On 64bit, local_t is of size long, and thus we make local64_t an alias.
On 32bit, we fall back to atomic64_t. (architecture can provide optimized
32-bit version)

(This new facility is to be used by perf events optimizations.)

Signed-off-by: Peter Zijlstra
Cc: linux-arch@vger.kernel.org
Cc: Andrew Morton
Cc: Linus Torvalds
LKML-Reference:
Signed-off-by: Ingo Molnar