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From: Shakeel Butt To: Guopeng Zhang 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 1/3] selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries Message-ID: References: <20251124123816.486164-1-zhangguopeng@kylinos.cn> <20251124123816.486164-2-zhangguopeng@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251124123816.486164-2-zhangguopeng@kylinos.cn> X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 2871F40017 X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: ceurahrtms3kgfxde7o8rp9xgeh1g93m X-HE-Tag: 1764703469-155061 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 > Suggested-by: Michal Koutný Reviewed-by: Shakeel Butt