Dave Jones wrote: > On Wed, Apr 11, 2007 at 10:30:58PM -0700, Zachary Amsden wrote: > > In situations where page table updates need only be made locally, and there > > is no cross-processor A/D bit races involved, we need not use the > heavyweight > > xchg instruction to atomically fetch and clear page table entries. > Instead, > > we can just read and clear them directly. > > > > This introduces a neat optimization for non-SMP kernels; drop the atomic > > xchg operations from page table updates. > > Would it be feasible to do this using the smp_alternatives stuff? > Given many distros are now shipping SMP-only kernels, it'd be nice > to get that win without using having to rebuild their kernels. >
That's a good point. It is a fairly straightforward substitution for the static case: xchg reg, mem to mov mem, reg mov imm, mem I'll give it a spin and see how it drives. It is, though, less obvious how easy it will be for PAE kernels. Zach _______________________________________________ Virtualization mailing list [EMAIL PROTECTED] https://lists.linux-foundation.org/mailman/listinfo/virtualization
