Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751829AbbKVMzf (ORCPT ); Sun, 22 Nov 2015 07:55:35 -0500 Received: from mx2.suse.de ([195.135.220.15]:54473 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160AbbKVMzd (ORCPT ); Sun, 22 Nov 2015 07:55:33 -0500 Subject: Re: [PATCH] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves To: mhocko@kernel.org, Andrew Morton References: <1447249697-13380-1-git-send-email-mhocko@kernel.org> Cc: Johannes Weiner , Andrea Arcangeli , Mel Gorman , David Rientjes , linux-mm@kvack.org, LKML , Michal Hocko From: Vlastimil Babka Message-ID: <5651BB43.8030102@suse.cz> Date: Sun, 22 Nov 2015 13:55:31 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1447249697-13380-1-git-send-email-mhocko@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1605 Lines: 42 On 11.11.2015 14:48, mhocko@kernel.org wrote: > mm/page_alloc.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 8034909faad2..d30bce9d7ac8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2766,8 +2766,16 @@ __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|ALLOC_CPUSET, ac); > + WARN_ONCE(!page, "Unable to fullfil gfp_nofail allocation." > + " Consider increasing min_free_kbytes.\n"); It seems redundant to me to keep the WARN_ON_ONCE also above in the if () part? Also s/gfp_nofail/GFP_NOFAIL/ for consistency? Hm and probably out of scope of your patch, but I understand the WARN_ONCE (WARN_ON_ONCE) to be _ONCE just to prevent a flood from a single task looping here. But for distinct tasks and potentially far away in time, wouldn't we want to see all the warnings? Would that be feasible to implement? > + } > + } > out: > mutex_unlock(&oom_lock); > return page; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/