From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754210Ab0JFXsN (ORCPT ); Wed, 6 Oct 2010 19:48:13 -0400 Received: from shards.monkeyblade.net ([198.137.202.13]:45567 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751808Ab0JFXsM (ORCPT ); Wed, 6 Oct 2010 19:48:12 -0400 Message-ID: <4CAD0A5C.7030005@kernel.org> Date: Wed, 06 Oct 2010 16:46:36 -0700 From: "J.H." User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.12) Gecko/20100907 Fedora/3.0.7-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.7 MIME-Version: 1.0 To: Dave Chinner CC: Johannes Weiner , Alex Elder , xfs@oss.sgi.com, linux-kernel@vger.kernel.org, stable@kernel.org Subject: Re: [patch] xfs: properly account for reclaimed inodes References: <20101001074354.GF2618@cmpxchg.org> <1285953443.2422.4.camel@doink> <20101004071904.GH4681@dastard> <20101004102213.GJ2618@cmpxchg.org> <20101006045349.GA13191@dastard> In-Reply-To: <20101006045349.GA13191@dastard> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.3 (shards.monkeyblade.net [198.137.202.13]); Wed, 06 Oct 2010 16:46:38 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/05/2010 09:53 PM, Dave Chinner wrote: > On Mon, Oct 04, 2010 at 12:22:13PM +0200, Johannes Weiner wrote: >> Hi, >> >> On Mon, Oct 04, 2010 at 06:19:04PM +1100, Dave Chinner wrote: >>> On Fri, Oct 01, 2010 at 12:17:23PM -0500, Alex Elder wrote: >>>> On Fri, 2010-10-01 at 09:43 +0200, Johannes Weiner wrote: >>>>> When marking an inode reclaimable, a per-AG counter is increased, the >>>>> inode is tagged reclaimable in its per-AG tree, and, when this is the >>>>> first reclaimable inode in the AG, the AG entry in the per-mount tree >>>>> is also tagged. >>>>> >>>>> When an inode is finally reclaimed, however, it is only deleted from >>>>> the per-AG tree. Neither the counter is decreased, nor is the parent >>>>> tree's AG entry untagged properly. >>>>> >>>>> Since the tags in the per-mount tree are not cleared, the inode >>>>> shrinker iterates over all AGs that have had reclaimable inodes at one >>>>> point in time. >>>>> >>>>> The counters on the other hand signal an increasing amount of slab >>>>> objects to reclaim. Since "70e60ce xfs: convert inode shrinker to >>>>> per-filesystem context" this is not a real issue anymore because the >>>>> shrinker bails out after one iteration. >>>>> >>>>> But the problem was observable on a machine running v2.6.34, where the >>>>> reclaimable work increased and each process going into direct reclaim >>>>> eventually got stuck on the xfs inode shrinking path, trying to scan >>>>> several million objects. >>>>> >>>>> Fix this by properly unwinding the reclaimable-state tracking of an >>>>> inode when it is reclaimed. >>>>> >>>>> Signed-off-by: Johannes Weiner >>>>> Cc: stable@kernel.org >>>> >>>> Yes, this looks right to me. The state was correctly >>>> adjusted in xfs_iget_cache_hit() when a RECLAIMABLE >>>> inode is found in the cache, but it was not done when >>>> reclaim completes. >>>> >>>> Reviewed-by: Alex Elder >>> >>> Alex, can you push this to Linus ASAP? This needs to go back to >>> stable kernels as well.. >> >> Here is my suggestion of a backport to .34. Dave, Alex, do you >> approve? >> >> Hannes >> >> diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c >> index 6845db9..3314f2a 100644 >> --- a/fs/xfs/xfs_iget.c >> +++ b/fs/xfs/xfs_iget.c >> @@ -499,6 +499,7 @@ xfs_ireclaim( >> write_lock(&pag->pag_ici_lock); >> if (!radix_tree_delete(&pag->pag_ici_root, agino)) >> ASSERT(0); >> + pag->pag_ici_reclaimable--; >> write_unlock(&pag->pag_ici_lock); >> xfs_perag_put(pag); > > Looks good to me. > > Reviewed-by: Dave Chinner i've got this in production and things seem to be acting a lot more like I would expect. Tested-by: John 'Warthog9' Hawley