On Mon, Jun 10, 2013 at 10:43:52PM +0900, Takuya Yoshikawa wrote: > On Mon, 10 Jun 2013 16:39:37 +0800 > Xiao Guangrong <xiaoguangrong.eric@xxxxxxxxx> wrote: > > > On 06/10/2013 03:56 PM, Gleb Natapov wrote: > > > On Fri, Jun 07, 2013 at 04:51:22PM +0800, Xiao Guangrong wrote: > > > > Looks good to me, but doesn't tis obsolete kvm_mmu_zap_mmio_sptes() and > > > sp->mmio_cached, so they should be removed as part of the patch series? > > > > Yes, i agree, they should be removed. :) > > I'm fine with removing it but please make it clear that you all agree > on the same basis. > > Last time, Paolo mentioned the possibility to use some bits of spte for > other things. The suggestion there was to keep sp->mmio_cached code > for the time we would need to reduce the bits for generation numbers. > > Do you think that zap_all() is now preemptible and can treat the > situation reasonably well as the current kvm_mmu_zap_mmio_sptes()? > > One downside is the need to zap unrelated shadow pages, but if this case > is really very rare, yes I agree, it should not be a problem: it depends > on how many bits we can use. > > Just please reconfirm. > That was me who mention the possibility to use some bits of spte for other things. But for now I have a use for one bit only. Now that you have reminded me about that discussion I am not so sure we want to remove kvm_mmu_zap_mmio_sptes(), but on the other hand it is non preemptable, so large number of mmio sptes can cause soft lockups. zap_all() is better in this regards now. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
