Re: [PATCH RT 03/25] sched/deadline: Ensure inactive_timer runs in hardirq context
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2020-02-24 08:33:09
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lkml
On 2020-02-21 15:24:31 [-0600], zanussi@kernel.org wrote:
[ Upstream commit ba94e7aed7405c58251b1380e6e7d73aa8284b41 ] SCHED_DEADLINE inactive timer needs to run in hardirq context (as dl_task_timer already does) on PREEMPT_RT
The message says "dl_task_timer already does" but this is not true for v4.14 as it still runs in softirq context on RT. v4.19 has this either via https://lkml.kernel.org/r/20190731103715.4047-1-juri.lelli@redhat.com or the patch which got merged upstream. Juri, I guess we want this for v4.14, too?
quoted hunk ↗ jump to hunk
Change the mode to HRTIMER_MODE_REL_HARD. [ tglx: Fixed up the start site, so mode debugging works ] Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Thomas Gleixner <redacted> Link: https://lkml.kernel.org/r/20190731103715.4047-1-juri.lelli@redhat.com Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Tom Zanussi <zanussi@kernel.org> --- kernel/sched/deadline.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index eb68f7fb8a36..7b04e54bea01 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c@@ -252,7 +252,7 @@ static void task_non_contending(struct task_struct *p) dl_se->dl_non_contending = 1; get_task_struct(p); - hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL); + hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD); } static void task_contending(struct sched_dl_entity *dl_se, int flags)@@ -1234,7 +1234,7 @@ void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se) { struct hrtimer *timer = &dl_se->inactive_timer; - hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); timer->function = inactive_task_timer; }
Sebastian