Re: [RFC][PATCH 08/11] sched: Simplify preempt_count tests

From: Steven Rostedt
Date: Tue Sep 29 2015 - 11:43:06 EST


On Tue, 29 Sep 2015 11:28:33 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> Since we stopped setting PREEMPT_ACTIVE, there is no need to mask it
> out of preempt_count() tests.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---

Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

-- Steve

> include/linux/preempt.h | 3 +--
> kernel/sched/core.c | 2 +-
> 2 files changed, 2 insertions(+), 3 deletions(-)
>
> --- a/include/linux/preempt.h
> +++ b/include/linux/preempt.h
> @@ -126,8 +126,7 @@
> * Check whether we were atomic before we did preempt_disable():
> * (used by the scheduler)
> */
> -#define in_atomic_preempt_off() \
> - ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_DISABLE_OFFSET)
> +#define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
>
> #if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
> extern void preempt_count_add(int val);
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -7472,7 +7472,7 @@ void __init sched_init(void)
> #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
> static inline int preempt_count_equals(int preempt_offset)
> {
> - int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
> + int nested = preempt_count() + rcu_preempt_depth();
>
> return (nested == preempt_offset);
> }
>

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