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sched: Add enqueue/dequeue flags 

In order to reduce the dependency on TASK_WAKING rework the enqueue
interface to support a proper flags field.

Replace the int wakeup, bool head arguments with an int flags argument
and create the following flags:

  ENQUEUE_WAKEUP - the enqueue is a wakeup of a sleeping task,
  ENQUEUE_WAKING - the enqueue has relative vruntime due to
                   having sched_class::task_waking() called,
  ENQUEUE_HEAD - the waking task should be places on the head
                 of the priority queue (where appropriate).

For symmetry also convert sched_class::dequeue() to a flags scheme.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Peter Zijlstra 2010-03-24 16:38:48 +01:00 committed by Ingo Molnar
parent cc87f76a60
commit 371fd7e7a5
5 changed files with 38 additions and 40 deletions
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11
include/linux/sched.h
View File

@ -1032,12 +1032,17 @@ struct sched_domain;
#define WF_SYNC 0x01 /* waker goes to sleep after wakup */
#define WF_FORK 0x02 /* child wakeup after fork */
#define ENQUEUE_WAKEUP 1
#define ENQUEUE_WAKING 2
#define ENQUEUE_HEAD 4
#define DEQUEUE_SLEEP 1
struct sched_class {
const struct sched_class *next;
void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup,
bool head);
void (*dequeue_task) (struct rq *rq, struct task_struct *p, int sleep);
void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
void (*yield_task) (struct rq *rq);
void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);

32
kernel/sched.c
View File

@ -1877,44 +1877,43 @@ static void update_avg(u64 *avg, u64 sample)
*avg += diff >> 3;
}
static void
enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
sched_info_queued(p);
p->sched_class->enqueue_task(rq, p, wakeup, head);
p->sched_class->enqueue_task(rq, p, flags);
p->se.on_rq = 1;
}
static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
sched_info_dequeued(p);
p->sched_class->dequeue_task(rq, p, sleep);
p->sched_class->dequeue_task(rq, p, flags);
p->se.on_rq = 0;
}
/*
* activate_task - move a task to the runqueue.
*/
static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
static void activate_task(struct rq *rq, struct task_struct *p, int flags)
{
if (task_contributes_to_load(p))
rq->nr_uninterruptible--;
enqueue_task(rq, p, wakeup, false);
enqueue_task(rq, p, flags);
inc_nr_running(rq);
}
/*
* deactivate_task - remove a task from the runqueue.
*/
static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
static void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
{
if (task_contributes_to_load(p))
rq->nr_uninterruptible++;
dequeue_task(rq, p, sleep);
dequeue_task(rq, p, flags);
dec_nr_running(rq);
}
@ -2353,6 +2352,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
{
int cpu, orig_cpu, this_cpu, success = 0;
unsigned long flags;
unsigned long en_flags = ENQUEUE_WAKEUP;
struct rq *rq;
this_cpu = get_cpu();
@ -2386,8 +2386,10 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
}
p->state = TASK_WAKING;
if (p->sched_class->task_waking)
if (p->sched_class->task_waking) {
p->sched_class->task_waking(rq, p);
en_flags |= ENQUEUE_WAKING;
}
cpu = select_task_rq(rq, p, SD_BALANCE_WAKE, wake_flags);
if (cpu != orig_cpu)
@ -2432,7 +2434,7 @@ out_activate:
schedstat_inc(p, se.statistics.nr_wakeups_local);
else
schedstat_inc(p, se.statistics.nr_wakeups_remote);
activate_task(rq, p, 1);
activate_task(rq, p, en_flags);
success = 1;
out_running:
@ -3623,7 +3625,7 @@ need_resched_nonpreemptible:
if (unlikely(signal_pending_state(prev->state, prev)))
prev->state = TASK_RUNNING;
else
deactivate_task(rq, prev, 1);
deactivate_task(rq, prev, DEQUEUE_SLEEP);
switch_count = &prev->nvcsw;
}
@ -4193,7 +4195,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
if (running)
p->sched_class->set_curr_task(rq);
if (on_rq) {
enqueue_task(rq, p, 0, oldprio < prio);
enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
check_class_changed(rq, p, prev_class, oldprio, running);
}
@ -4236,7 +4238,7 @@ void set_user_nice(struct task_struct *p, long nice)
delta = p->prio - old_prio;
if (on_rq) {
enqueue_task(rq, p, 0, false);
enqueue_task(rq, p, 0);
/*
* If the task increased its priority or is running and
* lowered its priority, then reschedule its CPU:
@ -8180,7 +8182,7 @@ void sched_move_task(struct task_struct *tsk)
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);
if (on_rq)
enqueue_task(rq, tsk, 0, false);
enqueue_task(rq, tsk, 0);
task_rq_unlock(rq, &flags);
}

25
kernel/sched_fair.c
View File

@ -757,9 +757,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
se->vruntime = vruntime;
}
#define ENQUEUE_WAKEUP 1
#define ENQUEUE_MIGRATE 2
static void
enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
@ -767,7 +764,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
* Update the normalized vruntime before updating min_vruntime
* through callig update_curr().
*/
if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATE))
if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
se->vruntime += cfs_rq->min_vruntime;
/*
@ -803,7 +800,7 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
static void
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
/*
* Update run-time statistics of the 'current'.
@ -811,7 +808,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
update_curr(cfs_rq);
update_stats_dequeue(cfs_rq, se);
if (sleep) {
if (flags & DEQUEUE_SLEEP) {
#ifdef CONFIG_SCHEDSTATS
if (entity_is_task(se)) {
struct task_struct *tsk = task_of(se);
@ -836,7 +833,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
* update can refer to the ->curr item and we need to reflect this
* movement in our normalized position.
*/
if (!sleep)
if (!(flags & DEQUEUE_SLEEP))
se->vruntime -= cfs_rq->min_vruntime;
}
@ -1045,16 +1042,10 @@ static inline void hrtick_update(struct rq *rq)
* then put the task into the rbtree:
*/
static void
enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, bool head)
enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
int flags = 0;
if (wakeup)
flags |= ENQUEUE_WAKEUP;
if (p->state == TASK_WAKING)
flags |= ENQUEUE_MIGRATE;
for_each_sched_entity(se) {
if (se->on_rq)
@ -1072,18 +1063,18 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, bool head)
* decreased. We remove the task from the rbtree and
* update the fair scheduling stats:
*/
static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
dequeue_entity(cfs_rq, se, sleep);
dequeue_entity(cfs_rq, se, flags);
/* Don't dequeue parent if it has other entities besides us */
if (cfs_rq->load.weight)
break;
sleep = 1;
flags |= DEQUEUE_SLEEP;
}
hrtick_update(rq);

2
kernel/sched_idletask.c
View File

@ -33,7 +33,7 @@ static struct task_struct *pick_next_task_idle(struct rq *rq)
* message if some code attempts to do it:
*/
static void
dequeue_task_idle(struct rq *rq, struct task_struct *p, int sleep)
dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
{
raw_spin_unlock_irq(&rq->lock);
printk(KERN_ERR "bad: scheduling from the idle thread!\n");

8
kernel/sched_rt.c
View File

@ -888,20 +888,20 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
* Adding/removing a task to/from a priority array:
*/
static void
enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup, bool head)
enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
if (wakeup)
if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
enqueue_rt_entity(rt_se, head);
enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
}
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;