From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757739AbbLCABV (ORCPT ); Wed, 2 Dec 2015 19:01:21 -0500 Received: from mail-pa0-f43.google.com ([209.85.220.43]:33698 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757450AbbLCABU (ORCPT ); Wed, 2 Dec 2015 19:01:20 -0500 Date: Wed, 2 Dec 2015 16:01:18 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Michal Hocko cc: Andrew Morton , Johannes Weiner , Mel Gorman , linux-mm@kvack.org, LKML , Michal Hocko Subject: Re: [PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves In-Reply-To: <1449069190-7325-1-git-send-email-mhocko@kernel.org> Message-ID: References: <1448448054-804-2-git-send-email-mhocko@kernel.org> <1449069190-7325-1-git-send-email-mhocko@kernel.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2 Dec 2015, Michal Hocko wrote: > From: Michal Hocko > > __GFP_NOFAIL is a big hammer used to ensure that the allocation > request can never fail. This is a strong requirement and as such > it also deserves a special treatment when the system is OOM. The > primary problem here is that the allocation request might have > come with some locks held and the oom victim might be blocked > on the same locks. This is basically an OOM deadlock situation. > > This patch tries to reduce the risk of such a deadlocks by giving > __GFP_NOFAIL allocations a special treatment and let them dive into > memory reserves after oom killer invocation. This should help them > to make a progress and release resources they are holding. The OOM > victim should compensate for the reserves consumption. > > Suggested-by: Andrea Arcangeli > Signed-off-by: Michal Hocko Acked-by: David Rientjes