From d79fc0fc6645b0cf5cd980da76942ca6d6300fa4 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Sat, 10 Sep 2005 00:26:12 -0700
Subject: [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: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 kernel/sched.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'kernel/sched.c')

diff --git a/kernel/sched.c b/kernel/sched.c
index 24eed372d28..6da13bba3e2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1260,6 +1260,16 @@ out_activate:
 		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 @@ out_activate:
 	 * 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);
-- 
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