From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Subject: Re: [PATCH 0/4] enable migration of driver pages Date: Wed, 29 Jul 2015 13:16:14 +0100 Message-ID: <20150729121614.GA19352@techsingularity.net> References: <1436776519-17337-1-git-send-email-gioh.kim@lge.com> <20150729104945.GA30872@techsingularity.net> <20150729105554.GU16722@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Return-path: Content-Disposition: inline In-Reply-To: <20150729105554.GU16722@phenom.ffwll.local> Sender: owner-linux-mm@kvack.org To: 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 List-Id: linux-api@vger.kernel.org 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! -- Mel Gorman SUSE Labs -- 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