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Commit 3dee386e authored by Con Kolivas's avatar Con Kolivas Committed by Linus Torvalds
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[PATCH] sched: cleanup task_activated() 



The activated flag in task_struct is used to track different sleep types and
its usage is somewhat obfuscated.  Convert the variable to an enum with more
descriptive names without altering the function.

Signed-off-by: default avatarCon Kolivas <kernel@kolivas.org>
Acked-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 db1b1fef

include/linux/sched.h

+8 −1
Original line number Diff line number Diff line
@@ -684,6 +684,13 @@ static inline void prefetch_stack(struct task_struct *t) { } 
struct audit_context;		/* See audit.c */

struct mempolicy;



enum sleep_type {

	SLEEP_NORMAL,

	SLEEP_NONINTERACTIVE,

	SLEEP_INTERACTIVE,

	SLEEP_INTERRUPTED,

};



struct task_struct {

	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */

	struct thread_info *thread_info;
@@ -706,7 +713,7 @@ struct task_struct { 
	unsigned long sleep_avg;

	unsigned long long timestamp, last_ran;

	unsigned long long sched_time; /* sched_clock time spent running */

	int activated;

	enum sleep_type sleep_type;



	unsigned long policy;

	cpumask_t cpus_allowed;

kernel/sched.c

+15 −9
Original line number Diff line number Diff line
@@ -704,7 +704,7 @@ static int recalc_task_prio(task_t *p, unsigned long long now) 
		 * prevent them suddenly becoming cpu hogs and starving

		 * other processes.

		 */

		if (p->mm && p->activated != -1 &&

		if (p->mm && p->sleep_type != SLEEP_NONINTERACTIVE &&

			sleep_time > INTERACTIVE_SLEEP(p)) {

				p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG -

						DEF_TIMESLICE);
@@ -714,7 +714,7 @@ static int recalc_task_prio(task_t *p, unsigned long long now) 
			 * limited in their sleep_avg rise as they

			 * are likely to be waiting on I/O

			 */

			if (p->activated == -1 && p->mm) {

			if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) {

				if (p->sleep_avg >= INTERACTIVE_SLEEP(p))

					sleep_time = 0;

				else if (p->sleep_avg + sleep_time >=
@@ -769,7 +769,7 @@ static void activate_task(task_t *p, runqueue_t *rq, int local) 
	 * This checks to make sure it's not an uninterruptible task

	 * that is now waking up.

	 */

	if (!p->activated) {

	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
@@ -778,13 +778,13 @@ static void activate_task(task_t *p, runqueue_t *rq, int local) 
		 * on a CPU, first time around:

		 */

		if (in_interrupt())

			p->activated = 2;

			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->activated = 1;

			p->sleep_type = SLEEP_INTERACTIVE;

		}

	}

	p->timestamp = now;
@@ -1272,7 +1272,7 @@ static int try_to_wake_up(task_t *p, unsigned int state, int sync) 
		 * Tasks on involuntary sleep don't earn

		 * sleep_avg beyond just interactive state.

		 */

		p->activated = -1;

		p->sleep_type = SLEEP_NONINTERACTIVE;

	}



	/*
@@ -2875,6 +2875,12 @@ 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.

 */
@@ -2998,12 +3004,12 @@ asmlinkage void __sched schedule(void) 
	queue = array->queue + idx;

	next = list_entry(queue->next, task_t, run_list);



	if (!rt_task(next) && next->activated > 0) {

	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->activated == 1)

		if (next->sleep_type == SLEEP_INTERACTIVE)

			delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;



		array = next->array;
@@ -3016,7 +3022,7 @@ asmlinkage void __sched schedule(void) 
		} else

			requeue_task(next, array);

	}

	next->activated = 0;

	next->sleep_type = SLEEP_NORMAL;

switch_tasks:

	if (next == rq->idle)

		schedstat_inc(rq, sched_goidle);