blob: 4043df7c672fb6f5b1be298b8d510fd17a3bbf42 [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 Streetman90b0fc22015-09-09 15:35:21 -070085static char zswap_compressor[CRYPTO_MAX_ALG_NAME] = ZSWAP_COMPRESSOR_DEFAULT;
86static struct kparam_string zswap_compressor_kparam = {
87 .string = zswap_compressor,
88 .maxlen = sizeof(zswap_compressor),
89};
90static int zswap_compressor_param_set(const char *,
91 const struct kernel_param *);
92static struct kernel_param_ops zswap_compressor_param_ops = {
93 .set = zswap_compressor_param_set,
94 .get = param_get_string,
95};
96module_param_cb(compressor, &zswap_compressor_param_ops,
97 &zswap_compressor_kparam, 0644);
98
99/* Compressed storage zpool to use */
100#define ZSWAP_ZPOOL_DEFAULT "zbud"
101static char zswap_zpool_type[32 /* arbitrary */] = ZSWAP_ZPOOL_DEFAULT;
102static struct kparam_string zswap_zpool_kparam = {
103 .string = zswap_zpool_type,
104 .maxlen = sizeof(zswap_zpool_type),
105};
106static int zswap_zpool_param_set(const char *, const struct kernel_param *);
107static struct kernel_param_ops zswap_zpool_param_ops = {
108 .set = zswap_zpool_param_set,
109 .get = param_get_string,
110};
111module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_kparam, 0644);
Seth Jennings2b281112013-07-10 16:05:03 -0700112
113/* The maximum percentage of memory that the compressed pool can occupy */
114static unsigned int zswap_max_pool_percent = 20;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700115module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644);
Minchan Kim60105e12014-04-07 15:38:27 -0700116
Seth Jennings2b281112013-07-10 16:05:03 -0700117/*********************************
Seth Jennings2b281112013-07-10 16:05:03 -0700118* data structures
119**********************************/
Dan Streetmanf1c54842015-09-09 15:35:19 -0700120
121struct zswap_pool {
122 struct zpool *zpool;
123 struct crypto_comp * __percpu *tfm;
124 struct kref kref;
125 struct list_head list;
126 struct rcu_head rcu_head;
127 struct notifier_block notifier;
128 char tfm_name[CRYPTO_MAX_ALG_NAME];
129};
130
Seth Jennings2b281112013-07-10 16:05:03 -0700131/*
132 * struct zswap_entry
133 *
134 * This structure contains the metadata for tracking a single compressed
135 * page within zswap.
136 *
137 * rbnode - links the entry into red-black tree for the appropriate swap type
Dan Streetmanf1c54842015-09-09 15:35:19 -0700138 * offset - the swap offset for the entry. Index into the red-black tree.
Seth Jennings2b281112013-07-10 16:05:03 -0700139 * refcount - the number of outstanding reference to the entry. This is needed
140 * to protect against premature freeing of the entry by code
SeongJae Park6b452512014-04-07 15:38:25 -0700141 * concurrent calls to load, invalidate, and writeback. The lock
Seth Jennings2b281112013-07-10 16:05:03 -0700142 * for the zswap_tree structure that contains the entry must
143 * be held while changing the refcount. Since the lock must
144 * be held, there is no reason to also make refcount atomic.
Seth Jennings2b281112013-07-10 16:05:03 -0700145 * length - the length in bytes of the compressed page data. Needed during
SeongJae Park6b452512014-04-07 15:38:25 -0700146 * decompression
Dan Streetmanf1c54842015-09-09 15:35:19 -0700147 * pool - the zswap_pool the entry's data is in
148 * handle - zpool allocation handle that stores the compressed page data
Seth Jennings2b281112013-07-10 16:05:03 -0700149 */
150struct zswap_entry {
151 struct rb_node rbnode;
152 pgoff_t offset;
153 int refcount;
154 unsigned int length;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700155 struct zswap_pool *pool;
Seth Jennings2b281112013-07-10 16:05:03 -0700156 unsigned long handle;
157};
158
159struct zswap_header {
160 swp_entry_t swpentry;
161};
162
163/*
164 * The tree lock in the zswap_tree struct protects a few things:
165 * - the rbtree
166 * - the refcount field of each entry in the tree
167 */
168struct zswap_tree {
169 struct rb_root rbroot;
170 spinlock_t lock;
Seth Jennings2b281112013-07-10 16:05:03 -0700171};
172
173static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
174
Dan Streetmanf1c54842015-09-09 15:35:19 -0700175/* RCU-protected iteration */
176static LIST_HEAD(zswap_pools);
177/* protects zswap_pools list modification */
178static DEFINE_SPINLOCK(zswap_pools_lock);
