From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f172.google.com (mail-we0-f172.google.com [74.125.82.172]) by kanga.kvack.org (Postfix) with ESMTP id 09E756B0035 for ; Thu, 31 Jul 2014 11:27:19 -0400 (EDT) Received: by mail-we0-f172.google.com with SMTP id x48so2985377wes.3 for ; Thu, 31 Jul 2014 08:27:19 -0700 (PDT) Received: from zene.cmpxchg.org (zene.cmpxchg.org. [2a01:238:4224:fa00:ca1f:9ef3:caee:a2bd]) by mx.google.com with ESMTPS id ft4si114540wic.90.2014.07.31.08.27.14 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 31 Jul 2014 08:27:14 -0700 (PDT) Date: Thu, 31 Jul 2014 11:26:59 -0400 From: Johannes Weiner Subject: Re: [patch 2/3] mm, oom: remove unnecessary check for NULL zonelist Message-ID: <20140731152659.GB9952@cmpxchg.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , "Kirill A. Shutemov" , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, Jul 23, 2014 at 06:16:32PM -0700, David Rientjes wrote: > If the pagefault handler is modified to pass a non-NULL zonelist then an > unnecessary check for a NULL zonelist in constrained_alloc() can be removed. > > Signed-off-by: David Rientjes > --- > mm/oom_kill.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -208,8 +208,6 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist, > /* Default to all available memory */ > *totalpages = totalram_pages + total_swap_pages; > > - if (!zonelist) > - return CONSTRAINT_NONE; > /* > * Reach here only when __GFP_NOFAIL is used. So, we should avoid > * to kill current.We have to random task kill in this case. > @@ -696,7 +694,7 @@ void pagefault_out_of_memory(void) > > zonelist = node_zonelist(first_memory_node, GFP_KERNEL); > if (try_set_zonelist_oom(zonelist, GFP_KERNEL)) { > - out_of_memory(NULL, 0, 0, NULL, false); > + out_of_memory(zonelist, 0, 0, NULL, false); out_of_memory() wants the zonelist that was used during allocation, not just the random first node's zonelist that's simply picked to serialize page fault OOM kills system-wide. This would even change how panic_on_oom behaves for page fault OOMs (in a completely unpredictable way) if we get CONSTRAINED_CPUSET. This change makes no sense to me. -- 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