Commit a3464a10 authored by Chen Shang's avatar Chen Shang Committed by Linus Torvalds

[PATCH] sched: micro-optimize task requeueing in schedule()

micro-optimize task requeueing in schedule() & clean up recalc_task_prio().
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 77391d71
......@@ -673,7 +673,7 @@ static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
rq->nr_running++;
}
static void recalc_task_prio(task_t *p, unsigned long long now)
static int recalc_task_prio(task_t *p, unsigned long long now)
{
/* Caller must always ensure 'now >= p->timestamp' */
unsigned long long __sleep_time = now - p->timestamp;
......@@ -732,7 +732,7 @@ static void recalc_task_prio(task_t *p, unsigned long long now)
}
}
p->prio = effective_prio(p);
return effective_prio(p);
}
/*
......@@ -755,7 +755,7 @@ static void activate_task(task_t *p, runqueue_t *rq, int local)
}
#endif
recalc_task_prio(p, now);
p->prio = recalc_task_prio(p, now);
/*
* This checks to make sure it's not an uninterruptible task
......@@ -2751,7 +2751,7 @@ asmlinkage void __sched schedule(void)
struct list_head *queue;
unsigned long long now;
unsigned long run_time;
int cpu, idx;
int cpu, idx, new_prio;
/*
* Test if we are atomic. Since do_exit() needs to call into
......@@ -2873,9 +2873,14 @@ asmlinkage void __sched schedule(void)
delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
array = next->array;
new_prio = recalc_task_prio(next, next->timestamp + delta);
if (unlikely(next->prio != new_prio)) {
dequeue_task(next, array);
recalc_task_prio(next, next->timestamp + delta);
next->prio = new_prio;
enqueue_task(next, array);
} else
requeue_task(next, array);
}
next->activated = 0;
switch_tasks:
......
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