I noticed excessive time in the pid hash functions on a ppc64 box. It
turns out the pid hash is being sized way too small, eg on a 16GB box:

PID hash table entries: 16 (order 4: 256 bytes)

The reason is that the pid hash init function uses max_pfn before it was
setup on ppc64. With the following patch things are good again:

PID hash table entries: 4096 (order 12: 65536 bytes)
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>