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 46FB26B0003 for ; Mon, 28 May 2018 11:32:18 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id w8-v6so10639715wrn.10 for ; Mon, 28 May 2018 08:32:18 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id b15-v6si710764ede.438.2018.05.28.08.32.16 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 28 May 2018 08:32:16 -0700 (PDT) Subject: Re: [PATCH] mm, page_alloc: do not break __GFP_THISNODE by zonelist reset From: Vlastimil Babka References: <20180525130853.13915-1-vbabka@suse.cz> <20180525124300.964a1a15d953e8972625bb0f@linux-foundation.org> <4cd73f77-e6ab-bdd1-69a2-bd0f8413d189@suse.cz> Message-ID: <26adcbc0-7741-4f39-9fac-fc7f387bdbe6@suse.cz> Date: Mon, 28 May 2018 11:55:52 +0200 MIME-Version: 1.0 In-Reply-To: <4cd73f77-e6ab-bdd1-69a2-bd0f8413d189@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman , Michal Hocko , David Rientjes , Joonsoo Kim , stable@vger.kernel.org On 05/25/2018 10:48 PM, Vlastimil Babka wrote: > On 05/25/2018 09:43 PM, Andrew Morton wrote: >> On Fri, 25 May 2018 15:08:53 +0200 Vlastimil Babka wrote: >> >>> we might consider this for 4.17 although I don't know if there's anything >>> currently broken. Stable backports should be more important, but will have to >>> be reviewed carefully, as the code went through many changes. >>> BTW I think that also the ac->preferred_zoneref reset is currently useless if >>> we don't also reset ac->nodemask from a mempolicy to NULL first (which we >>> probably should for the OOM victims etc?), but I would leave that for a >>> separate patch. >> >> Confused. If nothing is currently broken then why is a backport >> needed? Presumably because we expect breakage in the future? Can you >> expand on this? > > I mean that SLAB is currently not affected, but in older kernels than > 4.7 that don't yet have 511e3a058812 ("mm/slab: make cache_grow() handle > the page allocated on arbitrary node") it is. That's at least 4.4 LTS. > Older ones I'll have to check. So I've checked the non-EOL LTS's at kernel.org and: 4.16, 4.14, 4.9 - same as mainline (__GFP_THISNODE broken, but SLAB is OK) 4.4, 4.1, 3.16 - SLAB potentially broken if it makes an ALLOC_NO_WATERMARKS allocation (our 4.4 kernel has backports that extend it to also !ALLOC_CPUSET so it's more likely).