Add a percpu pool

I'd like to keep track of available space to consume in a per-cpu pool.  The
space is added to the pool and divided among the cpu's.  We then can consume or
add space back to the pool.  You can also add space back to the pool and have it
balance the added space among the per cpu pools.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
3 files changed