From: Thomas Gleixner <[EMAIL PROTECTED]>
Problem description at:
http://bugzilla.kernel.org/show_bug.cgi?id=8048
Commit b18ec80396834497933d77b81ec0918519f4e2a7
[PATCH] sched: improve migration accuracy
optimized the scheduler time calculations, but broke posix-cpu-timers.
The problem is that the p->last_ran value is not updated after a context
switch. So a subsequent call to current_sched_time() calculates with a
stale p->last_ran value, i.e. accounts the full time, which the task was
scheduled away.
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
kernel/sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-2.6.20.1.orig/kernel/sched.c
+++ linux-2.6.20.1/kernel/sched.c
@@ -3547,7 +3547,7 @@ switch_tasks:
sched_info_switch(prev, next);
if (likely(prev != next)) {
- next->timestamp = now;
+ next->timestamp = next->last_ran = now;
rq->nr_switches++;
rq->curr = next;
++*switch_count;
--
-
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