fea68a7565
zswap_find_zpool() checks if ZSWAP_NR_ZPOOLS > 1, which is always true. This is a remnant from a patch version that had ZSWAP_NR_ZPOOLS as a config option and never made it upstream. Remove the unnecessary check. Link: https://lkml.kernel.org/r/20240311235210.2937484-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1863 lines
51 KiB
C
1863 lines
51 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* zswap.c - zswap driver file
|
|
*
|
|
* zswap is a cache that takes pages that are in the process
|
|
* of being swapped out and attempts to compress and store them in a
|
|
* RAM-based memory pool. This can result in a significant I/O reduction on
|
|
* the swap device and, in the case where decompressing from RAM is faster
|
|
* than reading from the swap device, can also improve workload performance.
|
|
*
|
|
* Copyright (C) 2012 Seth Jennings <sjenning@linux.vnet.ibm.com>
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/types.h>
|
|
#include <linux/atomic.h>
|
|
#include <linux/rbtree.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/crypto.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/mempolicy.h>
|
|
#include <linux/mempool.h>
|
|
#include <linux/zpool.h>
|
|
#include <crypto/acompress.h>
|
|
#include <linux/zswap.h>
|
|
#include <linux/mm_types.h>
|
|
#include <linux/page-flags.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/list_lru.h>
|
|
|
|
#include "swap.h"
|
|
#include "internal.h"
|
|
|
|
/*********************************
|
|
* statistics
|
|
**********************************/
|
|
/* The number of compressed pages currently stored in zswap */
|
|
atomic_t zswap_stored_pages = ATOMIC_INIT(0);
|
|
/* The number of same-value filled pages currently stored in zswap */
|
|
static atomic_t zswap_same_filled_pages = ATOMIC_INIT(0);
|
|
|
|
/*
|
|
* The statistics below are not protected from concurrent access for
|
|
* performance reasons so they may not be a 100% accurate. However,
|
|
* they do provide useful information on roughly how many times a
|
|
* certain event is occurring.
|
|
*/
|
|
|
|
/* Pool limit was hit (see zswap_max_pool_percent) */
|
|
static u64 zswap_pool_limit_hit;
|
|
/* Pages written back when pool limit was reached */
|
|
static u64 zswap_written_back_pages;
|
|
/* Store failed due to a reclaim failure after pool limit was reached */
|
|
static u64 zswap_reject_reclaim_fail;
|
|
/* Store failed due to compression algorithm failure */
|
|
static u64 zswap_reject_compress_fail;
|
|
/* Compressed page was too big for the allocator to (optimally) store */
|
|
static u64 zswap_reject_compress_poor;
|
|
/* Store failed because underlying allocator could not get memory */
|
|
static u64 zswap_reject_alloc_fail;
|
|
/* Store failed because the entry metadata could not be allocated (rare) */
|
|
static u64 zswap_reject_kmemcache_fail;
|
|
|
|
/* Shrinker work queue */
|
|
static struct workqueue_struct *shrink_wq;
|
|
/* Pool limit was hit, we need to calm down */
|
|
static bool zswap_pool_reached_full;
|
|
|
|
/*********************************
|
|
* tunables
|
|
**********************************/
|
|
|
|
#define ZSWAP_PARAM_UNSET ""
|
|
|
|
static int zswap_setup(void);
|
|
|
|
/* Enable/disable zswap */
|
|
static bool zswap_enabled = IS_ENABLED(CONFIG_ZSWAP_DEFAULT_ON);
|
|
static int zswap_enabled_param_set(const char *,
|
|
const struct kernel_param *);
|
|
static const struct kernel_param_ops zswap_enabled_param_ops = {
|
|
.set = zswap_enabled_param_set,
|
|
.get = param_get_bool,
|
|
};
|
|
module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644);
|
|
|
|
/* Crypto compressor to use */
|
|
static char *zswap_compressor = CONFIG_ZSWAP_COMPRESSOR_DEFAULT;
|
|
static int zswap_compressor_param_set(const char *,
|
|
const struct kernel_param *);
|
|
static const struct kernel_param_ops zswap_compressor_param_ops = {
|
|
.set = zswap_compressor_param_set,
|
|
.get = param_get_charp,
|
|
.free = param_free_charp,
|
|
};
|
|
module_param_cb(compressor, &zswap_compressor_param_ops,
|
|
&zswap_compressor, 0644);
|
|
|
|
/* Compressed storage zpool to use */
|
|
static char *zswap_zpool_type = CONFIG_ZSWAP_ZPOOL_DEFAULT;
|
|
static int zswap_zpool_param_set(const char *, const struct kernel_param *);
|
|
static const struct kernel_param_ops zswap_zpool_param_ops = {
|
|
.set = zswap_zpool_param_set,
|
|
.get = param_get_charp,
|
|
.free = param_free_charp,
|
|
};
|
|
module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644);
|
|
|
|
/* The maximum percentage of memory that the compressed pool can occupy */
|
|
static unsigned int zswap_max_pool_percent = 20;
|
|
module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644);
|
|
|
|
/* The threshold for accepting new pages after the max_pool_percent was hit */
|
|
static unsigned int zswap_accept_thr_percent = 90; /* of max pool size */
|
|
module_param_named(accept_threshold_percent, zswap_accept_thr_percent,
|
|
uint, 0644);
|
|
|
|
/*
|
|
* Enable/disable handling same-value filled pages (enabled by default).
|
|
* If disabled every page is considered non-same-value filled.
|
|
*/
|
|
static bool zswap_same_filled_pages_enabled = true;
|
|
module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled,
|
|
bool, 0644);
|
|
|
|
/* Enable/disable handling non-same-value filled pages (enabled by default) */
|
|
static bool zswap_non_same_filled_pages_enabled = true;
|
|
module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled,
|
|
bool, 0644);
|
|
|
|
/* Number of zpools in zswap_pool (empirically determined for scalability) */
|
|
#define ZSWAP_NR_ZPOOLS 32
|
|
|
|
/* Enable/disable memory pressure-based shrinker. */
|
|
static bool zswap_shrinker_enabled = IS_ENABLED(
|
|
CONFIG_ZSWAP_SHRINKER_DEFAULT_ON);
|
|
module_param_named(shrinker_enabled, zswap_shrinker_enabled, bool, 0644);
|
|
|
|
bool is_zswap_enabled(void)
|
|
{
|
|
return zswap_enabled;
|
|
}
|
|
|
|
/*********************************
|
|
* data structures
|
|
**********************************/
|
|
|
|
struct crypto_acomp_ctx {
|
|
struct crypto_acomp *acomp;
|
|
struct acomp_req *req;
|
|
struct crypto_wait wait;
|
|
u8 *buffer;
|
|
struct mutex mutex;
|
|
bool is_sleepable;
|
|
};
|
|
|
|
/*
|
|
* The lock ordering is zswap_tree.lock -> zswap_pool.lru_lock.
|
|
* The only case where lru_lock is not acquired while holding tree.lock is
|
|
* when a zswap_entry is taken off the lru for writeback, in that case it
|
|
* needs to be verified that it's still valid in the tree.
|
|
*/
|
|
struct zswap_pool {
|
|
struct zpool *zpools[ZSWAP_NR_ZPOOLS];
|
|
struct crypto_acomp_ctx __percpu *acomp_ctx;
|
|
struct percpu_ref ref;
|
|
struct list_head list;
|
|
struct work_struct release_work;
|
|
struct hlist_node node;
|
|
char tfm_name[CRYPTO_MAX_ALG_NAME];
|
|
};
|
|
|
|
/* Global LRU lists shared by all zswap pools. */
|
|
static struct list_lru zswap_list_lru;
|
|
/* counter of pages stored in all zswap pools. */
|
|
static atomic_t zswap_nr_stored = ATOMIC_INIT(0);
|
|
|
|
/* The lock protects zswap_next_shrink updates. */
|
|
static DEFINE_SPINLOCK(zswap_shrink_lock);
|
|
static struct mem_cgroup *zswap_next_shrink;
|
|
static struct work_struct zswap_shrink_work;
|
|
static struct shrinker *zswap_shrinker;
|
|
|
|
/*
|
|
* struct zswap_entry
|
|
*
|
|
* This structure contains the metadata for tracking a single compressed
|
|
* page within zswap.
|
|
*
|
|
* rbnode - links the entry into red-black tree for the appropriate swap type
|
|
* swpentry - associated swap entry, the offset indexes into the red-black tree
|
|
* length - the length in bytes of the compressed page data. Needed during
|
|
* decompression. For a same value filled page length is 0, and both
|
|
* pool and lru are invalid and must be ignored.
|
|
* pool - the zswap_pool the entry's data is in
|
|
* handle - zpool allocation handle that stores the compressed page data
|
|
* value - value of the same-value filled pages which have same content
|
|
* objcg - the obj_cgroup that the compressed memory is charged to
|
|
* lru - handle to the pool's lru used to evict pages.
