Re: [PATCH] mm, memcg: Optionally disable memcg by default using Kconfig

Michal Hocko
2015-05-19T14:51:20Z

On Tue 19-05-15 10:18:07, Johannes Weiner wrote:
> CC'ing Tejun and cgroups for the generic cgroup interface part
>
> On Tue, May 19, 2015 at 11:40:57AM +0100, Mel Gorman wrote:
[...]
> > /usr/src/linux-4.0-vanilla/mm/memcontrol.c 6.6441 395842
> > mem_cgroup_try_charge 2.950% 175781
>
> Ouch. Do you have a way to get the per-instruction breakdown of this?
> This function really isn't doing much. I'll try to reproduce it here
> too, I haven't seen such high costs with pft in the past.
>
> > try_charge 0.150% 8928
> > get_mem_cgroup_from_mm 0.121% 7184

Indeed! try_charge + get_mem_cgroup_from_mm which I would expect to be
the biggest consumers here are below 10% of the mem_cgroup_try_charge.
Other than that the function doesn't do much else than some flags
queries and css_put...

Do you have the full trace? Sorry for a stupid question but do inlines
from other header files get accounted to memcontrol.c?

[...]
--
Michal Hocko
SUSE Labs