[PATCH] sched/fair: Make hrtimer callback execute in the hard interrupt context

From: Zqiang
Date: Mon Mar 06 2023 - 02:05:01 EST


The scheduler related hrtimers callback will be executed in softirqd
context for PREEMPT_RT enabled kernel, this commit therefore mark
hrtimers as harded even on PREEMPT_RT enabled kernels, there is no
functional change.

Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
---
kernel/sched/fair.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c36aa54ae071..98c48d144089 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5610,7 +5610,7 @@ static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)

hrtimer_start(&cfs_b->slack_timer,
ns_to_ktime(cfs_bandwidth_slack_period),
- HRTIMER_MODE_REL);
+ HRTIMER_MODE_REL_HARD);
}

/* we know any runtime found here is valid as update_curr() precedes return */
@@ -5813,9 +5813,9 @@ void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
cfs_b->burst = 0;

INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
- hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+ hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
cfs_b->period_timer.function = sched_cfs_period_timer;
- hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
cfs_b->slack_timer.function = sched_cfs_slack_timer;
cfs_b->slack_started = false;
}
@@ -5835,7 +5835,7 @@ void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)

cfs_b->period_active = 1;
hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
- hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
+ hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED_HARD);
}

static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
--
2.25.1