|
|
*/
|
|
struct zswap_entry {
|
|
struct rb_node rbnode;
|
|
swp_entry_t swpentry;
|
|
unsigned int length;
|
|
struct zswap_pool *pool;
|
|
union {
|
|
unsigned long handle;
|
|
unsigned long value;
|
|
};
|
|
struct obj_cgroup *objcg;
|
|
struct list_head lru;
|
|
};
|
|
|
|
struct zswap_tree {
|
|
struct rb_root rbroot;
|
|
spinlock_t lock;
|
|
};
|
|
|
|
static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
|
|
static unsigned int nr_zswap_trees[MAX_SWAPFILES];
|
|
|
|
/* RCU-protected iteration */
|
|
static LIST_HEAD(zswap_pools);
|
|
/* protects zswap_pools list modification */
|
|
static DEFINE_SPINLOCK(zswap_pools_lock);
|
|
/* pool counter to provide unique names to zpool */
|
|
static atomic_t zswap_pools_count = ATOMIC_INIT(0);
|
|
|
|
enum zswap_init_type {
|
|
ZSWAP_UNINIT,
|
|
ZSWAP_INIT_SUCCEED,
|
|
ZSWAP_INIT_FAILED
|
|
};
|
|
|
|
static enum zswap_init_type zswap_init_state;
|
|
|
|
/* used to ensure the integrity of initialization */
|
|
static DEFINE_MUTEX(zswap_init_lock);
|
|
|
|
/* init completed, but couldn't create the initial pool */
|
|
static bool zswap_has_pool;
|
|
|
|
/*********************************
|
|
* helpers and fwd declarations
|
|
**********************************/
|
|
|
|
static inline struct zswap_tree *swap_zswap_tree(swp_entry_t swp)
|
|
{
|
|
return &zswap_trees[swp_type(swp)][swp_offset(swp)
|
|
>> SWAP_ADDRESS_SPACE_SHIFT];
|
|
}
|
|
|
|
#define zswap_pool_debug(msg, p) \
|
|
pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
|
|
zpool_get_type((p)->zpools[0]))
|
|
|
|
/*********************************
|
|
* pool functions
|
|
**********************************/
|
|
static void __zswap_pool_empty(struct percpu_ref *ref);
|
|
|
|
static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
|
|
{
|
|
int i;
|
|
struct zswap_pool *pool;
|
|
char name[38]; /* 'zswap' + 32 char (max) num + \0 */
|
|
gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
|
|
int ret;
|
|
|
|
if (!zswap_has_pool) {
|
|
/* if either are unset, pool initialization failed, and we
|
|
* need both params to be set correctly before trying to
|
|
* create a pool.
|
|
*/
|
|
if (!strcmp(type, ZSWAP_PARAM_UNSET))
|
|
return NULL;
|
|
if (!strcmp(compressor, ZSWAP_PARAM_UNSET))
|
|
return NULL;
|
|
}
|
|
|
|
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
|
|
if (!pool)
|
|
return NULL;
|
|
|
|
for (i = 0; i < ZSWAP_NR_ZPOOLS; i++) {
|
|
/* unique name for each pool specifically required by zsmalloc */
|
|
snprintf(name, 38, "zswap%x",
|
|
atomic_inc_return(&zswap_pools_count));
|
|
|
|
pool->zpools[i] = zpool_create_pool(type, name, gfp);
|
|
if (!pool->zpools[i]) {
|
|
pr_err("%s zpool not available\n", type);
|
|
goto error;
|
|
}
|
|
}
|
|
pr_debug("using %s zpool\n", zpool_get_type(pool->zpools[0]));
|
|
|
|
strscpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
|
|
|
|
pool->acomp_ctx = alloc_percpu(*pool->acomp_ctx);
|
|
if (!pool->acomp_ctx) {
|
|
pr_err("percpu alloc failed\n");
|
|
goto error;
|
|
}
|
|
|
|
ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE,
|
|
&pool->node);
|
|
if (ret)
|
|
goto error;
|
|
|
|
/* being the current pool takes 1 ref; this func expects the
|
|
* caller to always add the new pool as the current pool
|
|
*/
|
|
ret = percpu_ref_init(&pool->ref, __zswap_pool_empty,
|
|
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL);
|
|
if (ret)
|
|
goto ref_fail;
|
|
INIT_LIST_HEAD(&pool->list);
|
|
|
|
zswap_pool_debug("created", pool);
|
|
|
|
return pool;
|
|
|
|
ref_fail:
|
|
cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node);
|
|
error:
|
|
if (pool->acomp_ctx)
|
|
free_percpu(pool->acomp_ctx);
|
|
while (i--)
|
|
zpool_destroy_pool(pool->zpools[i]);
|
|
kfree(pool);
|
|
return NULL;
|
|
}
|
|
|
|
static struct zswap_pool *__zswap_pool_create_fallback(void)
|
|
{
|
|
bool has_comp, has_zpool;
|
|
|
|
has_comp = crypto_has_acomp(zswap_compressor, 0, 0);
|
|
if (!has_comp && strcmp(zswap_compressor,
|
|
CONFIG_ZSWAP_COMPRESSOR_DEFAULT)) {
|
|
pr_err("compressor %s not available, using default %s\n",
|
|
zswap_compressor, CONFIG_ZSWAP_COMPRESSOR_DEFAULT);
|
|
param_free_charp(&zswap_compressor);
|
|
zswap_compressor = CONFIG_ZSWAP_COMPRESSOR_DEFAULT;
|
|
has_comp = crypto_has_acomp(zswap_compressor, 0, 0);
|
|
}
|
|
if (!has_comp) {
|
|
pr_err("default compressor %s not available\n",
|
|
zswap_compressor);
|
|
param_free_charp(&zswap_compressor);
|
|
zswap_compressor = ZSWAP_PARAM_UNSET;
|
|
}
|
|
|
|
has_zpool = zpool_has_pool(zswap_zpool_type);
|
|
if (!has_zpool && strcmp(zswap_zpool_type,
|
|
CONFIG_ZSWAP_ZPOOL_DEFAULT)) {
|
|
pr_err("zpool %s not available, using default %s\n",
|
|
zswap_zpool_type, CONFIG_ZSWAP_ZPOOL_DEFAULT);
|
|
param_free_charp(&zswap_zpool_type);
|
|
zswap_zpool_type = CONFIG_ZSWAP_ZPOOL_DEFAULT;
|
|
has_zpool = zpool_has_pool(zswap_zpool_type);
|
|
}
|
|
if (!has_zpool) {
|
|
pr_err("default zpool %s not available\n",
|
|
zswap_zpool_type);
|
|
param_free_charp(&zswap_zpool_type);
|
|
zswap_zpool_type = ZSWAP_PARAM_UNSET;
|
|
}
|
|
|
|
if (!has_comp || !has_zpool)
|
|
return NULL;
|
|
|
|
return zswap_pool_create(zswap_zpool_type, zswap_compressor);
|
|
}
|
|
|
|
static void zswap_pool_destroy(struct zswap_pool *pool)
|
|
{
|
|
int i;
|
|
|
|
zswap_pool_debug("destroying", pool);
|
|
|
|
cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node);
|
|
free_percpu(pool->acomp_ctx);
|
|
|
|
for (i = 0; i < ZSWAP_NR_ZPOOLS; i++)
|
|
zpool_destroy_pool(pool->zpools[i]);
|
|
kfree(pool);
|
|
}
|
|
|
|
static void __zswap_pool_release(struct work_struct *work)
|
|
{
|
|
struct zswap_pool *pool = container_of(work, typeof(*pool),
|
|
release_work);
|
|
|
|
synchronize_rcu();
|
|
|
|
/* nobody should have been able to get a ref... */
|
|
WARN_ON(!percpu_ref_is_zero(&pool->ref));
|
|
percpu_ref_exit(&pool->ref);
|
|
|
|
/* pool is now off zswap_pools list and has no references. */
|
|
zswap_pool_destroy(pool);
|
|
}
|
|
|
|
static struct zswap_pool *zswap_pool_current(void);
|
|
|
|
static void __zswap_pool_empty(struct percpu_ref *ref)
|
|
{
|
|
struct zswap_pool *pool;
|
|
|
|
pool = container_of(ref, typeof(*pool), ref);
|
|
|
|
spin_lock_bh(&zswap_pools_lock);
|
|
|
|
WARN_ON(pool == zswap_pool_current());
|
|
|
|
list_del_rcu(&pool->list);
|
|
|
|
INIT_WORK(&pool->release_work, __zswap_pool_release);
|
|
schedule_work(&pool->release_work);
|
|
|
|
spin_unlock_bh(&zswap_pools_lock);
|
|
}
|
|
|
|
static int __must_check zswap_pool_get(struct zswap_pool *pool)
|
|
{
|
|
if (!pool)
|
|
return 0;
|
|
|
|
return percpu_ref_tryget(&pool->ref);
|
|
}
|
|
|
|
static void zswap_pool_put(struct zswap_pool *pool)
|
|
{
|
|
percpu_ref_put(&pool->ref);
|
|
}
|
|
|
|
static struct zswap_pool *__zswap_pool_current(void)
|
|
{
|
|
struct zswap_pool *pool;
|
|
|
|
pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
|
|
WARN_ONCE(!pool && zswap_has_pool,
|
|
"%s: no page storage pool!\n", __func__);
|
|
|
|
return pool;
|
|
}
|
|
|
|
static struct zswap_pool *zswap_pool_current(void)
|
|
{
|
|
assert_spin_locked(&zswap_pools_lock);
|
|
|
|
return __zswap_pool_current();
|
|
}
|
|
|
|
static struct zswap_pool *zswap_pool_current_get(void)
