From af065b8a19041554196971d8b6ae1459798d3b14 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 29 Apr 2008 00:59:39 -0700
Subject: [PATCH] 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>
---
 fs/drop_caches.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 50f9087635d8..3e5637fc3779 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -20,6 +20,8 @@ static void drop_pagecache_sb(struct super_block *sb)
 	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);
-- 
2.20.1