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mm/zpool: update zswap to use zpool 

Change zswap to use the zpool api instead of directly using zbud.  Add a
boot-time param to allow selecting which zpool implementation to use,
with zbud as the default.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Tested-by: Seth Jennings <sjennings@variantweb.net>
Cc: Weijie Yang <weijie.yang@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Streetman 2014-08-06 16:08:40 -07:00 committed by Linus Torvalds
parent c795779df2
commit 12d79d64bf
2 changed files with 46 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
mm/Kconfig
View File

@ -535,7 +535,7 @@ config ZSWAP
bool "Compressed cache for swap pages (EXPERIMENTAL)"
depends on FRONTSWAP && CRYPTO=y
select CRYPTO_LZO
select ZBUD
select ZPOOL
default n
help
A lightweight compressed cache for swap pages. It takes

75
mm/zswap.c
View File

@ -34,7 +34,7 @@
#include <linux/swap.h>
#include <linux/crypto.h>
#include <linux/mempool.h>
#include <linux/zbud.h>
#include <linux/zpool.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
@ -45,8 +45,8 @@
/*********************************
* statistics
**********************************/
/* Number of memory pages used by the compressed pool */
static u64 zswap_pool_pages;
/* Total bytes used by the compressed storage */
static u64 zswap_pool_total_size;
/* The number of compressed pages currently stored in zswap */
static atomic_t zswap_stored_pages = ATOMIC_INIT(0);
@ -89,8 +89,13 @@ static unsigned int zswap_max_pool_percent = 20;
module_param_named(max_pool_percent,
zswap_max_pool_percent, uint, 0644);
/* zbud_pool is shared by all of zswap backend */
static struct zbud_pool *zswap_pool;
/* Compressed storage to use */
#define ZSWAP_ZPOOL_DEFAULT "zbud"
static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
module_param_named(zpool, zswap_zpool_type, charp, 0444);
/* zpool is shared by all of zswap backend */
static struct zpool *zswap_pool;
/*********************************
* compression functions
@ -168,7 +173,7 @@ static void zswap_comp_exit(void)
* be held while changing the refcount. Since the lock must
* be held, there is no reason to also make refcount atomic.
* offset - the swap offset for the entry. Index into the red-black tree.
* handle - zbud allocation handle that stores the compressed page data
* handle - zpool allocation handle that stores the compressed page data
* length - the length in bytes of the compressed page data. Needed during
* decompression
*/
@ -284,15 +289,15 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
}
/*
* Carries out the common pattern of freeing and entry's zbud allocation,
* 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_free_entry(struct zswap_entry *entry)
{
zbud_free(zswap_pool, entry->handle);
zpool_free(zswap_pool, entry->handle);
zswap_entry_cache_free(entry);
atomic_dec(&zswap_stored_pages);
zswap_pool_pages = zbud_get_pool_size(zswap_pool);
zswap_pool_total_size = zpool_get_total_size(zswap_pool);
}
/* caller must hold the tree lock */
@ -409,7 +414,7 @@ cleanup:
static bool zswap_is_full(void)
{
return totalram_pages * zswap_max_pool_percent / 100 <
zswap_pool_pages;
DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
}
/*********************************
@ -525,7 +530,7 @@ static int zswap_get_swap_cache_page(swp_entry_t entry,
* the swap cache, the compressed version stored by zswap can be
* freed.
*/
static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
{
struct zswap_header *zhdr;
swp_entry_t swpentry;
@ -541,9 +546,9 @@ static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
};
/* extract swpentry from data */
zhdr = zbud_map(pool, handle);
zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
swpentry = zhdr->swpentry; /* here */
zbud_unmap(pool, handle);
zpool_unmap_handle(pool, handle);
tree = zswap_trees[swp_type(swpentry)];
offset = swp_offset(swpentry);
