool *pool;
501
502 pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
503 WARN_ON(!pool);
504
505 return pool;
506}
507
508static struct zswap_pool *zswap_pool_current(void)
509{
510 assert_spin_locked(&zswap_pools_lock);
511
512 return __zswap_pool_current();
513}
514
515static struct zswap_pool *zswap_pool_current_get(void)
516{
517 struct zswap_pool *pool;
518
519 rcu_read_lock();
520
521 pool = __zswap_pool_current();
522 if (!pool || !zswap_pool_get(pool))
523 pool = NULL;
524
525 rcu_read_unlock();
526
527 return pool;
528}
529
530static struct zswap_pool *zswap_pool_last_get(void)
531{
532 struct zswap_pool *pool, *last = NULL;
533
534 rcu_read_lock();
535
536 list_for_each_entry_rcu(pool, &zswap_pools, list)
537 last = pool;
538 if (!WARN_ON(!last) && !zswap_pool_get(last))
539 last = NULL;
540
541 rcu_read_unlock();
542
543 return last;
544}
545
Dan Streetman8bc8b222015-12-18 14:22:04 -0800546/* type and compressor must be null-terminated */
Dan Streetmanf1c54842015-09-09 15:35:19 -0700547static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
548{
549 struct zswap_pool *pool;
550
551 assert_spin_locked(&zswap_pools_lock);
552
553 list_for_each_entry_rcu(pool, &zswap_pools, list) {
Dan Streetman8bc8b222015-12-18 14:22:04 -0800554 if (strcmp(pool->tfm_name, compressor))
Dan Streetmanf1c54842015-09-09 15:35:19 -0700555 continue;
Dan Streetman8bc8b222015-12-18 14:22:04 -0800556 if (strcmp(zpool_get_type(pool->zpool), type))
Dan Streetmanf1c54842015-09-09 15:35:19 -0700557 continue;
558 /* if we can't get it, it's about to be destroyed */
559 if (!zswap_pool_get(pool))
560 continue;
561 return pool;
562 }
563
564 return NULL;
565}
566
567static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
568{
569 struct zswap_pool *pool;
Dan Streetman32a4e1692016-05-05 16:22:23 -0700570 char name[38]; /* 'zswap' + 32 char (max) num + \0 */
Mel Gormand0164ad2015-11-06 16:28:21 -0800571 gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700572
573 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
574 if (!pool) {
575 pr_err("pool alloc failed\n");
576 return NULL;
577 }
578
Dan Streetman32a4e1692016-05-05 16:22:23 -0700579 /* unique name for each pool specifically required by zsmalloc */
580 snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count));
581
582 pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700583 if (!pool->zpool) {
584 pr_err("%s zpool not available\n", type);
585 goto error;
586 }
587 pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
588
589 strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
590 pool->tfm = alloc_percpu(struct crypto_comp *);
591 if (!pool->tfm) {
592 pr_err("percpu alloc failed\n");
593 goto error;
594 }
595
596 if (zswap_cpu_comp_init(pool))
597 goto error;
598 pr_debug("using %s compressor\n", pool->tfm_name);
599
600 /* being the current pool takes 1 ref; this func expects the
601 * caller to always add the new pool as the current pool
602 */
603 kref_init(&pool->kref);
604 INIT_LIST_HEAD(&pool->list);
605
606 zswap_pool_debug("created", pool);
607
608 return pool;
609
610error:
611 free_percpu(pool->tfm);
612 if (pool->zpool)
613 zpool_destroy_pool(pool->zpool);
614 kfree(pool);
615 return NULL;
616}
617
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800618static __init struct zswap_pool *__zswap_pool_create_fallback(void)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700619{
620 if (!crypto_has_comp(zswap_compressor, 0, 0)) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800621 if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) {
