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authorDmitry Adamushko <dmitry.adamushko@gmail.com>2007-05-08 00:33:06 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:17 -0700
commitbd53f96ca54a21c07e7a0ae1886fa623d370b85f (patch)
treec908772406a055fcaa8a8742a36f61014a99b20a /kernel/sched.c
parent4953198b6ce07b008b0f1c2edd41c9d027a118b4 (diff)
sched: redundant reschedule when set_user_nice() boosts a prio of a task from the "expired" array
- Make TASK_PREEMPTS_CURR(task, rq) return "true" only if the task's prio is higher than the current's one and the task is in the "active" array. This ensures we don't make redundant resched_task() calls when the task is in the "expired" array (as may happen now in set_user_prio(), rt_mutex_setprio() and pull_task() ) ; - generalise conditions for a call to resched_task() in set_user_nice(), rt_mutex_setprio() and sched_setscheduler() Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Cc: Con Kolivas <kernel@kolivas.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c34
1 files changed, 16 insertions, 18 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index e60786eb731..be2706c885a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -169,7 +169,7 @@ unsigned long long __attribute__((weak)) sched_clock(void)
(MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1))
#define TASK_PREEMPTS_CURR(p, rq) \
- ((p)->prio < (rq)->curr->prio)
+ (((p)->prio < (rq)->curr->prio) && ((p)->array == (rq)->active))
#define SCALE_PRIO(x, prio) \
max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE)
@@ -4076,13 +4076,13 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
struct prio_array *array;
unsigned long flags;
struct rq *rq;
- int oldprio;
+ int delta;
BUG_ON(prio < 0 || prio > MAX_PRIO);
rq = task_rq_lock(p, &flags);
- oldprio = p->prio;
+ delta = prio - p->prio;
array = p->array;
if (array)
dequeue_task(p, array);
@@ -4098,13 +4098,11 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
enqueue_task(p, array);
/*
* 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
+ * our priority decreased, or if our priority became higher
+ * than the current's.
*/
- if (task_running(rq, p)) {
- if (p->prio > oldprio)
- resched_task(rq->curr);
- } else if (TASK_PREEMPTS_CURR(p, rq))
+ if (TASK_PREEMPTS_CURR(p, rq) ||
+ (delta > 0 && task_running(rq, p)))
resched_task(rq->curr);
}
task_rq_unlock(rq, &flags);
@@ -4152,10 +4150,12 @@ void set_user_nice(struct task_struct *p, long nice)
enqueue_task(p, array);
inc_raw_weighted_load(rq, p);
/*
- * If the task increased its priority or is running and
- * lowered its priority, then reschedule its CPU:
+ * Reschedule if we are currently running on this runqueue and
+ * our priority decreased, or if our priority became higher
+ * than the current's.
*/
- if (delta < 0 || (delta > 0 && task_running(rq, p)))
+ if (TASK_PREEMPTS_CURR(p, rq) ||
+ (delta > 0 && task_running(rq, p)))
resched_task(rq->curr);
}
out_unlock:
@@ -4382,13 +4382,11 @@ recheck:
__activate_task(p, rq);
/*
* 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
+ * our priority decreased, or our priority became higher
+ * than the current's.
*/
- if (task_running(rq, p)) {
- if (p->prio > oldprio)
- resched_task(rq->curr);
- } else if (TASK_PREEMPTS_CURR(p, rq))
+ if (TASK_PREEMPTS_CURR(p, rq) ||
+ (task_running(rq, p) && p->prio > oldprio))
resched_task(rq->curr);
}
__task_rq_unlock(rq);