From: David Rientjes <rientjes@google.com>
To: SeongJae Park <sjpark@amazon.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Yang Shi <shy828301@gmail.com>, Michal Hocko <mhocko@kernel.org>,
Shakeel Butt <shakeelb@google.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Roman Gushchin <guro@fb.com>, Greg Thelen <gthelen@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Re: [patch] mm, memcg: provide a stat to describe reclaimable memory
Date: Wed, 15 Jul 2020 10:33:52 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.23.453.2007151031020.2788464@chino.kir.corp.google.com> (raw)
In-Reply-To: <20200715071522.19663-1-sjpark@amazon.com>
On Wed, 15 Jul 2020, SeongJae Park wrote:
> > An alternative to this would also be to change from an "available" metric
> > to an "anon_reclaimable" metric since both the deferred split queues and
> > lazy freeable memory would pertain to anon. This would no longer attempt
> > to mimic MemAvailable and leave any such calculation to userspace
> > (anon_reclaimable + (file + slab_reclaimable) / 2).
> >
> > With this route, care would need to be taken to clearly indicate that
> > anon_reclaimable is not necessarily a subset of the "anon" metric since
> > reclaimable memory from compound pages on deferred split queues is not
> > mapped, so it doesn't show up in NR_ANON_MAPPED.
> >
> > I'm indifferent to either approach and would be happy to switch to
> > anon_reclaimable if others agree and doesn't foresee any extensibility
> > issues.
>
> Agreed, I was also once confused about the 'MemAvailable'. The 'reclaimable'
> might be better to understand.
>
Hi SeongJae,
I'm leaning in that direction now too, actually, because I reasoned that
determining the precise amount of anon that can be reclaimed would require
subtracting (file + slab_reclaimable) / 2, which is awkward :)
So I'll send a follow-up patch to add only an anon_reclaimable field which
is good enough for our purposes unless others would like to have more
discussion.
Thanks!
WARNING: multiple messages have this Message-ID (diff)
From: David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: SeongJae Park <sjpark-vV1OtcyAfmbQT0dZR+AlfA@public.gmane.org>
Cc: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Yang Shi <shy828301-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Yang Shi
<yang.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>,
Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>,
Greg Thelen <gthelen-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Vladimir Davydov
<vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Subject: Re: Re: [patch] mm, memcg: provide a stat to describe reclaimable memory
Date: Wed, 15 Jul 2020 10:33:52 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.23.453.2007151031020.2788464@chino.kir.corp.google.com> (raw)
In-Reply-To: <20200715071522.19663-1-sjpark-vV1OtcyAfmbQT0dZR+AlfA@public.gmane.org>
On Wed, 15 Jul 2020, SeongJae Park wrote:
> > An alternative to this would also be to change from an "available" metric
> > to an "anon_reclaimable" metric since both the deferred split queues and
> > lazy freeable memory would pertain to anon. This would no longer attempt
> > to mimic MemAvailable and leave any such calculation to userspace
> > (anon_reclaimable + (file + slab_reclaimable) / 2).
> >
> > With this route, care would need to be taken to clearly indicate that
> > anon_reclaimable is not necessarily a subset of the "anon" metric since
> > reclaimable memory from compound pages on deferred split queues is not
> > mapped, so it doesn't show up in NR_ANON_MAPPED.
> >
> > I'm indifferent to either approach and would be happy to switch to
> > anon_reclaimable if others agree and doesn't foresee any extensibility
> > issues.
>
> Agreed, I was also once confused about the 'MemAvailable'. The 'reclaimable'
> might be better to understand.
>
Hi SeongJae,
I'm leaning in that direction now too, actually, because I reasoned that
determining the precise amount of anon that can be reclaimed would require
subtracting (file + slab_reclaimable) / 2, which is awkward :)
So I'll send a follow-up patch to add only an anon_reclaimable field which
is good enough for our purposes unless others would like to have more
discussion.
Thanks!
next prev parent reply other threads:[~2020-07-15 17:33 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 3:18 [patch] mm, memcg: provide a stat to describe reclaimable memory David Rientjes
2020-07-15 3:18 ` David Rientjes
2020-07-15 7:00 ` David Rientjes
2020-07-15 7:00 ` David Rientjes
2020-07-15 7:15 ` SeongJae Park
2020-07-15 7:15 ` SeongJae Park
2020-07-15 17:33 ` David Rientjes [this message]
2020-07-15 17:33 ` David Rientjes
2020-07-16 20:58 ` [patch] mm, memcg: provide an anon_reclaimable stat David Rientjes
2020-07-16 20:58 ` David Rientjes
2020-07-16 21:07 ` Shakeel Butt
2020-07-16 21:07 ` Shakeel Butt
2020-07-16 21:28 ` David Rientjes
2020-07-16 21:28 ` David Rientjes
2020-07-17 1:37 ` Shakeel Butt
2020-07-17 1:37 ` Shakeel Butt
2020-07-17 8:34 ` Michal Hocko
2020-07-17 8:34 ` Michal Hocko
2020-07-17 14:39 ` Johannes Weiner
2020-07-17 14:39 ` Johannes Weiner
2020-07-15 13:10 ` [patch] mm, memcg: provide a stat to describe reclaimable memory Chris Down
2020-07-15 13:10 ` Chris Down
[not found] ` <20200715131048.GA176092-6Bi1550iOqEnzZ6mRAm98g@public.gmane.org>
2020-07-15 18:02 ` David Rientjes
2020-07-17 12:17 ` Chris Down
2020-07-17 12:17 ` Chris Down
2020-07-17 19:37 ` David Rientjes
2020-07-17 19:37 ` David Rientjes
2020-07-20 7:37 ` Michal Hocko
2020-07-20 7:37 ` Michal Hocko
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