Re: [RFC] Scalable statistics counters using kmalloc_percpu

Rusty Russell (rusty@rustcorp.com.au)
Sat, 27 Jul 2002 11:56:13 +1000


> > + for( i=0; i < NR_CPUS; i++ )
> > + res += *per_cpu_ptr(stctr->ctr, i);
> > + return res;
> > +}
>
> Oh dear. Most people only have two CPUs.
>
> Rusty, can we *please* fix this? Really soon?

Linus just applied the hotplug cpu boot patch in bk, which gives
cpu_possible(i), for exactly this purpose.

> General comment: we need to clean up the kernel_stat stuff. We
> cannot just make it per-cpu because it is 32k in size already. I
> would suggest that we should break out the disk accounting and
> make the rest of kernel_stat per CPU.

kernel_stat is dynamically allocated???

Personally, I think that dynamically allocated per-cpu datastructures,
like dynamically-allocated brlocks, are something we might need
eventually, but look at what a certain driver did with the "make it
per-cpu" concept already. I don't want to rush in that direction.

Cheers,
Rusty.

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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