blob: dbef27822a987fde3b90de71313f6e479cb44d46 [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;
Dan Streetmanf0c3a0a2017-02-03 13:13:09 -080081static int zswap_enabled_param_set(const char *,
82 const struct kernel_param *);
83static struct kernel_param_ops zswap_enabled_param_ops = {
84 .set = zswap_enabled_param_set,
85 .get = param_get_bool,
86};
87module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644);
Seth Jennings2b281112013-07-10 16:05:03 -070088
Dan Streetman90b0fc22015-09-09 15:35:21 -070089/* Crypto compressor to use */
Seth Jennings2b281112013-07-10 16:05:03 -070090#define ZSWAP_COMPRESSOR_DEFAULT "lzo"
Dan Streetmanc99b42c2015-11-06 16:29:15 -080091static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
Dan Streetman90b0fc22015-09-09 15:35:21 -070092static int zswap_compressor_param_set(const char *,
93 const struct kernel_param *);
94static struct kernel_param_ops zswap_compressor_param_ops = {
95 .set = zswap_compressor_param_set,
Dan Streetmanc99b42c2015-11-06 16:29:15 -080096 .get = param_get_charp,
97 .free = param_free_charp,
Dan Streetman90b0fc22015-09-09 15:35:21 -070098};
99module_param_cb(compressor, &zswap_compressor_param_ops,
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800100 &zswap_compressor, 0644);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700101
102/* Compressed storage zpool to use */
103#define ZSWAP_ZPOOL_DEFAULT "zbud"
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800104static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700105static int zswap_zpool_param_set(const char *, const struct kernel_param *);
106static struct kernel_param_ops zswap_zpool_param_ops = {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800107 .set = zswap_zpool_param_set,
108 .get = param_get_charp,
109 .free = param_free_charp,
Dan Streetman90b0fc22015-09-09 15:35:21 -0700110};
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800111module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 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;
Dan Streetman200867a2016-05-20 16:59:54 -0700126 struct work_struct work;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700127 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);
Dan Streetman32a4e162016-05-05 16:22:23 -0700179/* pool counter to provide unique names to zpool */
180static atomic_t zswap_pools_count = ATOMIC_INIT(0);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700181
Dan Streetman90b0fc22015-09-09 15:35:21 -0700182/* used by param callback function */
183static bool zswap_init_started;
184
Dan Streetmanf0c3a0a2017-02-03 13:13:09 -0800185/* fatal error during init */
186static bool zswap_init_failed;
187
Dan Streetmanf1c54842015-09-09 15:35:19 -0700188/*********************************
189* helpers and fwd declarations
190**********************************/
191
192#define zswap_pool_debug(msg, p) \
193 pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
194 zpool_get_type((p)->zpool))
195
196static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
197static int zswap_pool_get(struct zswap_pool *pool);
198static void zswap_pool_put(struct zswap_pool *pool);
199
200static const struct zpool_ops zswap_zpool_ops = {
201 .evict = zswap_writeback_entry
202};
203
204static bool zswap_is_full(void)
205{
206 return totalram_pages * zswap_max_pool_percent / 100 <
207 DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
208}
209
210static void zswap_update_total_size(void)
211{
212 struct zswap_pool *pool;
213 u64 total = 0;
214
215 rcu_read_lock();
216
217 list_for_each_entry_rcu(pool, &zswap_pools, list)
218 total += zpool_get_total_size(pool->zpool);
219
220 rcu_read_unlock();
221
222 zswap_pool_total_size = total;
223}
224
Seth Jennings2b281112013-07-10 16:05:03 -0700225/*********************************
226* zswap entry functions
227**********************************/
228static struct kmem_cache *zswap_entry_cache;
229
Mahendran Ganeshdd01d7d2014-12-12 16:57:15 -0800230static int __init zswap_entry_cache_create(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700231{
232 zswap_entry_cache = KMEM_CACHE(zswap_entry, 0);
SeongJae Park5d2d42d2014-04-07 15:38:28 -0700233 return zswap_entry_cache == NULL;
Seth Jennings2b281112013-07-10 16:05:03 -0700234}
235
Fabian Frederickc1192392014-08-08 14:19:35 -0700236static void __init zswap_entry_cache_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700237{
238 kmem_cache_destroy(zswap_entry_cache);
239}
240
241static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp)
242{
243 struct zswap_entry *entry;
244 entry = kmem_cache_alloc(zswap_entry_cache, gfp);
245 if (!entry)
246 return NULL;
247 entry->refcount = 1;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800248 RB_CLEAR_NODE(&entry->rbnode);
Seth Jennings2b281112013-07-10 16:05:03 -0700249 return entry;
250}
251
252static void zswap_entry_cache_free(struct zswap_entry *entry)
253{
254 kmem_cache_free(zswap_entry_cache, entry);
255}
256
Seth Jennings2b281112013-07-10 16:05:03 -0700257/*********************************
258* rbtree functions
259**********************************/
260static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset)
261{
262 struct rb_node *node = root->rb_node;
263 struct zswap_entry *entry;
264
265 while (node) {
266 entry = rb_entry(node, struct zswap_entry, rbnode);
267 if (entry->offset > offset)
268 node = node->rb_left;
269 else if (entry->offset < offset)
270 node = node->rb_right;
271 else
272 return entry;
273 }
274 return NULL;
275}
276
277/*
278 * In the case that a entry with the same offset is found, a pointer to
279 * the existing entry is stored in dupentry and the function returns -EEXIST
280 */
281static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry,
282 struct zswap_entry **dupentry)
283{
284 struct rb_node **link = &root->rb_node, *parent = NULL;
285 struct zswap_entry *myentry;
286
287 while (*link) {
288 parent = *link;
289 myentry = rb_entry(parent, struct zswap_entry, rbnode);
290 if (myentry->offset > entry->offset)
291 link = &(*link)->rb_left;
292 else if (myentry->offset < entry->offset)
293 link = &(*link)->rb_right;
294 else {
295 *dupentry = myentry;
296 return -EEXIST;
297 }
298 }
299 rb_link_node(&entry->rbnode, parent, link);
300 rb_insert_color(&entry->rbnode, root);
301 return 0;
302}
303
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800304static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
305{
306 if (!RB_EMPTY_NODE(&entry->rbnode)) {
307 rb_erase(&entry->rbnode, root);
308 RB_CLEAR_NODE(&entry->rbnode);
309 }
310}
311
312/*
Dan Streetman12d79d62014-08-06 16:08:40 -0700313 * Carries out the common pattern of freeing and entry's zpool allocation,
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800314 * freeing the entry itself, and decrementing the number of stored pages.