|
|
{
|
|
struct zswap_pool *pool;
|
|
|
|
rcu_read_lock();
|
|
|
|
pool = __zswap_pool_current();
|
|
if (!zswap_pool_get(pool))
|
|
pool = NULL;
|
|
|
|
rcu_read_unlock();
|
|
|
|
return pool;
|
|
}
|
|
|
|
/* type and compressor must be null-terminated */
|
|
static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
|
|
{
|
|
struct zswap_pool *pool;
|
|
|
|
assert_spin_locked(&zswap_pools_lock);
|
|
|
|
list_for_each_entry_rcu(pool, &zswap_pools, list) {
|
|
if (strcmp(pool->tfm_name, compressor))
|
|
continue;
|
|
/* all zpools share the same type */
|
|
if (strcmp(zpool_get_type(pool->zpools[0]), type))
|
|
continue;
|
|
/* if we can't get it, it's about to be destroyed */
|
|
if (!zswap_pool_get(pool))
|
|
continue;
|
|
return pool;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static unsigned long zswap_max_pages(void)
|
|
{
|
|
return totalram_pages() * zswap_max_pool_percent / 100;
|
|
}
|
|
|
|
static unsigned long zswap_accept_thr_pages(void)
|
|
{
|
|
return zswap_max_pages() * zswap_accept_thr_percent / 100;
|
|
}
|
|
|
|
unsigned long zswap_total_pages(void)
|
|
{
|
|
struct zswap_pool *pool;
|
|
unsigned long total = 0;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(pool, &zswap_pools, list) {
|
|
int i;
|
|
|
|
for (i = 0; i < ZSWAP_NR_ZPOOLS; i++)
|
|
total += zpool_get_total_pages(pool->zpools[i]);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return total;
|
|
}
|
|
|
|
/*********************************
|
|
* param callbacks
|
|
**********************************/
|
|
|
|
static bool zswap_pool_changed(const char *s, const struct kernel_param *kp)
|
|
{
|
|
/* no change required */
|
|
if (!strcmp(s, *(char **)kp->arg) && zswap_has_pool)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/* val must be a null-terminated string */
|
|
static int __zswap_param_set(const char *val, const struct kernel_param *kp,
|
|
char *type, char *compressor)
|
|
{
|
|
struct zswap_pool *pool, *put_pool = NULL;
|
|
char *s = strstrip((char *)val);
|
|
int ret = 0;
|
|
bool new_pool = false;
|
|
|
|
mutex_lock(&zswap_init_lock);
|
|
switch (zswap_init_state) {
|
|
case ZSWAP_UNINIT:
|
|
/* if this is load-time (pre-init) param setting,
|
|
* don't create a pool; that's done during init.
|
|
*/
|
|
ret = param_set_charp(s, kp);
|
|
break;
|
|
case ZSWAP_INIT_SUCCEED:
|
|
new_pool = zswap_pool_changed(s, kp);
|
|
break;
|
|
case ZSWAP_INIT_FAILED:
|
|
pr_err("can't set param, initialization failed\n");
|
|
ret = -ENODEV;
|
|
}
|
|
mutex_unlock(&zswap_init_lock);
|
|
|
|
/* no need to create a new pool, return directly */
|
|
if (!new_pool)
|
|
return ret;
|
|
|
|
if (!type) {
|
|
if (!zpool_has_pool(s)) {
|
|
pr_err("zpool %s not available\n", s);
|
|
return -ENOENT;
|
|
}
|
|
type = s;
|
|
} else if (!compressor) {
|
|
if (!crypto_has_acomp(s, 0, 0)) {
|
|
pr_err("compressor %s not available\n", s);
|
|
return -ENOENT;
|
|
}
|
|
compressor = s;
|
|
} else {
|
|
WARN_ON(1);
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_bh(&zswap_pools_lock);
|
|
|
|
pool = zswap_pool_find_get(type, compressor);
|
|
if (pool) {
|
|
zswap_pool_debug("using existing", pool);
|
|
WARN_ON(pool == zswap_pool_current());
|
|
list_del_rcu(&pool->list);
|
|
}
|
|
|
|
spin_unlock_bh(&zswap_pools_lock);
|
|
|
|
if (!pool)
|
|
pool = zswap_pool_create(type, compressor);
|
|
else {
|
|
/*
|
|
* Restore the initial ref dropped by percpu_ref_kill()
|
|
* when the pool was decommissioned and switch it again
|
|
* to percpu mode.
|
|
*/
|
|
percpu_ref_resurrect(&pool->ref);
|
|
|
|
/* Drop the ref from zswap_pool_find_get(). */
|
|
zswap_pool_put(pool);
|
|
}
|
|
|
|
if (pool)
|
|
ret = param_set_charp(s, kp);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
spin_lock_bh(&zswap_pools_lock);
|
|
|
|
if (!ret) {
|
|
put_pool = zswap_pool_current();
|
|
list_add_rcu(&pool->list, &zswap_pools);
|
|
zswap_has_pool = true;
|
|
} else if (pool) {
|
|
/* add the possibly pre-existing pool to the end of the pools
|
|
* list; if it's new (and empty) then it'll be removed and
|
|
* destroyed by the put after we drop the lock
|
|
*/
|
|
list_add_tail_rcu(&pool->list, &zswap_pools);
|
|
put_pool = pool;
|
|
}
|
|
|
|
spin_unlock_bh(&zswap_pools_lock);
|
|
|
|
if (!zswap_has_pool && !pool) {
|
|
/* if initial pool creation failed, and this pool creation also
|
|
* failed, maybe both compressor and zpool params were bad.
|
|
* Allow changing this param, so pool creation will succeed
|
|
* when the other param is changed. We already verified this
|
|
* param is ok in the zpool_has_pool() or crypto_has_acomp()
|
|
* checks above.
|
|
*/
|
|
ret = param_set_charp(s, kp);
|
|
}
|
|
|
|
/* drop the ref from either the old current pool,
|
|
* or the new pool we failed to add
|
|
*/
|
|
if (put_pool)
|
|
percpu_ref_kill(&put_pool->ref);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int zswap_compressor_param_set(const char *val,
|
|
const struct kernel_param *kp)
|
|
{
|
|
return __zswap_param_set(val, kp, zswap_zpool_type, NULL);
|
|
}
|
|
|
|
static int zswap_zpool_param_set(const char *val,
|
|
const struct kernel_param *kp)
|
|
{
|
|
return __zswap_param_set(val, kp, NULL, zswap_compressor);
|
|
}
|
|
|
|
static int zswap_enabled_param_set(const char *val,
|
|
const struct kernel_param *kp)
|
|
{
|
|
int ret = -ENODEV;
|
|
|
|
/* if this is load-time (pre-init) param setting, only set param. */
|
|
if (system_state != SYSTEM_RUNNING)
|
|
return param_set_bool(val, kp);
|
|
|
|
mutex_lock(&zswap_init_lock);
|
|
switch (zswap_init_state) {
|
|
case ZSWAP_UNINIT:
|
|
if (zswap_setup())
|
|
break;
|
|
fallthrough;
|
|
case ZSWAP_INIT_SUCCEED:
|
|
if (!zswap_has_pool)
|
|
pr_err("can't enable, no pool configured\n");
|
|
else
|
|
ret = param_set_bool(val, kp);
|
|
break;
|
|
case ZSWAP_INIT_FAILED:
|
|
pr_err("can't enable, initialization failed\n");
|
|
}
|
|
mutex_unlock(&zswap_init_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*********************************
|
|
* lru functions
|
|
**********************************/
|
|
|
|
/* should be called under RCU */
|
|
#ifdef CONFIG_MEMCG
|
|
static inline struct mem_cgroup *mem_cgroup_from_entry(struct zswap_entry *entry)
|
|
{
|
|
return entry->objcg ? obj_cgroup_memcg(entry->objcg) : NULL;
|
|
}
|
|
#else
|
|
static inline struct mem_cgroup *mem_cgroup_from_entry(struct zswap_entry *entry)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
static inline int entry_to_nid(struct zswap_entry *entry)
|
|
{
|
|
return page_to_nid(virt_to_page(entry));
|
|
}
|
|
|
|
static void zswap_lru_add(struct list_lru *list_lru, struct zswap_entry *entry)
|
|
{
|
|
atomic_long_t *nr_zswap_protected;
|
|
unsigned long lru_size, old, new;
|
|
int nid = entry_to_nid(entry);
|
|
struct mem_cgroup *memcg;
|
|
struct lruvec *lruvec;
|
|
|
|
/*
|
|
* Note that it is safe to use rcu_read_lock() here, even in the face of
|
|
* concurrent memcg offlining. Thanks to the memcg->kmemcg_id indirection
|
|
* used in list_lru lookup, only two scenarios are possible:
|
|
*
|
|
* 1. list_lru_add() is called before memcg->kmemcg_id is updated. The
|
|
* new entry will be reparented to memcg's parent's list_lru.
