sched: rework enqueue/dequeue_entity() to get rid of set_curr_task()
rework enqueue/dequeue_entity() to get rid of
sched_class::set_curr_task(). This simplifies sched_setscheduler(),
rt_mutex_setprio() and sched_move_tasks().
text data bss dec hex filename
24330 2734 20 27084 69cc sched.o.before
24233 2730 20 26983 6967 sched.o.after
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6616900..abcb027 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -871,7 +871,6 @@
struct sched_domain *sd, enum cpu_idle_type idle,
int *all_pinned, int *this_best_prio);
- void (*set_curr_task) (struct rq *rq);
void (*task_tick) (struct rq *rq, struct task_struct *p);
void (*task_new) (struct rq *rq, struct task_struct *p);
};
diff --git a/kernel/sched.c b/kernel/sched.c
index e1f784f..72c936d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3915,8 +3915,8 @@
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
- int oldprio, on_rq, running;
unsigned long flags;
+ int oldprio, on_rq;
struct rq *rq;
BUG_ON(prio < 0 || prio > MAX_PRIO);
@@ -3926,12 +3926,8 @@
oldprio = p->prio;
on_rq = p->se.on_rq;
- running = task_running(rq, p);
- if (on_rq) {
+ if (on_rq)
dequeue_task(rq, p, 0);
- if (running)
- p->sched_class->put_prev_task(rq, p);
- }
if (rt_prio(prio))
p->sched_class = &rt_sched_class;
@@ -3941,15 +3937,13 @@
p->prio = prio;
if (on_rq) {
- if (running)
- p->sched_class->set_curr_task(rq);
enqueue_task(rq, p, 0);
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
* this runqueue and our priority is higher than the current's
*/
- if (running) {
+ if (task_running(rq, p)) {
if (p->prio > oldprio)
resched_task(rq->curr);
} else {
@@ -4155,7 +4149,7 @@
int sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param)
{
- int retval, oldprio, oldpolicy = -1, on_rq, running;
+ int retval, oldprio, oldpolicy = -1, on_rq;
unsigned long flags;
struct rq *rq;
@@ -4237,24 +4231,20 @@
}
update_rq_clock(rq);
on_rq = p->se.on_rq;
- running = task_running(rq, p);
- if (on_rq) {
+ if (on_rq)
deactivate_task(rq, p, 0);
- if (running)
- p->sched_class->put_prev_task(rq, p);
- }
+
oldprio = p->prio;
__setscheduler(rq, p, policy, param->sched_priority);
+
if (on_rq) {
- if (running)
- p->sched_class->set_curr_task(rq);
activate_task(rq, p, 0);
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
* this runqueue and our priority is higher than the current's
*/
- if (running) {
+ if (task_running(rq, p)) {
if (p->prio > oldprio)
resched_task(rq->curr);
} else {
@@ -6855,19 +6845,13 @@
running = task_running(rq, tsk);
on_rq = tsk->se.on_rq;
- if (on_rq) {
+ if (on_rq)
dequeue_task(rq, tsk, 0);
- if (unlikely(running))
- tsk->sched_class->put_prev_task(rq, tsk);
- }
set_task_cfs_rq(tsk);
- if (on_rq) {
- if (unlikely(running))
- tsk->sched_class->set_curr_task(rq);
+ if (on_rq)
enqueue_task(rq, tsk, 0);
- }
done:
task_rq_unlock(rq, &flags);
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 4dd256d..568e922 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -472,9 +472,20 @@
}
static void
-enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
+enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
+ int wakeup, int set_curr)
{
/*
+ * In case of the 'current'.
+ */
+ if (unlikely(set_curr)) {
+ update_stats_curr_start(cfs_rq, se);
+ cfs_rq->curr = se;
+ account_entity_enqueue(cfs_rq, se);
+ return;
+ }
+
+ /*
* Update the fair clock.
*/
update_curr(cfs_rq);
@@ -485,8 +496,7 @@
}
update_stats_enqueue(cfs_rq, se);
- if (se != cfs_rq->curr)
- __enqueue_entity(cfs_rq, se);
+ __enqueue_entity(cfs_rq, se);
account_entity_enqueue(cfs_rq, se);
}
@@ -506,8 +516,12 @@
}
}
#endif
- if (se != cfs_rq->curr)
+ if (likely(se != cfs_rq->curr))
__dequeue_entity(cfs_rq, se);
+ else {
+ update_stats_curr_end(cfs_rq, se);
+ cfs_rq->curr = NULL;
+ }
account_entity_dequeue(cfs_rq, se);
}
@@ -689,12 +703,17 @@
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
+ int set_curr = 0;
+
+ /* Are we enqueuing the current task? */
+ if (unlikely(task_running(rq, p)))
+ set_curr = 1;
for_each_sched_entity(se) {
if (se->on_rq)
break;
cfs_rq = cfs_rq_of(se);
- enqueue_entity(cfs_rq, se, wakeup);
+ enqueue_entity(cfs_rq, se, wakeup, set_curr);
}
}
@@ -742,7 +761,7 @@
* position within the tree:
*/
dequeue_entity(cfs_rq, se, 0);
- enqueue_entity(cfs_rq, se, 0);
+ enqueue_entity(cfs_rq, se, 0, 1);
return;
}
@@ -985,29 +1004,6 @@
resched_task(rq->curr);
}
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* Account for a task changing its policy or group.
- *
- * This routine is mostly called to set cfs_rq->curr field when a task
- * migrates between groups/classes.
- */
-static void set_curr_task_fair(struct rq *rq)
-{
- struct sched_entity *se = &rq->curr->se;
-
- for_each_sched_entity(se)
- set_next_entity(cfs_rq_of(se), se);
-}
-#else
-static void set_curr_task_fair(struct rq *rq)
-{
- struct sched_entity *se = &rq->curr->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
-
- cfs_rq->curr = se;
-}
-#endif
-
/*
* All the scheduling class methods:
*/
@@ -1023,7 +1019,6 @@
.load_balance = load_balance_fair,
- .set_curr_task = set_curr_task_fair,
.task_tick = task_tick_fair,
.task_new = task_new_fair,
};
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c
index 5ebf829..3503fb2 100644
--- a/kernel/sched_idletask.c
+++ b/kernel/sched_idletask.c
@@ -50,10 +50,6 @@
{
}
-static void set_curr_task_idle(struct rq *rq)
-{
-}
-
/*
* Simple, special scheduling class for the per-CPU idle tasks:
*/
@@ -70,7 +66,6 @@
.load_balance = load_balance_idle,
- .set_curr_task = set_curr_task_idle,
.task_tick = task_tick_idle,
/* no .task_new for idle tasks */
};
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index b86944c..3c77c03 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -218,10 +218,6 @@
}
}
-static void set_curr_task_rt(struct rq *rq)
-{
-}
-
static struct sched_class rt_sched_class __read_mostly = {
.enqueue_task = enqueue_task_rt,
.dequeue_task = dequeue_task_rt,
@@ -234,6 +230,5 @@
.load_balance = load_balance_rt,
- .set_curr_task = set_curr_task_rt,
.task_tick = task_tick_rt,
};