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

Ingo Molnar
2003-12-20T19:23:55Z

* Nick Piggin <piggin@cyberone.com.au> 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) {