Re: [PATCH, RFC] v7 scalable classic RCU implementation

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Wed, Oct 22, 2008 at 11:24:30PM +0200, Manfred Spraul wrote:
> Paul E. McKenney wrote:
>> Hmmm...  Looks like rcu_pending is also always called with its cpu
>> parameter set to the current CPU, and same for rcu_needs_cpu().
>> And given that all the external uses of rcu_check_callbacks() are
>> of the following form:
>>
>> 	if (rcu_pending(cpu))
>> 		rcu_check_callbacks(cpu, whatever);
>>
>>
>> perhaps rcu_pending() should be an internal-to-RCU API invoked from
>> rcu_check_callbacks().
>>
>> Thoughts?
>>   
> From my point of view: Yes, change it.
>
> In the long run, I'd like to move the stall detector code to rcupdate.c, 
> with an 'rcu_cpu_missing' callback. That one would need a cpu flag, but 
> that's a new function.

Agreed.  Perhaps a good change to make while introducing stall detection
to preemptable RCU -- there would then be three examples, which should
allow good generalization.

							Thanx, Paul