From: Shakeel Butt <shakeel.butt@linux.dev>
To: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
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>
Subject: Re: [PATCH] memcg: add tracing for memcg stat updates
Date: Thu, 10 Oct 2024 10:27:20 -0700 [thread overview]
Message-ID: <hp45j5kdj5lrqltor5zsx5ti5fsw5j6pzomgtgixr3iq6z2qdd@6if6wvwmzi4h> (raw)
In-Reply-To: <Zwcj5SC_MYrPpNQq@google.com>
On Thu, Oct 10, 2024 at 12:46:29AM GMT, Roman Gushchin wrote:
> On Wed, Oct 09, 2024 at 05:35:50PM -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>
Thanks for the review.
next prev parent reply other threads:[~2024-10-10 17:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-10 0:35 Shakeel Butt
2024-10-10 0:46 ` Yosry Ahmed
2024-10-10 1:08 ` Steven Rostedt
2024-10-10 1:24 ` Yosry Ahmed
2024-10-10 17:26 ` Shakeel Butt
2024-10-15 0:15 ` Yosry Ahmed
2024-10-15 0:23 ` Daniel Xu
2024-10-15 8:02 ` Yosry Ahmed
2024-10-10 0:46 ` Roman Gushchin
2024-10-10 17:27 ` Shakeel Butt [this message]
2024-10-15 8:07 ` Yosry Ahmed
2024-10-15 18:39 ` Shakeel Butt
2024-10-15 18:47 ` Yosry Ahmed
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