From: Tejun Heo <tj@kernel.org>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: bpf@vger.kernel.org, "Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"John Fastabend" <john.fastabend@gmail.com>,
"Jiri Olsa" <jolsa@kernel.org>,
"Emil Tsalapatis" <emil@etsalapatis.com>,
"Ihor Solodrai" <ihor.solodrai@linux.dev>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
"Amery Hung" <ameryhung@gmail.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Meta kernel team" <kernel-team@meta.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next 0/3] bpf, cgroup: Don't wait for cgroup_mutex to read or free cgroup bpf state
Date: Sat, 14 Nov 2026 06:19:10 -1000 [thread overview]
Message-ID: <ec53c6d48e537677b488f5d82b3f3f0f@kernel.org> (raw)
In-Reply-To: <20261112172721.440275-1-shakeel.butt@linux.dev>
On Thu, Nov 12, 2026 at 09:27:12AM -0800, Shakeel Butt wrote:
> In the Meta fleet, BPF_PROG_QUERY callers, link-info readers and the
> cgroup bpf release work often wait minutes for cgroup_mutex. The holder is
> almost always a cgroup mkdir or rmdir stuck on kernfs_rwsem. In one day,
> hung-task reports showed this on 1,075 hosts (query), 94 hosts (link info)
> and 458 hosts (release work).
For the series,
Acked-by: Tejun Heo <tj@kernel.org>
Thanks.
--
tejun
prev parent reply other threads:[~2026-11-14 16:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-12 17:27 Shakeel Butt
2026-11-12 17:27 ` [PATCH bpf-next 1/3] bpf, cgroup: Don't read freed effective arrays in BPF_PROG_QUERY Shakeel Butt
2026-11-12 17:27 ` [PATCH bpf-next 2/3] bpf, cgroup: Don't attach to a removed cgroup Shakeel Butt
2026-11-12 17:27 ` [PATCH bpf-next 3/3] bpf, cgroup: Protect cgroup_bpf state with its own mutex Shakeel Butt
2026-11-14 16:19 ` Tejun Heo [this message]
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