[PATCH v7 08/21] workqueue: Use global variant for add_timer()

From: Anna-Maria Behnsen
Date: Wed May 24 2023 - 03:07:35 EST

The implementation of the NOHZ pull at expiry model will change the timer
bases per CPU. Timers, that have to expire on a specific CPU, require the
TIMER_PINNED flag. If the CPU doesn't matter, the TIMER_PINNED flag must be
dropped. This is required for call sites which use the timer alternately as
pinned and not pinned timer like workqueues do.

Therefore use add_timer_global() to make sure TIMER_PINNED flag is dropped.

Signed-off-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
- New patch: As v6 provides unconditially setting TIMER_PINNED flag in
add_timer_on() workqueue requires new add_timer_global() variant.
kernel/workqueue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4666a1a92a31..5c529f19e709 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1682,7 +1682,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
if (unlikely(cpu != WORK_CPU_UNBOUND))
add_timer_on(timer, cpu);
- add_timer(timer);
+ add_timer_global(timer);