|
|
* 2. list_lru_add() is called after memcg->kmemcg_id is updated. The
|
|
* new entry will be added directly to memcg's parent's list_lru.
|
|
*
|
|
* Similar reasoning holds for list_lru_del().
|
|
*/
|
|
rcu_read_lock();
|
|
memcg = mem_cgroup_from_entry(entry);
|
|
/* will always succeed */
|
|
list_lru_add(list_lru, &entry->lru, nid, memcg);
|
|
|
|
/* Update the protection area */
|
|
lru_size = list_lru_count_one(list_lru, nid, memcg);
|
|
lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
|
|
nr_zswap_protected = &lruvec->zswap_lruvec_state.nr_zswap_protected;
|
|
old = atomic_long_inc_return(nr_zswap_protected);
|
|
/*
|
|
* Decay to avoid overflow and adapt to changing workloads.
|
|
* This is based on LRU reclaim cost decaying heuristics.
|
|
*/
|
|
do {
|
|
new = old > lru_size / 4 ? old / 2 : old;
|
|
} while (!atomic_long_try_cmpxchg(nr_zswap_protected, &old, new));
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void zswap_lru_del(struct list_lru *list_lru, struct zswap_entry *entry)
|
|
{
|
|
int nid = entry_to_nid(entry);
|
|
struct mem_cgroup *memcg;
|
|
|
|
rcu_read_lock();
|
|
memcg = mem_cgroup_from_entry(entry);
|
|
/* will always succeed */
|
|
list_lru_del(list_lru, &entry->lru, nid, memcg);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
void zswap_lruvec_state_init(struct lruvec *lruvec)
|
|
{
|
|
atomic_long_set(&lruvec->zswap_lruvec_state.nr_zswap_protected, 0);
|
|
}
|
|
|
|
void zswap_folio_swapin(struct folio *folio)
|
|
{
|
|
struct lruvec *lruvec;
|
|
|
|
if (folio) {
|
|
lruvec = folio_lruvec(folio);
|
|
atomic_long_inc(&lruvec->zswap_lruvec_state.nr_zswap_protected);
|
|
}
|
|
}
|
|
|
|
void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg)
|
|
{
|
|
/* lock out zswap shrinker walking memcg tree */
|
|
spin_lock(&zswap_shrink_lock);
|
|
if (zswap_next_shrink == memcg)
|
|
zswap_next_shrink = mem_cgroup_iter(NULL, zswap_next_shrink, NULL);
|
|
spin_unlock(&zswap_shrink_lock);
|
|
}
|
|
|
|
/*********************************
|
|
* rbtree functions
|
|
**********************************/
|
|
static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset)
|
|
{
|
|
struct rb_node *node = root->rb_node;
|
|
struct zswap_entry *entry;
|
|
pgoff_t entry_offset;
|
|
|
|
while (node) {
|
|
entry = rb_entry(node, struct zswap_entry, rbnode);
|
|
entry_offset = swp_offset(entry->swpentry);
|
|
if (entry_offset > offset)
|
|
node = node->rb_left;
|
|
else if (entry_offset < offset)
|
|
node = node->rb_right;
|
|
else
|
|
return entry;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* In the case that a entry with the same offset is found, a pointer to
|
|
* the existing entry is stored in dupentry and the function returns -EEXIST
|
|
*/
|
|
static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry,
|
|
struct zswap_entry **dupentry)
|
|
{
|
|
struct rb_node **link = &root->rb_node, *parent = NULL;
|
|
struct zswap_entry *myentry;
|
|
pgoff_t myentry_offset, entry_offset = swp_offset(entry->swpentry);
|
|
|
|
while (*link) {
|
|
parent = *link;
|
|
myentry = rb_entry(parent, struct zswap_entry, rbnode);
|
|
myentry_offset = swp_offset(myentry->swpentry);
|
|
if (myentry_offset > entry_offset)
|
|
link = &(*link)->rb_left;
|
|
else if (myentry_offset < entry_offset)
|
|
link = &(*link)->rb_right;
|
|
else {
|
|
*dupentry = myentry;
|
|
return -EEXIST;
|
|
}
|
|
}
|
|
rb_link_node(&entry->rbnode, parent, link);
|
|
rb_insert_color(&entry->rbnode, root);
|
|
return 0;
|
|
}
|
|
|
|
static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
|
|
{
|
|
rb_erase(&entry->rbnode, root);
|
|
RB_CLEAR_NODE(&entry->rbnode);
|
|
}
|
|
|
|
/*********************************
|
|
* zswap entry functions
|
|
**********************************/
|
|
static struct kmem_cache *zswap_entry_cache;
|
|
|
|
static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp, int nid)
|
|
{
|
|
struct zswap_entry *entry;
|
|
entry = kmem_cache_alloc_node(zswap_entry_cache, gfp, nid);
|
|
if (!entry)
|
|
return NULL;
|
|
RB_CLEAR_NODE(&entry->rbnode);
|
|
return entry;
|
|
}
|
|
|
|
static void zswap_entry_cache_free(struct zswap_entry *entry)
|
|
{
|
|
kmem_cache_free(zswap_entry_cache, entry);
|
|
}
|
|
|
|
static struct zpool *zswap_find_zpool(struct zswap_entry *entry)
|
|
{
|
|
return entry->pool->zpools[hash_ptr(entry, ilog2(ZSWAP_NR_ZPOOLS))];
|
|
}
|
|
|
|
/*
|
|
* Carries out the common pattern of freeing and entry's zpool allocation,
|
|
* freeing the entry itself, and decrementing the number of stored pages.
|
|
*/
|
|
static void zswap_entry_free(struct zswap_entry *entry)
|
|
{
|
|
if (!entry->length)
|
|
atomic_dec(&zswap_same_filled_pages);
|
|
else {
|
|
zswap_lru_del(&zswap_list_lru, entry);
|
|
zpool_free(zswap_find_zpool(entry), entry->handle);
|
|
atomic_dec(&zswap_nr_stored);
|
|
zswap_pool_put(entry->pool);
|
|
}
|
|
if (entry->objcg) {
|
|
obj_cgroup_uncharge_zswap(entry->objcg, entry->length);
|
|
obj_cgroup_put(entry->objcg);
|
|
}
|
|
zswap_entry_cache_free(entry);
|
|
atomic_dec(&zswap_stored_pages);
|
|
}
|
|
|
|
/*
|
|
* The caller hold the tree lock and search the entry from the tree,
|
|
* so it must be on the tree, remove it from the tree and free it.
|
|
*/
|
|
static void zswap_invalidate_entry(struct zswap_tree *tree,
|
|
struct zswap_entry *entry)
|
|
{
|
|
zswap_rb_erase(&tree->rbroot, entry);
|
|
zswap_entry_free(entry);
|
|
}
|
|
|
|
/*********************************
|
|
* compressed storage functions
|
|
**********************************/
|
|
static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
|
|
{
|
|
struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
|
|
struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
|
|
struct crypto_acomp *acomp;
|
|
struct acomp_req *req;
|
|
int ret;
|
|
|
|
mutex_init(&acomp_ctx->mutex);
|
|
|
|
acomp_ctx->buffer = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
|
|
if (!acomp_ctx->buffer)
|
|
return -ENOMEM;
|
|
|
|
acomp = crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to_node(cpu));
|
|
if (IS_ERR(acomp)) {
|
|
pr_err("could not alloc crypto acomp %s : %ld\n",
|
|
pool->tfm_name, PTR_ERR(acomp));
|
|
ret = PTR_ERR(acomp);
|
|
goto acomp_fail;
|
|
}
|
|
acomp_ctx->acomp = acomp;
|
|
acomp_ctx->is_sleepable = acomp_is_async(acomp);
|
|
|
|
req = acomp_request_alloc(acomp_ctx->acomp);
|
|
if (!req) {
|
|
pr_err("could not alloc crypto acomp_request %s\n",
|
|
pool->tfm_name);
|
|
ret = -ENOMEM;
|
|
goto req_fail;
|
|
}
|
|
acomp_ctx->req = req;
|
|
|
|
crypto_init_wait(&acomp_ctx->wait);
|
|
/*
|
|
* if the backend of acomp is async zip, crypto_req_done() will wakeup
|
|
* crypto_wait_req(); if the backend of acomp is scomp, the callback
|
|
* won't be called, crypto_wait_req() will return without blocking.
