fs: consolidate {nr,free}_cached_objects args in shrink_control

We are going to make FS shrinkers memcg-aware.  To achieve that, we will
have to pass the memcg to scan to the nr_cached_objects and
free_cached_objects VFS methods, which currently take only the NUMA node
to scan.  Since the shrink_control structure already holds the node, and
the memcg to scan will be added to it when we introduce memcg-aware
vmscan, let us consolidate the methods' arguments in this structure to
keep things clean.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Suggested-by: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/super.c b/fs/super.c
index 4554ac2..a2b735a 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -75,7 +75,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
                return SHRINK_STOP;
 
        if (sb->s_op->nr_cached_objects)
-               fs_objects = sb->s_op->nr_cached_objects(sb, sc->nid);
+               fs_objects = sb->s_op->nr_cached_objects(sb, sc);
 
        inodes = list_lru_shrink_count(&sb->s_inode_lru, sc);
        dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc);
@@ -97,9 +97,10 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
        sc->nr_to_scan = inodes;
        freed += prune_icache_sb(sb, sc);
 
-       if (fs_objects)
-               freed += sb->s_op->free_cached_objects(sb, fs_objects,
-                                                      sc->nid);
+       if (fs_objects) {
+               sc->nr_to_scan = fs_objects;
+               freed += sb->s_op->free_cached_objects(sb, sc);
+       }
 
        drop_super(sb);
        return freed;
@@ -122,8 +123,7 @@ static unsigned long super_cache_count(struct shrinker *shrink,
         * s_op->nr_cached_objects().
         */
        if (sb->s_op && sb->s_op->nr_cached_objects)
-               total_objects = sb->s_op->nr_cached_objects(sb,
-                                                sc->nid);
+               total_objects = sb->s_op->nr_cached_objects(sb, sc);
 
        total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc);
        total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc);

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index f2449fd..8fcc4cc 100644 (file)
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1537,7 +1537,7 @@ xfs_fs_mount(
 static long
 xfs_fs_nr_cached_objects(
        struct super_block      *sb,
-       int                     nid)
+       struct shrink_control   *sc)
 {
        return xfs_reclaim_inodes_count(XFS_M(sb));
 }
@@ -1545,10 +1545,9 @@ xfs_fs_nr_cached_objects(
 static long
 xfs_fs_free_cached_objects(
        struct super_block      *sb,
-       long                    nr_to_scan,
-       int                     nid)
+       struct shrink_control   *sc)
 {
-       return xfs_reclaim_inodes_nr(XFS_M(sb), nr_to_scan);
+       return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
 }
 
 static const struct super_operations xfs_super_operations = {

diff --git a/include/linux/fs.h b/include/linux/fs.h
index cdcb1e9..a20d658 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1635,8 +1635,10 @@ struct super_operations {
        struct dquot **(*get_dquots)(struct inode *);
 #endif
        int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
-       long (*nr_cached_objects)(struct super_block *, int);
-       long (*free_cached_objects)(struct super_block *, long, int);
+       long (*nr_cached_objects)(struct super_block *,
+                                 struct shrink_control *);
+       long (*free_cached_objects)(struct super_block *,
+                                   struct shrink_control *);
 };
 
 /*