Re: [Xen-ia64-devel] Virtual mem map

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

[...]
> > >I think this structure is simple enough to be fast.
> > >
> > >For memory usage:
> > >* Each entry of the first array describes 1GB of memory.  An entry is 32
> > > bits. 16KB for the first array can describe 2**12 * 2**30 = 2**42 B of
> > > memory. (Dan's machine physical memory is bellow 2**40).
> > >* I think 1GB of granule is good enough, unless you have a machine with
> > > very small DIMM.  In this case, we can use 512MB or 256MB instead of
> > > 1GB. * 1GB is 2**16 to 2**18 pages.  Thus, the offset may be 18 bits
> > > and the length 14 bits (to be multiplied by 4).
> > >As a conclusion, the memory footprint is *very* small, maybe too small ?
> > >
> > >memmap related macros must be rewritten.
> > >
> > >Tristan.
Hugh,  I forgot we need also reverse mapping.  I now understand the root of 
virtual mem map!

Tristan.


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