From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f174.google.com (mail-pd0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id 301B36B0070 for ; Tue, 9 Jun 2015 20:08:49 -0400 (EDT) Received: by pdbnf5 with SMTP id nf5so24777297pdb.2 for ; Tue, 09 Jun 2015 17:08:48 -0700 (PDT) Received: from mail-pd0-x229.google.com (mail-pd0-x229.google.com. [2607:f8b0:400e:c02::229]) by mx.google.com with ESMTPS id cc3si10948910pdb.128.2015.06.09.17.08.44 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Jun 2015 17:08:48 -0700 (PDT) Received: by pdbnf5 with SMTP id nf5so24776279pdb.2 for ; Tue, 09 Jun 2015 17:08:44 -0700 (PDT) Date: Wed, 10 Jun 2015 09:08:51 +0900 From: Minchan Kim Subject: Re: [RFC 0/4] enable migration of non-LRU pages Message-ID: <20150610000850.GC13376@bgram> References: <1433230065-3573-1-git-send-email-gioh.kim@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433230065-3573-1-git-send-email-gioh.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Gioh Kim Cc: jlayton@poochiereds.net, bfields@fieldses.org, akpm@linux-foundation.org, vbabka@suse.cz, iamjoonsoo.kim@lge.com, mst@redhat.com, kirill@shutemov.name, mgorman@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, gunho.lee@lge.com Hello Gioh, On Tue, Jun 02, 2015 at 04:27:40PM +0900, Gioh Kim wrote: > Hello, > > This series try to enable migration of non-LRU pages, such as driver's page. > > 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. > > I found that many pages of GPU driver and zram are non-movable pages. So I > reported Minchan Kim, the maintainer of zram, and he made the internal > compaction logic of zram. And I made the internal compaction of GPU driver. > > They reduced some fragmentation but they are not enough effective. > They are activated by its own interface, /sys, so they are not cooperative > with kernel compaction. If there is too much fragmentation and kernel starts > to compaction, zram and GPU driver cannot work with the kernel compaction. > > The first this patch adds a generic isolate/migrate/putback callbacks for page > address-space. The zram and GPU, and any other modules can register > its own migration method. The kernel compaction can call the registered > migration when it works. Therefore all page in the system can be migrated > at once. > > The 2nd the generic migration callbacks are applied into balloon driver. > My gpu driver code is not open so I apply generic migration into balloon > to show how it works. I've tested it with qemu enabled by kvm like followings: > - turn on Ubuntu 14.04 with 1G memory on qemu. > - do kernel building > - after several seconds check more than 512MB is used with free command > - command "balloon 512" in qemu monitor > - check hundreds MB of pages are migrated > > Next kernel compaction code can call generic migration callbacks instead of > balloon driver interface. > Finally calling migration of balloon driver is removed. I didn't hava a time to review but it surely will help using zram with CMA as well as fragmentation of the system memory via making zram objects movable. If it lands on mainline, I will work for zram object migration. Thanks! -- 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