|
|
*/
|
|
acomp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
|
|
crypto_req_done, &acomp_ctx->wait);
|
|
|
|
return 0;
|
|
|
|
req_fail:
|
|
crypto_free_acomp(acomp_ctx->acomp);
|
|
acomp_fail:
|
|
kfree(acomp_ctx->buffer);
|
|
return ret;
|
|
}
|
|
|
|
static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
|
|
{
|
|
struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
|
|
struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu);
|
|
|
|
if (!IS_ERR_OR_NULL(acomp_ctx)) {
|
|
if (!IS_ERR_OR_NULL(acomp_ctx->req))
|
|
acomp_request_free(acomp_ctx->req);
|
|
if (!IS_ERR_OR_NULL(acomp_ctx->acomp))
|
|
crypto_free_acomp(acomp_ctx->acomp);
|
|
kfree(acomp_ctx->buffer);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static bool zswap_compress(struct folio *folio, struct zswap_entry *entry)
|
|
{
|
|
struct crypto_acomp_ctx *acomp_ctx;
|
|
struct scatterlist input, output;
|
|
int comp_ret = 0, alloc_ret = 0;
|
|
unsigned int dlen = PAGE_SIZE;
|
|
unsigned long handle;
|
|
struct zpool *zpool;
|
|
char *buf;
|
|
gfp_t gfp;
|
|
u8 *dst;
|
|
|
|
acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
|
|
|
|
mutex_lock(&acomp_ctx->mutex);
|
|
|
|
dst = acomp_ctx->buffer;
|
|
sg_init_table(&input, 1);
|
|
sg_set_page(&input, &folio->page, PAGE_SIZE, 0);
|
|
|
|
/*
|
|
* We need PAGE_SIZE * 2 here since there maybe over-compression case,
|
|
* and hardware-accelerators may won't check the dst buffer size, so
|
|
* giving the dst buffer with enough length to avoid buffer overflow.
|
|
*/
|
|
sg_init_one(&output, dst, PAGE_SIZE * 2);
|
|
acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
|
|
|
|
/*
|
|
* it maybe looks a little bit silly that we send an asynchronous request,
|
|
* then wait for its completion synchronously. This makes the process look
|
|
* synchronous in fact.
|
|
* Theoretically, acomp supports users send multiple acomp requests in one
|
|
* acomp instance, then get those requests done simultaneously. but in this
|
|
* case, zswap actually does store and load page by page, there is no
|
|
* existing method to send the second page before the first page is done
|
|
* in one thread doing zwap.
|
|
* but in different threads running on different cpu, we have different
|
|
* acomp instance, so multiple threads can do (de)compression in parallel.
|
|
*/
|
|
comp_ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
|
|
dlen = acomp_ctx->req->dlen;
|
|
if (comp_ret)
|
|
goto unlock;
|
|
|
|
zpool = zswap_find_zpool(entry);
|
|
gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
|
|
if (zpool_malloc_support_movable(zpool))
|
|
gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
|
|
alloc_ret = zpool_malloc(zpool, dlen, gfp, &handle);
|
|
if (alloc_ret)
|
|
goto unlock;
|
|
|
|
buf = zpool_map_handle(zpool, handle, ZPOOL_MM_WO);
|
|
memcpy(buf, dst, dlen);
|
|
zpool_unmap_handle(zpool, handle);
|
|
|
|
entry->handle = handle;
|
|
entry->length = dlen;
|
|
|
|
unlock:
|
|
if (comp_ret == -ENOSPC || alloc_ret == -ENOSPC)
|
|
zswap_reject_compress_poor++;
|
|
else if (comp_ret)
|
|
zswap_reject_compress_fail++;
|
|
else if (alloc_ret)
|
|
zswap_reject_alloc_fail++;
|
|
|
|
mutex_unlock(&acomp_ctx->mutex);
|
|
return comp_ret == 0 && alloc_ret == 0;
|
|
}
|
|
|
|
static void zswap_decompress(struct zswap_entry *entry, struct page *page)
|
|
{
|
|
struct zpool *zpool = zswap_find_zpool(entry);
|
|
struct scatterlist input, output;
|
|
struct crypto_acomp_ctx *acomp_ctx;
|
|
u8 *src;
|
|
|
|
acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
|
|
mutex_lock(&acomp_ctx->mutex);
|
|
|
|
src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO);
|
|
/*
|
|
* If zpool_map_handle is atomic, we cannot reliably utilize its mapped buffer
|
|
* to do crypto_acomp_decompress() which might sleep. In such cases, we must
|
|
* resort to copying the buffer to a temporary one.
|
|
* Meanwhile, zpool_map_handle() might return a non-linearly mapped buffer,
|
|
* such as a kmap address of high memory or even ever a vmap address.
|
|
* However, sg_init_one is only equipped to handle linearly mapped low memory.
|
|
* In such cases, we also must copy the buffer to a temporary and lowmem one.
|
|
*/
|
|
if ((acomp_ctx->is_sleepable && !zpool_can_sleep_mapped(zpool)) ||
|
|
!virt_addr_valid(src)) {
|
|
memcpy(acomp_ctx->buffer, src, entry->length);
|
|
src = acomp_ctx->buffer;
|
|
zpool_unmap_handle(zpool, entry->handle);
|
|
}
|
|
|
|
sg_init_one(&input, src, entry->length);
|
|
sg_init_table(&output, 1);
|
|
sg_set_page(&output, page, PAGE_SIZE, 0);
|
|
acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE);
|
|
BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait));
|
|
BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE);
|
|
mutex_unlock(&acomp_ctx->mutex);
|
|
|
|
if (src != acomp_ctx->buffer)
|
|
zpool_unmap_handle(zpool, entry->handle);
|
|
}
|
|
|
|
/*********************************
|
|
* writeback code
|
|
**********************************/
|
|
/*
|
|
* Attempts to free an entry by adding a folio to the swap cache,
|
|
* decompressing the entry data into the folio, and issuing a
|
|
* bio write to write the folio back to the swap device.
|
|
*
|
|
* This can be thought of as a "resumed writeback" of the folio
|
|
* to the swap device. We are basically resuming the same swap
|
|
* writeback path that was intercepted with the zswap_store()
|
|
* in the first place. After the folio has been decompressed into
|
|
* the swap cache, the compressed version stored by zswap can be
|
|
* freed.
|
|
*/
|
|
static int zswap_writeback_entry(struct zswap_entry *entry,
|
|
swp_entry_t swpentry)
|
|
{
|
|
struct zswap_tree *tree;
|
|
struct folio *folio;
|
|
struct mempolicy *mpol;
|
|
bool folio_was_allocated;
|
|
struct writeback_control wbc = {
|
|
.sync_mode = WB_SYNC_NONE,
|
|
};
|
|
|
|
/* try to allocate swap cache folio */
|
|
mpol = get_task_policy(current);
|
|
folio = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol,
|
|
NO_INTERLEAVE_INDEX, &folio_was_allocated, true);
|
|
if (!folio)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* Found an existing folio, we raced with swapin or concurrent
|
|
* shrinker. We generally writeback cold folios from zswap, and
|
|
* swapin means the folio just became hot, so skip this folio.
|
|
* For unlikely concurrent shrinker case, it will be unlinked
|
|
* and freed when invalidated by the concurrent shrinker anyway.
|
|
*/
|
|
if (!folio_was_allocated) {
|
|
folio_put(folio);
|
|
return -EEXIST;
|
|
}
|
|
|
|
/*
|
|
* folio is locked, and the swapcache is now secured against
|
|
* concurrent swapping to and from the slot, and concurrent
|
|
* swapoff so we can safely dereference the zswap tree here.
|
|
* Verify that the swap entry hasn't been invalidated and recycled
|
|
* behind our backs, to avoid overwriting a new swap folio with
|
|
* old compressed data. Only when this is successful can the entry
|
|
* be dereferenced.
|
|
*/
|
|
tree = swap_zswap_tree(swpentry);
|
|
spin_lock(&tree->lock);
|
|
if (zswap_rb_search(&tree->rbroot, swp_offset(swpentry)) != entry) {
|
|
spin_unlock(&tree->lock);
|
|
delete_from_swap_cache(folio);
|
|
folio_unlock(folio);
|
|
folio_put(folio);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Safe to deref entry after the entry is verified above. */
|
|
zswap_rb_erase(&tree->rbroot, entry);
|
|
spin_unlock(&tree->lock);
|
|
|
|
zswap_decompress(entry, &folio->page);
|
|
|
|
count_vm_event(ZSWPWB);
|
|
if (entry->objcg)
|
|
count_objcg_event(entry->objcg, ZSWPWB);
|
|
|
|
zswap_entry_free(entry);
|
|
|
|
/* folio is up to date */
|
|
folio_mark_uptodate(folio);
|
|
|
|
/* move it to the tail of the inactive list after end_writeback */
|
|
folio_set_reclaim(folio);
|
|
|
|
/* start writeback */
|
|
__swap_writepage(folio, &wbc);
|
|
folio_put(folio);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*********************************
|
|
* shrinker functions
|
|
**********************************/
|
|
static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_one *l,
|
|
spinlock_t *lock, void *arg)
|
|
{
|
|
struct zswap_entry *entry = container_of(item, struct zswap_entry, lru);
|
|
bool *encountered_page_in_swapcache = (bool *)arg;
|
|
swp_entry_t swpentry;
|
|
enum lru_status ret = LRU_REMOVED_RETRY;
|
|
int writeback_result;
|
|
|
|
/*
|
|
* As soon as we drop the LRU lock, the entry can be freed by
|
|
* a concurrent invalidation. This means the following:
|
|
*
|
|
* 1. We extract the swp_entry_t to the stack, allowing
|
|
* zswap_writeback_entry() to pin the swap entry and
|
|
* then validate the zwap entry against that swap entry's
|
|
* tree using pointer value comparison. Only when that
|
|
* is successful can the entry be dereferenced.
