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Fri, 11 Sep 2026 06:38:03 -0700 (PDT) Received: from localhost.localdomain ([2001:af0:8000:1409:193:86:92:181]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49d26d49d57sm148647335e9.14.2026.09.11.06.38.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Sep 2026 06:38:02 -0700 (PDT) Date: Fri, 11 Sep 2026 15:38:01 +0200 From: Michal =?utf-8?Q?Koutn=C3=BD?= To: Sebastian Andrzej Siewior Cc: cgroups@vger.kernel.org, Tejun Heo , Johannes Weiner Subject: Re: [PATCH] cgroup: Move cgrp_dead_ task+iwork into its own struct Message-ID: References: <20260911101900.984420-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="xwykti33if7bkyii" Content-Disposition: inline In-Reply-To: <20260911101900.984420-1-bigeasy@linutronix.de> --xwykti33if7bkyii Content-Type: text/plain; protected-headers=v1; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH] cgroup: Move cgrp_dead_ task+iwork into its own struct MIME-Version: 1.0 On Fri, Sep 11, 2026 at 12:19:00PM +0200, Sebastian Andrzej Siewior wrote: > cgrp_dead_tasks and cgrp_dead_tasks_iwork are independent per-CPU > variables and are independently accessed via a this_cpu_ptr(). >=20 > Having a custom struct with those two members makes it possible to have > only one per-CPU accessor and access the second member via an offset. > This makes the code a bit more compact and is micro-optimization. >=20 > Besides that, it allows cgrp_dead_tasks_iwork_fn() to access the list > pointer via the passed iwork pointer. This not only eliminates the > this_cpu_ptr() but also makes it possible to be invoked on a different > CPU. This does not happen as of today but might if I can flush the > irq_work items from another CPU during CPU-hotplug events. >=20 > Create struct cgroup_dead with the per-CPU variables as members. Access > the struct with a per-CPU accessor and use the cointer_of() in the > irq_work callback. >=20 > Signed-off-by: Sebastian Andrzej Siewior > --- > kernel/cgroup/cgroup.c | 23 +++++++++++++++-------- > 1 file changed, 15 insertions(+), 8 deletions(-) Acked-by: Michal Koutn=FD --xwykti33if7bkyii Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJEEABYKADkWIQRCE24Fn/AcRjnLivR+PQLnlNv4CAUCaqQENRsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMiwyLDIACgkQfj0C55Tb+Ah07wD/QHk6ijDMHWWVtRs0T6tN 4hMYgT4/oE3txfzgpwDOKYYBAJ8K8a3t0441GRf8yVMBArRz0dlxn8LuPgZoAc43 PCYB =nk72 -----END PGP SIGNATURE----- --xwykti33if7bkyii--