Re: [PATCH RFC tip/core/rcu 04/11] rcupdate: remove dead code

[Mathieu Desnoyers]

* Paul E. McKenney (paulmck@xxxxxxxxxxxxxxxxxx) wrote:
> From: Amerigo Wang <amwang@xxxxxxxxxx>
> 
> DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT, so #ifndef CONFIG_PREEMPT
> is totally useless in kernel/rcupdate.c.

Why does it depend on PREEMPT exactly ? Only for the fixup ?

Thanks,

Mathieu

> 
> Signed-off-by: WANG Cong <amwang@xxxxxxxxxx>
> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> ---
>  kernel/rcupdate.c |    5 -----
>  1 files changed, 0 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
> index a23a57a..afd21d1 100644
> --- a/kernel/rcupdate.c
> +++ b/kernel/rcupdate.c
> @@ -215,10 +215,6 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state)
>  		 * If we detect that we are nested in a RCU read-side critical
>  		 * section, we should simply fail, otherwise we would deadlock.
>  		 */
> -#ifndef CONFIG_PREEMPT
> -		WARN_ON(1);
> -		return 0;
> -#else
>  		if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
>  		    irqs_disabled()) {
>  			WARN_ON(1);
> @@ -229,7 +225,6 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state)
>  		rcu_barrier_bh();
>  		debug_object_free(head, &rcuhead_debug_descr);
>  		return 1;
> -#endif
>  	default:
>  		return 0;
>  	}
> -- 
> 1.7.3.2
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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