622 pr_err("default compressor %s not available\n",
623 zswap_compressor);
624 return NULL;
625 }
Dan Streetmanf1c54842015-09-09 15:35:19 -0700626 pr_err("compressor %s not available, using default %s\n",
627 zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800628 param_free_charp(&zswap_compressor);
629 zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700630 }
631 if (!zpool_has_pool(zswap_zpool_type)) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800632 if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
633 pr_err("default zpool %s not available\n",
634 zswap_zpool_type);
635 return NULL;
636 }
Dan Streetmanf1c54842015-09-09 15:35:19 -0700637 pr_err("zpool %s not available, using default %s\n",
638 zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800639 param_free_charp(&zswap_zpool_type);
640 zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700641 }
642
643 return zswap_pool_create(zswap_zpool_type, zswap_compressor);
644}
645
646static void zswap_pool_destroy(struct zswap_pool *pool)
647{
648 zswap_pool_debug("destroying", pool);
649
650 zswap_cpu_comp_destroy(pool);
651 free_percpu(pool->tfm);
652 zpool_destroy_pool(pool->zpool);
653 kfree(pool);
654}
655
656static int __must_check zswap_pool_get(struct zswap_pool *pool)
657{
658 return kref_get_unless_zero(&pool->kref);
659}
660
Dan Streetman200867a2016-05-20 16:59:54 -0700661static void __zswap_pool_release(struct work_struct *work)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700662{
Dan Streetman200867a2016-05-20 16:59:54 -0700663 struct zswap_pool *pool = container_of(work, typeof(*pool), work);
664
665 synchronize_rcu();
Dan Streetmanf1c54842015-09-09 15:35:19 -0700666
667 /* nobody should have been able to get a kref... */
668 WARN_ON(kref_get_unless_zero(&pool->kref));
669
670 /* pool is now off zswap_pools list and has no references. */
671 zswap_pool_destroy(pool);
672}
673
674static void __zswap_pool_empty(struct kref *kref)
675{
676 struct zswap_pool *pool;
677
678 pool = container_of(kref, typeof(*pool), kref);
679
680 spin_lock(&zswap_pools_lock);
681
682 WARN_ON(pool == zswap_pool_current());
683
684 list_del_rcu(&pool->list);
Dan Streetman200867a2016-05-20 16:59:54 -0700685
686 INIT_WORK(&pool->work, __zswap_pool_release);
687 schedule_work(&pool->work);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700688
689 spin_unlock(&zswap_pools_lock);
690}
691
692static void zswap_pool_put(struct zswap_pool *pool)
693{
694 kref_put(&pool->kref, __zswap_pool_empty);
Seth Jennings2b281112013-07-10 16:05:03 -0700695}
696
Seth Jennings2b281112013-07-10 16:05:03 -0700697/*********************************
Dan Streetman90b0fc22015-09-09 15:35:21 -0700698* param callbacks
699**********************************/
700
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800701/* val must be a null-terminated string */
Dan Streetman90b0fc22015-09-09 15:35:21 -0700702static int __zswap_param_set(const char *val, const struct kernel_param *kp,
703 char *type, char *compressor)
704{
705 struct zswap_pool *pool, *put_pool = NULL;
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800706 char *s = strstrip((char *)val);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700707 int ret;
708
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800709 /* no change required */
710 if (!strcmp(s, *(char **)kp->arg))
711 return 0;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700712
713 /* if this is load-time (pre-init) param setting,
714 * don't create a pool; that's done during init.
