[Artful] mlx5e-Introduce RX Page-Reuse

[Talat Batheesh]

This feature is a Page-Reuse mechanism in non-Striding RQ RX datapath.
A WQE (RX descriptor) buffer is a page, that in most cases was fully
wasted on a packet that is much smaller, requiring a new page for
the next round.

In this feature, we implement a page-reuse mechanism, that resembles a
`SW Striding RQ`.
We allow the WQE to reuse its allocated page as much as it could,
until the page is fully consumed. In each round, the WQE is capable
of receiving packet of maximal size (MTU). Yet, upon the reception of
a packet, the WQE knows the actual packet size, and consumes the exact
amount of memory needed to build a linear SKB. Then, it updates the
buffer pointer within the page accordingly, for the next round.

Feature is mutually exclusive with XDP (packet-per-page)
and LRO (session size is a power of two, needs unused page).

 Upstream acceptance Commits

accd58833237 net/mlx5e: Introduce RX Page-Reuse
bce2b2bf6682 net/mlx5e: Enhance RX SKB headroom logic
78aedd327982 net/mlx5e: Build SKB with exact frag_size

[Joseph Salisbury (jsalisbury)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1701892

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Joseph Salisbury (jsalisbury)]

These patches don't pick cleanly against the current artful kernel, which is 4.11 based. We may want to wait untile artful -proposed is at a later version, so we don't have to do any back porting to these patches. Artful is going to be 4.13 based.