179
Dan Streetman90b0fc22015-09-09 15:35:21 -0700180/* used by param callback function */
181static bool zswap_init_started;
182
Dan Streetmanf1c54842015-09-09 15:35:19 -0700183/*********************************
184* helpers and fwd declarations
185**********************************/
186
187#define zswap_pool_debug(msg, p) \
188 pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
189 zpool_get_type((p)->zpool))
190
191static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
192static int zswap_pool_get(struct zswap_pool *pool);
193static void zswap_pool_put(struct zswap_pool *pool);
194
195static const struct zpool_ops zswap_zpool_ops = {
196 .evict = zswap_writeback_entry
197};
198
199static bool zswap_is_full(void)
200{
201 return totalram_pages * zswap_max_pool_percent / 100 <
202 DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
203}
204
205static void zswap_update_total_size(void)
206{
207 struct zswap_pool *pool;
208 u64 total = 0;
209
210 rcu_read_lock();
211
212 list_for_each_entry_rcu(pool, &zswap_pools, list)
213 total += zpool_get_total_size(pool->zpool);
214
215 rcu_read_unlock();
216
217 zswap_pool_total_size = total;
218}
219
Seth Jennings2b281112013-07-10 16:05:03 -0700220/*********************************
221* zswap entry functions
222**********************************/
223static struct kmem_cache *zswap_entry_cache;
224
Mahendran Ganeshdd01d7d2014-12-12 16:57:15 -0800225static int __init zswap_entry_cache_create(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700226{
227 zswap_entry_cache = KMEM_CACHE(zswap_entry, 0);
SeongJae Park5d2d42d2014-04-07 15:38:28 -0700228 return zswap_entry_cache == NULL;
Seth Jennings2b281112013-07-10 16:05:03 -0700229}
230
Fabian Frederickc1192392014-08-08 14:19:35 -0700231static void __init zswap_entry_cache_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700232{
233 kmem_cache_destroy(zswap_entry_cache);
234}
235
236static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp)
237{
238 struct zswap_entry *entry;
239 entry = kmem_cache_alloc(zswap_entry_cache, gfp);
240 if (!entry)
241 return NULL;
242 entry->refcount = 1;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800243 RB_CLEAR_NODE(&entry->rbnode);
Seth Jennings2b281112013-07-10 16:05:03 -0700244 return entry;
245}
246
247static void zswap_entry_cache_free(struct zswap_entry *entry)
248{
249 kmem_cache_free(zswap_entry_cache, entry);
250}
251
Seth Jennings2b281112013-07-10 16:05:03 -0700252/*********************************
253* rbtree functions
254**********************************/
255static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset)
256{
257 struct rb_node *node = root->rb_node;
258 struct zswap_entry *entry;
259
260 while (node) {
261 entry = rb_entry(node, struct zswap_entry, rbnode);
262 if (entry->offset > offset)
263 node = node->rb_left;
264 else if (entry->offset < offset)
265 node = node->rb_right;
266 else
267 return entry;
268 }
269 return NULL;
270}
271
272/*
273 * In the case that a entry with the same offset is found, a pointer to
274 * the existing entry is stored in dupentry and the function returns -EEXIST
275 */
276static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry,
277 struct zswap_entry **dupentry)
278{
279 struct rb_node **link = &root->rb_node, *parent = NULL;
280 struct zswap_entry *myentry;
281
282 while (*link) {
283 parent = *link;
284 myentry = rb_entry(parent, struct zswap_entry, rbnode);
285 if (myentry->offset > entry->offset)
286 link = &(*link)->rb_left;
287 else if (myentry->offset < entry->offset)
288 link = &(*link)->rb_right;
289 else {
290 *dupentry = myentry;
291 return -EEXIST;
292 }
293 }
294 rb_link_node(&entry->rbnode, parent, link);
295 rb_insert_color(&entry->rbnode, root);
296 return 0;
297}
298
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800299static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
300{
301 if (!RB_EMPTY_NODE(&entry->rbnode)) {
302 rb_erase(&entry->rbnode, root);
303 RB_CLEAR_NODE(&entry->rbnode);
304 }
305}
306
307/*
Dan Streetman12d79d62014-08-06 16:08:40 -0700308 * Carries out the common pattern of freeing and entry's zpool allocation,
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800309 * freeing the entry itself, and decrementing the number of stored pages.