|
|
*
|
|
* 2. Usually, objects are taken off the LRU for reclaim. In
|
|
* this case this isn't possible, because if reclaim fails
|
|
* for whatever reason, we have no means of knowing if the
|
|
* entry is alive to put it back on the LRU.
|
|
*
|
|
* So rotate it before dropping the lock. If the entry is
|
|
* written back or invalidated, the free path will unlink
|
|
* it. For failures, rotation is the right thing as well.
|
|
*
|
|
* Temporary failures, where the same entry should be tried
|
|
* again immediately, almost never happen for this shrinker.
|
|
* We don't do any trylocking; -ENOMEM comes closest,
|
|
* but that's extremely rare and doesn't happen spuriously
|
|
* either. Don't bother distinguishing this case.
|
|
*/
|
|
list_move_tail(item, &l->list);
|
|
|
|
/*
|
|
* Once the lru lock is dropped, the entry might get freed. The
|
|
* swpentry is copied to the stack, and entry isn't deref'd again
|
|
* until the entry is verified to still be alive in the tree.
|
|
*/
|
|
swpentry = entry->swpentry;
|
|
|
|
/*
|
|
* It's safe to drop the lock here because we return either
|
|
* LRU_REMOVED_RETRY or LRU_RETRY.
|
|
*/
|
|
spin_unlock(lock);
|
|
|
|
writeback_result = zswap_writeback_entry(entry, swpentry);
|
|
|
|
if (writeback_result) {
|
|
zswap_reject_reclaim_fail++;
|
|
ret = LRU_RETRY;
|
|
|
|
/*
|
|
* Encountering a page already in swap cache is a sign that we are shrinking
|
|
* into the warmer region. We should terminate shrinking (if we're in the dynamic
|
|
* shrinker context).
|
|
*/
|
|
if (writeback_result == -EEXIST && encountered_page_in_swapcache) {
|
|
ret = LRU_STOP;
|
|
*encountered_page_in_swapcache = true;
|
|
}
|
|
} else {
|
|
zswap_written_back_pages++;
|
|
}
|
|
|
|
spin_lock(lock);
|
|
return ret;
|
|
}
|
|
|
|
static unsigned long zswap_shrinker_scan(struct shrinker *shrinker,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct lruvec *lruvec = mem_cgroup_lruvec(sc->memcg, NODE_DATA(sc->nid));
|
|
unsigned long shrink_ret, nr_protected, lru_size;
|
|
bool encountered_page_in_swapcache = false;
|
|
|
|
if (!zswap_shrinker_enabled ||
|
|
!mem_cgroup_zswap_writeback_enabled(sc->memcg)) {
|
|
sc->nr_scanned = 0;
|
|
return SHRINK_STOP;
|
|
}
|
|
|
|
nr_protected =
|
|
atomic_long_read(&lruvec->zswap_lruvec_state.nr_zswap_protected);
|
|
lru_size = list_lru_shrink_count(&zswap_list_lru, sc);
|
|
|
|
/*
|
|
* Abort if we are shrinking into the protected region.
|
|
*
|
|
* This short-circuiting is necessary because if we have too many multiple
|
|
* concurrent reclaimers getting the freeable zswap object counts at the
|
|
* same time (before any of them made reasonable progress), the total
|
|
* number of reclaimed objects might be more than the number of unprotected
|
|
* objects (i.e the reclaimers will reclaim into the protected area of the
|
|
* zswap LRU).
|
|
*/
|
|
if (nr_protected >= lru_size - sc->nr_to_scan) {
|
|
sc->nr_scanned = 0;
|
|
return SHRINK_STOP;
|
|
}
|
|
|
|
shrink_ret = list_lru_shrink_walk(&zswap_list_lru, sc, &shrink_memcg_cb,
|
|
&encountered_page_in_swapcache);
|
|
|
|
if (encountered_page_in_swapcache)
|
|
return SHRINK_STOP;
|
|
|
|
return shrink_ret ? shrink_ret : SHRINK_STOP;
|
|
}
|
|
|
|
static unsigned long zswap_shrinker_count(struct shrinker *shrinker,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct mem_cgroup *memcg = sc->memcg;
|
|
struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(sc->nid));
|
|
unsigned long nr_backing, nr_stored, nr_freeable, nr_protected;
|
|
|
|
if (!zswap_shrinker_enabled || !mem_cgroup_zswap_writeback_enabled(memcg))
|
|
return 0;
|
|
|
|
/*
|
|
* The shrinker resumes swap writeback, which will enter block
|
|
* and may enter fs. XXX: Harmonize with vmscan.c __GFP_FS
|
|
* rules (may_enter_fs()), which apply on a per-folio basis.
|
|
*/
|
|
if (!gfp_has_io_fs(sc->gfp_mask))
|
|
return 0;
|
|
|
|
/*
|
|
* For memcg, use the cgroup-wide ZSWAP stats since we don't
|
|
* have them per-node and thus per-lruvec. Careful if memcg is
|
|
* runtime-disabled: we can get sc->memcg == NULL, which is ok
|
|
* for the lruvec, but not for memcg_page_state().
|
|
*
|
|
* Without memcg, use the zswap pool-wide metrics.
|
|
*/
|
|
if (!mem_cgroup_disabled()) {
|
|
mem_cgroup_flush_stats(memcg);
|
|
nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT;
|
|
nr_stored = memcg_page_state(memcg, MEMCG_ZSWAPPED);
|
|
} else {
|
|
nr_backing = zswap_total_pages();
|
|
nr_stored = atomic_read(&zswap_nr_stored);
|
|
}
|
|
|
|
if (!nr_stored)
|
|
return 0;
|
|
|
|
nr_protected =
|
|
atomic_long_read(&lruvec->zswap_lruvec_state.nr_zswap_protected);
|
|
nr_freeable = list_lru_shrink_count(&zswap_list_lru, sc);
|
|
/*
|
|
* Subtract the lru size by an estimate of the number of pages
|
|
* that should be protected.
|
|
*/
|
|
nr_freeable = nr_freeable > nr_protected ? nr_freeable - nr_protected : 0;
|
|
|
|
/*
|
|
* Scale the number of freeable pages by the memory saving factor.
|
|
* This ensures that the better zswap compresses memory, the fewer
|
|
* pages we will evict to swap (as it will otherwise incur IO for
|
|
* relatively small memory saving).
|
|
*/
|
|
return mult_frac(nr_freeable, nr_backing, nr_stored);
|
|
}
|
|
|
|
static struct shrinker *zswap_alloc_shrinker(void)
|
|
{
|
|
struct shrinker *shrinker;
|
|
|
|
shrinker =
|
|
shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE, "mm-zswap");
|
|
if (!shrinker)
|
|
return NULL;
|
|
|
|
shrinker->scan_objects = zswap_shrinker_scan;
|
|
shrinker->count_objects = zswap_shrinker_count;
|
|
shrinker->batch = 0;
|
|
shrinker->seeks = DEFAULT_SEEKS;
|
|
return shrinker;
|
|
}
|
|
|
|
static int shrink_memcg(struct mem_cgroup *memcg)
|
|
{
|
|
int nid, shrunk = 0;
|
|
|
|
if (!mem_cgroup_zswap_writeback_enabled(memcg))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Skip zombies because their LRUs are reparented and we would be
|
|
* reclaiming from the parent instead of the dead memcg.
