diff options
| author | Marco Crivellari <marco.crivellari@suse.com> | 2026-03-09 14:15:28 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-03-09 06:45:08 -1000 |
| commit | c116737e972ea74f4468a1bd0703d623a3c0ee4a (patch) | |
| tree | adca77c11c66abf69dd8579d5ae4fb1edd466107 /kernel/workqueue.c | |
| parent | 25e1a46cc3b7dccb1e2c86ddb15a1c8b92b564f0 (diff) | |
workqueue: Add system_dfl_long_wq for long unbound works
Currently there are users of queue_delayed_work() who specify
system_long_wq, the per-cpu workqueue. This workqueue should
be used for long per-cpu works, but queue_delayed_work()
queue the work using:
queue_delayed_work_on(WORK_CPU_UNBOUND, ...);
This would end up calling __queue_delayed_work() that does:
if (housekeeping_enabled(HK_TYPE_TIMER)) {
// [....]
} else {
if (likely(cpu == WORK_CPU_UNBOUND))
add_timer_global(timer);
else
add_timer_on(timer, cpu);
}
So when cpu == WORK_CPU_UNBOUND the timer is global and is
not using a specific CPU. Later, when __queue_work() is called:
if (req_cpu == WORK_CPU_UNBOUND) {
if (wq->flags & WQ_UNBOUND)
cpu = wq_select_unbound_cpu(raw_smp_processor_id());
else
cpu = raw_smp_processor_id();
}
Because the wq is not unbound, it takes the CPU where the timer
fired and enqueue the work on that CPU.
The consequence of all of this is that the work can run anywhere,
depending on where the timer fired.
Introduce system_dfl_long_wq in order to change, in a future step,
users that are still calling:
queue_delayed_work(system_long_wq, ...);
with the new system_dfl_long_wq instead, so that the work may
benefit from scheduler task placement.
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 2f95cb0d2f1b..2d8ff903f113 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -530,6 +530,8 @@ struct workqueue_struct *system_bh_wq; EXPORT_SYMBOL_GPL(system_bh_wq); struct workqueue_struct *system_bh_highpri_wq; EXPORT_SYMBOL_GPL(system_bh_highpri_wq); +struct workqueue_struct *system_dfl_long_wq __ro_after_init; +EXPORT_SYMBOL_GPL(system_dfl_long_wq); static int worker_thread(void *__worker); static void workqueue_sysfs_unregister(struct workqueue_struct *wq); @@ -7954,11 +7956,12 @@ void __init workqueue_init_early(void) system_bh_wq = alloc_workqueue("events_bh", WQ_BH | WQ_PERCPU, 0); system_bh_highpri_wq = alloc_workqueue("events_bh_highpri", WQ_BH | WQ_HIGHPRI | WQ_PERCPU, 0); + system_dfl_long_wq = alloc_workqueue("events_dfl_long", WQ_UNBOUND, WQ_MAX_ACTIVE); BUG_ON(!system_wq || !system_percpu_wq|| !system_highpri_wq || !system_long_wq || !system_unbound_wq || !system_freezable_wq || !system_dfl_wq || !system_power_efficient_wq || !system_freezable_power_efficient_wq || - !system_bh_wq || !system_bh_highpri_wq); + !system_bh_wq || !system_bh_highpri_wq || !system_dfl_long_wq); } static void __init wq_cpu_intensive_thresh_init(void) |