715 */
716 if (!zswap_init_started)
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800717 return param_set_charp(s, kp);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700718
719 if (!type) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800720 if (!zpool_has_pool(s)) {
721 pr_err("zpool %s not available\n", s);
722 return -ENOENT;
723 }
Dan Streetman90b0fc22015-09-09 15:35:21 -0700724 type = s;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700725 } else if (!compressor) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800726 if (!crypto_has_comp(s, 0, 0)) {
727 pr_err("compressor %s not available\n", s);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700728 return -ENOENT;
729 }
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800730 compressor = s;
731 } else {
732 WARN_ON(1);
733 return -EINVAL;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700734 }
735
736 spin_lock(&zswap_pools_lock);
737
738 pool = zswap_pool_find_get(type, compressor);
739 if (pool) {
740 zswap_pool_debug("using existing", pool);
741 list_del_rcu(&pool->list);
742 } else {
743 spin_unlock(&zswap_pools_lock);
744 pool = zswap_pool_create(type, compressor);
745 spin_lock(&zswap_pools_lock);
746 }
747
748 if (pool)
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800749 ret = param_set_charp(s, kp);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700750 else
751 ret = -EINVAL;
752
753 if (!ret) {
754 put_pool = zswap_pool_current();
755 list_add_rcu(&pool->list, &zswap_pools);
756 } else if (pool) {
757 /* add the possibly pre-existing pool to the end of the pools
758 * list; if it's new (and empty) then it'll be removed and
759 * destroyed by the put after we drop the lock
760 */
761 list_add_tail_rcu(&pool->list, &zswap_pools);
762 put_pool = pool;
763 }
764
765 spin_unlock(&zswap_pools_lock);
766
767 /* drop the ref from either the old current pool,
768 * or the new pool we failed to add
769 */
770 if (put_pool)
771 zswap_pool_put(put_pool);
772
773 return ret;
774}
775
776static int zswap_compressor_param_set(const char *val,
777 const struct kernel_param *kp)
778{
779 return __zswap_param_set(val, kp, zswap_zpool_type, NULL);
780}
781
782static int zswap_zpool_param_set(const char *val,
783 const struct kernel_param *kp)
784{
785 return __zswap_param_set(val, kp, NULL, zswap_compressor);
786}
787
788/*********************************
Seth Jennings2b281112013-07-10 16:05:03 -0700789* writeback code
790**********************************/
791/* return enum for zswap_get_swap_cache_page */
792enum zswap_get_swap_ret {
793 ZSWAP_SWAPCACHE_NEW,
794 ZSWAP_SWAPCACHE_EXIST,
Weijie Yang67d13fe2013-11-12 15:08:26 -0800795 ZSWAP_SWAPCACHE_FAIL,
Seth Jennings2b281112013-07-10 16:05:03 -0700796};
797
798/*
799 * zswap_get_swap_cache_page
800 *
801 * This is an adaption of read_swap_cache_async()
802 *
803 * This function tries to find a page with the given swap entry
804 * in the swapper_space address space (the swap cache). If the page
805 * is found, it is returned in retpage. Otherwise, a page is allocated,
806 * added to the swap cache, and returned in retpage.
807 *
808 * If success, the swap cache page is returned in retpage
Weijie Yang67d13fe2013-11-12 15:08:26 -0800809 * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache
810 * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated,
811 * the new page is added to swapcache and locked
812 * Returns ZSWAP_SWAPCACHE_FAIL on error
Seth Jennings2b281112013-07-10 16:05:03 -0700813 */
814static int zswap_get_swap_cache_page(swp_entry_t entry,
815 struct page **retpage)
816{
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700817 bool page_was_allocated;
Seth Jennings2b281112013-07-10 16:05:03 -0700818
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700819 *retpage = __read_swap_cache_async(entry, GFP_KERNEL,
820 NULL, 0, &page_was_allocated);
821 if (page_was_allocated)
822 return ZSWAP_SWAPCACHE_NEW;
823 if (!*retpage)
Weijie Yang67d13fe2013-11-12 15:08:26 -0800824 return ZSWAP_SWAPCACHE_FAIL;
Seth Jennings2b281112013-07-10 16:05:03 -0700825 return ZSWAP_SWAPCACHE_EXIST;
826}
827
828/*
829 * Attempts to free an entry by adding a page to the swap cache,
830 * decompressing the entry data into the page, and issuing a
831 * bio write to write the page back to the swap device.
832 *
833 * This can be thought of as a "resumed writeback" of the page
834 * to the swap device. We are basically resuming the same swap
835 * writeback path that was intercepted with the frontswap_store()
836 * in the first place. After the page has been decompressed into
837 * the swap cache, the compressed version stored by zswap can be
838 * freed.
