From: "Michal Koutný" <mkoutny@suse.com>
To: Guopeng Zhang <zhangguopeng@kylinos.cn>
Cc: tj@kernel.org, hannes@cmpxchg.org, shuah@kernel.org,
roman.gushchin@linux.dev, lance.yang@linux.dev,
shakeel.butt@linux.dev, muchun.song@linux.dev,
linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries
Date: Thu, 4 Dec 2025 16:04:30 +0100 [thread overview]
Message-ID: <jp3gp3qbbqmq7nbn5i7qbsgxj3vwquibsxubvvkhc37p3pcc2m@24bljtuw6diy> (raw)
In-Reply-To: <20251203115631.947908-2-zhangguopeng@kylinos.cn>
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On Wed, Dec 03, 2025 at 07:56:29PM +0800, Guopeng Zhang <zhangguopeng@kylinos.cn> wrote:
> Introduce a new helper function `cg_read_key_long_poll()` in
> cgroup_util.h. This function polls the specified key in a cgroup file
> until it matches the expected value or the retry limit is reached,
> with configurable wait intervals between retries.
>
> This helper is particularly useful for handling asynchronously updated
> cgroup statistics (e.g., memory.stat), where immediate reads may
> observe stale values, especially on busy systems. It allows tests and
> other utilities to handle such cases more flexibly.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
> Suggested-by: Michal Koutný <mkoutny@suse.com>
> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
> ---
> .../selftests/cgroup/lib/cgroup_util.c | 21 +++++++++++++++++++
> .../cgroup/lib/include/cgroup_util.h | 5 +++++
> 2 files changed, 26 insertions(+)
Acked-by: Michal Koutný <mkoutny@suse.com>
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next prev parent reply other threads:[~2025-12-04 15:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-03 11:56 [PATCH v5 0/3] selftests: cgroup: Enhance robustness with polling helpers Guopeng Zhang
2025-12-03 11:56 ` [PATCH v5 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries Guopeng Zhang
2025-12-04 15:04 ` Michal Koutný [this message]
2025-12-03 11:56 ` [PATCH v5 2/3] selftests: cgroup: make test_memcg_sock robust against delayed sock stats Guopeng Zhang
2025-12-04 15:04 ` Michal Koutný
2025-12-03 11:56 ` [PATCH v5 3/3] selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants Guopeng Zhang
2025-12-04 15:04 ` Michal Koutný
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