[PATCH] CPU scheduler CAN_MIGRATE fix

From: Andrew Theurer <habanero@us.ibm.com>

This change:
http://linux.bkbits.net:8080/linux-2.5/diffs/kernel/sched.c@1.202

does not seem to make sense:

#define CAN_MIGRATE_TASK(p,rq,this_cpu)					\
	((!idle || (jiffies - (p)->last_run > cache_decay_ticks)) &&    \
		!task_running(rq, p) &&					\
			cpu_isset(this_cpu, (p)->cpus_allowed))

It should be just the opposite; an idle cpu should be able to have a more
aggressive steal, and a busy cpu should not.

diff --git a/kernel/sched.c b/kernel/sched.c
index 51241d70f924fbaba1219adc5eac6fdcc1739430..89f1bb28dacdc994e97ae3cddd0930aabdc0ec72 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1064,7 +1064,7 @@ skip_queue:
         */
 
 #define CAN_MIGRATE_TASK(p,rq,this_cpu)                                        \
-       ((!idle || (jiffies - (p)->last_run > cache_decay_ticks)) &&    \
+       ((idle || (jiffies - (p)->last_run > cache_decay_ticks)) &&     \
                !task_running(rq, p) &&                                 \
                        cpu_isset(this_cpu, (p)->cpus_allowed))