Re: [PATCH] mm: per-cgroup memory reclaim stats

[Roman Gushchin]

Hi Michal!

On Tue, May 16, 2017 at 11:29:56AM +0200, Michal Hocko wrote:
> On Thu 11-05-17 20:16:23, Roman Gushchin wrote:
> > Track the following reclaim counters for every memory cgroup:
> > PGREFILL, PGSCAN, PGSTEAL, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE and
> > PGLAZYFREED.
> 
> yes, those are definitely useful. I have an old patch to add them as
> well but never managed to clean it up and post...
> 
> > These values are exposed using the memory.stats interface of cgroup v2.
> 
> Is there any reason to not add them to v1?

Not really, I'm just not sure, if it worth it to change v1 interface here.
If you want, I can add them.

> This should be rather trivial after recent changes from Johannes.

If you're about memcg1_events[]/memcg1_event_names[], they can't be reused,
because the pgscan and pgsteal values are both sums of direct and kswapd values:
e.g. events[PGSTEAL_KSWAPD] + events[PGSTEAL_DIRECT].

> 
> > The meaning of each value is the same as for global counters,
> > available using /proc/vmstat.
> > 
> > Also, for consistency, rename mem_cgroup_count_vm_event() to
> > count_memcg_event_mm().
> > 
> > Signed-off-by: Roman Gushchin <guro@xxxxxx>
> > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> > Cc: Tejun Heo <tj@xxxxxxxxxx>
> > Cc: Li Zefan <lizefan@xxxxxxxxxx>
> > Cc: Michal Hocko <mhocko@xxxxxxxxxx>
> > Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
> > Cc: cgroups@xxxxxxxxxxxxxxx
> > Cc: linux-doc@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Cc: linux-mm@xxxxxxxxx
> 
> the patch itself looks good to me. I will have to double check it after
> I am done with what I am doing currently and then will add my Acked-by

Thank you!