310 */
Minchan Kim60105e12014-04-07 15:38:27 -0700311static void zswap_free_entry(struct zswap_entry *entry)
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800312{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700313 zpool_free(entry->pool->zpool, entry->handle);
314 zswap_pool_put(entry->pool);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800315 zswap_entry_cache_free(entry);
316 atomic_dec(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700317 zswap_update_total_size();
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800318}
319
320/* caller must hold the tree lock */
321static void zswap_entry_get(struct zswap_entry *entry)
322{
323 entry->refcount++;
324}
325
326/* caller must hold the tree lock
327* remove from the tree and free it, if nobody reference the entry
328*/
329static void zswap_entry_put(struct zswap_tree *tree,
330 struct zswap_entry *entry)
331{
332 int refcount = --entry->refcount;
333
334 BUG_ON(refcount < 0);
335 if (refcount == 0) {
336 zswap_rb_erase(&tree->rbroot, entry);
Minchan Kim60105e12014-04-07 15:38:27 -0700337 zswap_free_entry(entry);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800338 }
339}
340
341/* caller must hold the tree lock */
342static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
343 pgoff_t offset)
344{
345 struct zswap_entry *entry = NULL;
346
347 entry = zswap_rb_search(root, offset);
348 if (entry)
349 zswap_entry_get(entry);
350
351 return entry;
352}
353
Seth Jennings2b281112013-07-10 16:05:03 -0700354/*********************************
355* per-cpu code
356**********************************/
357static DEFINE_PER_CPU(u8 *, zswap_dstmem);
358
Dan Streetmanf1c54842015-09-09 15:35:19 -0700359static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700360{
Seth Jennings2b281112013-07-10 16:05:03 -0700361 u8 *dst;
362
363 switch (action) {
364 case CPU_UP_PREPARE:
Eric Dumazet72d09632014-06-04 16:11:11 -0700365 dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
Seth Jennings2b281112013-07-10 16:05:03 -0700366 if (!dst) {
367 pr_err("can't allocate compressor buffer\n");
Seth Jennings2b281112013-07-10 16:05:03 -0700368 return NOTIFY_BAD;
369 }
370 per_cpu(zswap_dstmem, cpu) = dst;
371 break;
372 case CPU_DEAD:
373 case CPU_UP_CANCELED:
Seth Jennings2b281112013-07-10 16:05:03 -0700374 dst = per_cpu(zswap_dstmem, cpu);
375 kfree(dst);
376 per_cpu(zswap_dstmem, cpu) = NULL;
377 break;
378 default:
379 break;
380 }
381 return NOTIFY_OK;
382}
383
Dan Streetmanf1c54842015-09-09 15:35:19 -0700384static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
385 unsigned long action, void *pcpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700386{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700387 return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
Seth Jennings2b281112013-07-10 16:05:03 -0700388}
389
Dan Streetmanf1c54842015-09-09 15:35:19 -0700390static struct notifier_block zswap_dstmem_notifier = {
391 .notifier_call = zswap_cpu_dstmem_notifier,
Seth Jennings2b281112013-07-10 16:05:03 -0700392};
393
Dan Streetmanf1c54842015-09-09 15:35:19 -0700394static int __init zswap_cpu_dstmem_init(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700395{
396 unsigned long cpu;
397
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530398 cpu_notifier_register_begin();
Seth Jennings2b281112013-07-10 16:05:03 -0700399 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700400 if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
401 NOTIFY_BAD)
Seth Jennings2b281112013-07-10 16:05:03 -0700402 goto cleanup;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700403 __register_cpu_notifier(&zswap_dstmem_notifier);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530404 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700405 return 0;
406
407cleanup:
408 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700409 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530410 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700411 return -ENOMEM;
412}
413
Dan Streetmanf1c54842015-09-09 15:35:19 -0700414static void zswap_cpu_dstmem_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700415{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700416 unsigned long cpu;
417
418 cpu_notifier_register_begin();
419 for_each_online_cpu(cpu)
420 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
421 __unregister_cpu_notifier(&zswap_dstmem_notifier);
422 cpu_notifier_register_done();
423}
424
425static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
426 unsigned long action, unsigned long cpu)
427{
428 struct crypto_comp *tfm;
429
430 switch (action) {
431 case CPU_UP_PREPARE:
432 if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
433 break;
434 tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
435 if (IS_ERR_OR_NULL(tfm)) {
436 pr_err("could not alloc crypto comp %s : %ld\n",
437 pool->tfm_name, PTR_ERR(tfm));
438 return NOTIFY_BAD;
439 }
440 *per_cpu_ptr(pool->tfm, cpu) = tfm;
441 break;
442 case CPU_DEAD:
443 case CPU_UP_CANCELED:
444 tfm = *per_cpu_ptr(pool->tfm, cpu);
445 if (!IS_ERR_OR_NULL(tfm))
446 crypto_free_comp(tfm);
447 *per_cpu_ptr(pool->tfm, cpu) = NULL;
448 break;
449 default:
450 break;
451 }
452 return NOTIFY_OK;
453}
454
455static int zswap_cpu_comp_notifier(struct notifier_block *nb,
456 unsigned long action, void *pcpu)
457{
458 unsigned long cpu = (unsigned long)pcpu;
459 struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
460
461 return __zswap_cpu_comp_notifier(pool, action, cpu);
462}
463
464static int zswap_cpu_comp_init(struct zswap_pool *pool)
