Commit e7c38cb4 authored Mar 31, 2006 by Con Kolivas Committed by Linus Torvalds Mar 31, 2006

[PATCH] sched: make task_noninteractive use sleep_type

Alterations to the pipe code in the kernel made it possible for relative
starvation to occur with tasks that slept waiting on a pipe getting unfair
priority bonuses even if they were otherwise fully cpu bound so the
TASK_NONINTERACTIVE flag was introduced which prevented any change to
sleep_avg while sleeping waiting on a pipe. This change also leads to the
converse though, preventing any priority boost from occurring in truly
interactive tasks that wait on pipes.

Convert the TASK_NONINTERACTIVE flag to set sleep_type to SLEEP_NONINTERACTIVE
which will allow a linear bonus to priority based on sleep time thus allowing
interactive tasks to get high priority if they sleep enough.

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 3dee386e

kernel/sched.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -1273,17 +1273,17 @@ static int try_to_wake_up(task_t *p, unsigned int state, int sync)
		* sleep_avg beyond just interactive state.
		*/
		p->sleep_type = SLEEP_NONINTERACTIVE;
		}
		} else

		/*
		* 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.)
		* woken up with their sleep average not weighted in an
		* interactive way.
		*/
		if (old_state & TASK_NONINTERACTIVE)
		__activate_task(p, rq);
		else
		p->sleep_type = SLEEP_NONINTERACTIVE;


		activate_task(p, rq, cpu == this_cpu);
		/*
		* Sync wakeups (i.e. those types of wakeups where the waker