From: Larry Woodman <lwoodman@redhat.com> Date: Fri, 12 Jun 2009 15:18:33 -0400 Subject: [fs] skip inodes w/o pages to free in drop_pagecache_sb Message-id: <1244819913.3212.12.camel@dhcp-100-19-198.bos.redhat.com> Patchwork-id: 20287 O-Subject: [RHEL5 patch] skip inodes without pages to free in drop_pagecache_sb() Bugzilla: 528070 RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com> RH-Acked-by: Peter Staubach <staubach@redhat.com> RH-Acked-by: Jeff Layton <jlayton@redhat.com> The attached patch is an upstream backport that prevents weird locking behavior when dropping the pagecache under heavy load. -------------------------------------------------------------------------- commit af065b8a19041554196971d8b6ae1459798d3b14 Author: Jan Kara <jack@suse.cz> Date: Tue Apr 29 00:59:39 2008 -0700 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 16db525..2b405cd 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_CLEAR|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);