From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id A5EEC6B0003 for ; Thu, 12 Apr 2018 01:51:27 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id f9-v6so2955350plo.17 for ; Wed, 11 Apr 2018 22:51:27 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id n2si1826508pgs.500.2018.04.11.22.51.25 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 11 Apr 2018 22:51:26 -0700 (PDT) Date: Thu, 12 Apr 2018 07:51:22 +0200 From: Michal Hocko Subject: Re: [LSF/MM TOPIC] CMA and larger page sizes Message-ID: <20180412055122.GP23400@dhcp22.suse.cz> References: <3a3d724e-4d74-9bd8-60f3-f6896cffac7a@redhat.com> <20180126172527.GI5027@dhcp22.suse.cz> <20180404051115.GC6628@js1304-desktop> <075843db-ec6e-3822-a60c-ae7487981f09@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Laura Abbott Cc: Vlastimil Babka , Joonsoo Kim , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org On Wed 11-04-18 18:06:59, Laura Abbott wrote: > On 04/11/2018 01:02 PM, Vlastimil Babka wrote: > > On 04/11/2018 09:55 PM, Laura Abbott wrote: > > > On 04/03/2018 10:11 PM, Joonsoo Kim wrote: > > > > If the patchset 'manage the memory of the CMA area by using the ZONE_MOVABLE' is > > > > merged, this restriction can be removed since there is no unmovable > > > > pageblock in ZONE_MOVABLE. Just quick thought. :) > > > > > > > > Thanks. > > > > > > > > > > Thanks for that pointer. What's the current status of that patchset? Was that > > > one that needed more review/testing? > > > > It was merged by Linus today, see around commit bad8c6c0b114 ("mm/cma: > > manage the memory of the CMA area by using the ZONE_MOVABLE") > > > > Congrats, Joonsoo :) > > > > I took a look at this a little bit more and while it's true we don't > have the unmovable restriction anymore, CMA is still tied to the pageblock > size (512MB) because we still have MIGRATE_CMA. I guess making the > pageblock smaller seems like the most plausible approach? Maybe I am wrong but my take on what Joonsoo said is that we really do not have to care about page blocks and MIGRATE_CMA because GFP_MOVABLE can be allocated from that migrate type as it is by definition movable. The size of the page block shouldn't matter. -- Michal Hocko SUSE Labs