From: Shakeel Butt <shakeelb@google.com>
To: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] memcg: add pagetable comsumption to memory.stat
Date: Mon, 30 Nov 2020 13:01:18 -0800 [thread overview]
Message-ID: <CALvZod4qiFuiByjh0+fwRoVw_EYVzqADNsiThf42-zDiXyYvpg@mail.gmail.com> (raw)
In-Reply-To: <20201130203425.GA1360286@carbon.DHCP.thefacebook.com>
On Mon, Nov 30, 2020 at 12:34 PM Roman Gushchin <guro@fb.com> wrote:
>
> On Wed, Nov 25, 2020 at 04:56:01PM -0800, Shakeel Butt wrote:
> > Many workloads consumes significant amount of memory in pagetables. This
> > patch series exposes the pagetable comsumption for each memory cgroup.
>
> Hi Shakeel!
>
> The code looks good to me. However I'm not sure I understand what's the
> use case for the new statistics? Can you, please, elaborate a bit more here?
>
> From a very first glance, the size of pagetables should be _roughly_ equal
> to the size_of(pte)/PAGE_SIZE*(size of a cgroup) and should not exceed 1%
> of the cgroup size. So for all but very large cgroups the value will be
> in the noise of per-cpu counters. Perhaps I'm missing some important cases?
>
I think this is in general a good metric to have but one specific
use-case we have is the user space network driver which mmaps the
memory of the applications for zero copy data transfers. This driver
can consume a large amount of memory in page tables. So, this metric
becomes really useful here.
Shakeel
next prev parent reply other threads:[~2020-11-30 21:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 0:56 [PATCH 0/2] memcg: add pagetable comsumption to memory.stat Shakeel Butt
2020-11-26 0:56 ` Shakeel Butt
2020-11-26 0:56 ` [PATCH 1/2] mm: move lruvec stats update functions to vmstat.h Shakeel Butt
2020-11-26 0:56 ` Shakeel Butt
2020-11-30 20:09 ` Johannes Weiner
2020-11-26 0:56 ` [PATCH 2/2] mm: memcontrol: account pagetables per node Shakeel Butt
2020-11-26 0:56 ` Shakeel Butt
2020-11-30 20:19 ` Johannes Weiner
2020-11-30 20:54 ` Shakeel Butt
2020-11-30 20:54 ` Shakeel Butt
2020-11-30 20:34 ` [PATCH 0/2] memcg: add pagetable comsumption to memory.stat Roman Gushchin
2020-11-30 21:01 ` Shakeel Butt [this message]
2020-11-30 21:01 ` Shakeel Butt
2020-11-30 21:10 ` Roman Gushchin
2020-11-30 21:13 ` Shakeel Butt
2020-11-30 21:13 ` Shakeel Butt
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