From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 6BEBC6B0255 for ; Thu, 22 Oct 2015 10:22:02 -0400 (EDT) Received: by pabrc13 with SMTP id rc13so87966356pab.0 for ; Thu, 22 Oct 2015 07:22:02 -0700 (PDT) Received: from mail-pa0-x22f.google.com (mail-pa0-x22f.google.com. [2607:f8b0:400e:c03::22f]) by mx.google.com with ESMTPS id pq4si21441744pac.95.2015.10.22.07.22.01 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Oct 2015 07:22:01 -0700 (PDT) Received: by padhk11 with SMTP id hk11so88231001pad.1 for ; Thu, 22 Oct 2015 07:22:01 -0700 (PDT) Date: Thu, 22 Oct 2015 23:21:55 +0900 From: Tejun Heo Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks Message-ID: <20151022142155.GB30579@mtj.duckdns.org> References: <20151021143337.GD8805@dhcp22.suse.cz> <20151021145505.GE8805@dhcp22.suse.cz> <201510222037.ACH86458.OFOLFtQFOHJSVM@I-love.SAKURA.ne.jp> <20151022140944.GA30579@mtj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151022140944.GA30579@mtj.duckdns.org> Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Tetsuo Handa , mhocko@kernel.org, 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 Thu, Oct 22, 2015 at 11:09:44PM +0900, Tejun Heo wrote: > On Thu, Oct 22, 2015 at 08:39:11AM -0500, Christoph Lameter wrote: > > On Thu, 22 Oct 2015, Tetsuo Handa wrote: > > > > > The problem would be that the "struct task_struct" to execute vmstat_update > > > job does not exist, and will not be able to create one on demand because we > > > are stuck at __GFP_WAIT allocation. Therefore adding a dedicated kernel > > > thread for vmstat_update job would work. But ... > > > > Yuck. Can someone please get this major screwup out of the work queue > > subsystem? Tejun? > > Hmmm? Just use a dedicated workqueue with WQ_MEM_RECLAIM. If > concurrency management is a problem and there's something live-locking > for that work item (really?), WQ_CPU_INTENSIVE escapes it. If this is > a common occurrence that it makes sense to give vmstat higher > priority, set WQ_HIGHPRI. Oooh, HIGHPRI + CPU_INTENSIVE immediate scheduling guarantee got lost while converting HIGHPRI to a separate pool but guaranteeing immediate scheduling for CPU_INTENSIVE is trivial. If vmstat requires that, please let me know. 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