blkio: Some debugging aids for CFQ

o Some debugging aids for CFQ.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index cd50a2f8733e..3573199b298b 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -27,12 +27,25 @@ struct blkio_group {
         void *key;
         struct hlist_node blkcg_node;
         unsigned short blkcg_id;
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+        /* Store cgroup path */
+        char path[128];
+#endif
 };
 
 #define BLKIO_WEIGHT_MIN        100
 #define BLKIO_WEIGHT_MAX        1000
 #define BLKIO_WEIGHT_DEFAULT    500
 
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+static inline char *blkg_path(struct blkio_group *blkg)
+{
+        return blkg->path;
+}
+#else
+static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
+#endif
+
 #ifdef CONFIG_BLK_CGROUP
 extern struct blkio_cgroup blkio_root_cgroup;
 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);