From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 28 Jul 2011 04:55:13 +0000 (+0200)
Subject: vfs: avoid call to inode_lru_list_del() if possible
X-Git-Tag: firefly_0821_release~3680^2~4783^2~9
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c4ae0c65455c1bb30d1b71c6dd9a1a62aadde8ef;p=firefly-linux-kernel-4.4.55.git

vfs: avoid call to inode_lru_list_del() if possible

inode_lru_list_del() is expensive because of per superblock lru locking,
while some inodes are not in lru list.

Adding a check in iput_final() can speedup pipe/sockets workloads on
SMP.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/inode.c b/fs/inode.c
index e445be2a18f9..5aab80dc008c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1330,7 +1330,8 @@ static void iput_final(struct inode *inode)
 	}
 
 	inode->i_state |= I_FREEING;
-	inode_lru_list_del(inode);
+	if (!list_empty(&inode->i_lru))
+		inode_lru_list_del(inode);
 	spin_unlock(&inode->i_lock);
 
 	evict(inode);