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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
