Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751654AbbKBTU6 (ORCPT ); Mon, 2 Nov 2015 14:20:58 -0500 Received: from mail-yk0-f170.google.com ([209.85.160.170]:34273 "EHLO mail-yk0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750887AbbKBTU5 (ORCPT ); Mon, 2 Nov 2015 14:20:57 -0500 Date: Mon, 2 Nov 2015 14:20:53 -0500 From: Tejun Heo To: Michal Hocko Cc: Christoph Lameter , Tetsuo Handa , linux-mm@kvack.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, David Rientjes , oleg@redhat.com, kwalker@redhat.com, akpm@linux-foundation.org, hannes@cmpxchg.org, vdavydov@parallels.com, skozina@redhat.com, mgorman@suse.de, riel@redhat.com Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks Message-ID: <20151102192053.GC9553@mtj.duckdns.org> References: <20151022140944.GA30579@mtj.duckdns.org> <20151022142155.GB30579@mtj.duckdns.org> <20151022142429.GC30579@mtj.duckdns.org> <20151022143349.GD30579@mtj.duckdns.org> <20151022151414.GF30579@mtj.duckdns.org> <20151023042649.GB18907@mtj.duckdns.org> <20151102150137.GB3442@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151102150137.GB3442@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1052 Lines: 24 On Mon, Nov 02, 2015 at 04:01:37PM +0100, Michal Hocko wrote: ... > which is perfectly suited for the stable backport, OOM sysrq resp. any > sysrq which runs from the WQ context should be as robust as possible and > shouldn't rely on all the code running from WQ context to issue a sleep > to get unstuck. So I definitely support something like this patch. Well, sysrq wouldn't run successfully either on a cpu which is busy looping with preemption off. I don't think this calls for a new flag to modify workqueue behavior especially given that missing such flag would lead to the same kind of lockup. It's a shitty solution. If the possibility of sysrq getting stuck behind concurrency management is an issue, queueing them on an unbound or highpri workqueue should be good enough. Thanks. -- tejun -- 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/