Re: [PATCH] memcg: implement boost mode

Michal Hocko
2013-04-01T09:37:40Z

On Mon 01-04-13 13:30:22, Glauber Costa wrote:
> 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:
> http://www.dilbert.com/fast/2008-05-08/

:)

--
Michal Hocko
SUSE Labs