Re: [PATCH] mm/pdx: Add comments throughout the codebase for pdx

[Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>]

On Thu, Jun 22, 2023 at 03:28:14PM +0200, Jan Beulich wrote:
> > Unless I'm missing some non-obvious piece of the puzzle, I'd say that for a
> > truly general compressor we'd need some kind of loop over the hole mask.
> 
> Well, further compression might be possible that way, yes, but that's
> entirely orthogonal to the number of discontiguous regions we're
> talking about. Consider
> 
> 0x0000100000000000-0x00001000ffffffff
> 0x0000200000000000-0x00002000ffffffff
> 0x0000300000000000-0x00003000ffffffff
> 0x0000400000000000-0x00004000ffffffff
> 
> The reference system's arrangement was slightly more complex (first and
> foremost because of the memory below 4G that node 0 had), but came close
> to the above conceptually.
> 
> Jan
Ah, I now see what you mean. A single hole can compress several regions if
they are all share sequences of zeroes. Fair point. I'll reflect that in that
paragraph.

Alejandro