* [Patch] rcupdate: remove dead code
@ 2011-01-30 10:23 Amerigo Wang
2011-01-30 10:25 ` Cong Wang
2011-01-31 7:59 ` Paul E. McKenney
0 siblings, 2 replies; 4+ messages in thread
From: Amerigo Wang @ 2011-01-30 10:23 UTC (permalink / raw)
To: linux-kernel; +Cc: WANG Cong, Paul E. McKenney, Dipankar Sarma
DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT, so #ifndef CONFIG_PREEMPT
is totally useless in kernel/rcupdate.c.
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
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;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Patch] rcupdate: remove dead code
2011-01-30 10:23 [Patch] rcupdate: remove dead code Amerigo Wang
@ 2011-01-30 10:25 ` Cong Wang
2011-01-31 7:59 ` Paul E. McKenney
2011-01-31 7:59 ` Paul E. McKenney
1 sibling, 1 reply; 4+ messages in thread
From: Cong Wang @ 2011-01-30 10:25 UTC (permalink / raw)
To: Amerigo Wang; +Cc: linux-kernel, Paul E. McKenney, Dipankar Sarma
于 2011年01月30日 18:23, Amerigo Wang 写道:
> DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT, so #ifndef CONFIG_PREEMPT
> is totally useless in kernel/rcupdate.c.
By "useless" I meant the code under #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD,
of course. :)
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] rcupdate: remove dead code
2011-01-30 10:25 ` Cong Wang
@ 2011-01-31 7:59 ` Paul E. McKenney
0 siblings, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2011-01-31 7:59 UTC (permalink / raw)
To: Cong Wang; +Cc: linux-kernel, Dipankar Sarma
On Sun, Jan 30, 2011 at 06:25:48PM +0800, Cong Wang wrote:
> 于 2011年01月30日 18:23, Amerigo Wang 写道:
> >DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT, so #ifndef CONFIG_PREEMPT
> >is totally useless in kernel/rcupdate.c.
>
> By "useless" I meant the code under #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD,
> of course. :)
Yep, I did interpret it that way. ;-)
Thanx, Paul
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] rcupdate: remove dead code
2011-01-30 10:23 [Patch] rcupdate: remove dead code Amerigo Wang
2011-01-30 10:25 ` Cong Wang
@ 2011-01-31 7:59 ` Paul E. McKenney
1 sibling, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2011-01-31 7:59 UTC (permalink / raw)
To: Amerigo Wang; +Cc: linux-kernel, Dipankar Sarma
On Sun, Jan 30, 2011 at 06:23:08PM +0800, Amerigo Wang wrote:
> DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT, so #ifndef CONFIG_PREEMPT
> is totally useless in kernel/rcupdate.c.
Queued, thank you, Amerigo!
I added a patch on top of this commenting why DEBUG_OBJECTS_RCU_HEAD
is disallowed if !PREEMPT, FYI.
Thanx, Paul
> Signed-off-by: WANG Cong <amwang@redhat.com>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
>
> ---
> 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;
> }
^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-01-30 10:23 [Patch] rcupdate: remove dead code Amerigo Wang
2011-01-30 10:25 ` Cong Wang
2011-01-31 7:59 ` Paul E. McKenney
2011-01-31 7:59 ` Paul E. McKenney
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