From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id B03536B0010 for ; Thu, 28 Jun 2018 15:03:44 -0400 (EDT) Received: by mail-ed1-f71.google.com with SMTP id w22-v6so1416515edr.14 for ; Thu, 28 Jun 2018 12:03:44 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id h2-v6si3600317edr.245.2018.06.28.12.03.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Jun 2018 12:03:38 -0700 (PDT) Date: Thu, 28 Jun 2018 13:39:42 +0200 From: Michal Hocko Subject: Re: [PATCH] mm,oom: Bring OOM notifier callbacks to outside of OOM killer. Message-ID: <20180628113942.GD32348@dhcp22.suse.cz> References: <1529493638-6389-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> <20180621073142.GA10465@dhcp22.suse.cz> <2d8c3056-1bc2-9a32-d745-ab328fd587a1@i-love.sakura.ne.jp> <20180626170345.GA3593@linux.vnet.ibm.com> <20180627072207.GB32348@dhcp22.suse.cz> <20180627143125.GW3593@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180627143125.GW3593@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Paul E. McKenney" Cc: Tetsuo Handa , David Rientjes , linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org On Wed 27-06-18 07:31:25, Paul E. McKenney wrote: > On Wed, Jun 27, 2018 at 09:22:07AM +0200, Michal Hocko wrote: > > On Tue 26-06-18 10:03:45, Paul E. McKenney wrote: > > [...] > > > 3. Something else? > > > > How hard it would be to use a different API than oom notifiers? E.g. a > > shrinker which just kicks all the pending callbacks if the reclaim > > priority reaches low values (e.g. 0)? > > Beats me. What is a shrinker? ;-) This is a generich mechanism to reclaim memory that is not on standard LRU lists. Lwn.net surely has some nice coverage (e.g. https://lwn.net/Articles/548092/). > More seriously, could you please point me at an exemplary shrinker > use case so I can see what is involved? Well, I am not really sure what is the objective of the oom notifier to point you to the right direction. IIUC you just want to kick callbacks to be handled sooner under a heavy memory pressure, right? How is that achieved? Kick a worker? -- Michal Hocko SUSE Labs