From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
vincent.guittot@linaro.org, rostedt@goodmis.org,
dietmar.eggemann@arm.com, bristot@redhat.com, bsegall@google.com,
mgorman@suse.de, Mark Simmons <msimmons@redhat.com>
Subject: Re: [PATCH] sched/rt: Fix double enqueue caused by rt_effective_prio
Date: Thu, 8 Jul 2021 12:26:33 +0200 [thread overview]
Message-ID: <YObS2Rudg4osS7Ic@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YObOIwH7MbfagklQ@hirez.programming.kicks-ass.net>
On Thu, Jul 08, 2021 at 12:06:27PM +0200, Peter Zijlstra wrote:
> Slightly larger patch, but perhaps a little cleaner.. still pondering if
> we can share a little more between __sched_setscheduler() and
> rt_mutex_setprio().
Best I can seem to come up with...
---
kernel/sched/core.c | 45 +++++++++++++++++----------------------------
1 file changed, 17 insertions(+), 28 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ede10642612c..c686f0c70656 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6341,6 +6341,18 @@ int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flag
}
EXPORT_SYMBOL(default_wake_function);
+static void __setscheduler_prio(struct task_struct *p, int prio)
+{
+ if (dl_prio(prio))
+ p->sched_class = &dl_sched_class;
+ else if (rt_prio(prio))
+ p->sched_class = &rt_sched_class;
+ else
+ p->sched_class = &fair_sched_class;
+
+ p->prio = prio;
+}
+
#ifdef CONFIG_RT_MUTEXES
static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
@@ -6456,22 +6468,19 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
} else {
p->dl.pi_se = &p->dl;
}
- p->sched_class = &dl_sched_class;
} else if (rt_prio(prio)) {
if (dl_prio(oldprio))
p->dl.pi_se = &p->dl;
if (oldprio < prio)
queue_flag |= ENQUEUE_HEAD;
- p->sched_class = &rt_sched_class;
} else {
if (dl_prio(oldprio))
p->dl.pi_se = &p->dl;
if (rt_prio(oldprio))
p->rt.timeout = 0;
- p->sched_class = &fair_sched_class;
}
- p->prio = prio;
+ __setscheduler_prio(p, prio);
if (queued)
enqueue_task(rq, p, queue_flag);
@@ -6824,29 +6833,6 @@ static void __setscheduler_params(struct task_struct *p,
set_load_weight(p, true);
}
-/* Actually do priority change: must hold pi & rq lock. */
-static void __setscheduler(struct rq *rq, struct task_struct *p,
- const struct sched_attr *attr, int newprio)
-{
- /*
- * If params can't change scheduling class changes aren't allowed
- * either.
- */
- if (attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)
- return;
-
- __setscheduler_params(p, attr);
-
- p->prio = newprio;
-
- if (dl_prio(p->prio))
- p->sched_class = &dl_sched_class;
- else if (rt_prio(p->prio))
- p->sched_class = &rt_sched_class;
- else
- p->sched_class = &fair_sched_class;
-}
-
/*
* Check the target process has a UID that matches the current process's:
*/
@@ -7089,7 +7075,10 @@ static int __sched_setscheduler(struct task_struct *p,
prev_class = p->sched_class;
- __setscheduler(rq, p, attr, newprio);
+ if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
+ __setscheduler_params(p, attr);
+ __setscheduler_prio(p, newprio);
+ }
__setscheduler_uclamp(p, attr);
if (queued) {
next prev parent reply other threads:[~2021-07-08 10:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 9:14 [PATCH] sched/rt: Fix double enqueue caused by rt_effective_prio Juri Lelli
2021-07-06 14:48 ` Dietmar Eggemann
2021-07-07 8:47 ` Juri Lelli
2021-07-08 10:06 ` Peter Zijlstra
2021-07-08 10:26 ` Peter Zijlstra [this message]
2021-07-09 8:33 ` Juri Lelli
2021-08-02 7:35 ` Juri Lelli
2021-08-02 13:38 ` Peter Zijlstra
2021-07-08 11:35 ` Peter Zijlstra
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