[v11] timers: Move from a push remote at enqueue to a pull at expiry model

[PATCH v11 06/20] workqueue: Use global variant for add_timer()

Posted by Anna-Maria Behnsen 1 year, 9 months ago

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@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
---
v6:
  - 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 7b482a26d741..78eaea2e5d72 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1961,7 +1961,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
 	if (unlikely(cpu != WORK_CPU_UNBOUND))
 		add_timer_on(timer, cpu);
 	else
-		add_timer(timer);
+		add_timer_global(timer);
 }
 
 /**
-- 
2.39.2

[tip: timers/core] workqueue: Use global variant for add_timer()

Posted by tip-bot2 for Anna-Maria Behnsen 1 year, 9 months ago

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     c0e8c5b59949e8b8b004481c99e102df606fc312
Gitweb:        https://git.kernel.org/tip/c0e8c5b59949e8b8b004481c99e102df606fc312
Author:        Anna-Maria Behnsen <anna-maria@linutronix.de>
AuthorDate:    Wed, 21 Feb 2024 10:05:34 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 22 Feb 2024 17:52:30 +01:00

workqueue: Use global variant for add_timer()

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() in __queue_delayed_work() for non-bound
delayed work to make sure the TIMER_PINNED flag is dropped.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-7-anna-maria@linutronix.de

---
 kernel/workqueue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 7b482a2..78eaea2 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1961,7 +1961,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
 	if (unlikely(cpu != WORK_CPU_UNBOUND))
 		add_timer_on(timer, cpu);
 	else
-		add_timer(timer);
+		add_timer_global(timer);
 }
 
 /**