From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com [74.125.82.52]) by kanga.kvack.org (Postfix) with ESMTP id 51F686B0255 for ; Sun, 22 Nov 2015 07:55:34 -0500 (EST) Received: by wmec201 with SMTP id c201so73474348wme.1 for ; Sun, 22 Nov 2015 04:55:33 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id q133si12563727wmb.22.2015.11.22.04.55.32 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 22 Nov 2015 04:55:32 -0800 (PST) Subject: Re: [PATCH] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves References: <1447249697-13380-1-git-send-email-mhocko@kernel.org> From: Vlastimil Babka Message-ID: <5651BB43.8030102@suse.cz> Date: Sun, 22 Nov 2015 13:55:31 +0100 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: owner-linux-mm@kvack.org List-ID: To: mhocko@kernel.org, Andrew Morton Cc: Johannes Weiner , Andrea Arcangeli , Mel Gorman , David Rientjes , linux-mm@kvack.org, LKML , Michal Hocko 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, 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