315 */
Minchan Kim60105e12014-04-07 15:38:27 -0700316static void zswap_free_entry(struct zswap_entry *entry)
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800317{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700318 zpool_free(entry->pool->zpool, entry->handle);
319 zswap_pool_put(entry->pool);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800320 zswap_entry_cache_free(entry);
321 atomic_dec(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700322 zswap_update_total_size();
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800323}
324
325/* caller must hold the tree lock */
326static void zswap_entry_get(struct zswap_entry *entry)
327{
328 entry->refcount++;
329}
330
331/* caller must hold the tree lock
332* remove from the tree and free it, if nobody reference the entry
333*/
334static void zswap_entry_put(struct zswap_tree *tree,
335 struct zswap_entry *entry)
336{
337 int refcount = --entry->refcount;
338
339 BUG_ON(refcount < 0);
340 if (refcount == 0) {
341 zswap_rb_erase(&tree->rbroot, entry);
Minchan Kim60105e12014-04-07 15:38:27 -0700342 zswap_free_entry(entry);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800343 }
344}
345
346/* caller must hold the tree lock */
347static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
348 pgoff_t offset)
349{
Alexey Klimovb0c98652015-11-06 16:29:09 -0800350 struct zswap_entry *entry;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800351
352 entry = zswap_rb_search(root, offset);
353 if (entry)
354 zswap_entry_get(entry);
355
356 return entry;
357}
358
Seth Jennings2b281112013-07-10 16:05:03 -0700359/*********************************
360* per-cpu code
361**********************************/
362static DEFINE_PER_CPU(u8 *, zswap_dstmem);
363
Dan Streetmanf1c54842015-09-09 15:35:19 -0700364static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700365{
Seth Jennings2b281112013-07-10 16:05:03 -0700366 u8 *dst;
367
368 switch (action) {
369 case CPU_UP_PREPARE:
Eric Dumazet72d09632014-06-04 16:11:11 -0700370 dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
Seth Jennings2b281112013-07-10 16:05:03 -0700371 if (!dst) {
372 pr_err("can't allocate compressor buffer\n");
Seth Jennings2b281112013-07-10 16:05:03 -0700373 return NOTIFY_BAD;
374 }
375 per_cpu(zswap_dstmem, cpu) = dst;
376 break;
377 case CPU_DEAD:
378 case CPU_UP_CANCELED:
Seth Jennings2b281112013-07-10 16:05:03 -0700379 dst = per_cpu(zswap_dstmem, cpu);
380 kfree(dst);
381 per_cpu(zswap_dstmem, cpu) = NULL;
382 break;
383 default:
384 break;
385 }
386 return NOTIFY_OK;
387}
388
Dan Streetmanf1c54842015-09-09 15:35:19 -0700389static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
390 unsigned long action, void *pcpu)
Seth Jennings2b281112013-07-10 16:05:03 -0700391{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700392 return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
Seth Jennings2b281112013-07-10 16:05:03 -0700393}
394
Dan Streetmanf1c54842015-09-09 15:35:19 -0700395static struct notifier_block zswap_dstmem_notifier = {
396 .notifier_call = zswap_cpu_dstmem_notifier,
Seth Jennings2b281112013-07-10 16:05:03 -0700397};
398
Dan Streetmanf1c54842015-09-09 15:35:19 -0700399static int __init zswap_cpu_dstmem_init(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700400{
401 unsigned long cpu;
402
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530403 cpu_notifier_register_begin();
Seth Jennings2b281112013-07-10 16:05:03 -0700404 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700405 if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
406 NOTIFY_BAD)
Seth Jennings2b281112013-07-10 16:05:03 -0700407 goto cleanup;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700408 __register_cpu_notifier(&zswap_dstmem_notifier);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530409 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700410 return 0;
411
412cleanup:
413 for_each_online_cpu(cpu)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700414 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
Srivatsa S. Bhat57637822014-03-11 02:12:40 +0530415 cpu_notifier_register_done();
Seth Jennings2b281112013-07-10 16:05:03 -0700416 return -ENOMEM;
417}
418
Dan Streetmanf1c54842015-09-09 15:35:19 -0700419static void zswap_cpu_dstmem_destroy(void)
Seth Jennings2b281112013-07-10 16:05:03 -0700420{
Dan Streetmanf1c54842015-09-09 15:35:19 -0700421 unsigned long cpu;
422
423 cpu_notifier_register_begin();
424 for_each_online_cpu(cpu)
425 __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
426 __unregister_cpu_notifier(&zswap_dstmem_notifier);
427 cpu_notifier_register_done();
428}
429
430static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
431 unsigned long action, unsigned long cpu)
432{
433 struct crypto_comp *tfm;
434
435 switch (action) {
436 case CPU_UP_PREPARE:
437 if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
438 break;
439 tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
440 if (IS_ERR_OR_NULL(tfm)) {
441 pr_err("could not alloc crypto comp %s : %ld\n",
442 pool->tfm_name, PTR_ERR(tfm));
443 return NOTIFY_BAD;
444 }
445 *per_cpu_ptr(pool->tfm, cpu) = tfm;
446 break;
447 case CPU_DEAD:
448 case CPU_UP_CANCELED:
449 tfm = *per_cpu_ptr(pool->tfm, cpu);
450 if (!IS_ERR_OR_NULL(tfm))
451 crypto_free_comp(tfm);
