2006-02-15 11:42:13

by Con Kolivas

[permalink] [raw]
Subject: [PATCH] sched: remove on runqueue requeueing

Andrew please apply. Thanks Mike.

Cheers,
Con
---
On runqueue time is used to elevate priority in schedule().

In the code it currently requeues tasks even if their priority is not
elevated, which would end up placing them at the end of their runqueue
array effectively delaying them instead of improving their priority.

Bug spotted by Mike Galbraith <[email protected]>

This patch removes this requeueing.

Signed-off-by: Con Kolivas <[email protected]>

kernel/sched.c | 3 +--
1 files changed, 1 insertion(+), 2 deletions(-)

Index: linux-2.6.16-rc3-mm1/kernel/sched.c
===================================================================
--- linux-2.6.16-rc3-mm1.orig/kernel/sched.c 2006-02-15 22:29:15.000000000 +1100
+++ linux-2.6.16-rc3-mm1/kernel/sched.c 2006-02-15 22:32:20.000000000 +1100
@@ -3107,8 +3107,7 @@ go_idle:
dequeue_task(next, array);
next->prio = new_prio;
enqueue_task(next, array);
- } else
- requeue_task(next, array);
+ }
}
next->sleep_type = SLEEP_NORMAL;
switch_tasks: