RE: [PATCH] mlx4_en: map entire pages to increase throughput

quoted

Would there be any mileage in permanently allocating IOMMU
virtual address to the ring entries, then 'just' assigning
the correct physical address during rx/tx setup?

There is a not a one to one mapping between these two entities,
in particular on the transmit side.

A transmit packet can have multiple segments, some of which are
larger than one IOMMU page.

A SMOP :-) TX is probably easier than RX.
Each tx segment will already go into a separate ring entry,
page boundaries could do the same.
The driver will already have to cope with 'too many segments'
(I remember being passed a full sized frame made of a list
of 1-byte message blocks...)

Or allocate enough sequential IOMMU pages for the longest
tx segment for every ring entry - after all that is already
the 'worst case' allocation!

	David