From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id CB9296B0005 for ; Fri, 9 Mar 2018 21:45:06 -0500 (EST) Received: by mail-pl0-f70.google.com with SMTP id c41-v6so4572695plj.10 for ; Fri, 09 Mar 2018 18:45:06 -0800 (PST) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id e2si1679474pgq.596.2018.03.09.18.45.04 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 09 Mar 2018 18:45:04 -0800 (PST) Subject: Re: Removing GFP_NOFS From: Tetsuo Handa References: <20180308234618.GE29073@bombadil.infradead.org> <20180309013535.GU7000@dastard> <20180309040650.GV7000@dastard> <20180309223812.GW7000@dastard> In-Reply-To: <20180309223812.GW7000@dastard> Message-Id: <201803101144.IHI87002.MFOtLJOFQVHSFO@I-love.SAKURA.ne.jp> Date: Sat, 10 Mar 2018 11:44:33 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, rgoldwyn@suse.de, mhocko@kernel.org Cc: willy@infradead.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Dave Chinner wrote: > > OTOH (contradicting myself here), writepages, in essence writebacks, are > > performed by per-BDI flusher threads which are kicked by the mm code in > > low memory situations, as opposed to the thread performing the allocation. > > > > As Tetsuo pointed out, direct reclaims are the real problematic scenarios. > > Sure, but I've been saying for more than 10 years we need to get rid > of direct reclaim because it's horribly inefficient when there's > lots of concurrent allocation pressure, not to mention it's full of > deadlock scenarios like this. > > Really, though I'm tired of having the same arguments over and over > again about architectural problems that people just don't seem to > understand or want to fix. > Yeah, it is sad that developers are not interested in lowmem situation. Suspect the MM subsystem when your Linux system hung up!? https://elinux.org/images/4/49/CELFJP-Jamboree63-handa-en.pdf