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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>
This commit is contained in:
Dmitry Adamushko 2007-10-15 17:00:08 +02:00 committed by Ingo Molnar
parent 4530d7ab0f
commit f6b53205e1
5 changed files with 35 additions and 67 deletions
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1
include/linux/sched.h
View File

@ -871,7 +871,6 @@ struct sched_class {
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);
};

36
kernel/sched.c
View File

@ -3915,8 +3915,8 @@ EXPORT_SYMBOL(sleep_on_timeout);
*/
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 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
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 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
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 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
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 @@ recheck:
}
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 @@ static void sched_move_task(struct container_subsys *ss, struct container *cont,
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);

55
kernel/sched_fair.c
View File

@ -472,8 +472,19 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
}
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.
*/
@ -485,8 +496,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
}
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 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
}
}
#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 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
{
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 @@ static void yield_task_fair(struct rq *rq)
* 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 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
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 @@ struct sched_class fair_sched_class __read_mostly = {
.load_balance = load_balance_fair,
.set_curr_task = set_curr_task_fair,
.task_tick = task_tick_fair,
.task_new = task_new_fair,
};

5
kernel/sched_idletask.c
View File

@ -50,10 +50,6 @@ static void task_tick_idle(struct rq *rq, struct task_struct *curr)
{
}
static void set_curr_task_idle(struct rq *rq)
{
}
/*
* Simple, special scheduling class for the per-CPU idle tasks:
*/
@ -70,7 +66,6 @@ static struct sched_class idle_sched_class __read_mostly = {
.load_balance = load_balance_idle,
.set_curr_task = set_curr_task_idle,
.task_tick = task_tick_idle,
/* no .task_new for idle tasks */
};

5
kernel/sched_rt.c
View File

@ -218,10 +218,6 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p)
}
}
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 @@ static struct sched_class rt_sched_class __read_mostly = {
.load_balance = load_balance_rt,
.set_curr_task = set_curr_task_rt,
.task_tick = task_tick_rt,
};