Merge branch 'netdev_page_frags'

Merge branch 'netdev_page_frags'

Alexander Duyck says:

====================
Refactor netdev page frags and move them into mm/

This patch series addresses several things.

First I found an issue in the performance of the pfmemalloc check from
build_skb.  To work around it I have provided a cached copy of pfmemalloc
to be used in __netdev_alloc_skb and __napi_alloc_skb.

Second I moved the page fragment allocation logic into the mm tree and
added functionality for freeing page fragments.  I had to fix igb before I
could do this as it was using a reference to NETDEV_FRAG_PAGE_MAX_SIZE
incorrectly.

Finally I went through and replaced all of the duplicate code that was
calling put_page and replaced it with calls to skb_free_frag.

With these changes in place a simple receive and drop test increased from a
packet rate of 8.9Mpps to 9.8Mpps.  The gains breakdown as follows:

8.9Mpps	Before			9.8Mpps	After
------------------------	------------------------
7.8%	put_compound_page	9.1%	__free_page_frag
3.9%	skb_free_head
1.1%	put_page

4.9%	build_skb		3.8%	__napi_alloc_skb
2.5%	__alloc_rx_skb
1.9%	__napi_alloc_skb
====================

Signed-off-by: David S. Miller <davem@davemloft.net>