Re: [PATCH v4 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries

On Mon, Nov 24, 2025 at 08:38:14PM +0800, Guopeng Zhang 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