Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932583Ab3DBPDq (ORCPT ); Tue, 2 Apr 2013 11:03:46 -0400 Received: from mail-da0-f50.google.com ([209.85.210.50]:42739 "EHLO mail-da0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932122Ab3DBPDp (ORCPT ); Tue, 2 Apr 2013 11:03:45 -0400 Message-ID: <515AF348.7060209@gmail.com> Date: Tue, 02 Apr 2013 23:03:36 +0800 From: Zheng Liu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Mel Gorman CC: linux-ext4@vger.kernel.org, LKML , Linux-MM , Jiri Slaby Subject: Re: Excessive stall times on ext4 in 3.9-rc2 References: <20130402142717.GH32241@suse.de> In-Reply-To: <20130402142717.GH32241@suse.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1371 Lines: 31 Hi Mel, Thanks for reporting it. On 04/02/2013 10:27 PM, Mel Gorman wrote: > I'm testing a page-reclaim-related series on my laptop that is partially > aimed at fixing long stalls when doing metadata-intensive operations on > low memory such as a git checkout. I've been running 3.9-rc2 with the > series applied but found that the interactive performance was awful even > when there was plenty of free memory. > > I activated a monitor from mmtests that logs when a process is stuck for > a long time in D state and found that there are a lot of stalls in ext4. > The report first states that processes have been stalled for a total of > 6498 seconds on IO which seems like a lot. Here is a breakdown of the > recorded events. In this merge window, we add a status tree as a extent cache. Meanwhile a es_cache shrinker is registered to try to reclaim from this cache when we are under a high memory pressure. So I suspect that the root cause is this shrinker. Could you please tell me how to reproduce this problem? If I understand correctly, I can run mmtest to reproduce this problem, right? Thanks, - Zheng -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/