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authorTrond Myklebust <Trond.Myklebust@netapp.com>2006-07-25 11:28:19 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-09-22 23:24:29 -0400
commit979df72e6f963b42ee484f2eca049c3344da0ba7 (patch)
treef3ba48a16203c899dbe57482c1ff7f1c02e0c9ca
parentcfcea3e8c66c2dcde98d5c2693d4bff50b5cac97 (diff)
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 <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/dir.c44
-rw-r--r--fs/nfs/internal.h3
-rw-r--r--fs/nfs/super.c5
3 files changed, 52 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index bf4f5ffda703..067d144d141b 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 e4f4e5def0fc..660e9ff5341c 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 e8a9bee74d9d..06c321beacfe 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();