On Tue, 2013-04-09 at 17:43 -0700, H. Peter Anvin wrote: > OK, thinking about the GDT here. > > The GDT is quite small -- 256 bytes on i386, 128 bytes on x86-64. As > such, we probably don't want to allocate a full page to it for only > that. This means that in order to create a readonly mapping we have to > pack GDTs from different CPUs together in the same pages, *or* we > tolerate that other things on the same page gets reflected in the same > mapping. What about grouping via nodes? > > However, the packing solution has the advantage of reducing address > space consumption which matters on 32 bits: even on i386 we can easily > burn a megabyte of address space for 4096 processors, but burning 16 > megabytes starts to hurt. Having 4096 32 bit processors, you deserve what you get. ;-) -- Steve > > It would be important to measure the performance impact on task switch, > though. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
