Re: [PATCH tip/core/rcu 5/9] rcu: Make RCU use the new is_idle_task() API

[Josh Triplett <josh@joshtriplett.org>]

On Tue, Nov 15, 2011 at 12:28:01PM -0800, Paul E. McKenney wrote:
> From: Paul E. McKenney <paul.mckenney@linaro.org>
> 
> Change from direct comparison of ->pid with zero to is_idle_task().
> 
> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  kernel/rcutiny.c |    4 ++--
>  kernel/rcutree.c |    4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
> index 4e16ce3..e5bd949 100644
> --- a/kernel/rcutiny.c
> +++ b/kernel/rcutiny.c
> @@ -64,7 +64,7 @@ static void rcu_idle_enter_common(long long oldval)
>  		return;
>  	}
>  	RCU_TRACE(trace_rcu_dyntick("Start", oldval, rcu_dynticks_nesting));
> -	if (current->pid != 0) {
> +	if (!is_idle_task(current)) {
>  		struct task_struct *idle = idle_task(smp_processor_id());
>  
>  		RCU_TRACE(trace_rcu_dyntick("Error on entry: not idle task",
> @@ -118,7 +118,7 @@ static void rcu_idle_exit_common(long long oldval)
>  		return;
>  	}
>  	RCU_TRACE(trace_rcu_dyntick("End", oldval, rcu_dynticks_nesting));
> -	if (current->pid != 0) {
> +	if (!is_idle_task(current)) {
>  		struct task_struct *idle = idle_task(smp_processor_id());
>  
>  		RCU_TRACE(trace_rcu_dyntick("Error on exit: not idle task",
> diff --git a/kernel/rcutree.c b/kernel/rcutree.c
> index 49e0783..7fb8b0e 100644
> --- a/kernel/rcutree.c
> +++ b/kernel/rcutree.c
> @@ -355,7 +355,7 @@ static void rcu_idle_enter_common(struct rcu_dynticks *rdtp, long long oldval)
>  		return;
>  	}
>  	trace_rcu_dyntick("Start", oldval, rdtp->dynticks_nesting);
> -	if (current->pid != 0) {
> +	if (!is_idle_task(current)) {
>  		struct task_struct *idle = idle_task(smp_processor_id());
>  
>  		trace_rcu_dyntick("Error on entry: not idle task",
> @@ -449,7 +449,7 @@ static void rcu_idle_exit_common(struct rcu_dynticks *rdtp, long long oldval)
>  	smp_mb__after_atomic_inc();  /* See above. */
>  	WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1));
>  	trace_rcu_dyntick("End", oldval, rdtp->dynticks_nesting);
> -	if (current->pid != 0) {
> +	if (!is_idle_task(current)) {
>  		struct task_struct *idle = idle_task(smp_processor_id());
>  
>  		trace_rcu_dyntick("Error on exit: not idle task",
> -- 
> 1.7.3.2
>