465{
466 unsigned long cpu;
467
468 memset(&pool->notifier, 0, sizeof(pool->notifier));
469 pool->notifier.notifier_call = zswap_cpu_comp_notifier;
470
471 cpu_notifier_register_begin();
472 for_each_online_cpu(cpu)
473 if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
474 NOTIFY_BAD)
475 goto cleanup;
476 __register_cpu_notifier(&pool->notifier);
477 cpu_notifier_register_done();
478 return 0;
479
480cleanup:
481 for_each_online_cpu(cpu)
482 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
483 cpu_notifier_register_done();
484 return -ENOMEM;
485}
486
487static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
488{
489 unsigned long cpu;
490
491 cpu_notifier_register_begin();
492 for_each_online_cpu(cpu)
493 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
494 __unregister_cpu_notifier(&pool->notifier);
495 cpu_notifier_register_done();
496}
497
498/*********************************
499* pool functions
500**********************************/
501
502static struct zswap_pool *__zswap_pool_current(void)
503{
504 struct zswap_pool *pool;
505
506 pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
507 WARN_ON(!pool);
508
509 return pool;
510}
511
512static struct zswap_pool *zswap_pool_current(void)
513{
514 assert_spin_locked(&zswap_pools_lock);
515
516 return __zswap_pool_current();
517}
518
519static struct zswap_pool *zswap_pool_current_get(void)
520{
521 struct zswap_pool *pool;
522
523 rcu_read_lock();
524
525 pool = __zswap_pool_current();
526 if (!pool || !zswap_pool_get(pool))
527 pool = NULL;
528
529 rcu_read_unlock();
530
531 return pool;
532}
533
534static struct zswap_pool *zswap_pool_last_get(void)
535{
536 struct zswap_pool *pool, *last = NULL;
537
538 rcu_read_lock();
539
540 list_for_each_entry_rcu(pool, &zswap_pools, list)
541 last = pool;
542 if (!WARN_ON(!last) && !zswap_pool_get(last))
543 last = NULL;
544
545 rcu_read_unlock();
546
547 return last;
548}
549
550static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
551{
552 struct zswap_pool *pool;
553
554 assert_spin_locked(&zswap_pools_lock);
555
556 list_for_each_entry_rcu(pool, &zswap_pools, list) {
557 if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
558 continue;
559 if (strncmp(zpool_get_type(pool->zpool), type,
560 sizeof(zswap_zpool_type)))
561 continue;
562 /* if we can't get it, it's about to be destroyed */
563 if (!zswap_pool_get(pool))
564 continue;
565 return pool;
566 }
567
568 return NULL;
569}
570
571static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
572{
573 struct zswap_pool *pool;
574 gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
575
576 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
577 if (!pool) {
578 pr_err("pool alloc failed\n");
579 return NULL;
580 }
581
582 pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
583 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
618static struct zswap_pool *__zswap_pool_create_fallback(void)
619{
620 if (!crypto_has_comp(zswap_compressor, 0, 0)) {
621 pr_err("compressor %s not available, using default %s\n",
622 zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
623 strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
624 sizeof(zswap_compressor));
625 }
626 if (!zpool_has_pool(zswap_zpool_type)) {
627 pr_err("zpool %s not available, using default %s\n",
628 zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
629 strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
630 sizeof(zswap_zpool_type));
631 }
632
633 return zswap_pool_create(zswap_zpool_type, zswap_compressor);
634}
635
636static void zswap_pool_destroy(struct zswap_pool *pool)
637{
638 zswap_pool_debug("destroying", pool);
639
640 zswap_cpu_comp_destroy(pool);
641 free_percpu(pool->tfm);
642 zpool_destroy_pool(pool->zpool);
643 kfree(pool);
644}
645
646static int __must_check zswap_pool_get(struct zswap_pool *pool)
647{
648 return kref_get_unless_zero(&pool->kref);
649}
650
651static void __zswap_pool_release(struct rcu_head *head)
652{
653 struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
654
655 /* nobody should have been able to get a kref... */
656 WARN_ON(kref_get_unless_zero(&pool->kref));
657
658 /* pool is now off zswap_pools list and has no references. */
659 zswap_pool_destroy(pool);
660}
661
662static void __zswap_pool_empty(struct kref *kref)
663{
664 struct zswap_pool *pool;
665
666 pool = container_of(kref, typeof(*pool), kref);
667
668 spin_lock(&zswap_pools_lock);
669
670 WARN_ON(pool == zswap_pool_current());
671
672 list_del_rcu(&pool->list);
673 call_rcu(&pool->rcu_head, __zswap_pool_release);
674
675 spin_unlock(&zswap_pools_lock);
676}
677
678static void zswap_pool_put(struct zswap_pool *pool)
679{
680 kref_put(&pool->kref, __zswap_pool_empty);
Seth Jennings2b281112013-07-10 16:05:03 -0700681}
682
Seth Jennings2b281112013-07-10 16:05:03 -0700683/*********************************
Dan Streetman90b0fc22015-09-09 15:35:21 -0700684* param callbacks
685**********************************/
686
687static int __zswap_param_set(const char *val, const struct kernel_param *kp,
688 char *type, char *compressor)
689{
690 struct zswap_pool *pool, *put_pool = NULL;
691 char str[kp->str->maxlen], *s;
692 int ret;
693
694 /*
695 * kp is either zswap_zpool_kparam or zswap_compressor_kparam, defined
696 * at the top of this file, so maxlen is CRYPTO_MAX_ALG_NAME (64) or
697 * 32 (arbitrary).
698 */
699 strlcpy(str, val, kp->str->maxlen);
700 s = strim(str);
701
702 /* if this is load-time (pre-init) param setting,
703 * don't create a pool; that's done during init.
