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Wed, 12 Nov 2025 08:18:29 -0800 (PST) X-Google-Smtp-Source: AGHT+IFMW+EukiVm6iXR4uufSLudxwVy58ZpPfr7lhld1V2UmYylFNmDUJdZqJ3kdrY3F/ZMecdzng== X-Received: by 2002:a05:600c:1c2a:b0:471:131f:85b7 with SMTP id 5b1f17b1804b1-4778704da9dmr34412485e9.15.1762964308758; Wed, 12 Nov 2025 08:18:28 -0800 (PST) Received: from gmonaco-thinkpadt14gen3.rmtit.csb ([185.107.56.40]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47788aacb59sm17393155e9.5.2025.11.12.08.18.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Nov 2025 08:18:28 -0800 (PST) Message-ID: <446f97f9663c1bda011d4171d17f1470d21fb7df.camel@redhat.com> Subject: Re: [PATCH v14 7/7] timers: Exclude isolated cpus from timer migration From: Gabriele Monaco To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, Anna-Maria Behnsen , Thomas Gleixner , Waiman Long , "John B . Wyatt IV" , "John B . Wyatt IV" Date: Wed, 12 Nov 2025 17:18:26 +0100 In-Reply-To: References: <20251104104740.70512-1-gmonaco@redhat.com> <20251104104740.70512-8-gmonaco@redhat.com> Autocrypt: addr=gmonaco@redhat.com; prefer-encrypt=mutual; keydata=mDMEZuK5YxYJKwYBBAHaRw8BAQdAmJ3dM9Sz6/Hodu33Qrf8QH2bNeNbOikqYtxWFLVm0 1a0JEdhYnJpZWxlIE1vbmFjbyA8Z21vbmFjb0BrZXJuZWwub3JnPoiZBBMWCgBBFiEEysoR+AuB3R Zwp6j270psSVh4TfIFAmjKX2MCGwMFCQWjmoAFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgk Q70psSVh4TfIQuAD+JulczTN6l7oJjyroySU55Fbjdvo52xiYYlMjPG7dCTsBAMFI7dSL5zg98I+8 cXY1J7kyNsY6/dcipqBM4RMaxXsOtCRHYWJyaWVsZSBNb25hY28gPGdtb25hY29AcmVkaGF0LmNvb T6InAQTFgoARAIbAwUJBaOagAULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgBYhBMrKEfgLgd0WcK eo9u9KbElYeE3yBQJoymCyAhkBAAoJEO9KbElYeE3yjX4BAJ/ETNnlHn8OjZPT77xGmal9kbT1bC1 7DfrYVISWV2Y1AP9HdAMhWNAvtCtN2S1beYjNybuK6IzWYcFfeOV+OBWRDQ== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-11-12 at 17:04 +0100, Frederic Weisbecker wrote: > Le Tue, Nov 04, 2025 at 11:47:39AM +0100, Gabriele Monaco a =C3=A9crit : >=20 >=20 > This duplicates a lot tmigr_isolated_exclude_cpumask(). > Would this work? >=20 > static int __init tmigr_init_isolation(void) > { > cpumask_var_t cpumask __free(free_cpumask_var) =3D CPUMASK_VAR_NULL; >=20 > static_branch_enable(&tmigr_exclude_isolated); >=20 > if (!housekeeping_enabled(HK_TYPE_DOMAIN)) > return 0; > if (!alloc_cpumask_var(&cpumask, GFP_KERNEL)) > return -ENOMEM; >=20 > cpumask_andnot(cpumask, cpu_possible_mask, > housekeeping_cpumask(HK_TYPE_DOMAIN)); >=20 > return tmigr_isolated_exclude_cpumask(cpumask); > } >=20 > If so please add my Reviewed-by to the next version. Good point, it should work, I'm going to test it tomorrow. What comes to my mind is that tmigr_isolated_exclude_cpumask expects the ho= tplug lock to be held, so I should probably just hold it before calling it: static int __init tmigr_init_isolation(void) { cpumask_var_t cpumask __free(free_cpumask_var) =3D CPUMASK_VAR_NULL; static_branch_enable(&tmigr_exclude_isolated); if (!housekeeping_enabled(HK_TYPE_DOMAIN)) return 0; if (!alloc_cpumask_var(&cpumask, GFP_KERNEL)) return -ENOMEM; cpumask_andnot(cpumask, cpu_possible_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)); + guard(cpus_read_lock)(); return tmigr_isolated_exclude_cpumask(cpumask); } Thanks, Gabriele