|
|
*/
|
|
if (memcg && !mem_cgroup_online(memcg))
|
|
return -ENOENT;
|
|
|
|
for_each_node_state(nid, N_NORMAL_MEMORY) {
|
|
unsigned long nr_to_walk = 1;
|
|
|
|
shrunk += list_lru_walk_one(&zswap_list_lru, nid, memcg,
|
|
&shrink_memcg_cb, NULL, &nr_to_walk);
|
|
}
|
|
return shrunk ? 0 : -EAGAIN;
|
|
}
|
|
|
|
static void shrink_worker(struct work_struct *w)
|
|
{
|
|
struct mem_cgroup *memcg;
|
|
int ret, failures = 0;
|
|
unsigned long thr;
|
|
|
|
/* Reclaim down to the accept threshold */
|
|
thr = zswap_accept_thr_pages();
|
|
|
|
/* global reclaim will select cgroup in a round-robin fashion. */
|
|
do {
|
|
spin_lock(&zswap_shrink_lock);
|
|
zswap_next_shrink = mem_cgroup_iter(NULL, zswap_next_shrink, NULL);
|
|
memcg = zswap_next_shrink;
|
|
|
|
/*
|
|
* We need to retry if we have gone through a full round trip, or if we
|
|
* got an offline memcg (or else we risk undoing the effect of the
|
|
* zswap memcg offlining cleanup callback). This is not catastrophic
|
|
* per se, but it will keep the now offlined memcg hostage for a while.
|
|
*
|
|
* Note that if we got an online memcg, we will keep the extra
|
|
* reference in case the original reference obtained by mem_cgroup_iter
|
|
* is dropped by the zswap memcg offlining callback, ensuring that the
|
|
* memcg is not killed when we are reclaiming.
|
|
*/
|
|
if (!memcg) {
|
|
spin_unlock(&zswap_shrink_lock);
|
|
if (++failures == MAX_RECLAIM_RETRIES)
|
|
break;
|
|
|
|
goto resched;
|
|
}
|
|
|
|
if (!mem_cgroup_tryget_online(memcg)) {
|
|
/* drop the reference from mem_cgroup_iter() */
|
|
mem_cgroup_iter_break(NULL, memcg);
|
|
zswap_next_shrink = NULL;
|
|
spin_unlock(&zswap_shrink_lock);
|
|
|
|
if (++failures == MAX_RECLAIM_RETRIES)
|
|
break;
|
|
|
|
goto resched;
|
|
}
|
|
spin_unlock(&zswap_shrink_lock);
|
|
|
|
ret = shrink_memcg(memcg);
|
|
/* drop the extra reference */
|
|
mem_cgroup_put(memcg);
|
|
|
|
if (ret == -EINVAL)
|
|
break;
|
|
if (ret && ++failures == MAX_RECLAIM_RETRIES)
|
|
break;
|
|
resched:
|
|
cond_resched();
|
|
} while (zswap_total_pages() > thr);
|
|
}
|
|
|
|
static int zswap_is_page_same_filled(void *ptr, unsigned long *value)
|
|
{
|
|
unsigned long *page;
|
|
unsigned long val;
|
|
unsigned int pos, last_pos = PAGE_SIZE / sizeof(*page) - 1;
|
|
|
|
page = (unsigned long *)ptr;
|
|
val = page[0];
|
|
|
|
if (val != page[last_pos])
|
|
return 0;
|
|
|
|
for (pos = 1; pos < last_pos; pos++) {
|
|
if (val != page[pos])
|
|
return 0;
|
|
}
|
|
|
|
*value = val;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void zswap_fill_page(void *ptr, unsigned long value)
|
|
{
|
|
unsigned long *page;
|
|
|
|
page = (unsigned long *)ptr;
|
|
memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
|
|
}
|
|
|
|
bool zswap_store(struct folio *folio)
|
|
{
|
|
swp_entry_t swp = folio->swap;
|
|
pgoff_t offset = swp_offset(swp);
|
|
struct zswap_tree *tree = swap_zswap_tree(swp);
|
|
struct zswap_entry *entry, *dupentry;
|
|
struct obj_cgroup *objcg = NULL;
|
|
struct mem_cgroup *memcg = NULL;
|
|
unsigned long max_pages, cur_pages;
|
|
|
|
VM_WARN_ON_ONCE(!folio_test_locked(folio));
|
|
VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
|
|
|
|
/* Large folios aren't supported */
|
|
if (folio_test_large(folio))
|
|
return false;
|
|
|
|
if (!zswap_enabled)
|
|
goto check_old;
|
|
|
|
/* Check cgroup limits */
|
|
objcg = get_obj_cgroup_from_folio(folio);
|
|
if (objcg && !obj_cgroup_may_zswap(objcg)) {
|
|
memcg = get_mem_cgroup_from_objcg(objcg);
|
|
if (shrink_memcg(memcg)) {
|
|
mem_cgroup_put(memcg);
|
|
goto reject;
|
|
}
|
|
mem_cgroup_put(memcg);
|
|
}
|
|
|
|
/* Check global limits */
|
|
cur_pages = zswap_total_pages();
|
|
max_pages = zswap_max_pages();
|
|
|
|
if (cur_pages >= max_pages) {
|
|
zswap_pool_limit_hit++;
|
|
zswap_pool_reached_full = true;
|
|
goto shrink;
|
|
}
|
|
|
|
if (zswap_pool_reached_full) {
|
|
if (cur_pages > zswap_accept_thr_pages())
|
|
goto shrink;
|
|
else
|
|
zswap_pool_reached_full = false;
|
|
}
|
|
|
|
/* allocate entry */
|
|
entry = zswap_entry_cache_alloc(GFP_KERNEL, folio_nid(folio));
|
|
if (!entry) {
|
|
zswap_reject_kmemcache_fail++;
|
|
goto reject;
|
|
}
|
|
|
|
if (zswap_same_filled_pages_enabled) {
|
|
unsigned long value;
|
|
u8 *src;
|
|
|
|
src = kmap_local_folio(folio, 0);
|
|
if (zswap_is_page_same_filled(src, &value)) {
|
|
kunmap_local(src);
|
|
entry->length = 0;
|
|
entry->value = value;
|
|
atomic_inc(&zswap_same_filled_pages);
|
|
goto insert_entry;
|
|
}
|
|
kunmap_local(src);
|
|
}
|
|
|
|
if (!zswap_non_same_filled_pages_enabled)
|
|
goto freepage;
|
|
|
|
/* if entry is successfully added, it keeps the reference */
|
|
entry->pool = zswap_pool_current_get();
|
|
if (!entry->pool)
|
|
goto freepage;
|
|
|
|
if (objcg) {
|
|
memcg = get_mem_cgroup_from_objcg(objcg);
|
|
if (memcg_list_lru_alloc(memcg, &zswap_list_lru, GFP_KERNEL)) {
|
|
mem_cgroup_put(memcg);
|
|
goto put_pool;
|
|
}
|
|
mem_cgroup_put(memcg);
|
|
}
|
|
|
|
if (!zswap_compress(folio, entry))
|
|
goto put_pool;
|
|
|
|
insert_entry:
|
|
entry->swpentry = swp;
|
|
entry->objcg = objcg;
|
|
if (objcg) {
|
|
obj_cgroup_charge_zswap(objcg, entry->length);
|
|
/* Account before objcg ref is moved to tree */
|
|
count_objcg_event(objcg, ZSWPOUT);
|
|
}
|
|
|
|
/* map */
|
|
spin_lock(&tree->lock);
|
|
/*
|
|
* The folio may have been dirtied again, invalidate the
|
|
* possibly stale entry before inserting the new entry.
|
|
*/
|
|
if (zswap_rb_insert(&tree->rbroot, entry, &dupentry) == -EEXIST) {
|
|
zswap_invalidate_entry(tree, dupentry);
|
|
WARN_ON(zswap_rb_insert(&tree->rbroot, entry, &dupentry));
|
|
}
|
|
if (entry->length) {
|
|
INIT_LIST_HEAD(&entry->lru);
|
|
zswap_lru_add(&zswap_list_lru, entry);
|
|
atomic_inc(&zswap_nr_stored);
|
|
}
|
|
spin_unlock(&tree->lock);
|
|
|
|
/* update stats */
|
|
atomic_inc(&zswap_stored_pages);
|
|
count_vm_event(ZSWPOUT);
|
|
|
|
return true;
|
|
|
|
put_pool:
|
|
zswap_pool_put(entry->pool);
|
|
freepage:
|
|
zswap_entry_cache_free(entry);
|
|
reject:
|
|
obj_cgroup_put(objcg);
|
|
check_old:
|
|
/*
|
|
* If the zswap store fails or zswap is disabled, we must invalidate the
|
|
* possibly stale entry which was previously stored at this offset.
|
|
* Otherwise, writeback could overwrite the new data in the swapfile.
|
|
*/
|
|
spin_lock(&tree->lock);
|
|
entry = zswap_rb_search(&tree->rbroot, offset);
|
|
if (entry)
|
|
zswap_invalidate_entry(tree, entry);
|
|
spin_unlock(&tree->lock);
|
|
return false;
|
|
|
|
shrink:
|
|
queue_work(shrink_wq, &zswap_shrink_work);
|
|
goto reject;
|
|
}
|
|
|
|
bool zswap_load(struct folio *folio)
|
|
{
|
|
swp_entry_t swp = folio->swap;
|
|
pgoff_t offset = swp_offset(swp);
|
|
struct page *page = &folio->page;
|
|
bool swapcache = folio_test_swapcache(folio);
|
|
struct zswap_tree *tree = swap_zswap_tree(swp);
|
|
struct zswap_entry *entry;
|
|
u8 *dst;
|
|
|
|
VM_WARN_ON_ONCE(!folio_test_locked(folio));
|
|
|
|
spin_lock(&tree->lock);
|
|
entry = zswap_rb_search(&tree->rbroot, offset);
|
|
if (!entry) {
|
|
spin_unlock(&tree->lock);
|
|
return false;
|
|
}
|
|
/*
|
|
* When reading into the swapcache, invalidate our entry. The
|
|
* swapcache can be the authoritative owner of the page and
|
|
* its mappings, and the pressure that results from having two
|
|
* in-memory copies outweighs any benefits of caching the
|
|
* compression work.
