Re: [PATCH] mm/vmscan: add pgstall to memcg

[Michal Hocko <mhocko@suse.com>]

On Tue 12-07-22 17:28:50, Chuyi Zhou wrote:
> 
> 
> 在 2022/6/25 上午4:42, Andrew Morton 写道:
> > (cc memcg developers)
> > On Thu, 23 Jun 2022 16:01:03 +0800 zhouchuyi <zhouchuyi@bytedance.com> wrote:
> > 
> > > Add pgstall to indicate the times of entering direct reclaim of memcg, use
> > > the item of ALLOCSTALL_NORMAL in vmevents to save the data.
> > > 
> > > Signed-off-by: zhouchuyi <zhouchuyi@bytedance.com>
> > > ---
> > > 
> > > 
> > > Hi，
> > > 
> > > I notice memcg uses some items to indicate the situation of direct reclaim in memory.stat，such as pgsteal and pgscan.
> > > I think there is no harm in adding another item to show the times of entering direct reclaim.
> > > 
> > 
> > Why do you consider this useful?  Do you have a use case?  If so,
> > please describe it in detail.
> > 
> Since there are allocstall in proc/vmstat which indicate the number of
> entering direct reclaim of !cgroup_reclaim, So I think it maybe useful. For
> example, users could adjust memory.max to prevent entering direct reclaim
> through this item.So what do you think about it ?

We already do have events for that - have a look MEMCG_MAX. Can you work
with that?
-- 
Michal Hocko
SUSE Labs