704 */
705 if (!zswap_init_started)
706 return param_set_copystring(s, kp);
707
708 /* no change required */
709 if (!strncmp(kp->str->string, s, kp->str->maxlen))
710 return 0;
711
712 if (!type) {
713 type = s;
714 if (!zpool_has_pool(type)) {
715 pr_err("zpool %s not available\n", type);
716 return -ENOENT;
717 }
718 } else if (!compressor) {
719 compressor = s;
720 if (!crypto_has_comp(compressor, 0, 0)) {
721 pr_err("compressor %s not available\n", compressor);
722 return -ENOENT;
723 }
724 }
725
726 spin_lock(&zswap_pools_lock);
727
728 pool = zswap_pool_find_get(type, compressor);
729 if (pool) {
730 zswap_pool_debug("using existing", pool);
731 list_del_rcu(&pool->list);
732 } else {
733 spin_unlock(&zswap_pools_lock);
734 pool = zswap_pool_create(type, compressor);
735 spin_lock(&zswap_pools_lock);
736 }
737
738 if (pool)
739 ret = param_set_copystring(s, kp);
740 else
741 ret = -EINVAL;
742
743 if (!ret) {
744 put_pool = zswap_pool_current();
745 list_add_rcu(&pool->list, &zswap_pools);
746 } else if (pool) {
747 /* add the possibly pre-existing pool to the end of the pools
748 * list; if it's new (and empty) then it'll be removed and
749 * destroyed by the put after we drop the lock
750 */
751 list_add_tail_rcu(&pool->list, &zswap_pools);
752 put_pool = pool;
753 }
754
755 spin_unlock(&zswap_pools_lock);
756
757 /* drop the ref from either the old current pool,
758 * or the new pool we failed to add
759 */
760 if (put_pool)
761 zswap_pool_put(put_pool);
762
763 return ret;
764}
765
766static int zswap_compressor_param_set(const char *val,
767 const struct kernel_param *kp)
768{
769 return __zswap_param_set(val, kp, zswap_zpool_type, NULL);
770}
771
772static int zswap_zpool_param_set(const char *val,
773 const struct kernel_param *kp)
774{
775 return __zswap_param_set(val, kp, NULL, zswap_compressor);
776}
777
778/*********************************
Seth Jennings2b281112013-07-10 16:05:03 -0700779* writeback code
780**********************************/
781/* return enum for zswap_get_swap_cache_page */
782enum zswap_get_swap_ret {
783 ZSWAP_SWAPCACHE_NEW,
784 ZSWAP_SWAPCACHE_EXIST,
Weijie Yang67d13fe2013-11-12 15:08:26 -0800785 ZSWAP_SWAPCACHE_FAIL,
Seth Jennings2b281112013-07-10 16:05:03 -0700786};
787
788/*
789 * zswap_get_swap_cache_page
790 *
791 * This is an adaption of read_swap_cache_async()
792 *
793 * This function tries to find a page with the given swap entry
794 * in the swapper_space address space (the swap cache). If the page
795 * is found, it is returned in retpage. Otherwise, a page is allocated,
796 * added to the swap cache, and returned in retpage.
797 *
798 * If success, the swap cache page is returned in retpage
Weijie Yang67d13fe2013-11-12 15:08:26 -0800799 * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache
800 * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated,
801 * the new page is added to swapcache and locked
802 * Returns ZSWAP_SWAPCACHE_FAIL on error
Seth Jennings2b281112013-07-10 16:05:03 -0700803 */
804static int zswap_get_swap_cache_page(swp_entry_t entry,
805 struct page **retpage)
806{
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700807 bool page_was_allocated;
Seth Jennings2b281112013-07-10 16:05:03 -0700808
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700809 *retpage = __read_swap_cache_async(entry, GFP_KERNEL,
810 NULL, 0, &page_was_allocated);
811 if (page_was_allocated)
812 return ZSWAP_SWAPCACHE_NEW;
813 if (!*retpage)
Weijie Yang67d13fe2013-11-12 15:08:26 -0800814 return ZSWAP_SWAPCACHE_FAIL;
Seth Jennings2b281112013-07-10 16:05:03 -0700815 return ZSWAP_SWAPCACHE_EXIST;
816}
817
818/*
819 * Attempts to free an entry by adding a page to the swap cache,
820 * decompressing the entry data into the page, and issuing a
821 * bio write to write the page back to the swap device.
822 *
823 * This can be thought of as a "resumed writeback" of the page
824 * to the swap device. We are basically resuming the same swap
825 * writeback path that was intercepted with the frontswap_store()
826 * in the first place. After the page has been decompressed into
827 * the swap cache, the compressed version stored by zswap can be
828 * freed.
