Re: 32-bit dma allocations on 64-bit platforms

[David Mosberger]

Terence,

>>>>> On Wed, 23 Jun 2004 13:35:35 -0500, Terence Ripperda <tripperda@xxxxxxxxxx> said:

  Terence> based on each architecture's paging_init routines, the
  Terence> zones look like this:

  Terence>                 x86:         ia64:      x86_64:
  Terence> ZONE_DMA:       < 16M        < ~4G      < 16M
  Terence> ZONE_NORMAL:    16M - ~1G    > ~4G      > 16M
  Terence> ZONE_HIMEM:     1G+

Not that it matters here, but for correctness let me note that the
ia64 column is correct only for machines which don't have an I/O MMU.
With I/O MMU, ZONE_DMA will have the same coverage as ZONE_NORMAL with
a recent enough kernel (older kernels had a bug which limited ZONE_DMA
to < 4GB, but that was unintentional).

	--david
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