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[195.250.132.146]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4792b152a68sm38677005e9.15.2025.12.04.07.04.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Dec 2025 07:04:42 -0800 (PST) Date: Thu, 4 Dec 2025 16:04:41 +0100 From: Michal =?utf-8?Q?Koutn=C3=BD?= To: Guopeng Zhang 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 3/3] selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants Message-ID: References: <20251203115631.947908-1-zhangguopeng@kylinos.cn> <20251203115631.947908-4-zhangguopeng@kylinos.cn> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="254t2h75sguwzjq3" Content-Disposition: inline In-Reply-To: <20251203115631.947908-4-zhangguopeng@kylinos.cn> X-Rspamd-Queue-Id: 3DB95140018 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: nrzn59yum8aow94m11y8yhczse3pq1du X-HE-Tag: 1764860685-443284 X-HE-Meta: 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 hFIqJt6C 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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: --254t2h75sguwzjq3 Content-Type: text/plain; protected-headers=v1; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v5 3/3] selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants MIME-Version: 1.0 On Wed, Dec 03, 2025 at 07:56:31PM +0800, Guopeng Zhang wrote: > Replace 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. >=20 > Additionally, increase the retry timeout to 8 seconds (from 5 seconds) > based on testing results: > - With 5-second timeout: 4/20 runs passed. > - With 8-second timeout: 20/20 runs passed. >=20 > The 8 second timeout is based on stress testing of test_kmem_dead_cgroups= () > under load: 5 seconds was occasionally not enough for reclaim of dying > descendants to complete, whereas 8 seconds consistently covered the obser= ved > latencies. This value is intended as a generous upper bound for the > asynchronous reclaim and is not tied to any specific kernel constant, so = it > can be adjusted in the future if reclaim behavior changes. Great! >=20 > Signed-off-by: Guopeng Zhang > Reviewed-by: Shakeel Butt > --- > tools/testing/selftests/cgroup/test_kmem.c | 33 ++++++++++------------ > 1 file changed, 15 insertions(+), 18 deletions(-) Acked-by: Michal Koutn=FD --254t2h75sguwzjq3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJEEABYKADkWIQRCE24Fn/AcRjnLivR+PQLnlNv4CAUCaTGjBhsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMSwyLDIACgkQfj0C55Tb+Ag4/AEA8vnYZURHlpYUdZIwoG6K cj1NLOcwOwt2c17lJN9cY3gBAOy6FJ7n6hKdI/nDTvB65mNiVjVrKrmHDFdRgBX1 GTQL =2g5W -----END PGP SIGNATURE----- --254t2h75sguwzjq3--