Re: [PATCH] memcg: implement boost mode

Glauber Costa
2013-04-01T09:30:22Z

On 04/01/2013 01:27 PM, Kamezawa Hiroyuki wrote:
> (2013/04/01 16:34), Glauber Costa wrote:
>> There are scenarios in which we would like our programs to run faster.
>> It is a hassle, when they are contained in memcg, that some of its
>> allocations will fail and start triggering reclaim. This is not good
>> for the program, that will now be slower.
>>
>> This patch implements boost mode for memcg. It exposes a u64 file
>> "memcg boost". Every time you write anything to it, it will reduce the
>> counters by ~20 %. Note that we don't want to actually reclaim pages,
>> which would defeat the very goal of boost mode. We just make the
>> res_counters able to accomodate more.
>>
>> This file is also available in the root cgroup. But with a slightly
>> different effect. Writing to it will make more memory physically
>> available so our programs can profit.
>>
>> Please ack and apply.
>>
> Nack.
>
>> Signed-off-by: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
>
> Please update limit temporary. If you need call-shrink-explicitly-by-user,
> I think you can add it.
>

I don't want to shrink memory because that will make applications
slower. I want them to be faster, so they need to have more memory.
There is solid research backing up my approach: