diff options
Diffstat (limited to 'mm/zswap.c')
| -rw-r--r-- | mm/zswap.c | 101 |
1 files changed, 63 insertions, 38 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 0e22744a76cb..55094e63b72d 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -32,6 +32,7 @@ #include <linux/swapops.h> #include <linux/writeback.h> #include <linux/pagemap.h> +#include <linux/workqueue.h> /********************************* * statistics @@ -65,6 +66,11 @@ static u64 zswap_reject_kmemcache_fail; /* Duplicate store was encountered (rare) */ static u64 zswap_duplicate_entry; +/* 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 **********************************/ @@ -109,6 +115,11 @@ module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); 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) */ static bool zswap_same_filled_pages_enabled = true; module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled, @@ -123,7 +134,8 @@ struct zswap_pool { struct crypto_comp * __percpu *tfm; struct kref kref; struct list_head list; - struct work_struct work; + struct work_struct release_work; + struct work_struct shrink_work; struct hlist_node node; char tfm_name[CRYPTO_MAX_ALG_NAME]; }; @@ -214,6 +226,13 @@ static bool zswap_is_full(void) DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); } +static bool zswap_can_accept(void) +{ + return totalram_pages() * zswap_accept_thr_percent / 100 * + zswap_max_pool_percent / 100 > + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); +} + static void zswap_update_total_size(void) { struct zswap_pool *pool; @@ -501,6 +520,16 @@ static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) return NULL; } +static void shrink_worker(struct work_struct *w) +{ + struct zswap_pool *pool = container_of(w, typeof(*pool), + shrink_work); + + if (zpool_shrink(pool->zpool, 1, NULL)) + zswap_reject_reclaim_fail++; + zswap_pool_put(pool); +} + static struct zswap_pool *zswap_pool_create(char *type, char *compressor) { struct zswap_pool *pool; @@ -551,6 +580,7 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor) */ kref_init(&pool->kref); INIT_LIST_HEAD(&pool->list); + INIT_WORK(&pool->shrink_work, shrink_worker); zswap_pool_debug("created", pool); @@ -624,7 +654,8 @@ static int __must_check zswap_pool_get(struct zswap_pool *pool) static void __zswap_pool_release(struct work_struct *work) { - struct zswap_pool *pool = container_of(work, typeof(*pool), work); + struct zswap_pool *pool = container_of(work, typeof(*pool), + release_work); synchronize_rcu(); @@ -647,8 +678,8 @@ static void __zswap_pool_empty(struct kref *kref) list_del_rcu(&pool->list); - INIT_WORK(&pool->work, __zswap_pool_release); - schedule_work(&pool->work); + INIT_WORK(&pool->release_work, __zswap_pool_release); + schedule_work(&pool->release_work); spin_unlock(&zswap_pools_lock); } @@ -856,7 +887,6 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) /* extract swpentry from data */ zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); swpentry = zhdr->swpentry; /* here */ - zpool_unmap_handle(pool, handle); tree = zswap_trees[swp_type(swpentry)]; offset = swp_offset(swpentry); @@ -866,6 +896,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) if (!entry) { /* entry was invalidated */ spin_unlock(&tree->lock); + zpool_unmap_handle(pool, handle); return 0; } spin_unlock(&tree->lock); @@ -886,15 +917,13 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) case ZSWAP_SWAPCACHE_NEW: /* page is locked */ /* decompress */ dlen = PAGE_SIZE; - src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, - ZPOOL_MM_RO) + sizeof(struct zswap_header); + src = (u8 *)zhdr + sizeof(struct zswap_header); dst = kmap_atomic(page); tfm = *get_cpu_ptr(entry->pool->tfm); ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); put_cpu_ptr(entry->pool->tfm); kunmap_atomic(dst); - zpool_unmap_handle(entry->pool->zpool, entry->handle); BUG_ON(ret); BUG_ON(dlen != PAGE_SIZE); @@ -940,22 +969,7 @@ fail: spin_unlock(&tree->lock); end: - return ret; -} - -static int zswap_shrink(void) -{ - struct zswap_pool *pool; - int ret; - - pool = zswap_pool_last_get(); - if (!pool) - return -ENOENT; - - ret = zpool_shrink(pool->zpool, 1, NULL); - - zswap_pool_put(pool); - + zpool_unmap_handle(pool, handle); return ret; } @@ -997,6 +1011,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset, char *buf; u8 *src, *dst; struct zswap_header zhdr = { .swpentry = swp_entry(type, offset) }; + gfp_t gfp; /* THP isn't supported */ if (PageTransHuge(page)) { @@ -1011,21 +1026,23 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset, /* reclaim space if needed */ if (zswap_is_full()) { + struct zswap_pool *pool; + zswap_pool_limit_hit++; - if (zswap_shrink()) { - zswap_reject_reclaim_fail++; - ret = -ENOMEM; - goto reject; - } + zswap_pool_reached_full = true; + pool = zswap_pool_last_get(); + if (pool) + queue_work(shrink_wq, &pool->shrink_work); + ret = -ENOMEM; + goto reject; + } - /* A second zswap_is_full() check after - * zswap_shrink() to make sure it's now - * under the max_pool_percent - */ - if (zswap_is_full()) { + if (zswap_pool_reached_full) { + if (!zswap_can_accept()) { ret = -ENOMEM; goto reject; - } + } else + zswap_pool_reached_full = false; } /* allocate entry */ @@ -1070,9 +1087,10 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset, /* store */ hlen = zpool_evictable(entry->pool->zpool) ? sizeof(zhdr) : 0; - ret = zpool_malloc(entry->pool->zpool, hlen + dlen, - __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM, - &handle); + gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; + if (zpool_malloc_support_movable(entry->pool->zpool)) + gfp |= __GFP_HIGHMEM | __GFP_MOVABLE; + ret = zpool_malloc(entry->pool->zpool, hlen + dlen, gfp, &handle); if (ret == -ENOSPC) { zswap_reject_compress_poor++; goto put_dstmem; @@ -1331,11 +1349,18 @@ static int __init init_zswap(void) zswap_enabled = false; } + shrink_wq = create_workqueue("zswap-shrink"); + if (!shrink_wq) + goto fallback_fail; + frontswap_register_ops(&zswap_frontswap_ops); if (zswap_debugfs_init()) pr_warn("debugfs initialization failed\n"); return 0; +fallback_fail: + if (pool) + zswap_pool_destroy(pool); hp_fail: cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE); dstmem_fail: |
