[PATCH -mm 02/14] fs: consolidate {nr,free}_cached_objects args in shrink_control

Vladimir Davydov
2014-09-21T15:14:34Z

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.

Suggested-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
---
fs/super.c | 12 ++++++------
fs/xfs/xfs_super.c | 7 +++----
include/linux/fs.h | 6 ++++--
3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index 4554ac257647..a2b735a42e74 100644
--- 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 b194652033cd..d7e5c93c1a28 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1521,7 +1521,7 @@ 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));
}
@@ -1529,10 +1529,9 @@ 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 ddd10c70a01d..63fbf6f4bd36 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1573,8 +1573,10 @@ 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);
- 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 *);
};