Rusty Russell wrote: > On Wed, 2007-02-21 at 23:15 +0100, Andi Kleen wrote: > >> On Wednesday 21 February 2007 21:52, Jeremy Fitzhardinge wrote: >> >>> Add a set of accessors to pack, unpack and modify page table entries >>> (at all levels). This allows a paravirt implementation to control the >>> contents of pgd/pmd/pte entries. For example, Xen uses this to >>> convert the (pseudo-)physical address into a machine address when >>> populating a pagetable entry, and converting back to pphys address >>> when an entry is read. >>> >> Do you have some lmbench numbers before/after this change? >> iirc at least fork and exit do a lot of pte accesses in various forms. >> If it's measurable it might be needed to patch those for the native case. >> > > Yes, __mkpte must be patched to avoid performance embarrassment. > > Jeremy, did you want me to do this, or are you happy to? > I'm working on it now. I'll mail out a proposal in a little bit. J