829 */
Dan Streetman12d79d62014-08-06 16:08:40 -0700830static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
Seth Jennings2b281112013-07-10 16:05:03 -0700831{
832 struct zswap_header *zhdr;
833 swp_entry_t swpentry;
834 struct zswap_tree *tree;
835 pgoff_t offset;
836 struct zswap_entry *entry;
837 struct page *page;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700838 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700839 u8 *src, *dst;
840 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800841 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -0700842 struct writeback_control wbc = {
843 .sync_mode = WB_SYNC_NONE,
844 };
845
846 /* extract swpentry from data */
Dan Streetman12d79d62014-08-06 16:08:40 -0700847 zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
Seth Jennings2b281112013-07-10 16:05:03 -0700848 swpentry = zhdr->swpentry; /* here */
Dan Streetman12d79d62014-08-06 16:08:40 -0700849 zpool_unmap_handle(pool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700850 tree = zswap_trees[swp_type(swpentry)];
851 offset = swp_offset(swpentry);
Seth Jennings2b281112013-07-10 16:05:03 -0700852
853 /* find and ref zswap entry */
854 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800855 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -0700856 if (!entry) {
857 /* entry was invalidated */
858 spin_unlock(&tree->lock);
859 return 0;
860 }
Seth Jennings2b281112013-07-10 16:05:03 -0700861 spin_unlock(&tree->lock);
862 BUG_ON(offset != entry->offset);
863
864 /* try to allocate swap cache page */
865 switch (zswap_get_swap_cache_page(swpentry, &page)) {
Weijie Yang67d13fe2013-11-12 15:08:26 -0800866 case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */
Seth Jennings2b281112013-07-10 16:05:03 -0700867 ret = -ENOMEM;
868 goto fail;
869
Weijie Yang67d13fe2013-11-12 15:08:26 -0800870 case ZSWAP_SWAPCACHE_EXIST:
Seth Jennings2b281112013-07-10 16:05:03 -0700871 /* page is already in the swap cache, ignore for now */
872 page_cache_release(page);
873 ret = -EEXIST;
874 goto fail;
875
876 case ZSWAP_SWAPCACHE_NEW: /* page is locked */
877 /* decompress */
878 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700879 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -0700880 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -0700881 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700882 tfm = *get_cpu_ptr(entry->pool->tfm);
883 ret = crypto_comp_decompress(tfm, src, entry->length,
884 dst, &dlen);
885 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -0700886 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700887 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700888 BUG_ON(ret);
889 BUG_ON(dlen != PAGE_SIZE);
890
891 /* page is up to date */
892 SetPageUptodate(page);
893 }
894
Weijie Yangb349acc2013-11-12 15:07:52 -0800895 /* move it to the tail of the inactive list after end_writeback */
896 SetPageReclaim(page);
897
Seth Jennings2b281112013-07-10 16:05:03 -0700898 /* start writeback */
899 __swap_writepage(page, &wbc, end_swap_bio_write);
900 page_cache_release(page);
901 zswap_written_back_pages++;
902
903 spin_lock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700904 /* drop local reference */
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800905 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700906
907 /*
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800908 * There are two possible situations for entry here:
909 * (1) refcount is 1(normal case), entry is valid and on the tree
910 * (2) refcount is 0, entry is freed and not on the tree
911 * because invalidate happened during writeback
912 * search the tree and free the entry if find entry
913 */
914 if (entry == zswap_rb_search(&tree->rbroot, offset))
915 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700916 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700917
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800918 goto end;
919
920 /*
921 * if we get here due to ZSWAP_SWAPCACHE_EXIST
922 * a load may happening concurrently
923 * it is safe and okay to not free the entry
924 * if we free the entry in the following put
925 * it it either okay to return !0
926 */
Seth Jennings2b281112013-07-10 16:05:03 -0700927fail:
928 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800929 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700930 spin_unlock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800931
932end:
Seth Jennings2b281112013-07-10 16:05:03 -0700933 return ret;
934}
935
Dan Streetmanf1c54842015-09-09 15:35:19 -0700936static int zswap_shrink(void)
937{
938 struct zswap_pool *pool;
939 int ret;
940
941 pool = zswap_pool_last_get();
942 if (!pool)
943 return -ENOENT;
944
945 ret = zpool_shrink(pool->zpool, 1, NULL);
946
947 zswap_pool_put(pool);
948
949 return ret;
950}
951
Seth Jennings2b281112013-07-10 16:05:03 -0700952/*********************************
953* frontswap hooks
954**********************************/
955/* attempts to compress and store an single page */
956static int zswap_frontswap_store(unsigned type, pgoff_t offset,
957 struct page *page)
958{
959 struct zswap_tree *tree = zswap_trees[type];
960 struct zswap_entry *entry, *dupentry;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700961 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700962 int ret;
963 unsigned int dlen = PAGE_SIZE, len;
964 unsigned long handle;
965 char *buf;
966 u8 *src, *dst;
967 struct zswap_header *zhdr;
968
Dan Streetmanc00ed162015-06-25 15:00:35 -0700969 if (!zswap_enabled || !tree) {
Seth Jennings2b281112013-07-10 16:05:03 -0700970 ret = -ENODEV;
971 goto reject;
972 }
973
974 /* reclaim space if needed */
975 if (zswap_is_full()) {