839 */
Dan Streetman12d79d62014-08-06 16:08:40 -0700840static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
Seth Jennings2b281112013-07-10 16:05:03 -0700841{
842 struct zswap_header *zhdr;
843 swp_entry_t swpentry;
844 struct zswap_tree *tree;
845 pgoff_t offset;
846 struct zswap_entry *entry;
847 struct page *page;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700848 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700849 u8 *src, *dst;
850 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800851 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -0700852 struct writeback_control wbc = {
853 .sync_mode = WB_SYNC_NONE,
854 };
855
856 /* extract swpentry from data */
Dan Streetman12d79d62014-08-06 16:08:40 -0700857 zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
Seth Jennings2b281112013-07-10 16:05:03 -0700858 swpentry = zhdr->swpentry; /* here */
Dan Streetman12d79d62014-08-06 16:08:40 -0700859 zpool_unmap_handle(pool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700860 tree = zswap_trees[swp_type(swpentry)];
861 offset = swp_offset(swpentry);
Seth Jennings2b281112013-07-10 16:05:03 -0700862
863 /* find and ref zswap entry */
864 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800865 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -0700866 if (!entry) {
867 /* entry was invalidated */
868 spin_unlock(&tree->lock);
869 return 0;
870 }
Seth Jennings2b281112013-07-10 16:05:03 -0700871 spin_unlock(&tree->lock);
872 BUG_ON(offset != entry->offset);
873
874 /* try to allocate swap cache page */
875 switch (zswap_get_swap_cache_page(swpentry, &page)) {
Weijie Yang67d13fe2013-11-12 15:08:26 -0800876 case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */
Seth Jennings2b281112013-07-10 16:05:03 -0700877 ret = -ENOMEM;
878 goto fail;
879
Weijie Yang67d13fe2013-11-12 15:08:26 -0800880 case ZSWAP_SWAPCACHE_EXIST:
Seth Jennings2b281112013-07-10 16:05:03 -0700881 /* page is already in the swap cache, ignore for now */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300882 put_page(page);
Seth Jennings2b281112013-07-10 16:05:03 -0700883 ret = -EEXIST;
884 goto fail;
885
886 case ZSWAP_SWAPCACHE_NEW: /* page is locked */
887 /* decompress */
888 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700889 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -0700890 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -0700891 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700892 tfm = *get_cpu_ptr(entry->pool->tfm);
893 ret = crypto_comp_decompress(tfm, src, entry->length,
894 dst, &dlen);
895 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -0700896 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700897 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700898 BUG_ON(ret);
899 BUG_ON(dlen != PAGE_SIZE);
900
901 /* page is up to date */
902 SetPageUptodate(page);
903 }
904
Weijie Yangb349acc2013-11-12 15:07:52 -0800905 /* move it to the tail of the inactive list after end_writeback */
906 SetPageReclaim(page);
907
Seth Jennings2b281112013-07-10 16:05:03 -0700908 /* start writeback */
909 __swap_writepage(page, &wbc, end_swap_bio_write);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300910 put_page(page);
Seth Jennings2b281112013-07-10 16:05:03 -0700911 zswap_written_back_pages++;
912
913 spin_lock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700914 /* drop local reference */
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800915 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700916
917 /*
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800918 * There are two possible situations for entry here:
919 * (1) refcount is 1(normal case), entry is valid and on the tree
920 * (2) refcount is 0, entry is freed and not on the tree
921 * because invalidate happened during writeback
922 * search the tree and free the entry if find entry
923 */
924 if (entry == zswap_rb_search(&tree->rbroot, offset))
925 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700926 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700927
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800928 goto end;
929
930 /*
931 * if we get here due to ZSWAP_SWAPCACHE_EXIST
932 * a load may happening concurrently
933 * it is safe and okay to not free the entry
934 * if we free the entry in the following put
935 * it it either okay to return !0
