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Date: Thu, 13 Feb 2014 14:34:01 -0500
From: Garrett Wollman <wollman@bimajority.org>
To: Scott Long <scott4long@yahoo.com>
Subject: Re: Use of contiguous physical memory in cxgbe driver
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<<On Thu, 13 Feb 2014 10:05:18 -0800, Scott Long <scott4long@yahoo.com>=
 said:

> So what you=92re saying is that all of the other memory allocations t=
hat 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.

I should mention that this behavior is particularly problematic when
only some clients are even sending jumbo frames.  Demanding three
physically contiguous pages when 70% of the packets received are not
more than 1514 bytes is particularly wasteful, although hopefully this
is mitigated with LRO in the common case.  (I don't know if LRO even
works with NFS.  How would I check?)

-GAWollman