From: Marco Crivellari Date: Fri, 19 Sep 2025 14:50:37 +0000 (+0200) Subject: rcu: replace use of system_wq with system_percpu_wq X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=143ddfa169bbb733275b1a720bafd5a4366b3d89;p=users%2Fhch%2Fmisc.git rcu: replace use of system_wq with system_percpu_wq Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. system_wq is a per-CPU worqueue, yet nothing in its name tells about that CPU affinity constraint, which is very often not required by users. Make it clear by adding a system_percpu_wq. The old wq will be kept for a few release cylces. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Reviewed-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index f92443561d36..2dc044fd126e 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -553,13 +553,13 @@ static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu rtpcp_next = rtp->rtpcp_array[index]; if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) { cpuwq = rcu_cpu_beenfullyonline(rtpcp_next->cpu) ? rtpcp_next->cpu : WORK_CPU_UNBOUND; - queue_work_on(cpuwq, system_wq, &rtpcp_next->rtp_work); + queue_work_on(cpuwq, system_percpu_wq, &rtpcp_next->rtp_work); index++; if (index < num_possible_cpus()) { rtpcp_next = rtp->rtpcp_array[index]; if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) { cpuwq = rcu_cpu_beenfullyonline(rtpcp_next->cpu) ? rtpcp_next->cpu : WORK_CPU_UNBOUND; - queue_work_on(cpuwq, system_wq, &rtpcp_next->rtp_work); + queue_work_on(cpuwq, system_percpu_wq, &rtpcp_next->rtp_work); } } }