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Date: Wed, 27 Apr 2016 13:20:35 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Vlastimil Babka <vbabka@suse.cz>, dri-devel@lists.freedesktop.org,
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        Jonathan Corbet <corbet@lwn.net>, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Konstantin Khlebnikov <koct9i@gmail.com>, Mel Gorman <mgorman@suse.de>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
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        virtualization@lists.linux-foundation.org,
        Gioh Kim <gi-oh.kim@profitbricks.com>,
        Chan Gyun Jeong <chan.jeong@lge.com>,
        Sangseok Lee <sangseok.lee@lge.com>,
        Kyeongdon Kim <kyeongdon.kim@lge.com>,
        Chulmin Kim <cmlaika.kim@samsung.com>
Subject: Re: [PATCH v4 00/13] Support non-lru page migration
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On Wed, 27 Apr 2016 16:48:13 +0900 Minchan Kim <minchan@kernel.org> 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.