Re: [PATCH 1/5] 2.6.0 fix preempt ctx switch accounting

[Ingo Molnar]

* Nick Piggin <piggin@xxxxxxxxxxxxxxx> wrote:

> Make sure to count kernel preemption as a context switch. A short cut
> has been preventing it.

i'd prefer the much simpler patch below. This also keeps the kernel
preemption logic isolated instead of mixing it into the normal path.

	Ingo

--- linux/kernel/sched.c.orig	
+++ linux/kernel/sched.c	
@@ -1520,8 +1520,10 @@ need_resched:
 	 * if entering off of a kernel preemption go straight
 	 * to picking the next task.
 	 */
-	if (unlikely(preempt_count() & PREEMPT_ACTIVE))
+	if (unlikely(preempt_count() & PREEMPT_ACTIVE)) {
+		prev->nivcsw++;
 		goto pick_next_task;
+	}
 
 	switch (prev->state) {
 	case TASK_INTERRUPTIBLE:
-
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