Messages in this thread |  | | Date | Fri, 10 Oct 2014 11:54:52 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/1] sched: fix the PREEMPT_ACTIVE check in __trace_sched_switch_state() |
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On Tue, Oct 07, 2014 at 09:51:08PM +0200, Oleg Nesterov wrote: > task_preempt_count() has nothing to do with the actual preempt counter, > thread_info->saved_preempt_count is only valid right after switch_to(). > > __trace_sched_switch_state() can use preempt_count(), prev is still the > current task when trace_sched_switch() is called.
This is true, but the paranoid in me would like a BUG_ON(p != current) right along with that to make sure we don't accidentally change this.
But yes, its good to get rid of task_preempt_count(), its horrible.
> Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > include/trace/events/sched.h | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h > index 0a68d5a..a7d67bc 100644 > --- a/include/trace/events/sched.h > +++ b/include/trace/events/sched.h > @@ -100,7 +100,7 @@ static inline long __trace_sched_switch_state(struct task_struct *p) > /* > * For all intents and purposes a preempted task is a running task. > */ > - if (task_preempt_count(p) & PREEMPT_ACTIVE) > + if (preempt_count() & PREEMPT_ACTIVE) > state = TASK_RUNNING | TASK_STATE_MAX; > #endif > > -- > 1.5.5.1 > >
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