452 *per_cpu_ptr(pool->tfm, cpu) = NULL;
453 break;
454 default:
455 break;
456 }
457 return NOTIFY_OK;
458}
459
460static int zswap_cpu_comp_notifier(struct notifier_block *nb,
461 unsigned long action, void *pcpu)
462{
463 unsigned long cpu = (unsigned long)pcpu;
464 struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
465
466 return __zswap_cpu_comp_notifier(pool, action, cpu);
467}
468
469static int zswap_cpu_comp_init(struct zswap_pool *pool)
470{
471 unsigned long cpu;
472
473 memset(&pool->notifier, 0, sizeof(pool->notifier));
474 pool->notifier.notifier_call = zswap_cpu_comp_notifier;
475
476 cpu_notifier_register_begin();
477 for_each_online_cpu(cpu)
478 if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
479 NOTIFY_BAD)
480 goto cleanup;
481 __register_cpu_notifier(&pool->notifier);
482 cpu_notifier_register_done();
483 return 0;
484
485cleanup:
486 for_each_online_cpu(cpu)
487 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
488 cpu_notifier_register_done();
489 return -ENOMEM;
490}
491
492static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
493{
494 unsigned long cpu;
495
496 cpu_notifier_register_begin();
497 for_each_online_cpu(cpu)
498 __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
499 __unregister_cpu_notifier(&pool->notifier);
500 cpu_notifier_register_done();
501}
502
503/*********************************
504* pool functions
505**********************************/
506
507static struct zswap_pool *__zswap_pool_current(void)
508{
509 struct zswap_pool *pool;
510
511 pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
512 WARN_ON(!pool);
513
514 return pool;
515}
516
517static struct zswap_pool *zswap_pool_current(void)
518{
519 assert_spin_locked(&zswap_pools_lock);
520
521 return __zswap_pool_current();
522}
523
524static struct zswap_pool *zswap_pool_current_get(void)
525{
526 struct zswap_pool *pool;
527
528 rcu_read_lock();
529
530 pool = __zswap_pool_current();
531 if (!pool || !zswap_pool_get(pool))
532 pool = NULL;
533
534 rcu_read_unlock();
535
536 return pool;
537}
538
539static struct zswap_pool *zswap_pool_last_get(void)
540{
541 struct zswap_pool *pool, *last = NULL;
542
543 rcu_read_lock();
544
545 list_for_each_entry_rcu(pool, &zswap_pools, list)
546 last = pool;
547 if (!WARN_ON(!last) && !zswap_pool_get(last))
548 last = NULL;
549
550 rcu_read_unlock();
551
552 return last;
553}
554
Dan Streetman8bc8b222015-12-18 14:22:04 -0800555/* type and compressor must be null-terminated */
Dan Streetmanf1c54842015-09-09 15:35:19 -0700556static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
557{
558 struct zswap_pool *pool;
559
560 assert_spin_locked(&zswap_pools_lock);
561
562 list_for_each_entry_rcu(pool, &zswap_pools, list) {
Dan Streetman8bc8b222015-12-18 14:22:04 -0800563 if (strcmp(pool->tfm_name, compressor))
Dan Streetmanf1c54842015-09-09 15:35:19 -0700564 continue;
Dan Streetman8bc8b222015-12-18 14:22:04 -0800565 if (strcmp(zpool_get_type(pool->zpool), type))
Dan Streetmanf1c54842015-09-09 15:35:19 -0700566 continue;
567 /* if we can't get it, it's about to be destroyed */
568 if (!zswap_pool_get(pool))
569 continue;
570 return pool;
571 }
572
573 return NULL;
574}
575
576static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
577{
578 struct zswap_pool *pool;
Dan Streetman32a4e162016-05-05 16:22:23 -0700579 char name[38]; /* 'zswap' + 32 char (max) num + \0 */
Mel Gormand0164ad2015-11-06 16:28:21 -0800580 gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700581
582 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
583 if (!pool) {
584 pr_err("pool alloc failed\n");
585 return NULL;
586 }
587
Dan Streetman32a4e162016-05-05 16:22:23 -0700588 /* unique name for each pool specifically required by zsmalloc */
589 snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count));
590
591 pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700592 if (!pool->zpool) {
593 pr_err("%s zpool not available\n", type);
594 goto error;
595 }
596 pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
597
598 strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
599 pool->tfm = alloc_percpu(struct crypto_comp *);
600 if (!pool->tfm) {
601 pr_err("percpu alloc failed\n");
602 goto error;
603 }
604
605 if (zswap_cpu_comp_init(pool))
606 goto error;
607 pr_debug("using %s compressor\n", pool->tfm_name);
608
609 /* being the current pool takes 1 ref; this func expects the
610 * caller to always add the new pool as the current pool
611 */
612 kref_init(&pool->kref);
613 INIT_LIST_HEAD(&pool->list);
614
615 zswap_pool_debug("created", pool);
616
617 return pool;
618
619error:
620 free_percpu(pool->tfm);
621 if (pool->zpool)
622 zpool_destroy_pool(pool->zpool);
623 kfree(pool);
624 return NULL;
625}
626
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800627static __init struct zswap_pool *__zswap_pool_create_fallback(void)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700628{
629 if (!crypto_has_comp(zswap_compressor, 0, 0)) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800630 if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) {
631 pr_err("default compressor %s not available\n",
632 zswap_compressor);
633 return NULL;
634 }
Dan Streetmanf1c54842015-09-09 15:35:19 -0700635 pr_err("compressor %s not available, using default %s\n",
