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Commit d79fc0fc authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] sched: TASK_NONINTERACTIVE 



This patch implements a task state bit (TASK_NONINTERACTIVE), which can be
used by blocking points to mark the task's wait as "non-interactive".  This
does not mean the task will be considered a CPU-hog - the wait will simply
not have an effect on the waiting task's priority - positive or negative
alike.  Right now only pipe_wait() will make use of it, because it's a
common source of not-so-interactive waits (kernel compilation jobs, etc.).

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 95cdf3b7

fs/pipe.c

+5 −1
Original line number Diff line number Diff line
@@ -39,7 +39,11 @@ void pipe_wait(struct inode * inode) 
{

	DEFINE_WAIT(wait);



	prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE);

	/*

	 * Pipes are system-local resources, so sleeping on them

	 * is considered a noninteractive wait:

	 */

	prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE);

	up(PIPE_SEM(*inode));

	schedule();

	finish_wait(PIPE_WAIT(*inode), &wait);

include/linux/sched.h

+1 −0
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ extern unsigned long nr_iowait(void); 
#define TASK_TRACED		8

#define EXIT_ZOMBIE		16

#define EXIT_DEAD		32

#define TASK_NONINTERACTIVE	64



#define __set_task_state(tsk, state_value)		\

	do { (tsk)->state = (state_value); } while (0)

kernel/sched.c

+10 −1
Original line number Diff line number Diff line
@@ -1260,6 +1260,16 @@ static int try_to_wake_up(task_t *p, unsigned int state, int sync) 
		p->activated = -1;

	}



	/*

	 * Tasks that have marked their sleep as noninteractive get

	 * woken up without updating their sleep average. (i.e. their

	 * sleep is handled in a priority-neutral manner, no priority

	 * boost and no penalty.)

	 */

	if (old_state & TASK_NONINTERACTIVE)

		__activate_task(p, rq);

	else

		activate_task(p, rq, cpu == this_cpu);

	/*

	 * Sync wakeups (i.e. those types of wakeups where the waker

	 * has indicated that it will leave the CPU in short order)
@@ -1268,7 +1278,6 @@ static int try_to_wake_up(task_t *p, unsigned int state, int sync) 
	 * the waker guarantees that the freshly woken up task is going

	 * to be considered on this CPU.)

	 */

	activate_task(p, rq, cpu == this_cpu);

	if (!sync || cpu != this_cpu) {

		if (TASK_PREEMPTS_CURR(p, rq))

			resched_task(rq->curr);