936 */
Seth Jennings2b281112013-07-10 16:05:03 -0700937fail:
938 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800939 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700940 spin_unlock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800941
942end:
Seth Jennings2b281112013-07-10 16:05:03 -0700943 return ret;
944}
945
Dan Streetmanf1c54842015-09-09 15:35:19 -0700946static int zswap_shrink(void)
947{
948 struct zswap_pool *pool;
949 int ret;
950
951 pool = zswap_pool_last_get();
952 if (!pool)
953 return -ENOENT;
954
955 ret = zpool_shrink(pool->zpool, 1, NULL);
956
957 zswap_pool_put(pool);
958
959 return ret;
960}
961
Seth Jennings2b281112013-07-10 16:05:03 -0700962/*********************************
963* frontswap hooks
964**********************************/
965/* attempts to compress and store an single page */
966static int zswap_frontswap_store(unsigned type, pgoff_t offset,
967 struct page *page)
968{
969 struct zswap_tree *tree = zswap_trees[type];
970 struct zswap_entry *entry, *dupentry;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700971 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700972 int ret;
973 unsigned int dlen = PAGE_SIZE, len;
974 unsigned long handle;
975 char *buf;
976 u8 *src, *dst;
977 struct zswap_header *zhdr;
978
Dan Streetmanc00ed162015-06-25 15:00:35 -0700979 if (!zswap_enabled || !tree) {
Seth Jennings2b281112013-07-10 16:05:03 -0700980 ret = -ENODEV;
981 goto reject;
982 }
983
984 /* reclaim space if needed */
985 if (zswap_is_full()) {
986 zswap_pool_limit_hit++;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700987 if (zswap_shrink()) {
Seth Jennings2b281112013-07-10 16:05:03 -0700988 zswap_reject_reclaim_fail++;
989 ret = -ENOMEM;
990 goto reject;
991 }
992 }
993
994 /* allocate entry */
995 entry = zswap_entry_cache_alloc(GFP_KERNEL);
996 if (!entry) {
997 zswap_reject_kmemcache_fail++;
998 ret = -ENOMEM;
999 goto reject;
1000 }
1001
Dan Streetmanf1c54842015-09-09 15:35:19 -07001002 /* if entry is successfully added, it keeps the reference */
1003 entry->pool = zswap_pool_current_get();
1004 if (!entry->pool) {
Seth Jennings2b281112013-07-10 16:05:03 -07001005 ret = -EINVAL;
1006 goto freepage;
1007 }
1008
Dan Streetmanf1c54842015-09-09 15:35:19 -07001009 /* compress */
1010 dst = get_cpu_var(zswap_dstmem);
1011 tfm = *get_cpu_ptr(entry->pool->tfm);
1012 src = kmap_atomic(page);
1013 ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
1014 kunmap_atomic(src);
1015 put_cpu_ptr(entry->pool->tfm);
1016 if (ret) {
1017 ret = -EINVAL;
1018 goto put_dstmem;
1019 }
1020
Seth Jennings2b281112013-07-10 16:05:03 -07001021 /* store */
1022 len = dlen + sizeof(struct zswap_header);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001023 ret = zpool_malloc(entry->pool->zpool, len,
Mel Gormand0164ad2015-11-06 16:28:21 -08001024 __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM,
1025 &handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001026 if (ret == -ENOSPC) {
1027 zswap_reject_compress_poor++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001028 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001029 }
1030 if (ret) {
1031 zswap_reject_alloc_fail++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001032 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001033 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001034 zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
Seth Jennings2b281112013-07-10 16:05:03 -07001035 zhdr->swpentry = swp_entry(type, offset);
1036 buf = (u8 *)(zhdr + 1);
1037 memcpy(buf, dst, dlen);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001038 zpool_unmap_handle(entry->pool->zpool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001039 put_cpu_var(zswap_dstmem);
1040
1041 /* populate entry */
1042 entry->offset = offset;
1043 entry->handle = handle;
1044 entry->length = dlen;
1045
1046 /* map */
1047 spin_lock(&tree->lock);
1048 do {
1049 ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry);
1050 if (ret == -EEXIST) {
1051 zswap_duplicate_entry++;
1052 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001053 zswap_rb_erase(&tree->rbroot, dupentry);
1054 zswap_entry_put(tree, dupentry);
Seth Jennings2b281112013-07-10 16:05:03 -07001055 }
1056 } while (ret == -EEXIST);
1057 spin_unlock(&tree->lock);
1058
1059 /* update stats */
