On 11/24/2014 09:22 AM, Paul E. McKenney wrote:
> On Mon, Nov 24, 2014 at 08:35:46AM -0700, Jens Axboe wrote:
>> On 11/24/2014 01:21 AM, Christoph Hellwig wrote:
>>> On Fri, Nov 21, 2014 at 02:56:00PM -0500, David Miller wrote:
>>>> I would suggest looking into the possibility that we allocate the memory
>>>> using the count of valid cpus, rather than the largest cpu number.
>>>>
>>>> That's a common error that runs into problems with discontiguous
>>>> cpu numbering like Sparc sometimes has.
>>>
>>> Yes, that does look like the case.  Do you have a good trick on how
>>> to allocate a map for the highest possible cpu number without first
>>> iterating the cpu map?  I couldn't find something that looks like a
>>> highest_possible_cpu() helper.
>>
>> Honestly I think that num_posible_cpus() should return the max of
>> number of CPUs (weigt), and the highest numbered CPU. It's a pain in
>> the butt to handle this otherwise.
>
> Hear, hear!!!  That would make my life easier, and would make this sort
> of problem much less likely to occur!

How about this one?

-- 
Jens Axboe