[PATCH] sched: micro-optimize task requeueing in schedule() (a3464a10) · Commits · 戴 / test

kernel/sched.c

+12 −7

Original line number	Diff line number	Diff line
		@@ -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 @@ go_idle:
		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: