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Date: Thu, 13 Feb 2014 10:07:36 -0800
From: John-Mark Gurney <jmg@funkthat.com>
To: Garrett Wollman <wollman@bimajority.org>
Subject: Re: Use of contiguous physical memory in cxgbe driver
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Garrett Wollman wrote this message on Thu, Feb 13, 2014 at 12:44 -0500:
> <<On Wed, 12 Feb 2014 23:56:51 -0800, John-Mark Gurney <jmg@funkthat.com> said:
> 
> > Though we might want to keep a few mbufs reserved for receive now that
> > you mention it...  We should never get to the point where we can't
> > allocate even one frame for receive...
> 
> It's very easy to get to that state if the driver insists on getting
> three physically contiguous pages (which is what it takes to allocate
> a single 9k cluster)

Well, if you're using a cheap NIC that can't do scatter/gather DMA,
then you get what you pay for...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."