636 zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800637 param_free_charp(&zswap_compressor);
638 zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700639 }
640 if (!zpool_has_pool(zswap_zpool_type)) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800641 if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
642 pr_err("default zpool %s not available\n",
643 zswap_zpool_type);
644 return NULL;
645 }
Dan Streetmanf1c54842015-09-09 15:35:19 -0700646 pr_err("zpool %s not available, using default %s\n",
647 zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800648 param_free_charp(&zswap_zpool_type);
649 zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700650 }
651
652 return zswap_pool_create(zswap_zpool_type, zswap_compressor);
653}
654
655static void zswap_pool_destroy(struct zswap_pool *pool)
656{
657 zswap_pool_debug("destroying", pool);
658
659 zswap_cpu_comp_destroy(pool);
660 free_percpu(pool->tfm);
661 zpool_destroy_pool(pool->zpool);
662 kfree(pool);
663}
664
665static int __must_check zswap_pool_get(struct zswap_pool *pool)
666{
667 return kref_get_unless_zero(&pool->kref);
668}
669
Dan Streetman200867a2016-05-20 16:59:54 -0700670static void __zswap_pool_release(struct work_struct *work)
Dan Streetmanf1c54842015-09-09 15:35:19 -0700671{
Dan Streetman200867a2016-05-20 16:59:54 -0700672 struct zswap_pool *pool = container_of(work, typeof(*pool), work);
673
674 synchronize_rcu();
Dan Streetmanf1c54842015-09-09 15:35:19 -0700675
676 /* nobody should have been able to get a kref... */
677 WARN_ON(kref_get_unless_zero(&pool->kref));
678
679 /* pool is now off zswap_pools list and has no references. */
680 zswap_pool_destroy(pool);
681}
682
683static void __zswap_pool_empty(struct kref *kref)
684{
685 struct zswap_pool *pool;
686
687 pool = container_of(kref, typeof(*pool), kref);
688
689 spin_lock(&zswap_pools_lock);
690
691 WARN_ON(pool == zswap_pool_current());
692
693 list_del_rcu(&pool->list);
Dan Streetman200867a2016-05-20 16:59:54 -0700694
695 INIT_WORK(&pool->work, __zswap_pool_release);
696 schedule_work(&pool->work);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700697
698 spin_unlock(&zswap_pools_lock);
699}
700
701static void zswap_pool_put(struct zswap_pool *pool)
702{
703 kref_put(&pool->kref, __zswap_pool_empty);
Seth Jennings2b281112013-07-10 16:05:03 -0700704}
705
Seth Jennings2b281112013-07-10 16:05:03 -0700706/*********************************
Dan Streetman90b0fc22015-09-09 15:35:21 -0700707* param callbacks
708**********************************/
709
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800710/* val must be a null-terminated string */
Dan Streetman90b0fc22015-09-09 15:35:21 -0700711static int __zswap_param_set(const char *val, const struct kernel_param *kp,
712 char *type, char *compressor)
713{
714 struct zswap_pool *pool, *put_pool = NULL;
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800715 char *s = strstrip((char *)val);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700716 int ret;
717
Dan Streetmanf0c3a0a2017-02-03 13:13:09 -0800718 if (zswap_init_failed) {
719 pr_err("can't set param, initialization failed\n");
720 return -ENODEV;
721 }
722
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800723 /* no change required */
724 if (!strcmp(s, *(char **)kp->arg))
725 return 0;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700726
727 /* if this is load-time (pre-init) param setting,
728 * don't create a pool; that's done during init.
729 */
730 if (!zswap_init_started)
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800731 return param_set_charp(s, kp);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700732
733 if (!type) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800734 if (!zpool_has_pool(s)) {
735 pr_err("zpool %s not available\n", s);
736 return -ENOENT;
737 }
Dan Streetman90b0fc22015-09-09 15:35:21 -0700738 type = s;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700739 } else if (!compressor) {
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800740 if (!crypto_has_comp(s, 0, 0)) {
741 pr_err("compressor %s not available\n", s);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700742 return -ENOENT;
743 }
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800744 compressor = s;
745 } else {
746 WARN_ON(1);
747 return -EINVAL;
Dan Streetman90b0fc22015-09-09 15:35:21 -0700748 }
749
750 spin_lock(&zswap_pools_lock);
751
752 pool = zswap_pool_find_get(type, compressor);
753 if (pool) {
754 zswap_pool_debug("using existing", pool);
755 list_del_rcu(&pool->list);
756 } else {
757 spin_unlock(&zswap_pools_lock);
758 pool = zswap_pool_create(type, compressor);
759 spin_lock(&zswap_pools_lock);
760 }
761
762 if (pool)
Dan Streetmanc99b42c2015-11-06 16:29:15 -0800763 ret = param_set_charp(s, kp);
Dan Streetman90b0fc22015-09-09 15:35:21 -0700764 else
765 ret = -EINVAL;
766
767 if (!ret) {
768 put_pool = zswap_pool_current();
769 list_add_rcu(&pool->list, &zswap_pools);
770 } else if (pool) {
771 /* add the possibly pre-existing pool to the end of the pools
772 * list; if it's new (and empty) then it'll be removed and
773 * destroyed by the put after we drop the lock
774 */
775 list_add_tail_rcu(&pool->list, &zswap_pools);
776 put_pool = pool;
777 }
