Re: [PATCH v6 2/6] mm/cma: introduce new zone, ZONE_CMA
From: Chen Feng
Date: Mon Nov 07 2016 - 02:47:20 EST
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.
> 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 .
CMA-ZONE with fallback.PNG
Description: PNG image