From: "Michal Koutný" <mkoutny@suse.com>
To: Quanyang Wang <quanyang.wang@windriver.com>
Cc: Ming Lei <ming.lei@redhat.com>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Jens Axboe <axboe@kernel.dk>,
Roman Gushchin <guro@fb.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline
Date: Tue, 19 Oct 2021 19:10:26 +0200 [thread overview]
Message-ID: <YW78AohHqgqM9Cuw@blackbook> (raw)
In-Reply-To: <a84aedfe-6ecf-7f48-505e-a11acfd6204c@windriver.com>
Hi.
On Tue, Oct 19, 2021 at 06:41:14PM +0800, Quanyang Wang <quanyang.wang@windriver.com> wrote:
> So I add 2 "Fixes tags" here to indicate that 2 commits introduce two
> different issues.
AFAIU, both the changes are needed to cause the leak, a single patch
alone won't cause the issue. Is that correct? (Perhaps not as I realize,
see below.)
But on second thought, the problem is the missing percpu_ref_exit() in
the (root) cgroup release path and percpu counter would allocate the
percpu_count_ptr anyway, so 4bfc0bb2c60e is only making the leak more
visible. Is this correct?
I agree the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of
percpu_ref in fast path") alone did nothing wrong.
[On a related (but independent) note, there seems to be an optimization
opportunity in not dealing with cgroup_bpf at all on the non-default
hierarchies.]
Regards,
Michal
next prev parent reply other threads:[~2021-10-19 17:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 7:56 [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline quanyang.wang
2021-10-18 9:02 ` Ming Lei
2021-10-18 10:06 ` Quanyang Wang
[not found] ` <8fdcaded-474e-139b-a9bc-5ab6f91fbd4f-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
2021-10-18 12:59 ` Ming Lei
2021-10-19 10:41 ` Quanyang Wang
2021-10-19 17:10 ` Michal Koutný [this message]
2021-10-20 2:17 ` Ming Lei
2021-10-20 5:22 ` Quanyang Wang
2021-10-20 17:28 ` Michal Koutný
2021-10-22 11:03 ` Quanyang Wang
2021-10-20 5:16 ` Quanyang Wang
2021-10-19 10:41 ` Quanyang Wang
[not found] ` <20211018075623.26884-1-quanyang.wang-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
2021-10-22 1:30 ` Roman Gushchin
2021-10-22 11:55 ` Quanyang Wang
[not found] ` <35e9e89f-d92f-06f9-b919-ef956d99d7df-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
2021-10-22 21:29 ` Alexei Starovoitov
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