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From:   Yosry Ahmed <yosryahmed@google.com>
Date:   Tue, 3 Oct 2023 12:47:25 -0700
Message-ID: <CAJD7tkbfq8P514-8Y1uZG9E0fMN2HwEaBmxEutBhjVtbtyEdCQ@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] mm: memcg: refactor page state unit helpers
To:     =?UTF-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Shakeel Butt <shakeelb@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Muchun Song <muchun.song@linux.dev>, linux-mm@kvack.org,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
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On Tue, Oct 3, 2023 at 11:11=E2=80=AFAM Michal Koutn=C3=BD <mkoutny@suse.co=
m> wrote:
>
> On Fri, Sep 22, 2023 at 05:57:39PM +0000, Yosry Ahmed <yosryahmed@google.=
com> wrote:
> > memcg_page_state_unit() is currently used to identify the unit of a
> > memcg state item so that all stats in memory.stat are in bytes. However=
,
> > it lies about the units of WORKINGSET_* stats. These stats actually
> > represent pages, but we present them to userspace as a scalar number of
> > events. In retrospect, maybe those stats should have been memcg "events=
"
> > rather than memcg "state".
>
> Why isn't it possible to move WORKINGSET_* stats under the events now?
> (Instead of using internal and external units.)

Those constants are shared with code outside of memcg, namely enum
node_stat_item and enum vm_event_item, and IIUC they are used
differently outside of memcg. Did I miss something?

>
> Thanks,
> Michal