igb: Add support for using order 1 pages to receive large frames

igb: Add support for using order 1 pages to receive large frames

This patch adds support for using 3K buffers in order 1 pages the same way
we were using 2K buffers in 4K pages.  We are reserving 1K of room for now
to have space available for future headroom and tailroom when we enable
build_skb support.

One side effect of this patch is that we can end up using a larger buffer
if jumbo frames is enabled.  The impact shouldn't be too great, but it
could hurt small packet performance for UDP workloads if jumbo frames is
enabled as the truesize of frames will be larger.

Signed-off-by: Alexander Duyck <[email protected]>
Tested-by: Aaron Brown <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>