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@xxxxxxxx> Cc: Seth Jennings <sjennings@xxxxxxxxxxxxxx> Cc: Weijie Yang <weijie.yang@xxxxxxxxxxx> --- Changes since v3 : https://lkml.org/lkml/2014/5/24/131 -use new parameters in call to zpool_shrink() Changes since v2 : https://lkml.org/lkml/2014/5/7/894 -change zswap to select ZPOOL instead of ZBUD -only try zbud default if not already tried Changes since v1 https://lkml.org/lkml/2014/4/19/102 -since zpool fallback is removed, manually fall back to zbud if specified type fails mm/Kconfig | 2 +- mm/zswap.c | 76 +++++++++++++++++++++++++++++++++++++------------------------- 2 files changed, 46 insertions(+), 32 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index 00f7720..5ae0016 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -531,7 +531,7 @@ 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 diff --git a/mm/zswap.c b/mm/zswap.c index 1cc6770..67cf9d8 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -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, &handle); + ret = zpool_malloc(zswap_pool, len, &handle); if (ret == -ENOSPC) { zswap_reject_compress_poor++; goto freepage; @@ -688,11 +693,11 @@ 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 */ @@ -715,7 +720,7 @@ 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; @@ -751,13 +756,13 @@ 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); @@ -810,7 +815,7 @@ 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 }; @@ -868,8 +873,8 @@ 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); @@ -894,17 +899,26 @@ 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_NORETRY | __GFP_NOWARN, - &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 +942,7 @@ pcpufail: compfail: zswap_entry_cache_destory(); cachefail: - zbud_destroy_pool(zswap_pool); + zpool_destroy_pool(zswap_pool); error: return -ENOMEM; } -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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