From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id A474C6B0069 for ; Mon, 10 Oct 2016 02:44:35 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id x79so32426824lff.2 for ; Sun, 09 Oct 2016 23:44:35 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id wt3si16863094wjb.9.2016.10.09.23.44.34 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 09 Oct 2016 23:44:34 -0700 (PDT) Subject: Re: [RFC PATCH] mm, compaction: allow compaction for GFP_NOFS requests References: <20161004081215.5563-1-mhocko@kernel.org> <20161007065019.GA18439@dhcp22.suse.cz> <20161007092107.GJ18439@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: <84149b25-95f3-2ddc-8e67-c3b2114922cd@suse.cz> Date: Mon, 10 Oct 2016 08:44:33 +0200 MIME-Version: 1.0 In-Reply-To: <20161007092107.GJ18439@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Mel Gorman , Joonsoo Kim , Andrew Morton , linux-mm@kvack.org, LKML On 10/07/2016 11:21 AM, Michal Hocko wrote: > On Fri 07-10-16 10:15:07, Vlastimil Babka wrote: >> On 10/07/2016 08:50 AM, Michal Hocko wrote: >>> On Fri 07-10-16 07:27:37, Vlastimil Babka wrote: > [...] >>>> But make sure you don't break kcompactd and manual compaction from /proc, as >>>> they don't currently set cc->gfp_mask. Looks like until now it was only used >>>> to determine direct compactor's migratetype which is irrelevant in those >>>> contexts. >>> >>> OK, I see. This is really subtle. One way to go would be to provide a >>> fake gfp_mask for them. How does the following look to you? >> >> Looks OK. I'll have to think about the kcompactd case, as gfp mask implying >> unmovable migratetype might restrict it without good reason. But that would >> be separate patch anyway, yours doesn't change that (empty gfp_mask also >> means unmovable migratetype) and that's good. > > OK, I see. A follow up patch would be really trivial AFAICS. Just add > __GFP_MOVABLE to the mask. But I am not familiar with all these details > enough to propose a patch with full description. Hm, actually the migratetype only matters for async compaction, and kcompactd uses sync_light, so __GFP_MOVABLE will have no effect right now. -- 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