976 zswap_pool_limit_hit++;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700977 if (zswap_shrink()) {
Seth Jennings2b281112013-07-10 16:05:03 -0700978 zswap_reject_reclaim_fail++;
979 ret = -ENOMEM;
980 goto reject;
981 }
982 }
983
984 /* allocate entry */
985 entry = zswap_entry_cache_alloc(GFP_KERNEL);
986 if (!entry) {
987 zswap_reject_kmemcache_fail++;
988 ret = -ENOMEM;
989 goto reject;
990 }
991
Dan Streetmanf1c54842015-09-09 15:35:19 -0700992 /* if entry is successfully added, it keeps the reference */
993 entry->pool = zswap_pool_current_get();
994 if (!entry->pool) {
Seth Jennings2b281112013-07-10 16:05:03 -0700995 ret = -EINVAL;
996 goto freepage;
997 }
998
Dan Streetmanf1c54842015-09-09 15:35:19 -0700999 /* compress */
1000 dst = get_cpu_var(zswap_dstmem);
1001 tfm = *get_cpu_ptr(entry->pool->tfm);
1002 src = kmap_atomic(page);
1003 ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
1004 kunmap_atomic(src);
1005 put_cpu_ptr(entry->pool->tfm);
1006 if (ret) {
1007 ret = -EINVAL;
1008 goto put_dstmem;
1009 }
1010
Seth Jennings2b281112013-07-10 16:05:03 -07001011 /* store */
1012 len = dlen + sizeof(struct zswap_header);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001013 ret = zpool_malloc(entry->pool->zpool, len,
1014 __GFP_NORETRY | __GFP_NOWARN, &handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001015 if (ret == -ENOSPC) {
1016 zswap_reject_compress_poor++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001017 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001018 }
1019 if (ret) {
1020 zswap_reject_alloc_fail++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001021 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001022 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001023 zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
Seth Jennings2b281112013-07-10 16:05:03 -07001024 zhdr->swpentry = swp_entry(type, offset);
1025 buf = (u8 *)(zhdr + 1);
1026 memcpy(buf, dst, dlen);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001027 zpool_unmap_handle(entry->pool->zpool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001028 put_cpu_var(zswap_dstmem);
1029
1030 /* populate entry */
1031 entry->offset = offset;
1032 entry->handle = handle;
1033 entry->length = dlen;
1034
1035 /* map */
1036 spin_lock(&tree->lock);
1037 do {
1038 ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry);
1039 if (ret == -EEXIST) {
1040 zswap_duplicate_entry++;
1041 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001042 zswap_rb_erase(&tree->rbroot, dupentry);
1043 zswap_entry_put(tree, dupentry);
Seth Jennings2b281112013-07-10 16:05:03 -07001044 }
1045 } while (ret == -EEXIST);
1046 spin_unlock(&tree->lock);
1047
1048 /* update stats */
1049 atomic_inc(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001050 zswap_update_total_size();
Seth Jennings2b281112013-07-10 16:05:03 -07001051
1052 return 0;
1053
Dan Streetmanf1c54842015-09-09 15:35:19 -07001054put_dstmem:
Seth Jennings2b281112013-07-10 16:05:03 -07001055 put_cpu_var(zswap_dstmem);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001056 zswap_pool_put(entry->pool);
1057freepage:
Seth Jennings2b281112013-07-10 16:05:03 -07001058 zswap_entry_cache_free(entry);
1059reject:
1060 return ret;
1061}
1062
1063/*
1064 * returns 0 if the page was successfully decompressed
1065 * return -1 on entry not found or error
1066*/
1067static int zswap_frontswap_load(unsigned type, pgoff_t offset,
1068 struct page *page)
1069{
1070 struct zswap_tree *tree = zswap_trees[type];
1071 struct zswap_entry *entry;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001072 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -07001073 u8 *src, *dst;
1074 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001075 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -07001076
1077 /* find */
1078 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001079 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -07001080 if (!entry) {
1081 /* entry was written back */
1082 spin_unlock(&tree->lock);
1083 return -1;
1084 }
Seth Jennings2b281112013-07-10 16:05:03 -07001085 spin_unlock(&tree->lock);
1086
1087 /* decompress */
1088 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001089 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -07001090 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -07001091 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001092 tfm = *get_cpu_ptr(entry->pool->tfm);
1093 ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
1094 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -07001095 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001096 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001097 BUG_ON(ret);
1098
1099 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001100 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001101 spin_unlock(&tree->lock);
1102
Seth Jennings2b281112013-07-10 16:05:03 -07001103 return 0;
1104}
1105
1106/* frees an entry in zswap */
1107static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset)
1108{
1109 struct zswap_tree *tree = zswap_trees[type];
1110 struct zswap_entry *entry;
Seth Jennings2b281112013-07-10 16:05:03 -07001111
1112 /* find */
1113 spin_lock(&tree->lock);
1114 entry = zswap_rb_search(&tree->rbroot, offset);
1115 if (!entry) {
1116 /* entry was written back */
1117 spin_unlock(&tree->lock);
1118 return;
1119 }
1120
1121 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001122 zswap_rb_erase(&tree->rbroot, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001123
1124 /* drop the initial reference from entry creation */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001125 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001126
