From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753215AbdKND3H (ORCPT ); Mon, 13 Nov 2017 22:29:07 -0500 Received: from mga05.intel.com ([192.55.52.43]:56317 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750806AbdKND3F (ORCPT ); Mon, 13 Nov 2017 22:29:05 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,392,1505804400"; d="scan'208";a="173207943" Date: Tue, 14 Nov 2017 11:31:37 +0800 From: Yu Chen To: "Luis R. Rodriguez" Cc: Michal Hocko , Hendrik Woltersdorf , Dave Chinner , "Rafael J. Wysocki" , "Darrick J. Wong" , Jiri Kosina , Len Brown , Rui Zhang , Dan Williams , Yu Chen , linux-xfs@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Regression/XFS/PM] Freeze tasks failed in xfsaild Message-ID: <20171114033137.GA23219@yu-chen.sh.intel.com> References: <20171113103139.GA18936@yu-chen.sh.intel.com> <20171113201414.GD16026@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171113201414.GD16026@wotan.suse.de> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 13, 2017 at 09:14:14PM +0100, Luis R. Rodriguez wrote: > On Mon, Nov 13, 2017 at 06:31:39PM +0800, Yu Chen wrote: > > The xfs-buf/dm-1 should be freezed according to > > commit 8018ec083c72 ("xfs: mark all internal workqueues > > as freezable"), thus a easier way might be have to revert > > commit 18f1df4e00ce ("xfs: Make xfsaild freezeable > > again") for now, after this reverting the xfsaild/dm-1 > > becomes non-freezable again, thus pm does not see this > > thread - unless we find a graceful way to treat xfsaild/dm-1 > > as 'frozen' if it is waiting for an already 'frozen' task, > > or if the filesystem freeze is added in. > > > > Any comments would be much appreciated. > > Reverting 18f1df4e00ce ("xfs: Make xfsaild freezeable again") > would break the proper form of the kthread for it to be freezable. > This "form" is not defined formally, and sadly its just a form > learned throughout years over different kthreads in the kernel. > > I'm also not convinced all our hibernation / suspend woes would be fixed by > reverting this commit, its why I worked instead on formalizing a proper freeze > / thaw, which a lot of filesystems already implement prior to system > hibernation / suspend / resume [0]. > > I'll be respinning this series without the last patch, provided I'm able to > ensure I don't need the ext[234] hack I did in that thread. Can you test the > first 3 patches *only* on that series and seeing if that helps on your XFS > front as well? > > [0] https://lkml.kernel.org/r/20171003185313.1017-1-mcgrof@kernel.org > > Luis Thanks for the comment Luis, Yes, I agree the freezing of filesystem is a proper/thorough fix for such kind issues, but as Dan said, it might be a little risky for us to to deploy it on our products currently, unless it is in the mainline/stable branch. Although the XFS issue might not be 100% reproducible, we can help test the patch set while seeking for a lightweight 'fix'. Thanks, Yu