tick: Move tick cancellation up to CPUHP_AP_TICK_DYING

The tick hrtimer is cancelled right before hrtimers are migrated. This
is done from the hrtimer subsystem even though it shouldn't know about
its actual users.

Move instead the tick hrtimer cancellation to the relevant CPU hotplug
state that aims at centralizing high level tick shutdown operations so
that the related flow is easy to follow.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-9-frederic@kernel.org

Author: Frederic Weisbecker

kernel/time/hrtimer.c

@@ -2229,8 +2229,6 @@ int hrtimers_cpu_dying(unsigned int dying_cpu)
 	int i, ncpu = cpumask_any_and(cpu_active_mask, housekeeping_cpumask(HK_TYPE_TIMER));
 	struct hrtimer_cpu_base *old_base, *new_base;
 
-	tick_cancel_sched_timer(dying_cpu);
-
 	old_base = this_cpu_ptr(&hrtimer_bases);
 	new_base = &per_cpu(hrtimer_bases, ncpu);
 

kernel/time/tick-common.c

@@ -410,6 +410,8 @@ int tick_cpu_dying(unsigned int dying_cpu)
 	if (tick_do_timer_cpu == dying_cpu)
 		tick_do_timer_cpu = cpumask_first(cpu_online_mask);
 
+	tick_cancel_sched_timer(dying_cpu);
+
 	return 0;
 }