1127 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -07001128}
1129
1130/* frees all zswap entries for the given swap type */
1131static void zswap_frontswap_invalidate_area(unsigned type)
1132{
1133 struct zswap_tree *tree = zswap_trees[type];
Cody P Schafer0bd42132013-09-11 14:25:33 -07001134 struct zswap_entry *entry, *n;
Seth Jennings2b281112013-07-10 16:05:03 -07001135
1136 if (!tree)
1137 return;
1138
1139 /* walk the tree and free everything */
1140 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001141 rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode)
Minchan Kim60105e12014-04-07 15:38:27 -07001142 zswap_free_entry(entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001143 tree->rbroot = RB_ROOT;
1144 spin_unlock(&tree->lock);
Weijie Yangaa9bca02013-10-16 13:46:54 -07001145 kfree(tree);
1146 zswap_trees[type] = NULL;
Seth Jennings2b281112013-07-10 16:05:03 -07001147}
1148
Seth Jennings2b281112013-07-10 16:05:03 -07001149static void zswap_frontswap_init(unsigned type)
1150{
1151 struct zswap_tree *tree;
1152
1153 tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL);
Minchan Kim60105e12014-04-07 15:38:27 -07001154 if (!tree) {
1155 pr_err("alloc failed, zswap disabled for swap type %d\n", type);
1156 return;
1157 }
1158
Seth Jennings2b281112013-07-10 16:05:03 -07001159 tree->rbroot = RB_ROOT;
1160 spin_lock_init(&tree->lock);
1161 zswap_trees[type] = tree;
Seth Jennings2b281112013-07-10 16:05:03 -07001162}
1163
1164static struct frontswap_ops zswap_frontswap_ops = {
1165 .store = zswap_frontswap_store,
1166 .load = zswap_frontswap_load,
1167 .invalidate_page = zswap_frontswap_invalidate_page,
1168 .invalidate_area = zswap_frontswap_invalidate_area,
1169 .init = zswap_frontswap_init
1170};
1171
1172/*********************************
1173* debugfs functions
1174**********************************/
1175#ifdef CONFIG_DEBUG_FS
1176#include <linux/debugfs.h>
1177
1178static struct dentry *zswap_debugfs_root;
1179
1180static int __init zswap_debugfs_init(void)
1181{
1182 if (!debugfs_initialized())
1183 return -ENODEV;
1184
1185 zswap_debugfs_root = debugfs_create_dir("zswap", NULL);
1186 if (!zswap_debugfs_root)
1187 return -ENOMEM;
1188
1189 debugfs_create_u64("pool_limit_hit", S_IRUGO,
1190 zswap_debugfs_root, &zswap_pool_limit_hit);
1191 debugfs_create_u64("reject_reclaim_fail", S_IRUGO,
1192 zswap_debugfs_root, &zswap_reject_reclaim_fail);
1193 debugfs_create_u64("reject_alloc_fail", S_IRUGO,
1194 zswap_debugfs_root, &zswap_reject_alloc_fail);
1195 debugfs_create_u64("reject_kmemcache_fail", S_IRUGO,
1196 zswap_debugfs_root, &zswap_reject_kmemcache_fail);
1197 debugfs_create_u64("reject_compress_poor", S_IRUGO,
1198 zswap_debugfs_root, &zswap_reject_compress_poor);
1199 debugfs_create_u64("written_back_pages", S_IRUGO,
1200 zswap_debugfs_root, &zswap_written_back_pages);
1201 debugfs_create_u64("duplicate_entry", S_IRUGO,
1202 zswap_debugfs_root, &zswap_duplicate_entry);
Dan Streetman12d79d62014-08-06 16:08:40 -07001203 debugfs_create_u64("pool_total_size", S_IRUGO,
1204 zswap_debugfs_root, &zswap_pool_total_size);
Seth Jennings2b281112013-07-10 16:05:03 -07001205 debugfs_create_atomic_t("stored_pages", S_IRUGO,
1206 zswap_debugfs_root, &zswap_stored_pages);
1207
1208 return 0;
1209}
1210
1211static void __exit zswap_debugfs_exit(void)
1212{
1213 debugfs_remove_recursive(zswap_debugfs_root);
1214}
1215#else
1216static int __init zswap_debugfs_init(void)
1217{
1218 return 0;
1219}
1220
1221static void __exit zswap_debugfs_exit(void) { }
1222#endif
1223
1224/*********************************
1225* module init and exit
1226**********************************/
1227static int __init init_zswap(void)
1228{
Dan Streetmanf1c54842015-09-09 15:35:19 -07001229 struct zswap_pool *pool;
Minchan Kim60105e12014-04-07 15:38:27 -07001230
Dan Streetman90b0fc22015-09-09 15:35:21 -07001231 zswap_init_started = true;
1232
Seth Jennings2b281112013-07-10 16:05:03 -07001233 if (zswap_entry_cache_create()) {
1234 pr_err("entry cache creation failed\n");
Dan Streetmanf1c54842015-09-09 15:35:19 -07001235 goto cache_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001236 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001237
1238 if (zswap_cpu_dstmem_init()) {
1239 pr_err("dstmem alloc failed\n");
1240 goto dstmem_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001241 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001242
1243 pool = __zswap_pool_create_fallback();
1244 if (!pool) {
1245 pr_err("pool creation failed\n");
1246 goto pool_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001247 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001248 pr_info("loaded using pool %s/%s\n", pool->tfm_name,
1249 zpool_get_type(pool->zpool));
1250
1251 list_add(&pool->list, &zswap_pools);
Minchan Kim60105e12014-04-07 15:38:27 -07001252
Seth Jennings2b281112013-07-10 16:05:03 -07001253 frontswap_register_ops(&zswap_frontswap_ops);
1254 if (zswap_debugfs_init())
1255 pr_warn("debugfs initialization failed\n");
1256 return 0;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001257
1258pool_fail:
1259 zswap_cpu_dstmem_destroy();
1260dstmem_fail:
Fabian Frederickc1192392014-08-08 14:19:35 -07001261 zswap_entry_cache_destroy();
Dan Streetmanf1c54842015-09-09 15:35:19 -07001262cache_fail:
Seth Jennings2b281112013-07-10 16:05:03 -07001263 return -ENOMEM;
1264}
1265/* must be late so crypto has time to come up */
1266late_initcall(init_zswap);
1267
1268MODULE_LICENSE("GPL");
Seth Jennings68386da2014-11-12 21:08:46 -06001269MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>");
Seth Jennings2b281112013-07-10 16:05:03 -07001270MODULE_DESCRIPTION("Compressed cache for swap pages");