Re: 2.4.19pre1aa1

[Andrea Arcangeli <andrea@suse.de>]

On Tue, Mar 05, 2002 at 07:29:11AM -0800, Martin J. Bligh wrote:
> --On Tuesday, March 05, 2002 9:22 AM -0300 Rik van Riel 
> <riel@conectiva.com.br> wrote:
> 
> >On Tue, 5 Mar 2002, Andrea Arcangeli wrote:
> >>On Mon, Mar 04, 2002 at 10:26:30PM -0300, Rik van Riel wrote:
> >>> On Tue, 5 Mar 2002, Andrea Arcangeli wrote:
> >>> > On Mon, Mar 04, 2002 at 09:01:31PM -0300, Rik van Riel wrote:
> >>> > > This could be expressed as:
> >>> > >
> >>> > > "node A"  HIGHMEM A -> HIGHMEM B -> NORMAL -> DMA
> >>> > > "node B"  HIGHMEM B -> HIGHMEM A -> NORMAL -> DMA
> >
> >>the example you made doesn't have highmem at all.
> >>
> >>> has 1 ZONE_NORMAL and 1 ZONE_DMA while it has multiple
> >>> HIGHMEM zones...
> >>
> >>it has multiple zone normal and only one zone dma. I'm not forgetting
> >>that.
> >
> >Your reality doesn't seem to correspond well with NUMA-Q
> >reality.
> 
> I think the difference is that he has a 64 bit vaddr space,
> and I don't ;-) Thus all mem to him is ZONE_NORMAL (not sure
> why he still has a ZONE_DMA, unless he reused it for the 4Gb
> boundary). Andrea, is my assumtpion correct?

correct, but the current code from SGI should be just fine for NUMA-Q
too, if you've highmem, your zonelist will automatically be setup
accordingly, I don't see problems there.

> 
> On a 32 bit arch (eg ia32) everything above 896Mb (by default)
> is ZONE_HIGHMEM. Thus if I have > 896Mb in the first node,
> I will have one ZONE_NORMAL in node 0, and a ZONE_HIGHMEM
> in every node. If I have < 896Mb in the first node, then
> I have a ZONE_NORMAL in every node up to and including the
> 896 breakpoint, and a ZONE_HIGHMEM in every node from the
> breakpoint up (including the breakpoint node). Thus the number
> of zones = number of nodes + 1.
> 
> M.


Andrea