|
|
*
|
|
* (Most swapins go through the swapcache. The notable
|
|
* exception is the singleton fault on SWP_SYNCHRONOUS_IO
|
|
* files, which reads into a private page and may free it if
|
|
* the fault fails. We remain the primary owner of the entry.)
|
|
*/
|
|
if (swapcache)
|
|
zswap_rb_erase(&tree->rbroot, entry);
|
|
spin_unlock(&tree->lock);
|
|
|
|
if (entry->length)
|
|
zswap_decompress(entry, page);
|
|
else {
|
|
dst = kmap_local_page(page);
|
|
zswap_fill_page(dst, entry->value);
|
|
kunmap_local(dst);
|
|
}
|
|
|
|
count_vm_event(ZSWPIN);
|
|
if (entry->objcg)
|
|
count_objcg_event(entry->objcg, ZSWPIN);
|
|
|
|
if (swapcache) {
|
|
zswap_entry_free(entry);
|
|
folio_mark_dirty(folio);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void zswap_invalidate(swp_entry_t swp)
|
|
{
|
|
pgoff_t offset = swp_offset(swp);
|
|
struct zswap_tree *tree = swap_zswap_tree(swp);
|
|
struct zswap_entry *entry;
|
|
|
|
spin_lock(&tree->lock);
|
|
entry = zswap_rb_search(&tree->rbroot, offset);
|
|
if (entry)
|
|
zswap_invalidate_entry(tree, entry);
|
|
spin_unlock(&tree->lock);
|
|
}
|
|
|
|
int zswap_swapon(int type, unsigned long nr_pages)
|
|
{
|
|
struct zswap_tree *trees, *tree;
|
|
unsigned int nr, i;
|
|
|
|
nr = DIV_ROUND_UP(nr_pages, SWAP_ADDRESS_SPACE_PAGES);
|
|
trees = kvcalloc(nr, sizeof(*tree), GFP_KERNEL);
|
|
if (!trees) {
|
|
pr_err("alloc failed, zswap disabled for swap type %d\n", type);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < nr; i++) {
|
|
tree = trees + i;
|
|
tree->rbroot = RB_ROOT;
|
|
spin_lock_init(&tree->lock);
|
|
}
|
|
|
|
nr_zswap_trees[type] = nr;
|
|
zswap_trees[type] = trees;
|
|
return 0;
|
|
}
|
|
|
|
void zswap_swapoff(int type)
|
|
{
|
|
struct zswap_tree *trees = zswap_trees[type];
|
|
unsigned int i;
|
|
|
|
if (!trees)
|
|
return;
|
|
|
|
/* try_to_unuse() invalidated all the entries already */
|
|
for (i = 0; i < nr_zswap_trees[type]; i++)
|
|
WARN_ON_ONCE(!RB_EMPTY_ROOT(&trees[i].rbroot));
|
|
|
|
kvfree(trees);
|
|
nr_zswap_trees[type] = 0;
|
|
zswap_trees[type] = NULL;
|
|
}
|
|
|
|
/*********************************
|
|
* debugfs functions
|
|
**********************************/
|
|
#ifdef CONFIG_DEBUG_FS
|
|
#include <linux/debugfs.h>
|
|
|
|
static struct dentry *zswap_debugfs_root;
|
|
|
|
static int debugfs_get_total_size(void *data, u64 *val)
|
|
{
|
|
*val = zswap_total_pages() * PAGE_SIZE;
|
|
return 0;
|
|
}
|
|
DEFINE_DEBUGFS_ATTRIBUTE(total_size_fops, debugfs_get_total_size, NULL, "%llu\n");
|
|
|
|
static int zswap_debugfs_init(void)
|
|
{
|
|
if (!debugfs_initialized())
|
|
return -ENODEV;
|
|
|
|
zswap_debugfs_root = debugfs_create_dir("zswap", NULL);
|
|
|
|
debugfs_create_u64("pool_limit_hit", 0444,
|
|
zswap_debugfs_root, &zswap_pool_limit_hit);
|
|
debugfs_create_u64("reject_reclaim_fail", 0444,
|
|
zswap_debugfs_root, &zswap_reject_reclaim_fail);
|
|
debugfs_create_u64("reject_alloc_fail", 0444,
|
|
zswap_debugfs_root, &zswap_reject_alloc_fail);
|
|
debugfs_create_u64("reject_kmemcache_fail", 0444,
|
|
zswap_debugfs_root, &zswap_reject_kmemcache_fail);
|
|
debugfs_create_u64("reject_compress_fail", 0444,
|
|
zswap_debugfs_root, &zswap_reject_compress_fail);
|
|
debugfs_create_u64("reject_compress_poor", 0444,
|
|
zswap_debugfs_root, &zswap_reject_compress_poor);
|
|
debugfs_create_u64("written_back_pages", 0444,
|
|
zswap_debugfs_root, &zswap_written_back_pages);
|
|
debugfs_create_file("pool_total_size", 0444,
|
|
zswap_debugfs_root, NULL, &total_size_fops);
|
|
debugfs_create_atomic_t("stored_pages", 0444,
|
|
zswap_debugfs_root, &zswap_stored_pages);
|
|
debugfs_create_atomic_t("same_filled_pages", 0444,
|
|
zswap_debugfs_root, &zswap_same_filled_pages);
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
static int zswap_debugfs_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
/*********************************
|
|
* module init and exit
|
|
**********************************/
|
|
static int zswap_setup(void)
|
|
{
|
|
struct zswap_pool *pool;
|
|
int ret;
|
|
|
|
zswap_entry_cache = KMEM_CACHE(zswap_entry, 0);
|
|
if (!zswap_entry_cache) {
|
|
pr_err("entry cache creation failed\n");
|
|
goto cache_fail;
|
|
}
|
|
|
|
ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE,
|
|
"mm/zswap_pool:prepare",
|
|
zswap_cpu_comp_prepare,
|
|
zswap_cpu_comp_dead);
|
|
if (ret)
|
|
goto hp_fail;
|
|
|
|
shrink_wq = alloc_workqueue("zswap-shrink",
|
|
WQ_UNBOUND|WQ_MEM_RECLAIM, 1);
|
|
if (!shrink_wq)
|
|
goto shrink_wq_fail;
|
|
|
|
zswap_shrinker = zswap_alloc_shrinker();
|
|
if (!zswap_shrinker)
|
|
goto shrinker_fail;
|
|
if (list_lru_init_memcg(&zswap_list_lru, zswap_shrinker))
|
|
goto lru_fail;
|
|
shrinker_register(zswap_shrinker);
|
|
|
|
INIT_WORK(&zswap_shrink_work, shrink_worker);
|
|
|
|
pool = __zswap_pool_create_fallback();
|
|
if (pool) {
|
|
pr_info("loaded using pool %s/%s\n", pool->tfm_name,
|
|
zpool_get_type(pool->zpools[0]));
|
|
list_add(&pool->list, &zswap_pools);
|
|
zswap_has_pool = true;
|
|
} else {
|
|
pr_err("pool creation failed\n");
|
|
zswap_enabled = false;
|
|
}
|
|
|
|
if (zswap_debugfs_init())
|
|
pr_warn("debugfs initialization failed\n");
|
|
zswap_init_state = ZSWAP_INIT_SUCCEED;
|
|
return 0;
|
|
|
|
lru_fail:
|
|
shrinker_free(zswap_shrinker);
|
|
shrinker_fail:
|
|
destroy_workqueue(shrink_wq);
|
|
shrink_wq_fail:
|
|
cpuhp_remove_multi_state(CPUHP_MM_ZSWP_POOL_PREPARE);
|
|
hp_fail:
|
|
kmem_cache_destroy(zswap_entry_cache);
|
|
cache_fail:
|
|
/* if built-in, we aren't unloaded on failure; don't allow use */
|
|
zswap_init_state = ZSWAP_INIT_FAILED;
|
|
zswap_enabled = false;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int __init zswap_init(void)
|
|
{
|
|
if (!zswap_enabled)
|
|
return 0;
|
|
return zswap_setup();
|
|
}
|
|
/* must be late so crypto has time to come up */
|
|
late_initcall(zswap_init);
|
|
|
|
MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>");
|
|
MODULE_DESCRIPTION("Compressed cache for swap pages");
|