778
779 spin_unlock(&zswap_pools_lock);
780
781 /* drop the ref from either the old current pool,
782 * or the new pool we failed to add
783 */
784 if (put_pool)
785 zswap_pool_put(put_pool);
786
787 return ret;
788}
789
790static int zswap_compressor_param_set(const char *val,
791 const struct kernel_param *kp)
792{
793 return __zswap_param_set(val, kp, zswap_zpool_type, NULL);
794}
795
796static int zswap_zpool_param_set(const char *val,
797 const struct kernel_param *kp)
798{
799 return __zswap_param_set(val, kp, NULL, zswap_compressor);
800}
801
Dan Streetmanf0c3a0a2017-02-03 13:13:09 -0800802static int zswap_enabled_param_set(const char *val,
803 const struct kernel_param *kp)
804{
805 if (zswap_init_failed) {
806 pr_err("can't enable, initialization failed\n");
807 return -ENODEV;
808 }
809
810 return param_set_bool(val, kp);
811}
812
Dan Streetman90b0fc22015-09-09 15:35:21 -0700813/*********************************
Seth Jennings2b281112013-07-10 16:05:03 -0700814* writeback code
815**********************************/
816/* return enum for zswap_get_swap_cache_page */
817enum zswap_get_swap_ret {
818 ZSWAP_SWAPCACHE_NEW,
819 ZSWAP_SWAPCACHE_EXIST,
Weijie Yang67d13fe2013-11-12 15:08:26 -0800820 ZSWAP_SWAPCACHE_FAIL,
Seth Jennings2b281112013-07-10 16:05:03 -0700821};
822
823/*
824 * zswap_get_swap_cache_page
825 *
826 * This is an adaption of read_swap_cache_async()
827 *
828 * This function tries to find a page with the given swap entry
829 * in the swapper_space address space (the swap cache). If the page
830 * is found, it is returned in retpage. Otherwise, a page is allocated,
831 * added to the swap cache, and returned in retpage.
832 *
833 * If success, the swap cache page is returned in retpage
Weijie Yang67d13fe2013-11-12 15:08:26 -0800834 * Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache
835 * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated,
836 * the new page is added to swapcache and locked
837 * Returns ZSWAP_SWAPCACHE_FAIL on error
Seth Jennings2b281112013-07-10 16:05:03 -0700838 */
839static int zswap_get_swap_cache_page(swp_entry_t entry,
840 struct page **retpage)
841{
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700842 bool page_was_allocated;
Seth Jennings2b281112013-07-10 16:05:03 -0700843
Dmitry Safonov5b999aa2015-09-08 15:05:00 -0700844 *retpage = __read_swap_cache_async(entry, GFP_KERNEL,
845 NULL, 0, &page_was_allocated);
846 if (page_was_allocated)
847 return ZSWAP_SWAPCACHE_NEW;
848 if (!*retpage)
Weijie Yang67d13fe2013-11-12 15:08:26 -0800849 return ZSWAP_SWAPCACHE_FAIL;
Seth Jennings2b281112013-07-10 16:05:03 -0700850 return ZSWAP_SWAPCACHE_EXIST;
851}
852
853/*
854 * Attempts to free an entry by adding a page to the swap cache,
855 * decompressing the entry data into the page, and issuing a
856 * bio write to write the page back to the swap device.
857 *
858 * This can be thought of as a "resumed writeback" of the page
859 * to the swap device. We are basically resuming the same swap
860 * writeback path that was intercepted with the frontswap_store()
861 * in the first place. After the page has been decompressed into
862 * the swap cache, the compressed version stored by zswap can be
863 * freed.
864 */
Dan Streetman12d79d62014-08-06 16:08:40 -0700865static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
Seth Jennings2b281112013-07-10 16:05:03 -0700866{
867 struct zswap_header *zhdr;
868 swp_entry_t swpentry;
869 struct zswap_tree *tree;
870 pgoff_t offset;
871 struct zswap_entry *entry;
872 struct page *page;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700873 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700874 u8 *src, *dst;
875 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800876 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -0700877 struct writeback_control wbc = {
878 .sync_mode = WB_SYNC_NONE,
879 };
880
881 /* extract swpentry from data */
Dan Streetman12d79d62014-08-06 16:08:40 -0700882 zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
Seth Jennings2b281112013-07-10 16:05:03 -0700883 swpentry = zhdr->swpentry; /* here */
Dan Streetman12d79d62014-08-06 16:08:40 -0700884 zpool_unmap_handle(pool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700885 tree = zswap_trees[swp_type(swpentry)];
886 offset = swp_offset(swpentry);
Seth Jennings2b281112013-07-10 16:05:03 -0700887
888 /* find and ref zswap entry */
889 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800890 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -0700891 if (!entry) {
892 /* entry was invalidated */
893 spin_unlock(&tree->lock);
894 return 0;
895 }
Seth Jennings2b281112013-07-10 16:05:03 -0700896 spin_unlock(&tree->lock);
897 BUG_ON(offset != entry->offset);
898
899 /* try to allocate swap cache page */
900 switch (zswap_get_swap_cache_page(swpentry, &page)) {
Weijie Yang67d13fe2013-11-12 15:08:26 -0800901 case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */
Seth Jennings2b281112013-07-10 16:05:03 -0700902 ret = -ENOMEM;
903 goto fail;
904
Weijie Yang67d13fe2013-11-12 15:08:26 -0800905 case ZSWAP_SWAPCACHE_EXIST:
Seth Jennings2b281112013-07-10 16:05:03 -0700906 /* page is already in the swap cache, ignore for now */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300907 put_page(page);
