[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.

[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.
9e3a8956 · Andrew Morton · Linus Torvalds · dd3f51c2 · 9e3a8956
Commit 9e3a8956 authored Sep 09, 2003 by Andrew Morton Committed by Linus Torvalds Sep 09, 2003
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kernel/sched.c kernel/sched.c +1 -1

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--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1064,7 +1064,7 @@ static void load_balance(runqueue_t *this_rq, int idle, cpumask_t cpumask)
 	 */
 #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))