1060 atomic_inc(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001061 zswap_update_total_size();
Seth Jennings2b281112013-07-10 16:05:03 -07001062
1063 return 0;
1064
Dan Streetmanf1c54842015-09-09 15:35:19 -07001065put_dstmem:
Seth Jennings2b281112013-07-10 16:05:03 -07001066 put_cpu_var(zswap_dstmem);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001067 zswap_pool_put(entry->pool);
1068freepage:
Seth Jennings2b281112013-07-10 16:05:03 -07001069 zswap_entry_cache_free(entry);
1070reject:
1071 return ret;
1072}
1073
1074/*
1075 * returns 0 if the page was successfully decompressed
1076 * return -1 on entry not found or error
1077*/
1078static int zswap_frontswap_load(unsigned type, pgoff_t offset,
1079 struct page *page)
1080{
1081 struct zswap_tree *tree = zswap_trees[type];
1082 struct zswap_entry *entry;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001083 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -07001084 u8 *src, *dst;
1085 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001086 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -07001087
1088 /* find */
1089 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001090 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -07001091 if (!entry) {
1092 /* entry was written back */
1093 spin_unlock(&tree->lock);
1094 return -1;
1095 }
Seth Jennings2b281112013-07-10 16:05:03 -07001096 spin_unlock(&tree->lock);
1097
1098 /* decompress */
1099 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001100 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -07001101 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -07001102 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001103 tfm = *get_cpu_ptr(entry->pool->tfm);
1104 ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
1105 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -07001106 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001107 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001108 BUG_ON(ret);
1109
1110 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001111 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001112 spin_unlock(&tree->lock);
1113
Seth Jennings2b281112013-07-10 16:05:03 -07001114 return 0;
1115}
1116
1117/* frees an entry in zswap */
1118static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset)
1119{
1120 struct zswap_tree *tree = zswap_trees[type];
1121 struct zswap_entry *entry;
Seth Jennings2b281112013-07-10 16:05:03 -07001122
1123 /* find */
1124 spin_lock(&tree->lock);
1125 entry = zswap_rb_search(&tree->rbroot, offset);
1126 if (!entry) {
1127 /* entry was written back */
1128 spin_unlock(&tree->lock);
1129 return;
1130 }
1131
1132 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001133 zswap_rb_erase(&tree->rbroot, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001134
1135 /* drop the initial reference from entry creation */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001136 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001137
1138 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -07001139}
1140
1141/* frees all zswap entries for the given swap type */
1142static void zswap_frontswap_invalidate_area(unsigned type)
1143{
1144 struct zswap_tree *tree = zswap_trees[type];
Cody P Schafer0bd42132013-09-11 14:25:33 -07001145 struct zswap_entry *entry, *n;
Seth Jennings2b281112013-07-10 16:05:03 -07001146
1147 if (!tree)
1148 return;
1149
1150 /* walk the tree and free everything */
1151 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001152 rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode)
Minchan Kim60105e12014-04-07 15:38:27 -07001153 zswap_free_entry(entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001154 tree->rbroot = RB_ROOT;
1155 spin_unlock(&tree->lock);
Weijie Yangaa9bca02013-10-16 13:46:54 -07001156 kfree(tree);
1157 zswap_trees[type] = NULL;
Seth Jennings2b281112013-07-10 16:05:03 -07001158}
1159
Seth Jennings2b281112013-07-10 16:05:03 -07001160static void zswap_frontswap_init(unsigned type)
1161{
1162 struct zswap_tree *tree;
1163
1164 tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL);
Minchan Kim60105e12014-04-07 15:38:27 -07001165 if (!tree) {
1166 pr_err("alloc failed, zswap disabled for swap type %d\n", type);
1167 return;
1168 }
1169
Seth Jennings2b281112013-07-10 16:05:03 -07001170 tree->rbroot = RB_ROOT;