Seth Jennings2b281112013-07-10 16:05:03 -0700908 ret = -EEXIST;
909 goto fail;
910
911 case ZSWAP_SWAPCACHE_NEW: /* page is locked */
912 /* decompress */
913 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700914 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -0700915 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -0700916 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700917 tfm = *get_cpu_ptr(entry->pool->tfm);
918 ret = crypto_comp_decompress(tfm, src, entry->length,
919 dst, &dlen);
920 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -0700921 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -0700922 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -0700923 BUG_ON(ret);
924 BUG_ON(dlen != PAGE_SIZE);
925
926 /* page is up to date */
927 SetPageUptodate(page);
928 }
929
Weijie Yangb349acc2013-11-12 15:07:52 -0800930 /* move it to the tail of the inactive list after end_writeback */
931 SetPageReclaim(page);
932
Seth Jennings2b281112013-07-10 16:05:03 -0700933 /* start writeback */
934 __swap_writepage(page, &wbc, end_swap_bio_write);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300935 put_page(page);
Seth Jennings2b281112013-07-10 16:05:03 -0700936 zswap_written_back_pages++;
937
938 spin_lock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700939 /* drop local reference */
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800940 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700941
942 /*
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800943 * There are two possible situations for entry here:
944 * (1) refcount is 1(normal case), entry is valid and on the tree
945 * (2) refcount is 0, entry is freed and not on the tree
946 * because invalidate happened during writeback
947 * search the tree and free the entry if find entry
948 */
949 if (entry == zswap_rb_search(&tree->rbroot, offset))
950 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700951 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -0700952
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800953 goto end;
954
955 /*
956 * if we get here due to ZSWAP_SWAPCACHE_EXIST
957 * a load may happening concurrently
958 * it is safe and okay to not free the entry
959 * if we free the entry in the following put
960 * it it either okay to return !0
961 */
Seth Jennings2b281112013-07-10 16:05:03 -0700962fail:
963 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800964 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -0700965 spin_unlock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -0800966
967end:
Seth Jennings2b281112013-07-10 16:05:03 -0700968 return ret;
969}
970
Dan Streetmanf1c54842015-09-09 15:35:19 -0700971static int zswap_shrink(void)
972{
973 struct zswap_pool *pool;
974 int ret;
975
976 pool = zswap_pool_last_get();
977 if (!pool)
978 return -ENOENT;
979
980 ret = zpool_shrink(pool->zpool, 1, NULL);
981
982 zswap_pool_put(pool);
983
984 return ret;
985}
986
Seth Jennings2b281112013-07-10 16:05:03 -0700987/*********************************
988* frontswap hooks
989**********************************/
990/* attempts to compress and store an single page */
991static int zswap_frontswap_store(unsigned type, pgoff_t offset,
992 struct page *page)
993{
994 struct zswap_tree *tree = zswap_trees[type];
995 struct zswap_entry *entry, *dupentry;
Dan Streetmanf1c54842015-09-09 15:35:19 -0700996 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -0700997 int ret;
998 unsigned int dlen = PAGE_SIZE, len;
999 unsigned long handle;
1000 char *buf;
1001 u8 *src, *dst;
1002 struct zswap_header *zhdr;
1003
Dan Streetmanc00ed162015-06-25 15:00:35 -07001004 if (!zswap_enabled || !tree) {
Seth Jennings2b281112013-07-10 16:05:03 -07001005 ret = -ENODEV;
1006 goto reject;
1007 }
1008
1009 /* reclaim space if needed */
1010 if (zswap_is_full()) {
1011 zswap_pool_limit_hit++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001012 if (zswap_shrink()) {
Seth Jennings2b281112013-07-10 16:05:03 -07001013 zswap_reject_reclaim_fail++;
1014 ret = -ENOMEM;
1015 goto reject;
1016 }
1017 }
1018
1019 /* allocate entry */
1020 entry = zswap_entry_cache_alloc(GFP_KERNEL);
1021 if (!entry) {
1022 zswap_reject_kmemcache_fail++;
1023 ret = -ENOMEM;
1024 goto reject;
1025 }
1026
Dan Streetmanf1c54842015-09-09 15:35:19 -07001027 /* if entry is successfully added, it keeps the reference */
1028 entry->pool = zswap_pool_current_get();
1029 if (!entry->pool) {
Seth Jennings2b281112013-07-10 16:05:03 -07001030 ret = -EINVAL;
1031 goto freepage;
1032 }
1033
Dan Streetmanf1c54842015-09-09 15:35:19 -07001034 /* compress */
1035 dst = get_cpu_var(zswap_dstmem);
1036 tfm = *get_cpu_ptr(entry->pool->tfm);
1037 src = kmap_atomic(page);
1038 ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
1039 kunmap_atomic(src);
1040 put_cpu_ptr(entry->pool->tfm);
1041 if (ret) {
1042 ret = -EINVAL;
1043 goto put_dstmem;
1044 }
1045
Seth Jennings2b281112013-07-10 16:05:03 -07001046 /* store */
1047 len = dlen + sizeof(struct zswap_header);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001048 ret = zpool_malloc(entry->pool->zpool, len,
Mel Gormand0164ad2015-11-06 16:28:21 -08001049 __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM,
1050 &handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001051 if (ret == -ENOSPC) {
