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Date:   Tue, 17 May 2022 16:52:16 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Michal =?ISO-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>,
        Michal Hocko <mhocko@suse.com>, Roman Gushchin <guro@fb.com>,
        Shakeel Butt <shakeelb@google.com>,
        Seth Jennings <sjenning@redhat.com>,
        Dan Streetman <ddstreet@ieee.org>,
        Minchan Kim <minchan@kernel.org>, linux-mm@kvack.org,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@fb.com
Subject: Re: [PATCH v2 6/6] zswap: memcg accounting
Message-Id: <20220517165216.7acd8434f8b25606836e21e6@linux-foundation.org>
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On Mon, 16 May 2022 16:01:05 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:

> > > Flushing unnecessary groups with a ratelimit doesn't sound like an
> > > improvement to me.
> > 
> > Then I'm only concerned about a situation when there's a single deep
> > memcg that undergoes both workingset_refault() and zswap querying.
> > The latter (bare call to cgroup_rstat_flush()) won't reset
> > stats_flush_threshold, so the former (or the async flush more likely)
> > would attempt a flush too. The flush work (on the leaf memcg) would be
> > done twice even though it may be within the tolerance of cumulated
> > error the second time.
> > 
> > This is a thing that might require attention in the future (depending on
> > some data how it actually performs). I see how the current approach is
> > justified.
> 
> Yes, we can optimize it should the need arise. So far it's been fine.
> 
> Thanks for your thoughts, Michal.

Me too.

I think everything is settled here so I plan to import this series into
mm-stable in a couple of days.

at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/

 documentation-filesystems-proc-update-meminfo-section.patch
 documentation-filesystems-proc-update-meminfo-section-fix.patch
 documentation-filesystems-proc-update-meminfo-section-fix-2.patch
 mm-kconfig-move-swap-and-slab-config-options-to-the-mm-section.patch
 mm-kconfig-group-swap-slab-hotplug-and-thp-options-into-submenus.patch
 mm-kconfig-group-swap-slab-hotplug-and-thp-options-into-submenus-fix.patch
 mm-kconfig-group-swap-slab-hotplug-and-thp-options-into-submenus-fix-fix.patch
 mm-kconfig-simplify-zswap-configuration.patch
 mm-zswap-add-basic-meminfo-and-vmstat-coverage.patch
 zswap-memcg-accounting.patch
 zswap-memcg-accounting-fix.patch
 zswap-memcg-accounting-fix-2.patch