From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yk0-f176.google.com (mail-yk0-f176.google.com [209.85.160.176]) by kanga.kvack.org (Postfix) with ESMTP id 8CB0082F64 for ; Mon, 2 Nov 2015 14:20:57 -0500 (EST) Received: by ykft191 with SMTP id t191so149471426ykf.0 for ; Mon, 02 Nov 2015 11:20:57 -0800 (PST) Received: from mail-yk0-x232.google.com (mail-yk0-x232.google.com. [2607:f8b0:4002:c07::232]) by mx.google.com with ESMTPS id w23si10191894ywa.92.2015.11.02.11.20.56 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Nov 2015 11:20:56 -0800 (PST) Received: by ykft191 with SMTP id t191so149471061ykf.0 for ; Mon, 02 Nov 2015 11:20:56 -0800 (PST) Date: Mon, 2 Nov 2015 14:20:53 -0500 From: Tejun Heo 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> Sender: owner-linux-mm@kvack.org List-ID: 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 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org