From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 909066B0033 for ; Tue, 5 Dec 2017 08:42:23 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id l33so144148wrl.5 for ; Tue, 05 Dec 2017 05:42:23 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id b37si314945eda.69.2017.12.05.05.42.21 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 05 Dec 2017 05:42:21 -0800 (PST) Date: Tue, 5 Dec 2017 14:42:20 +0100 From: Michal Hocko Subject: Re: [PATCH 1/3] mm,oom: Move last second allocation to inside the OOM killer. Message-ID: <20171205134220.vwz5d23vtr3nocfs@dhcp22.suse.cz> References: <20171201151715.yiep5wkmxmp77nxn@dhcp22.suse.cz> <20171201155711.GA11057@cmpxchg.org> <20171201163830.on5mykdtet2wa5is@dhcp22.suse.cz> <20171205104601.GA1898@cmpxchg.org> <20171205130215.bxkgzbzo25sljmgd@dhcp22.suse.cz> <201712052217.DGB21370.FHOFMLOJOFtVQS@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201712052217.DGB21370.FHOFMLOJOFtVQS@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, aarcange@redhat.com On Tue 05-12-17 22:17:27, Tetsuo Handa wrote: > Michal Hocko wrote: > > > I do understand the upsides you're advocating for - although you > > > haven't quantified them. They're just not worth the downsides. > > > > OK, fair enough. Let's drop the patch then. There is no _strong_ > > justification for it and what I've seen as "nice to have" is indeed > > really hard to quantify and not really worth merging without a full > > consensus. > > Dropping "mm,oom: move last second allocation to inside the OOM killer" > means dropping "mm,oom: remove oom_lock serialization from the OOM reaper" > together, right? No, I believe that we can drop the lock even without this patch. This will need more investigation though. > The latter patch helped mitigating > schedule_timeout_killable(1) lockup problem though... > > Also, what is the alternative for "mm,oom: use ALLOC_OOM for OOM victim's > last second allocation" ? I proposed "mm, oom: task_will_free_mem(current) > should ignore MMF_OOM_SKIP for once." and rejected by you. I also proposed > "mm,oom: Set ->signal->oom_mm to all thread groups sharing the victim's mm." > and rejected by you. Yes, and so far I am not really sure we have to care all that much. I haven't seen any real world workload actually hitting this condition. -- Michal Hocko SUSE Labs -- 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