1171 spin_lock_init(&tree->lock);
1172 zswap_trees[type] = tree;
Seth Jennings2b281112013-07-10 16:05:03 -07001173}
1174
1175static struct frontswap_ops zswap_frontswap_ops = {
1176 .store = zswap_frontswap_store,
1177 .load = zswap_frontswap_load,
1178 .invalidate_page = zswap_frontswap_invalidate_page,
1179 .invalidate_area = zswap_frontswap_invalidate_area,
1180 .init = zswap_frontswap_init
1181};
1182
1183/*********************************
1184* debugfs functions
1185**********************************/
1186#ifdef CONFIG_DEBUG_FS
1187#include <linux/debugfs.h>
1188
1189static struct dentry *zswap_debugfs_root;
1190
1191static int __init zswap_debugfs_init(void)
1192{
1193 if (!debugfs_initialized())
1194 return -ENODEV;
1195
1196 zswap_debugfs_root = debugfs_create_dir("zswap", NULL);
1197 if (!zswap_debugfs_root)
1198 return -ENOMEM;
1199
1200 debugfs_create_u64("pool_limit_hit", S_IRUGO,
1201 zswap_debugfs_root, &zswap_pool_limit_hit);
1202 debugfs_create_u64("reject_reclaim_fail", S_IRUGO,
1203 zswap_debugfs_root, &zswap_reject_reclaim_fail);
1204 debugfs_create_u64("reject_alloc_fail", S_IRUGO,
1205 zswap_debugfs_root, &zswap_reject_alloc_fail);
1206 debugfs_create_u64("reject_kmemcache_fail", S_IRUGO,
1207 zswap_debugfs_root, &zswap_reject_kmemcache_fail);
1208 debugfs_create_u64("reject_compress_poor", S_IRUGO,
1209 zswap_debugfs_root, &zswap_reject_compress_poor);
1210 debugfs_create_u64("written_back_pages", S_IRUGO,
1211 zswap_debugfs_root, &zswap_written_back_pages);
1212 debugfs_create_u64("duplicate_entry", S_IRUGO,
1213 zswap_debugfs_root, &zswap_duplicate_entry);
Dan Streetman12d79d62014-08-06 16:08:40 -07001214 debugfs_create_u64("pool_total_size", S_IRUGO,
1215 zswap_debugfs_root, &zswap_pool_total_size);
Seth Jennings2b281112013-07-10 16:05:03 -07001216 debugfs_create_atomic_t("stored_pages", S_IRUGO,
1217 zswap_debugfs_root, &zswap_stored_pages);
1218
1219 return 0;
1220}
1221
1222static void __exit zswap_debugfs_exit(void)
1223{
1224 debugfs_remove_recursive(zswap_debugfs_root);
1225}
1226#else
1227static int __init zswap_debugfs_init(void)
1228{
1229 return 0;
1230}
1231
1232static void __exit zswap_debugfs_exit(void) { }
1233#endif
1234
1235/*********************************
1236* module init and exit
1237**********************************/
1238static int __init init_zswap(void)
1239{
Dan Streetmanf1c54842015-09-09 15:35:19 -07001240 struct zswap_pool *pool;
Minchan Kim60105e12014-04-07 15:38:27 -07001241
Dan Streetman90b0fc22015-09-09 15:35:21 -07001242 zswap_init_started = true;
1243
Seth Jennings2b281112013-07-10 16:05:03 -07001244 if (zswap_entry_cache_create()) {
1245 pr_err("entry cache creation failed\n");
Dan Streetmanf1c54842015-09-09 15:35:19 -07001246 goto cache_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001247 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001248
1249 if (zswap_cpu_dstmem_init()) {
1250 pr_err("dstmem alloc failed\n");
1251 goto dstmem_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001252 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001253
1254 pool = __zswap_pool_create_fallback();
1255 if (!pool) {
1256 pr_err("pool creation failed\n");
1257 goto pool_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001258 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001259 pr_info("loaded using pool %s/%s\n", pool->tfm_name,
1260 zpool_get_type(pool->zpool));
1261
1262 list_add(&pool->list, &zswap_pools);
Minchan Kim60105e12014-04-07 15:38:27 -07001263
Seth Jennings2b281112013-07-10 16:05:03 -07001264 frontswap_register_ops(&zswap_frontswap_ops);
1265 if (zswap_debugfs_init())
1266 pr_warn("debugfs initialization failed\n");
1267 return 0;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001268
1269pool_fail:
1270 zswap_cpu_dstmem_destroy();
1271dstmem_fail:
Fabian Frederickc1192392014-08-08 14:19:35 -07001272 zswap_entry_cache_destroy();
Dan Streetmanf1c54842015-09-09 15:35:19 -07001273cache_fail:
Seth Jennings2b281112013-07-10 16:05:03 -07001274 return -ENOMEM;
1275}
1276/* must be late so crypto has time to come up */
1277late_initcall(init_zswap);
1278
1279MODULE_LICENSE("GPL");
Seth Jennings68386da2014-11-12 21:08:46 -06001280MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>");
Seth Jennings2b281112013-07-10 16:05:03 -07001281MODULE_DESCRIPTION("Compressed cache for swap pages");