[PATCH 2/4] Move the remaining __dl_{sub,add}_ac() calls from core.c to deadline.c

From: Luca Abeni
Date: Mon Feb 22 2016 - 05:57:49 EST


To move these calls from dl_overflow() to deadline.c, we must change
the meaning of the third parameter of prio_changed_dl().
Instead of passing the "old priority" (which is always equal to the current
one, for SCHED_DEADLINE) we pass the old utilization. An alternative approach
is to change the prototype of the "prio_changed" method of the scheduling
class.
---
kernel/sched/core.c | 10 ++++++----
kernel/sched/deadline.c | 10 +++++++---
2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a4f08d1..5dc12db 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2449,9 +2449,7 @@ static int dl_overflow(struct task_struct *p, int policy,
} else if (dl_policy(policy) && task_has_dl_policy(p) &&
!__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) {
__dl_clear(dl_b, p->dl.dl_bw);
- __dl_sub_ac(task_rq(p), p->dl.dl_bw);
__dl_add(dl_b, new_bw);
- __dl_add_ac(task_rq(p), new_bw);
err = 0;
} else if (!dl_policy(policy) && task_has_dl_policy(p)) {
__dl_clear(dl_b, p->dl.dl_bw);
@@ -3522,6 +3520,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
} else
p->dl.dl_boosted = 0;
p->sched_class = &dl_sched_class;
+ oldprio = 0;
} else if (rt_prio(prio)) {
if (dl_prio(oldprio))
p->dl.dl_boosted = 0;
@@ -3891,7 +3890,7 @@ static int __sched_setscheduler(struct task_struct *p,
{
int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
MAX_RT_PRIO - 1 - attr->sched_priority;
- int retval, oldprio, oldpolicy = -1, queued, running;
+ int retval, oldprio, oldbw, oldpolicy = -1, queued, running;
int new_effective_prio, policy = attr->sched_policy;
unsigned long flags;
const struct sched_class *prev_class;
@@ -4069,6 +4068,7 @@ change:

p->sched_reset_on_fork = reset_on_fork;
oldprio = p->prio;
+ oldbw = p->dl.dl_bw;

if (pi) {
/*
@@ -4081,6 +4081,8 @@ change:
new_effective_prio = rt_mutex_get_effective_prio(p, newprio);
if (new_effective_prio == oldprio) {
__setscheduler_params(p, attr);
+ if (p->sched_class == &dl_sched_class)
+ p->sched_class->prio_changed(rq, p, oldbw);
task_rq_unlock(rq, p, &flags);
return 0;
}
@@ -4110,7 +4112,7 @@ change:
enqueue_task(rq, p, enqueue_flags);
}

- check_class_changed(rq, p, prev_class, oldprio);
+ check_class_changed(rq, p, prev_class, ((prev_class == &dl_sched_class) && (p->sched_class == &dl_sched_class)) ? oldbw : oldprio);
preempt_disable(); /* avoid rq from going away on us */
task_rq_unlock(rq, p, &flags);

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 4cc713a..959e7b7 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1757,8 +1757,13 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
* a push or pull operation might be needed.
*/
static void prio_changed_dl(struct rq *rq, struct task_struct *p,
- int oldprio)
+ int oldbw)
{
+ if (oldbw) {
+ __dl_sub_ac(rq, oldbw);
+ __dl_add_ac(rq, p->dl.dl_bw);
+ }
+
if (task_on_rq_queued(p) || rq->curr == p) {
#ifdef CONFIG_SMP
/*
@@ -1785,8 +1790,7 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
*/
resched_curr(rq);
#endif /* CONFIG_SMP */
- } else
- switched_to_dl(rq, p);
+ }
}

const struct sched_class dl_sched_class = {
--
2.5.0