Re: [PATCH] mm, memcg: add workingset_restore in memory.stat

[Yafang Shao <laoar.shao@gmail.com>]

On Mon, May 4, 2020 at 5:10 PM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Sat 02-05-20 10:18:49, Yafang Shao wrote:
> > There's a new workingset counter introduced in commit 1899ad18c607 ("mm:
> > workingset: tell cache transitions from workingset thrashing"). With the
> > help of this counter we can know the workingset is transitioning or
> > thrashing. To leverage the benifit of this counter to memcg, we should
> > introduce it into memory.stat. Then we could know the workingset of the
> > workload inside a memcg better.
> >
> > Bellow is the verification of this new counter in memory.stat.
> > Read a file into the memory and then read it again to make these pages be
> > active. The size of this file is 1G. (memory.max is greater than file size)
> > The counters in memory.stat will be,
> >       inactive_file 0
> >       active_file 1073639424
> >
> >       workingset_refault 0
> >       workingset_activate 0
> >       workingset_restore 0
> >       workingset_nodereclaim 0
> > Trigger the memcg reclaim by setting a lower value to memory.high, and
> > then some pages will be demoted into inactive list, and then some pages
> > in the inactive list will be evicted into the storage.
> >       inactive_file 498094080
> >       active_file 310063104
> >
> >       workingset_refault 0
> >       workingset_activate 0
> >       workingset_restore 0
> >       workingset_nodereclaim 0
> > Then recover the memory.high and read the file into memory again. As a
> > result of it, the transitioning will occur. Bellow is the result of this
> > transitioning,
> >       inactive_file 498094080
> >       active_file 575397888
> >
> >       workingset_refault 64746
> >       workingset_activate 64746
> >       workingset_restore 64746
> >       workingset_nodereclaim 0
>
> Could you update Documentation/admin-guide/cgroup-v2.rst as well please?
>

Thanks for your reminder. I will update it.

> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
>
> Acked-by: Michal Hocko <mhocko@suse.com>
>

Thanks.

> > ---
> >  mm/memcontrol.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 5beea03dd58a..0395e479995b 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -1451,6 +1451,8 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> >                      memcg_page_state(memcg, WORKINGSET_REFAULT));
> >       seq_buf_printf(&s, "workingset_activate %lu\n",
> >                      memcg_page_state(memcg, WORKINGSET_ACTIVATE));
> > +     seq_buf_printf(&s, "workingset_restore %lu\n",
> > +                    memcg_page_state(memcg, WORKINGSET_RESTORE));
> >       seq_buf_printf(&s, "workingset_nodereclaim %lu\n",
> >                      memcg_page_state(memcg, WORKINGSET_NODERECLAIM));
> >
> > --
> > 2.18.2
>
> --
> Michal Hocko
> SUSE Labs



-- 
Thanks
Yafang