sched: remove sleep_type

remove the sleep_type heuristics from the core scheduler - scheduling
policy is implemented in the scheduling-policy modules. (and CFS does
not use this type of sleep-type heuristics)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/sched.h

@@ -788,13 +788,6 @@ struct mempolicy;
 struct pipe_inode_info;
 struct uts_namespace;
 
-enum sleep_type {
-	SLEEP_NORMAL,
-	SLEEP_NONINTERACTIVE,
-	SLEEP_INTERACTIVE,
-	SLEEP_INTERRUPTED,
-};
-
 struct prio_array;
 struct rq;
 struct sched_domain;
@@ -905,7 +898,6 @@ struct task_struct {
 	unsigned long sleep_avg;
 	unsigned long long timestamp, last_ran;
 	unsigned long long sched_time; /* sched_clock time spent running */
-	enum sleep_type sleep_type;
 
 	unsigned int policy;
 	cpumask_t cpus_allowed;

kernel/sched.c

@@ -990,32 +990,7 @@ static int recalc_task_prio(struct task_struct *p, unsigned long long now)
 			 * with one single large enough sleep.
 			 */
 			p->sleep_avg = ceiling;
-			/*
-			 * Using INTERACTIVE_SLEEP() as a ceiling places a
-			 * nice(0) task 1ms sleep away from promotion, and
-			 * gives it 700ms to round-robin with no chance of
-			 * being demoted.  This is more than generous, so
-			 * mark this sleep as non-interactive to prevent the
-			 * on-runqueue bonus logic from intervening should
-			 * this task not receive cpu immediately.
-			 */
-			p->sleep_type = SLEEP_NONINTERACTIVE;
 		} else {
-			/*
-			 * Tasks waking from uninterruptible sleep are
-			 * limited in their sleep_avg rise as they
-			 * are likely to be waiting on I/O
-			 */
-			if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) {
-				if (p->sleep_avg >= ceiling)
-					sleep_time = 0;
-				else if (p->sleep_avg + sleep_time >=
-					 ceiling) {
-						p->sleep_avg = ceiling;
-						sleep_time = 0;
-				}
-			}
-
 			/*
 			 * This code gives a bonus to interactive tasks.
 			 *
@@ -1069,29 +1044,6 @@ static void activate_task(struct task_struct *p, struct rq *rq, int local)
 	}
 
 	p->prio = recalc_task_prio(p, now);
-
-	/*
-	 * This checks to make sure it's not an uninterruptible task
-	 * that is now waking up.
-	 */
-	if (p->sleep_type == SLEEP_NORMAL) {
-		/*
-		 * Tasks which were woken up by interrupts (ie. hw events)
-		 * are most likely of interactive nature. So we give them
-		 * the credit of extending their sleep time to the period
-		 * of time they spend on the runqueue, waiting for execution
-		 * on a CPU, first time around:
-		 */
-		if (in_interrupt())
-			p->sleep_type = SLEEP_INTERRUPTED;
-		else {
-			/*
-			 * Normal first-time wakeups get a credit too for
-			 * on-runqueue time, but it will be weighted down:
-			 */
-			p->sleep_type = SLEEP_INTERACTIVE;
-		}
-	}
 	p->timestamp = now;
 out:
 	__activate_task(p, rq);
@@ -1641,23 +1593,8 @@ out_set_cpu:
 
 out_activate:
 #endif /* CONFIG_SMP */
-	if (old_state == TASK_UNINTERRUPTIBLE) {
+	if (old_state == TASK_UNINTERRUPTIBLE)
 		rq->nr_uninterruptible--;
-		/*
-		 * Tasks on involuntary sleep don't earn
-		 * sleep_avg beyond just interactive state.
-		 */
-		p->sleep_type = SLEEP_NONINTERACTIVE;
-	} else
-
-	/*
-	 * Tasks that have marked their sleep as noninteractive get
-	 * woken up with their sleep average not weighted in an
-	 * interactive way.
-	 */
-		if (old_state & TASK_NONINTERACTIVE)
-			p->sleep_type = SLEEP_NONINTERACTIVE;
-
 
 	activate_task(p, rq, cpu == this_cpu);
 	/*
@@ -3533,12 +3470,6 @@ EXPORT_SYMBOL(sub_preempt_count);
 
 #endif
 
-static inline int interactive_sleep(enum sleep_type sleep_type)
-{
-	return (sleep_type == SLEEP_INTERACTIVE ||
-		sleep_type == SLEEP_INTERRUPTED);
-}
-
 /*
  * schedule() is the main scheduler function.
  */
@@ -3549,7 +3480,7 @@ asmlinkage void __sched schedule(void)
 	struct list_head *queue;
 	unsigned long long now;
 	unsigned long run_time;
-	int cpu, idx, new_prio;
+	int cpu, idx;
 	long *switch_count;
 	struct rq *rq;
 
@@ -3642,24 +3573,6 @@ need_resched_nonpreemptible:
 	queue = array->queue + idx;
 	next = list_entry(queue->next, struct task_struct, run_list);
 
-	if (!rt_task(next) && interactive_sleep(next->sleep_type)) {
-		unsigned long long delta = now - next->timestamp;
-		if (unlikely((long long)(now - next->timestamp) < 0))
-			delta = 0;
-
-		if (next->sleep_type == SLEEP_INTERACTIVE)
-			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);
-			next->prio = new_prio;
-			enqueue_task(next, array);
-		}
-	}
-	next->sleep_type = SLEEP_NORMAL;
 switch_tasks:
 	if (next == rq->idle)
 		schedstat_inc(rq, sched_goidle);