From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) by kanga.kvack.org (Postfix) with ESMTP id E61666B0253 for ; Wed, 29 Jul 2015 08:46:41 -0400 (EDT) Received: by wibud3 with SMTP id ud3so24583428wib.0 for ; Wed, 29 Jul 2015 05:46:41 -0700 (PDT) Received: from mail-wi0-x234.google.com (mail-wi0-x234.google.com. [2a00:1450:400c:c05::234]) by mx.google.com with ESMTPS id lt3si43663802wjb.33.2015.07.29.05.46.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Jul 2015 05:46:40 -0700 (PDT) Received: by wibxm9 with SMTP id xm9so24705673wib.1 for ; Wed, 29 Jul 2015 05:46:39 -0700 (PDT) Date: Wed, 29 Jul 2015 14:46:35 +0200 From: Daniel Vetter Subject: Re: [PATCH 0/4] enable migration of driver pages Message-ID: <20150729124635.GW16722@phenom.ffwll.local> References: <1436776519-17337-1-git-send-email-gioh.kim@lge.com> <20150729104945.GA30872@techsingularity.net> <20150729105554.GU16722@phenom.ffwll.local> <20150729121614.GA19352@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150729121614.GA19352@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Gioh Kim , jlayton@poochiereds.net, bfields@fieldses.org, vbabka@suse.cz, iamjoonsoo.kim@lge.com, viro@zeniv.linux.org.uk, mst@redhat.com, koct9i@gmail.com, minchan@kernel.org, aquini@redhat.com, linux-fsdevel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, dri-devel@lists.freedesktop.org, akpm@linux-foundation.org, Gioh Kim On Wed, Jul 29, 2015 at 01:16:14PM +0100, Mel Gorman wrote: > On Wed, Jul 29, 2015 at 12:55:54PM +0200, Daniel Vetter wrote: > > On Wed, Jul 29, 2015 at 11:49:45AM +0100, Mel Gorman wrote: > > > On Mon, Jul 13, 2015 at 05:35:15PM +0900, Gioh Kim wrote: > > > > My ARM-based platform occured severe fragmentation problem after long-term > > > > (several days) test. Sometimes even order-3 page allocation failed. It has > > > > memory size 512MB ~ 1024MB. 30% ~ 40% memory is consumed for graphic processing > > > > and 20~30 memory is reserved for zram. > > > > > > > > > > The primary motivation of this series is to reduce fragmentation by allowing > > > more kernel pages to be moved. Conceptually that is a worthwhile goal but > > > there should be at least one major in-kernel user and while balloon > > > pages were a good starting point, I think we really need to see what the > > > zram changes look like at the same time. > > > > I think gpu drivers really would be the perfect candidate for compacting > > kernel page allocations. And this also seems the primary motivation for > > this patch series, so I think that's really what we should use to judge > > these patches. > > > > Of course then there's the seemingly eternal chicken/egg problem of > > upstream gpu drivers for SoCs :( > > I recognised that the driver he had modified was not an in-tree user so > it did not really help the review or the design. I did not think it was > very fair to ask that an in-tree GPU driver be converted when it would not > help the embedded platform of interest. Converting zram is both a useful > illustration of the aops requirements and is expected to be beneficial on > the embedded platform. Now, if a GPU driver author was willing to convert > theirs as an example then that would be useful! Well my concern is more with merging infrastructure to upstream for drivers which aren't upstream and with no plan to make that happen anytime soon. Seems like just offload a bit to me ... but in the end core mm isn't my thing so not my decision. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- 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