vfs: add cond_resched_lock while scanning dentry LRU lists

Add cond_resched_lock(&dcache_lock) while scanning LRU lists on
superblocks in __shrink_dcache_sb()

Signed-off-by: Kentaro Makita <k-makita@np.css.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 3818d6ab76ca..f2584d22cb45 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -487,6 +487,7 @@ restart:
                                 if (!cnt)
                                         break;
                         }
+                        cond_resched_lock(&dcache_lock);
                 }
         }
         while (!list_empty(&tmp)) {