---

yaml
---
r: 257370
b: refs/heads/master
c: 0e1fdaf
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4f8c19fdf3f97402b68f058b1c72a6c7166c9e59
+refs/heads/master: 0e1fdafd93980eac62e778798549ce0f6073905c

trunk/Documentation/filesystems/vfs.txt

@@ -229,6 +229,8 @@ struct super_operations {
 
         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
+	int (*nr_cached_objects)(struct super_block *);
+	void (*free_cached_objects)(struct super_block *, int);
 };
 
 All methods are called without any locks being held, unless otherwise
@@ -301,6 +303,20 @@ or bottom half).
 
   quota_write: called by the VFS to write to filesystem quota file.
 
+  nr_cached_objects: called by the sb cache shrinking function for the
+	filesystem to return the number of freeable cached objects it contains.
+	Optional.
+
+  free_cache_objects: called by the sb cache shrinking function for the
+	filesystem to scan the number of objects indicated to try to free them.
+	Optional, but any filesystem implementing this method needs to also
+	implement ->nr_cached_objects for it to be called correctly.
+
+	We can't do anything with any errors that the filesystem might
+	encountered, hence the void return type. This will never be called if
+	the VM is trying to reclaim under GFP_NOFS conditions, hence this
+	method does not need to handle that situation itself.
+
 Whoever sets up the inode is responsible for filling in the "i_op" field. This
 is a pointer to a "struct inode_operations" which describes the methods that
 can be performed on individual inodes.

trunk/fs/super.c

@@ -48,7 +48,8 @@ DEFINE_SPINLOCK(sb_lock);
 static int prune_super(struct shrinker *shrink, struct shrink_control *sc)
 {
 	struct super_block *sb;
-	int count;
+	int	fs_objects = 0;
+	int	total_objects;
 
 	sb = container_of(shrink, struct super_block, s_shrink);
 
@@ -62,22 +63,42 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc)
 	if (!grab_super_passive(sb))
 		return -1;
 
-	if (sc->nr_to_scan) {
-		/* proportion the scan between the two caches */
-		int total;
+	if (sb->s_op && sb->s_op->nr_cached_objects)
+		fs_objects = sb->s_op->nr_cached_objects(sb);
+
+	total_objects = sb->s_nr_dentry_unused +
+			sb->s_nr_inodes_unused + fs_objects + 1;
 
-		total = sb->s_nr_dentry_unused + sb->s_nr_inodes_unused + 1;
-		count = (sc->nr_to_scan * sb->s_nr_dentry_unused) / total;
+	if (sc->nr_to_scan) {
+		int	dentries;
+		int	inodes;
+
+		/* proportion the scan between the caches */
+		dentries = (sc->nr_to_scan * sb->s_nr_dentry_unused) /
+							total_objects;
+		inodes = (sc->nr_to_scan * sb->s_nr_inodes_unused) /
+							total_objects;
+		if (fs_objects)
+			fs_objects = (sc->nr_to_scan * fs_objects) /
+							total_objects;
+		/*
+		 * prune the dcache first as the icache is pinned by it, then
+		 * prune the icache, followed by the filesystem specific caches
+		 */
+		prune_dcache_sb(sb, dentries);
+		prune_icache_sb(sb, inodes);
 
-		/* prune dcache first as icache is pinned by it */
-		prune_dcache_sb(sb, count);
-		prune_icache_sb(sb, sc->nr_to_scan - count);
+		if (fs_objects && sb->s_op->free_cached_objects) {
+			sb->s_op->free_cached_objects(sb, fs_objects);
+			fs_objects = sb->s_op->nr_cached_objects(sb);
+		}
+		total_objects = sb->s_nr_dentry_unused +
+				sb->s_nr_inodes_unused + fs_objects;
 	}
 
-	count = ((sb->s_nr_dentry_unused + sb->s_nr_inodes_unused) / 100)
-						* sysctl_vfs_cache_pressure;
+	total_objects = (total_objects / 100) * sysctl_vfs_cache_pressure;
 	drop_super(sb);
-	return count;
+	return total_objects;
 }
 
 /**

trunk/include/linux/fs.h

@@ -1655,6 +1655,8 @@ struct super_operations {
 	ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
 #endif
 	int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
+	int (*nr_cached_objects)(struct super_block *);
+	void (*free_cached_objects)(struct super_block *, int);
 };
 
 /*