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Subject: Re: [PATCH v6 2/6] mm/cma: introduce new zone, ZONE_CMA
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
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 <58184B28.8090405@hisilicon.com> <20161107061500.GA21159@js1304-P5Q-DELUXE>
CC: Andrew Morton <akpm@linux-foundation.org>,
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        Michal Nazarewicz <mina86@mina86.com>,
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From: Chen Feng <puck.chen@hisilicon.com>
Message-ID: <58202881.5030004@hisilicon.com>
Date: Mon, 7 Nov 2016 15:08:49 +0800
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On 2016/11/7 14:15, Joonsoo Kim wrote:
> On Tue, Nov 01, 2016 at 03:58:32PM +0800, Chen Feng wrote:
>> Hello, I hava a question on cma zone.
>>
>> When we have cma zone, cma zone will be the highest zone of system.
>>
>> In android system, the most memory allocator is ION. Media system will
>> alloc unmovable memory from it.
>>
>> On low memory scene, will the CMA zone always do balance?
> 
> Allocation request for low zone (normal zone) would not cause CMA zone
> to be balanced since it isn't helpful.
> 
Yes. But the cma zone will run out soon. And it always need to do balance.

How about use migrate cma before movable and let cma type to fallback movable.

https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1263745.html

>> Should we transmit the highest available zone to kswapd？
> 
> It is already done when necessary.
> 
> Thanks.
> 
> 
> .
>