From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f44.google.com (mail-pa0-f44.google.com [209.85.220.44]) by kanga.kvack.org (Postfix) with ESMTP id BD6F36B0038 for ; Fri, 23 Oct 2015 14:21:23 -0400 (EDT) Received: by pasz6 with SMTP id z6so124549177pas.2 for ; Fri, 23 Oct 2015 11:21:23 -0700 (PDT) Received: from mail-pa0-x22c.google.com (mail-pa0-x22c.google.com. [2607:f8b0:400e:c03::22c]) by mx.google.com with ESMTPS id sk1si31266398pbc.113.2015.10.23.11.21.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Oct 2015 11:21:22 -0700 (PDT) Received: by padhk11 with SMTP id hk11so124776617pad.1 for ; Fri, 23 Oct 2015 11:21:22 -0700 (PDT) Date: Sat, 24 Oct 2015 03:21:09 +0900 From: Tejun Heo Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks Message-ID: <20151023182109.GA14610@mtj.duckdns.org> References: <20151022140944.GA30579@mtj.duckdns.org> <20151022150623.GE26854@dhcp22.suse.cz> <20151022151528.GG30579@mtj.duckdns.org> <20151022153559.GF26854@dhcp22.suse.cz> <20151022153703.GA3899@mtj.duckdns.org> <20151022154922.GG26854@dhcp22.suse.cz> <20151022184226.GA19289@mtj.duckdns.org> <20151023083316.GB2410@dhcp22.suse.cz> <20151023103630.GA4170@mtj.duckdns.org> <20151023111145.GH2410@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151023111145.GH2410@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 Hello, On Fri, Oct 23, 2015 at 01:11:45PM +0200, Michal Hocko wrote: > > The problem here is not lack > > of execution resource but concurrency management misunderstanding the > > situation. > > And this sounds like a bug to me. I don't know. I can be argued either way, the other direction being a kernel thread going RUNNING non-stop is buggy. Given how this has been a complete non-issue for all the years, I'm not sure how useful plugging this is. > Don't we have some IO related paths which would suffer from the same > problem. I haven't checked all the WQ_MEM_RECLAIM users but from the > name I would expect they _do_ participate in the reclaim and so they > should be able to make a progress. Now if your new IMMEDIATE flag will Seriously, nobody goes full-on RUNNING. > guarantee that then I would argue that it should be implicit for > WQ_MEM_RECLAIM otherwise we always risk a similar situation. What would > be a counter argument for doing that? Not serving any actual purpose and degrading execution behavior. 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