raspi/linux
1
0
Fork 1
mirror of https://github.com/raspberrypi/linux.git synced 2025-12-06 01:49:46 +00:00
Code Issues Projects Releases Wiki Activity

sched/idle: Make the idle timer expire in hard interrupt context

Browse Source 
[ Upstream commit 9848417926 ]

The intel powerclamp driver will setup a per-CPU worker with RT
priority. The worker will then invoke play_idle() in which it remains in
the idle poll loop until it is stopped by the timer it started earlier.

That timer needs to expire in hard interrupt context on PREEMPT_RT.
Otherwise the timer will expire in ksoftirqd as a SOFT timer but that task
won't be scheduled on the CPU because its priority is lower than the
priority of the worker which is in the idle loop.

Always expire the idle timer in hard interrupt context.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210906113034.jgfxrjdvxnjqgtmc@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sebastian Andrzej Siewior
2021-09-06 13:30:34 +02:00
committed by Greg Kroah-Hartman
parent affd236df3
commit cacfce79af
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
kernel/sched/idle.c
View File

@@ -379,10 +379,10 @@ void play_idle_precise(u64 duration_ns, u64 latency_ns)
cpuidle_use_deepest_state(latency_ns);
it.done = 0;
hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
it.timer.function = idle_inject_timer_fn;
hrtimer_start(&it.timer, ns_to_ktime(duration_ns),
HRTIMER_MODE_REL_PINNED);
HRTIMER_MODE_REL_PINNED_HARD);
while (!READ_ONCE(it.done))
do_idle();