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([74.48.213.230]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c159e25dc7sm2786389eec.27.2026.03.25.02.10.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Mar 2026 02:10:34 -0700 (PDT) From: Qiliang Yuan Date: Wed, 25 Mar 2026 17:09:38 +0800 Subject: [PATCH 07/15] watchdog: Allow runtime toggle of lockup detector affinity Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260325-dhei-v12-final-v1-7-919cca23cadf@gmail.com> References: <20260325-dhei-v12-final-v1-0-919cca23cadf@gmail.com> In-Reply-To: <20260325-dhei-v12-final-v1-0-919cca23cadf@gmail.com> To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Thomas Gleixner , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Tejun Heo , Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Anna-Maria Behnsen , Ingo Molnar , Shuah Khan Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Qiliang Yuan X-Mailer: b4 0.13.0 The hardlockup detector threads are affined to CPUs based on the HK_TYPE_TIMER housekeeping mask at boot. If this mask is updated at runtime, these threads remain on their original CPUs, potentially running on isolated cores. Synchronize watchdog thread affinity with HK_TYPE_TIMER updates. This ensures that hardlockup detector threads correctly follow the dynamic housekeeping boundaries for timers. Signed-off-by: Qiliang Yuan --- kernel/watchdog.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 366122f4a0f87..ef93795729697 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -26,6 +26,7 @@ #include #include #include +#include =20 #include #include @@ -1359,6 +1360,29 @@ static int __init lockup_detector_check(void) } late_initcall_sync(lockup_detector_check); =20 +static int watchdog_housekeeping_reconfigure(struct notifier_block *nb, + unsigned long action, void *data) +{ + if (action =3D=3D HK_UPDATE_MASK) { + struct housekeeping_update *upd =3D data; + unsigned int type =3D upd->type; + + if (type =3D=3D HK_TYPE_TIMER) { + mutex_lock(&watchdog_mutex); + cpumask_copy(&watchdog_cpumask, + housekeeping_cpumask(HK_TYPE_TIMER)); + proc_watchdog_update(false); + mutex_unlock(&watchdog_mutex); + } + } + + return NOTIFY_OK; +} + +static struct notifier_block watchdog_housekeeping_nb =3D { + .notifier_call =3D watchdog_housekeeping_reconfigure, +}; + void __init lockup_detector_init(void) { if (tick_nohz_full_enabled()) @@ -1373,4 +1397,5 @@ void __init lockup_detector_init(void) allow_lockup_detector_init_retry =3D true; =20 lockup_detector_setup(); + housekeeping_register_notifier(&watchdog_housekeeping_nb); } --=20 2.43.0