vfs: skip inodes without pages to free in drop_pagecache_sb()
Many inodes have no pagecache, so we can avoid lots of lock-takings.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Fengguang Wu <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 50f9087..3e5637f 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -20,6 +20,8 @@
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE))
continue;
+ if (inode->i_mapping->nrpages == 0)
+ continue;
__iget(inode);
spin_unlock(&inode_lock);
__invalidate_mapping_pages(inode->i_mapping, 0, -1, true);