From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH v4 00/13] Support non-lru page migration Date: Wed, 27 Apr 2016 13:20:35 -0700 Message-ID: <20160427132035.e96f99f3420c8fb0020b0fc4@linux-foundation.org> References: <1461743305-19970-1-git-send-email-minchan@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1461743305-19970-1-git-send-email-minchan@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Minchan Kim Cc: Rik van Riel , Sergey Senozhatsky , Rafael Aquini , Jonathan Corbet , Chan Gyun Jeong , Hugh Dickins , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org, John Einar Reitan , linux-mm@kvack.org, Chulmin Kim , Gioh Kim , Konstantin Khlebnikov , Sangseok Lee , Joonsoo Kim , Kyeongdon Kim , Naoya Horiguchi , Vlastimil Babka , Mel Gorman List-Id: virtualization@lists.linuxfoundation.org On Wed, 27 Apr 2016 16:48:13 +0900 Minchan Kim wrote: > Recently, I got many reports about perfermance degradation in embedded > system(Android mobile phone, webOS TV and so on) and easy fork fail. > > The problem was fragmentation caused by zram and GPU driver mainly. > With memory pressure, their pages were spread out all of pageblock and > it cannot be migrated with current compaction algorithm which supports > only LRU pages. In the end, compaction cannot work well so reclaimer > shrinks all of working set pages. It made system very slow and even to > fail to fork easily which requires order-[2 or 3] allocations. > > Other pain point is that they cannot use CMA memory space so when OOM > kill happens, I can see many free pages in CMA area, which is not > memory efficient. In our product which has big CMA memory, it reclaims > zones too exccessively to allocate GPU and zram page although there are > lots of free space in CMA so system becomes very slow easily. > > To solve these problem, this patch tries to add facility to migrate > non-lru pages via introducing new functions and page flags to help > migration. I'm seeing some rejects here against Mel's changes and our patch bandwidth is getting waaay way ahead of our review bandwidth. So I think I'll loadshed this patchset at this time, sorry.