Il 30/10/2013 12:07, Gerd Hoffmann ha scritto: > On Fr, 2013-10-25 at 23:53 +0100, Paolo Bonzini wrote: >> Il 25/10/2013 20:50, Marcelo Tosatti ha scritto: >>> On Fri, Oct 25, 2013 at 09:52:34AM +0100, Paolo Bonzini wrote: >>>> Because offsets are zero, and lengths match the RAM block lengths, you >>>> do not need any complication with aliasing. This still has to be done >>>> only for new machine types. >>> >>> Not possible because you just wasted holesize bytes (if number of >>> additional bytes due to huge page alignment is smaller than holesize, a >>> new hugepage is required, which is not acceptable). >> >> Ok. Thanks for explaining---the patch seems good with the proper >> compatibility option in the machine type. Please run the >> guest_memory_dump_analysis test in autotest too. > > As the whole thing must depend on machine type anyway for live migration > compatibility we can also simply change the memory split, i.e. map 2GB > (-M q35) or 3GB (-M pc) below 4G instead of the odd sizes (2.75 / 3.5) > we have now.
For q35 it could be a possibility. For pc, I'm worried about old Windows systems that ignore all memory outside the first 4GB. They would lose 512 MB of memory. Paolo
