page_pool: Add allocation stats

mainline inclusion
from mainline-v5.18-rc1
commit 8610037e
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BNYE
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8610037e8106b48c79cfe0afb92b2b2466e51c3d



----------------------------------------------------------------------

Add per-pool statistics counters for the allocation path of a page pool.
These stats are incremented in softirq context, so no locking or per-cpu
variables are needed.

This code is disabled by default and a kernel config option is provided for
users who wish to enable them.

The statistics added are:
	- fast: successful fast path allocations
	- slow: slow path order-0 allocations
	- slow_high_order: slow path high order allocations
	- empty: ptr ring is empty, so a slow path allocation was forced.
	- refill: an allocation which triggered a refill of the cache
	- waive: pages obtained from the ptr ring that cannot be added to
	  the cache due to a NUMA mismatch.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>