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Message-ID: <5820313A.80207@hisilicon.com>
Date: Mon, 7 Nov 2016 15:46:02 +0800
From: Chen Feng <puck.chen@...ilicon.com>
To: Joonsoo Kim <iamjoonsoo.kim@....com>
CC: Andrew Morton <akpm@...ux-foundation.org>,
Rik van Riel <riel@...hat.com>,
Johannes Weiner <hannes@...xchg.org>,
<mgorman@...hsingularity.net>,
"Laura Abbott" <lauraa@...eaurora.org>,
Minchan Kim <minchan@...nel.org>,
"Marek Szyprowski" <m.szyprowski@...sung.com>,
Michal Nazarewicz <mina86@...a86.com>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
Vlastimil Babka <vbabka@...e.cz>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>, <saberlily.xia@...ilicon.com>,
Zhuangluan Su <suzhuangluan@...ilicon.com>,
Dan Zhao <dan.zhao@...ilicon.com>
Subject: Re: [PATCH v6 2/6] mm/cma: introduce new zone, ZONE_CMA
On 2016/11/7 15:44, Chen Feng wrote:
> On 2016/11/7 15:27, Joonsoo Kim wrote:
>> On Mon, Nov 07, 2016 at 03:08:49PM +0800, Chen Feng wrote:
>>>
>>>
>>> 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
>>
>> ZONE_CMA approach will act like as your solution. Could you elaborate
>> more on the problem of zone approach?
>>
>
> The ZONE approach is that makes cma pages in a zone. It can cause a higher swapin/out
> than use migrate cma first.
>
> The higher swapin/out may have a performance effect to application. The application may
> use too much time swapin memory.
>
> You can see my tested result attached for detail. And the baseline is result of [1].
>
>
My test case is run 60 applications and alloc 512MB ION memory.
Repeat this action 50 times
> [1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1263745.html
>> Thanks.
>>
>> .
>>
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