[RFC/PATCH] Make powerpc64 use __thread for per-cpu variables

[David S. Miller]

From: Paul Mackerras <paulus at samba.org>
Date: Wed, 10 May 2006 16:29:59 +1000

> I have moved current, smp_processor_id and a couple of other things to
> per-cpu variables, and that results in the kernel text being about 8k
> smaller than without any of these __thread patches.  Performance seems
> to be very slightly better but it's hard to be sure that the change is
> statistically significant, from the measurements I've done so far.

That first cache line of current_thread_info() should be so hot that
it's probably just fine to use current_thread_info()->task since
you're just doing a mask on a fixed register (r1) to implement that.