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Date:      Thu, 14 Sep 2000 16:53:59 -0400 (EDT)
From:      Bosko Milekic <bmilekic@dsuper.net>
To:        Charles Richmond <cmr@sitaranetworks.com>
Cc:        freebsd-net@FreeBSD.ORG
Subject:   RE: Clusters larger than PAGE_SIZE and contigmalloc()
Message-ID:  <Pine.BSF.4.21.0009141652480.4751-100000@jehovah.technokratis.com>
In-Reply-To: <31269226357BD211979E00A0C9866DABE411F5@rios.sitaranetworks.com>

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On Thu, 14 Sep 2000, Charles Richmond wrote:

> So maybe I am being blind on this, but...
> 
> It seems to me if the mbuf clusters cross page boundaries
> in an unaligned fashion as the earlier suggestion of 8 X 1.5k
> would do or if the size is privately configurable and thus not
> guaranteed to align, then the DMA code is forced into a scatter
> gather mode, even if the actual pages are contiguous.  Can someone
> clear up my blindness?
> 
> Charlie

	I'm unsure of what the DMA code is forced to do, but there are
  likely alignment problems with the buffer that will cross the page
  boundry.

  Bosko Milekic
  bmilekic@technokratis.com




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