Re: [PATCH v5 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries

[Michal Koutný]

On Wed, Dec 03, 2025 at 07:56:29PM +0800, Guopeng Zhang <zhangguopeng@xxxxxxxxxx> 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@xxxxxxxxxx>
> Suggested-by: Michal Koutný <mkoutny@xxxxxxxx>
> Reviewed-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
> ---
>  .../selftests/cgroup/lib/cgroup_util.c        | 21 +++++++++++++++++++
>  .../cgroup/lib/include/cgroup_util.h          |  5 +++++
>  2 files changed, 26 insertions(+)

Acked-by: Michal Koutný <mkoutny@xxxxxxxx>

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