Re: [LKP] Re: [mm/memcg] bd0b230fe1: will-it-scale.per_process_ops -22.7% regression

Michal Hocko
2020-11-02T10:02:52Z

On Mon 02-11-20 17:53:14, Rong Chen wrote:
>
>
> On 11/2/20 5:27 PM, Michal Hocko wrote:
> > On Mon 02-11-20 17:15:43, kernel test robot wrote:
> > > Greeting,
> > >
> > > FYI, we noticed a -22.7% regression of will-it-scale.per_process_ops due to commit:
> > >
> > >
> > > commit: bd0b230fe14554bfffbae54e19038716f96f5a41 ("mm/memcg: unify swap and memsw page counters")
> > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> > I really fail to see how this can be anything else than a data structure
> > layout change. There is one counter less.
> >
> > btw. are cgroups configured at all? What would be the configuration?
>
> Hi Michal,
>
> We used the default configure of cgroups, not sure what configuration you
> want,
> could you give me more details? and here is the cgroup info of will-it-scale
> process:
>
> $ cat /proc/3042/cgroup
> 12:hugetlb:/
> 11:memory:/system.slice/lkp-bootstrap.service

OK, this means that memory controler is enabled and in use. Btw. do you
get the original performance if you add one phony page_counter after the
union?
--
Michal Hocko
SUSE Labs