From: Leonid Moiseichuk <lmoiseichuk@magicleap.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: svc lmoiseichuk <svc_lmoiseichuk@magicleap.com>,
Johannes Weiner <hannes@cmpxchg.org>,
vdavydov.dev@gmail.com, tj@kernel.org, lizefan@huawei.com,
cgroups@vger.kernel.org, akpm@linux-foundation.org,
rientjes@google.com, minchan@kernel.org, vinmenon@codeaurora.org,
andriy.shevchenko@linux.intel.com, penberg@kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH 0/2] memcg, vmpressure: expose vmpressure controls
Date: Wed, 15 Apr 2020 08:33:01 -0400 [thread overview]
Message-ID: <CAELvCDRp+4HWBAqhQms9-_8za_FD=Un-_8jZNbFMAusiReseKA@mail.gmail.com> (raw)
In-Reply-To: <20200415122857.GL4629@dhcp22.suse.cz>
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Good point but at the current moment I am not ready to implement autotune
window size because my device only has 8 GB RAM and a very custom version
of Android-based SW.
So basically I cannot test in all possible combinations.
On Wed, Apr 15, 2020 at 8:29 AM Michal Hocko <mhocko@kernel.org> wrote:
> On Wed 15-04-20 08:17:42, Leonid Moiseichuk wrote:
> > As Chris Down stated cgroups v1 frozen, so no API changes in the mainline
> > kernel.
>
> Yes, this is true, _but_ if there are clear shortcomings in the existing
> vmpressure implementation which could be addressed reasonably then there
> is no reason to ignore them.
>
> [...]
>
> > > I still find this very confusing because the amount of used memory is
> > > not really important. It really only depends on the reclaim activity
> and
> > > that is either the memcg or the global reclaim. And you are getting
> > > critical levels only if the reclaim is failing to reclaim way too many
> > > pages.
> > >
> >
> > OK, agree from that point of view.
> > But for larger systems reclaiming happens not so often and we can
> > use larger window sizes to have better memory utilization approximation.
>
> Nobody is saying the the window size has to be fixed. This all can be
> auto tuned in the kernel. It would, however, require to define what
> "better utilization approximation" means much more specifically.
>
> [...]
> > > This looks more like a problem of vmpressure implementation than
> > > something you want to workaround by tuning to me.
> > >
> > Basically it is how it works - collect the scanned page and activate
> worker
> > activity to update the current level.
>
> That is the case only for some vmpressure invocations. And your data
> suggest that those might lead to misleading results. So this is likely
> good to focus on and find out whether this can be addressed.
> --
> Michal Hocko
> SUSE Labs
>
--
With Best Wishes,
Leonid
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next prev parent reply other threads:[~2020-04-15 12:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-13 21:57 [PATCH 0/2] memcg, vmpressure: expose vmpressure controls svc_lmoiseichuk
2020-04-13 21:57 ` [PATCH 1/2] memcg: expose vmpressure knobs svc_lmoiseichuk
2020-04-14 22:55 ` Chris Down
2020-04-14 23:00 ` Leonid Moiseichuk
2020-04-13 21:57 ` [PATCH 2/2] memcg, vmpressure: expose vmpressure controls svc_lmoiseichuk
2020-04-14 11:37 ` [PATCH 0/2] " Michal Hocko
2020-04-14 16:42 ` Leonid Moiseichuk
2020-04-14 18:49 ` Michal Hocko
2020-04-14 20:53 ` Leonid Moiseichuk
2020-04-15 7:51 ` Michal Hocko
2020-04-15 12:17 ` Leonid Moiseichuk
2020-04-15 12:28 ` Michal Hocko
2020-04-15 12:33 ` Leonid Moiseichuk [this message]
2020-04-14 19:23 ` Johannes Weiner
2020-04-14 22:12 ` Leonid Moiseichuk
2020-04-15 7:55 ` Michal Hocko
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