From 979df72e6f963b42ee484f2eca049c3344da0ba7 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 25 Jul 2006 11:28:19 -0400 Subject: [PATCH] NFS: Add an ACCESS cache memory shrinker A pinned inode may in theory end up filling memory with cached ACCESS calls. This patch ensures that the VM may shrink away the cache in these particular cases. The shrinker works by iterating through the list of inodes on the global nfs_access_lru_list, and removing the least recently used access cache entry until it is done (or until the entire cache is empty). Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/internal.h | 3 +++ fs/nfs/super.c | 5 +++++ 3 files changed, 52 insertions(+) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index bf4f5ffda7..067d144d14 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1651,6 +1651,50 @@ static void nfs_access_free_entry(struct nfs_access_entry *entry) smp_mb__after_atomic_dec(); } +int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask) +{ + LIST_HEAD(head); + struct nfs_inode *nfsi; + struct nfs_access_entry *cache; + + spin_lock(&nfs_access_lru_lock); +restart: + list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) { + struct inode *inode; + + if (nr_to_scan-- == 0) + break; + inode = igrab(&nfsi->vfs_inode); + if (inode == NULL) + continue; + spin_lock(&inode->i_lock); + if (list_empty(&nfsi->access_cache_entry_lru)) + goto remove_lru_entry; + cache = list_entry(nfsi->access_cache_entry_lru.next, + struct nfs_access_entry, lru); + list_move(&cache->lru, &head); + rb_erase(&cache->rb_node, &nfsi->access_cache); + if (!list_empty(&nfsi->access_cache_entry_lru)) + list_move_tail(&nfsi->access_cache_inode_lru, + &nfs_access_lru_list); + else { +remove_lru_entry: + list_del_init(&nfsi->access_cache_inode_lru); + clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); + } + spin_unlock(&inode->i_lock); + iput(inode); + goto restart; + } + spin_unlock(&nfs_access_lru_lock); + while (!list_empty(&head)) { + cache = list_entry(head.next, struct nfs_access_entry, lru); + list_del(&cache->lru); + nfs_access_free_entry(cache); + } + return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure; +} + static void __nfs_access_zap_cache(struct inode *inode) { struct nfs_inode *nfsi = NFS_I(inode); diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index e4f4e5def0..660e9ff534 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -66,6 +66,9 @@ extern int nfs4_proc_fs_locations(struct inode *dir, struct dentry *dentry, struct page *page); #endif +/* dir.c */ +extern int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask); + /* inode.c */ extern struct inode *nfs_alloc_inode(struct super_block *sb); extern void nfs_destroy_inode(struct inode *); diff --git a/fs/nfs/super.c b/fs/nfs/super.c index e8a9bee74d..06c321beac 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -221,6 +221,8 @@ module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int, &nfs_idmap_cache_timeout, 0644); #endif +static struct shrinker *acl_shrinker; + /* * Register the NFS filesystems */ @@ -240,6 +242,7 @@ int __init register_nfs_fs(void) if (ret < 0) goto error_2; #endif + acl_shrinker = set_shrinker(DEFAULT_SEEKS, nfs_access_cache_shrinker); return 0; #ifdef CONFIG_NFS_V4 @@ -257,6 +260,8 @@ error_0: */ void __exit unregister_nfs_fs(void) { + if (acl_shrinker != NULL) + remove_shrinker(acl_shrinker); #ifdef CONFIG_NFS_V4 unregister_filesystem(&nfs4_fs_type); nfs_unregister_sysctl(); -- 2.39.5