1052 zswap_reject_compress_poor++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001053 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001054 }
1055 if (ret) {
1056 zswap_reject_alloc_fail++;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001057 goto put_dstmem;
Seth Jennings2b281112013-07-10 16:05:03 -07001058 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001059 zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
Seth Jennings2b281112013-07-10 16:05:03 -07001060 zhdr->swpentry = swp_entry(type, offset);
1061 buf = (u8 *)(zhdr + 1);
1062 memcpy(buf, dst, dlen);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001063 zpool_unmap_handle(entry->pool->zpool, handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001064 put_cpu_var(zswap_dstmem);
1065
1066 /* populate entry */
1067 entry->offset = offset;
1068 entry->handle = handle;
1069 entry->length = dlen;
1070
1071 /* map */
1072 spin_lock(&tree->lock);
1073 do {
1074 ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry);
1075 if (ret == -EEXIST) {
1076 zswap_duplicate_entry++;
1077 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001078 zswap_rb_erase(&tree->rbroot, dupentry);
1079 zswap_entry_put(tree, dupentry);
Seth Jennings2b281112013-07-10 16:05:03 -07001080 }
1081 } while (ret == -EEXIST);
1082 spin_unlock(&tree->lock);
1083
1084 /* update stats */
1085 atomic_inc(&zswap_stored_pages);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001086 zswap_update_total_size();
Seth Jennings2b281112013-07-10 16:05:03 -07001087
1088 return 0;
1089
Dan Streetmanf1c54842015-09-09 15:35:19 -07001090put_dstmem:
Seth Jennings2b281112013-07-10 16:05:03 -07001091 put_cpu_var(zswap_dstmem);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001092 zswap_pool_put(entry->pool);
1093freepage:
Seth Jennings2b281112013-07-10 16:05:03 -07001094 zswap_entry_cache_free(entry);
1095reject:
1096 return ret;
1097}
1098
1099/*
1100 * returns 0 if the page was successfully decompressed
1101 * return -1 on entry not found or error
1102*/
1103static int zswap_frontswap_load(unsigned type, pgoff_t offset,
1104 struct page *page)
1105{
1106 struct zswap_tree *tree = zswap_trees[type];
1107 struct zswap_entry *entry;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001108 struct crypto_comp *tfm;
Seth Jennings2b281112013-07-10 16:05:03 -07001109 u8 *src, *dst;
1110 unsigned int dlen;
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001111 int ret;
Seth Jennings2b281112013-07-10 16:05:03 -07001112
1113 /* find */
1114 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001115 entry = zswap_entry_find_get(&tree->rbroot, offset);
Seth Jennings2b281112013-07-10 16:05:03 -07001116 if (!entry) {
1117 /* entry was written back */
1118 spin_unlock(&tree->lock);
1119 return -1;
1120 }
Seth Jennings2b281112013-07-10 16:05:03 -07001121 spin_unlock(&tree->lock);
1122
1123 /* decompress */
1124 dlen = PAGE_SIZE;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001125 src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
Dan Streetman12d79d62014-08-06 16:08:40 -07001126 ZPOOL_MM_RO) + sizeof(struct zswap_header);
Seth Jennings2b281112013-07-10 16:05:03 -07001127 dst = kmap_atomic(page);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001128 tfm = *get_cpu_ptr(entry->pool->tfm);
1129 ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
1130 put_cpu_ptr(entry->pool->tfm);
Seth Jennings2b281112013-07-10 16:05:03 -07001131 kunmap_atomic(dst);
Dan Streetmanf1c54842015-09-09 15:35:19 -07001132 zpool_unmap_handle(entry->pool->zpool, entry->handle);
Seth Jennings2b281112013-07-10 16:05:03 -07001133 BUG_ON(ret);
1134
1135 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001136 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001137 spin_unlock(&tree->lock);
1138
Seth Jennings2b281112013-07-10 16:05:03 -07001139 return 0;
1140}
1141
1142/* frees an entry in zswap */
1143static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset)
1144{
1145 struct zswap_tree *tree = zswap_trees[type];
1146 struct zswap_entry *entry;
Seth Jennings2b281112013-07-10 16:05:03 -07001147
1148 /* find */
1149 spin_lock(&tree->lock);
1150 entry = zswap_rb_search(&tree->rbroot, offset);
1151 if (!entry) {
1152 /* entry was written back */
1153 spin_unlock(&tree->lock);
1154 return;
1155 }
1156
1157 /* remove from rbtree */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001158 zswap_rb_erase(&tree->rbroot, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001159
1160 /* drop the initial reference from entry creation */
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001161 zswap_entry_put(tree, entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001162
1163 spin_unlock(&tree->lock);
Seth Jennings2b281112013-07-10 16:05:03 -07001164}
1165
1166/* frees all zswap entries for the given swap type */
1167static void zswap_frontswap_invalidate_area(unsigned type)
1168{
1169 struct zswap_tree *tree = zswap_trees[type];
Cody P Schafer0bd42132013-09-11 14:25:33 -07001170 struct zswap_entry *entry, *n;
Seth Jennings2b281112013-07-10 16:05:03 -07001171
1172 if (!tree)
1173 return;
1174
1175 /* walk the tree and free everything */
1176 spin_lock(&tree->lock);
Weijie Yang0ab0abc2013-11-12 15:08:27 -08001177 rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode)
