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
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