From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by kanga.kvack.org (Postfix) with ESMTP id 90E4E6B0253 for ; Mon, 30 Nov 2015 17:17:05 -0500 (EST) Received: by pabfh17 with SMTP id fh17so203895317pab.0 for ; Mon, 30 Nov 2015 14:17:05 -0800 (PST) Received: from mail-pa0-x22c.google.com (mail-pa0-x22c.google.com. [2607:f8b0:400e:c03::22c]) by mx.google.com with ESMTPS id t13si12239989pas.21.2015.11.30.14.17.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Nov 2015 14:17:04 -0800 (PST) Received: by pabfh17 with SMTP id fh17so203894987pab.0 for ; Mon, 30 Nov 2015 14:17:04 -0800 (PST) Date: Mon, 30 Nov 2015 14:17:03 -0800 (PST) From: David Rientjes Subject: Re: [PATCH 1/2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves In-Reply-To: <20151126093427.GA7953@dhcp22.suse.cz> Message-ID: References: <1448448054-804-1-git-send-email-mhocko@kernel.org> <1448448054-804-2-git-send-email-mhocko@kernel.org> <20151125111801.GD27283@dhcp22.suse.cz> <20151126093427.GA7953@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Mel Gorman , Johannes Weiner , linux-mm@kvack.org, LKML On Thu, 26 Nov 2015, Michal Hocko wrote: > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > > index 8034909faad2..94b04c1e894a 100644 > > > --- a/mm/page_alloc.c > > > +++ b/mm/page_alloc.c > > > @@ -2766,8 +2766,13 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, > > > goto out; > > > } > > > /* Exhausted what can be done so it's blamo time */ > > > - if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) > > > + if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { > > > *did_some_progress = 1; > > > + > > > + if (gfp_mask & __GFP_NOFAIL) > > > + page = get_page_from_freelist(gfp_mask, order, > > > + ALLOC_NO_WATERMARKS, ac); > > > + } > > > out: > > > mutex_unlock(&oom_lock); > > > return page; > > > > Well, sure, that's one way to do it, but for cpuset users, wouldn't this > > lead to a depletion of the first system zone since you've dropped > > ALLOC_CPUSET and are doing ALLOC_NO_WATERMARKS in the same call? > > Are you suggesting to do? > if (gfp_mask & __GFP_NOFAIL) { > page = get_page_from_freelist(gfp_mask, order, > ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac); > /* > * fallback to ignore cpuset if our nodes are > * depleted > */ > if (!page) > get_page_from_freelist(gfp_mask, order, > ALLOC_NO_WATERMARKS, ac); > } > > I am not really sure this worth complication. I'm objecting to the ability of a process that is doing a __GFP_NOFAIL allocation, which has been disallowed access from allocating on certain mems through cpusets, to cause an oom condition on those disallowed nodes, yes. -- 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