Re: [PATCH] reduce sizeof(percpu_data) and removes dependance against NR_CPUS

[Eric Dumazet <dada1@cosmosbay.com>]

Andrew Morton a écrit :
> Eric Dumazet <dada1@cosmosbay.com> wrote:
>> Current sizeof(percpu_data) is NR_CPUS*sizeof(void *)
>>
>>  This trivial patch makes percpu_data real size depends on 
>>  highest_possible_processor_id() instead of NR_CPUS
>>
>>  percpu_data allocations are not performance critical, we can spend few CPU 
>>  cycles and save some ram.
> 
> hm, highest_possible_processor_id() isn't very efficient.  And it's quite
> dopey that it's a macro.  We should turn it into a real function which
> caches its return result and goes BUG if it's called before
> cpu_possible_map is initialised.

I agree, I will see if I can do that without poking in every arch :(

More over, my patch has an error on pdsize computation, it should be :

size_t pdsize = (highest_possible_processor_id() + 1) * sizeof(void *);

Eric