@ -573,13 +578,13 @@ static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
case ZSWAP_SWAPCACHE_NEW: /* page is locked */
/* decompress */
dlen = PAGE_SIZE;
src = (u8 *)zbud_map(zswap_pool, entry->handle) +
sizeof(struct zswap_header);
src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
entry->length, dst, &dlen);
kunmap_atomic(dst);
zbud_unmap(zswap_pool, entry->handle);
zpool_unmap_handle(zswap_pool, entry->handle);
BUG_ON(ret);
BUG_ON(dlen != PAGE_SIZE);
@ -652,7 +657,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* reclaim space if needed */
if (zswap_is_full()) {
zswap_pool_limit_hit++;
if (zbud_reclaim_page(zswap_pool, 8)) {
if (zpool_shrink(zswap_pool, 1, NULL)) {
zswap_reject_reclaim_fail++;
ret = -ENOMEM;
goto reject;
@ -679,7 +684,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* store */
len = dlen + sizeof(struct zswap_header);
ret = zbud_alloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
&handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
@ -689,11 +694,11 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
zswap_reject_alloc_fail++;
goto freepage;
}
zhdr = zbud_map(zswap_pool, handle);
zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
zhdr->swpentry = swp_entry(type, offset);
buf = (u8 *)(zhdr + 1);
memcpy(buf, dst, dlen);
zbud_unmap(zswap_pool, handle);
zpool_unmap_handle(zswap_pool, handle);
put_cpu_var(zswap_dstmem);
/* populate entry */
@ -716,7 +721,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
/* update stats */
atomic_inc(&zswap_stored_pages);
zswap_pool_pages = zbud_get_pool_size(zswap_pool);
zswap_pool_total_size = zpool_get_total_size(zswap_pool);
return 0;
@ -752,13 +757,13 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
/* decompress */
dlen = PAGE_SIZE;
src = (u8 *)zbud_map(zswap_pool, entry->handle) +
sizeof(struct zswap_header);
src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
ZPOOL_MM_RO) + sizeof(struct zswap_header);
dst = kmap_atomic(page);
ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
dst, &dlen);
kunmap_atomic(dst);
zbud_unmap(zswap_pool, entry->handle);
zpool_unmap_handle(zswap_pool, entry->handle);
BUG_ON(ret);
spin_lock(&tree->lock);
@ -811,7 +816,7 @@ static void zswap_frontswap_invalidate_area(unsigned type)
zswap_trees[type] = NULL;
}
static struct zbud_ops zswap_zbud_ops = {
static struct zpool_ops zswap_zpool_ops = {
.evict = zswap_writeback_entry
};
@ -869,8 +874,8 @@ static int __init zswap_debugfs_init(void)
zswap_debugfs_root, &zswap_written_back_pages);
debugfs_create_u64("duplicate_entry", S_IRUGO,
zswap_debugfs_root, &zswap_duplicate_entry);
debugfs_create_u64("pool_pages", S_IRUGO,
zswap_debugfs_root, &zswap_pool_pages);
debugfs_create_u64("pool_total_size", S_IRUGO,
zswap_debugfs_root, &zswap_pool_total_size);
debugfs_create_atomic_t("stored_pages", S_IRUGO,
zswap_debugfs_root, &zswap_stored_pages);
@ -895,16 +900,26 @@ static void __exit zswap_debugfs_exit(void) { }
**********************************/
static int __init init_zswap(void)
{
gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
if (!zswap_enabled)
return 0;
pr_info("loading zswap\n");
zswap_pool = zbud_create_pool(GFP_KERNEL, &zswap_zbud_ops);
zswap_pool = zpool_create_pool(zswap_zpool_type, gfp, &zswap_zpool_ops);
if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
pr_info("%s zpool not available\n", zswap_zpool_type);
zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
zswap_pool = zpool_create_pool(zswap_zpool_type, gfp,
&zswap_zpool_ops);
}
if (!zswap_pool) {
pr_err("zbud pool creation failed\n");
pr_err("%s zpool not available\n", zswap_zpool_type);
pr_err("zpool creation failed\n");
goto error;
}
pr_info("using %s pool\n", zswap_zpool_type);
if (zswap_entry_cache_create()) {
pr_err("entry cache creation failed\n");
@ -928,7 +943,7 @@ pcpufail:
compfail:
zswap_entry_cache_destory();
cachefail:
zbud_destroy_pool(zswap_pool);
zpool_destroy_pool(zswap_pool);
error:
return -ENOMEM;
}