linux-kernel - [PATCH RFC 07/12] workqueue: Dynamic housekeeping mask update support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20260206-feature-dynamic_isolcpus_dhei-v1-7-00a711eb0c74@gmail.com>
Date: Fri, 06 Feb 2026 02:04:28 -0500
From: Qiliang Yuan <realwujing@...il.com>
To: Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
 Juri Lelli <juri.lelli@...hat.com>, 
 Vincent Guittot <vincent.guittot@...aro.org>, 
 Dietmar Eggemann <dietmar.eggemann@....com>, 
 Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, 
 Mel Gorman <mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>, 
 Thomas Gleixner <tglx@...nel.org>, "Paul E. McKenney" <paulmck@...nel.org>, 
 Frederic Weisbecker <frederic@...nel.org>, 
 Neeraj Upadhyay <neeraj.upadhyay@...nel.org>, 
 Joel Fernandes <joelagnelf@...dia.com>, 
 Josh Triplett <josh@...htriplett.org>, Boqun Feng <boqun.feng@...il.com>, 
 Uladzislau Rezki <urezki@...il.com>, 
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, 
 Lai Jiangshan <jiangshanlai@...il.com>, Zqiang <qiang.zhang@...ux.dev>, 
 Tejun Heo <tj@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, 
 Vlastimil Babka <vbabka@...e.cz>, Suren Baghdasaryan <surenb@...gle.com>, 
 Michal Hocko <mhocko@...e.com>, Brendan Jackman <jackmanb@...gle.com>, 
 Johannes Weiner <hannes@...xchg.org>, Zi Yan <ziy@...dia.com>, 
 Anna-Maria Behnsen <anna-maria@...utronix.de>, 
 Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org, rcu@...r.kernel.org, linux-mm@...ck.org, 
 Qiliang Yuan <realwujing@...il.com>, Qiliang Yuan <yuanql9@...natelecom.cn>
Subject: [PATCH RFC 07/12] workqueue: Dynamic housekeeping mask update
 support

Workqueues use housekeeping masks (HK_TYPE_WQ and HK_TYPE_DOMAIN) to
determine the default affinity for unbound workqueues. Currently,
these masks are only applied during early boot.

Register a housekeeping notifier to dynamically update the workqueue
unbound cpumask when these housekeeping masks are changed at runtime.
This ensures that unbound workqueues are re-affined to the new
housekeeping CPUs. Also update wq_isolated_cpumask to reflect the
changes in HK_TYPE_DOMAIN.

Signed-off-by: Qiliang Yuan <realwujing@...il.com>
Signed-off-by: Qiliang Yuan <yuanql9@...natelecom.cn>
---
 kernel/workqueue.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 253311af47c6..b8913935d5e8 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -7913,6 +7913,44 @@ static void __init wq_cpu_intensive_thresh_init(void)
  * executing the work items yet. Populate the worker pools with the initial
  * workers and enable future kworker creations.
  */
+static int wq_housekeeping_reconfigure(struct notifier_block *nb,
+				      unsigned long action, void *data)
+{
+	if (action == HK_UPDATE_MASK) {
+		unsigned int type = (unsigned long)data;
+
+		if (type == HK_TYPE_WQ || type == HK_TYPE_DOMAIN) {
+			cpumask_var_t cpumask;
+
+			if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
+				return NOTIFY_BAD;
+
+			cpumask_copy(cpumask, cpu_possible_mask);
+			if (!cpumask_empty(housekeeping_cpumask(HK_TYPE_WQ)))
+				cpumask_and(cpumask, cpumask, housekeeping_cpumask(HK_TYPE_WQ));
+			if (!cpumask_empty(housekeeping_cpumask(HK_TYPE_DOMAIN)))
+				cpumask_and(cpumask, cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));
+
+			workqueue_set_unbound_cpumask(cpumask);
+
+			if (type == HK_TYPE_DOMAIN) {
+				apply_wqattrs_lock();
+				cpumask_andnot(wq_isolated_cpumask, cpu_possible_mask,
+						housekeeping_cpumask(HK_TYPE_DOMAIN));
+				apply_wqattrs_unlock();
+			}
+
+			free_cpumask_var(cpumask);
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block wq_housekeeping_nb = {
+	.notifier_call = wq_housekeeping_reconfigure,
+};
+
 void __init workqueue_init(void)
 {
 	struct workqueue_struct *wq;
@@ -7964,6 +8002,7 @@ void __init workqueue_init(void)

 	wq_online = true;
 	wq_watchdog_init();
+	housekeeping_register_notifier(&wq_housekeeping_nb);
 }

 /*

-- 
2.51.0