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From:   Yosry Ahmed <yosryahmed@google.com>
Date:   Tue, 24 May 2022 12:01:01 -0700
Message-ID: <CAJD7tkZxvmnrrjc4yAe5mC+SL-MZqMkn21yjetiLYyq0B=AhtA@mail.gmail.com>
Subject: Re: [PATCH] memcg: provide reclaim stats via 'memory.reclaim'
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Michal Hocko <mhocko@suse.com>,
        Vaibhav Jain <vaibhav@linux.ibm.com>,
        Cgroups <cgroups@vger.kernel.org>, linux-doc@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>, Tejun Heo <tj@kernel.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Shakeel Butt <shakeelb@google.com>,
        David Rientjes <rientjes@google.com>
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On Tue, May 24, 2022 at 4:45 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Mon, May 23, 2022 at 03:50:34PM -0700, Yosry Ahmed wrote:
> > I think it might be useful to have a dedicated entry in memory.stat
> > for proactively reclaimed memory. A case where this would be useful is
> > tuning and evaluating userspace proactive reclaimers. For instance, if
> > a userspace agent is asking the kernel to reclaim 100M, but it could
> > only reclaim 10M, then most probably the proactive reclaimer is not
> > using a good methodology to figure out how much memory do we need to
> > reclaim.
> >
> > IMO this is more useful, and a superset of just reading the last
> > reclaim request status through memory.reclaim (read stat before and
> > after).
>
> +1

It might also be useful to have a breakdown of this by memory type:
file, anon, or shrinkers.

It would also fit in nicely with a potential type=file/anon/shrinker
argument to memory.reclaim. Thoughts on this?