Use of contiguous physical memory in cxgbe driver

[wollman at bimajority.org]

In article <5CAE71A4-EA1D-481D-AFBA-3738F8E66087 at yahoo.com>, Scott
Long writes:

>So what you’re saying is that all of the other memory allocations that
>go along with
>moving data through a socket wind up fragmenting the free memory pool to
>the point
>where it becomes impossible to find 3 contig pages for a 9k jumbo RX frame.

Yes.  I don't think it's even all that difficult, because drivers that
are of this type only ever allocate 9k clusters, and for outbound
packets the kernel never allocates anyting bigger than a page.  Since
the NIC driver allocates a new mbuf immediately to replenish its rx
ring, before the upper layers have had a chance to process the packet,
it's not hard to see how even a moderately busy system will soon
checkerboard all of physical memory.

-GAWollman