Minchan Kim60105e12014-04-07 15:38:27 -07001178 zswap_free_entry(entry);
Seth Jennings2b281112013-07-10 16:05:03 -07001179 tree->rbroot = RB_ROOT;
1180 spin_unlock(&tree->lock);
Weijie Yangaa9bca02013-10-16 13:46:54 -07001181 kfree(tree);
1182 zswap_trees[type] = NULL;
Seth Jennings2b281112013-07-10 16:05:03 -07001183}
1184
Seth Jennings2b281112013-07-10 16:05:03 -07001185static void zswap_frontswap_init(unsigned type)
1186{
1187 struct zswap_tree *tree;
1188
1189 tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL);
Minchan Kim60105e12014-04-07 15:38:27 -07001190 if (!tree) {
1191 pr_err("alloc failed, zswap disabled for swap type %d\n", type);
1192 return;
1193 }
1194
Seth Jennings2b281112013-07-10 16:05:03 -07001195 tree->rbroot = RB_ROOT;
1196 spin_lock_init(&tree->lock);
1197 zswap_trees[type] = tree;
Seth Jennings2b281112013-07-10 16:05:03 -07001198}
1199
1200static struct frontswap_ops zswap_frontswap_ops = {
1201 .store = zswap_frontswap_store,
1202 .load = zswap_frontswap_load,
1203 .invalidate_page = zswap_frontswap_invalidate_page,
1204 .invalidate_area = zswap_frontswap_invalidate_area,
1205 .init = zswap_frontswap_init
1206};
1207
1208/*********************************
1209* debugfs functions
1210**********************************/
1211#ifdef CONFIG_DEBUG_FS
1212#include <linux/debugfs.h>
1213
1214static struct dentry *zswap_debugfs_root;
1215
1216static int __init zswap_debugfs_init(void)
1217{
1218 if (!debugfs_initialized())
1219 return -ENODEV;
1220
1221 zswap_debugfs_root = debugfs_create_dir("zswap", NULL);
1222 if (!zswap_debugfs_root)
1223 return -ENOMEM;
1224
1225 debugfs_create_u64("pool_limit_hit", S_IRUGO,
1226 zswap_debugfs_root, &zswap_pool_limit_hit);
1227 debugfs_create_u64("reject_reclaim_fail", S_IRUGO,
1228 zswap_debugfs_root, &zswap_reject_reclaim_fail);
1229 debugfs_create_u64("reject_alloc_fail", S_IRUGO,
1230 zswap_debugfs_root, &zswap_reject_alloc_fail);
1231 debugfs_create_u64("reject_kmemcache_fail", S_IRUGO,
1232 zswap_debugfs_root, &zswap_reject_kmemcache_fail);
1233 debugfs_create_u64("reject_compress_poor", S_IRUGO,
1234 zswap_debugfs_root, &zswap_reject_compress_poor);
1235 debugfs_create_u64("written_back_pages", S_IRUGO,
1236 zswap_debugfs_root, &zswap_written_back_pages);
1237 debugfs_create_u64("duplicate_entry", S_IRUGO,
1238 zswap_debugfs_root, &zswap_duplicate_entry);
Dan Streetman12d79d62014-08-06 16:08:40 -07001239 debugfs_create_u64("pool_total_size", S_IRUGO,
1240 zswap_debugfs_root, &zswap_pool_total_size);
Seth Jennings2b281112013-07-10 16:05:03 -07001241 debugfs_create_atomic_t("stored_pages", S_IRUGO,
1242 zswap_debugfs_root, &zswap_stored_pages);
1243
1244 return 0;
1245}
1246
1247static void __exit zswap_debugfs_exit(void)
1248{
1249 debugfs_remove_recursive(zswap_debugfs_root);
1250}
1251#else
1252static int __init zswap_debugfs_init(void)
1253{
1254 return 0;
1255}
1256
1257static void __exit zswap_debugfs_exit(void) { }
1258#endif
1259
1260/*********************************
1261* module init and exit
1262**********************************/
1263static int __init init_zswap(void)
1264{
Dan Streetmanf1c54842015-09-09 15:35:19 -07001265 struct zswap_pool *pool;
Minchan Kim60105e12014-04-07 15:38:27 -07001266
Dan Streetman90b0fc22015-09-09 15:35:21 -07001267 zswap_init_started = true;
1268
Seth Jennings2b281112013-07-10 16:05:03 -07001269 if (zswap_entry_cache_create()) {
1270 pr_err("entry cache creation failed\n");
Dan Streetmanf1c54842015-09-09 15:35:19 -07001271 goto cache_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001272 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001273
1274 if (zswap_cpu_dstmem_init()) {
1275 pr_err("dstmem alloc failed\n");
1276 goto dstmem_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001277 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001278
1279 pool = __zswap_pool_create_fallback();
1280 if (!pool) {
1281 pr_err("pool creation failed\n");
1282 goto pool_fail;
Seth Jennings2b281112013-07-10 16:05:03 -07001283 }
Dan Streetmanf1c54842015-09-09 15:35:19 -07001284 pr_info("loaded using pool %s/%s\n", pool->tfm_name,
1285 zpool_get_type(pool->zpool));
1286
1287 list_add(&pool->list, &zswap_pools);
Minchan Kim60105e12014-04-07 15:38:27 -07001288
Seth Jennings2b281112013-07-10 16:05:03 -07001289 frontswap_register_ops(&zswap_frontswap_ops);
1290 if (zswap_debugfs_init())
1291 pr_warn("debugfs initialization failed\n");
1292 return 0;
Dan Streetmanf1c54842015-09-09 15:35:19 -07001293
1294pool_fail:
1295 zswap_cpu_dstmem_destroy();
1296dstmem_fail:
Fabian Frederickc1192392014-08-08 14:19:35 -07001297 zswap_entry_cache_destroy();
Dan Streetmanf1c54842015-09-09 15:35:19 -07001298cache_fail:
Dan Streetmanf0c3a0a2017-02-03 13:13:09 -08001299 /* if built-in, we aren't unloaded on failure; don't allow use */
1300 zswap_init_failed = true;
1301 zswap_enabled = false;
Seth Jennings2b281112013-07-10 16:05:03 -07001302 return -ENOMEM;
1303}
1304/* must be late so crypto has time to come up */
1305late_initcall(init_zswap);
1306
1307MODULE_LICENSE("GPL");
Seth Jennings68386da2014-11-12 21:08:46 -06001308MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>");
Seth Jennings2b281112013-07-10 16:05:03 -07001309MODULE_DESCRIPTION("Compressed cache for swap pages");