From: Cliff Wickman <[EMAIL PROTECTED]>
When a cpu is disabled, move_task_off_dead_cpu() is called for tasks
that have been running on that cpu.
Currently, such a task is migrated:
1) to any cpu on the same node as the disabled cpu, which is both online
and among that task's cpus_allowed
2) to any cpu which is both online and among that task's cpus_allowed
But the task's cpus_allowed may have been a single cpu.
This patch would insert a preference to migrate such a task to a cpu within
its cpuset (and set its cpus_allowed to its cpuset).
With this patch, migrate the task to:
1) to any cpu on the same node as the disabled cpu, which is both online
and among that task's cpus_allowed
2) to any online cpu within the task's cpuset
3) to any cpu which is both online and among that task's cpus_allowed
Diffed against 2.6.16.37
Signed-off-by: Cliff Wickman <[EMAIL PROTECTED]>
---
kernel/sched.c | 6 ++++++
1 file changed, 6 insertions(+)
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -4602,6 +4602,12 @@ static void move_task_off_dead_cpu(int d
if (dest_cpu == NR_CPUS)
dest_cpu = any_online_cpu(tsk->cpus_allowed);
+ /* try to stay on the same cpuset */
+ if (dest_cpu == NR_CPUS) {
+ tsk->cpus_allowed = cpuset_cpus_allowed(tsk);
+ dest_cpu = any_online_cpu(tsk->cpus_allowed);
+ }
+
/* No more Mr. Nice Guy. */
if (dest_cpu == NR_CPUS) {
cpus_setall(tsk->cpus_allowed);
-
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