From: Johannes Weiner <hannes@cmpxchg.org>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
Steven Rostedt <rostedt@goodmis.org>,
JP Kobryn <inwardvessel@gmail.com>,
Yosry Ahmed <yosryahmed@google.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
Meta kernel team <kernel-team@meta.com>,
Michal Hocko <mhocko@suse.com>,
Muchun Song <songmuchun@bytedance.com>
Subject: Re: [PATCH v2] memcg: add tracing for memcg stat updates
Date: Tue, 15 Oct 2024 17:52:36 -0400 [thread overview]
Message-ID: <20241015215236.GA1052@cmpxchg.org> (raw)
In-Reply-To: <20241015213721.3804209-1-shakeel.butt@linux.dev>
On Tue, Oct 15, 2024 at 02:37:21PM -0700, Shakeel Butt wrote:
> The memcg stats are maintained in rstat infrastructure which provides very
> fast updates side and reasonable read side. However memcg added plethora
> of stats and made the read side, which is cgroup rstat flush, very slow.
> To solve that, threshold was added in the memcg stats read side i.e. no
> need to flush the stats if updates are within the threshold.
>
> This threshold based improvement worked for sometime but more stats were
> added to memcg and also the read codepath was getting triggered in the
> performance sensitive paths which made threshold based ratelimiting
> ineffective. We need more visibility into the hot and cold stats i.e.
> stats with a lot of updates. Let's add trace to get that visibility.
>
> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
> Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Muchun Song <songmuchun@bytedance.com>
> Cc: JP Kobryn <inwardvessel@gmail.com>
> Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2024-10-15 21:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-15 21:37 [PATCH v2] memcg: add tracing for memcg stat updates Shakeel Butt
2024-10-15 21:52 ` Johannes Weiner [this message]
2024-10-16 17:17 ` T.J. Mercier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20241015215236.GA1052@cmpxchg.org \
--to=hannes@cmpxchg.org \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=inwardvessel@gmail.com \
--cc=kernel-team@meta.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mhocko@suse.com \
--cc=muchun.song@linux.dev \
--cc=roman.gushchin@linux.dev \
--cc=rostedt@goodmis.org \
--cc=shakeel.butt@linux.dev \
--cc=songmuchun@bytedance.com \
--cc=yosryahmed@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.