From: Shakeel Butt <shakeel.butt@linux.dev>
To: Guopeng Zhang <zhangguopeng@kylinos.cn>
Cc: tj@kernel.org, hannes@cmpxchg.org, mhocko@kernel.org,
roman.gushchin@linux.dev, mkoutny@suse.com,
muchun.song@linux.dev, lance.yang@linux.dev, shuah@kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 3/3] selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants
Date: Tue, 2 Dec 2025 15:18:42 -0800 [thread overview]
Message-ID: <3p7o2cxir6yz4baonmkrzumklg5zx3oddhi7mqlmxu26j7ze33@u2mrvj6pqad4> (raw)
In-Reply-To: <20251124123816.486164-4-zhangguopeng@kylinos.cn>
On Mon, Nov 24, 2025 at 08:38:16PM +0800, Guopeng Zhang wrote:
> Replaced the manual sleep and retry logic in test_kmem_dead_cgroups() with the new
> helper `cg_read_key_long_poll()`. This change improves the robustness of the test by
> polling the "nr_dying_descendants" counter in `cgroup.stat` until it reaches 0 or the timeout is exceeded.
>
> Additionally, increased the retry timeout to 8 seconds (from 5 seconds) based on testing results:
Why 8 seconds? What does it depend on? For memcg stats I see the 3
seconds driven from the 2 sec periodic rstat flush. Mainly how can we
make this more future proof?
> - With 5-second timeout: 4/20 runs passed.
> - With 8-second timeout: 20/20 runs passed.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Anyways, just add a sentence in the commit message on the reasoning
behind 8 seconds and a comment in code as well. With that, you can add:
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
next prev parent reply other threads:[~2025-12-02 23:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-24 12:38 [PATCH v4 0/3] selftests: cgroup: Enhance robustness with polling helpers Guopeng Zhang
2025-11-24 12:38 ` [PATCH v4 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries Guopeng Zhang
2025-12-02 19:24 ` Shakeel Butt
2025-11-24 12:38 ` [PATCH v4 2/3] selftests: cgroup: make test_memcg_sock robust against delayed sock stats Guopeng Zhang
2025-11-27 10:55 ` Lance Yang
2025-11-27 11:18 ` Guopeng Zhang
2025-11-27 11:29 ` Lance Yang
2025-12-02 23:12 ` Shakeel Butt
2025-12-03 3:27 ` Guopeng Zhang
2025-11-24 12:38 ` [PATCH v4 3/3] selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants Guopeng Zhang
2025-12-02 23:18 ` Shakeel Butt [this message]
2025-12-03 3:32 ` Guopeng Zhang
2025-12-02 5:45 ` [PATCH v4 0/3] selftests: cgroup: Enhance robustness with polling helpers Tejun Heo
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