On 06/09/2013 04:53 PM, Gleb Natapov wrote: > On Fri, May 31, 2013 at 08:36:19AM +0800, Xiao Guangrong wrote: >> Hi Gleb, Paolo, Marcelo, >> >> I have putted the potential controversial patches to the latter that are >> patch 8 ~ 10, patch 11 depends on patch 9. Other patches are fully reviewed, >> I think its are ready for being merged. If not luck enough, further >> discussion >> is needed, could you please apply that patches first? :) >> >> Thank you in advance! >> >> Some points are raised during discussion but missed in this version: >> 1) Gleb's idea that skip obsolete pages in the hast list walker >> >> Unfortunately, it is not safe. There has a window between updating >> valid-gen and reloading mmu, in that window, the obsolete page can >> be used by vcpu, but the guest page table fail to be write-protected >> (since the obsolete page is skipped in mmu_need_write_protect()). >> > Can you elaborate on how this can happen. valid_gen is updated under > mmu_lock and reloading of mmus happens under the same lock, so for all > other vcpus this should look like atomic thing.
You're right. Actually, i made another optimization patch in this version that moves kvm_reload_remote_mmus() out of mmu-lock, but did not attach it into this series. It seems my brain is not parallel-able enough. :( -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
