On Wed, Aug 21, 2013 at 12:03 PM, Cyrill Gorcunov <gorcu...@gmail.com> wrote: > On Wed, Aug 21, 2013 at 08:50:26PM +0200, H. Peter Anvin wrote: >> But is there a manifest bug or not? What is the deal with Xen? >> > > I personally don't see bug here because > > - this swapped page soft dirty bit is set for non-present entries only, > never for present ones, just at moment we form swap pte entry > > - i don't find any code which would test for this bit directly without > is_swap_pte call > > but the use of paw bit itself is confusing, so I'm working on patch which > won't use it. Again, if someone knows where exactly access to pse bit when > pte keeps swap entry may happen (for any purpose other than dirty page > tracking) please share.
I doubt that there are cacheability issues here, since the swap type already overlaps with PWT and PCD. What happens if the page being swapped is a THP page? (I have no idea how, or even if, this works, but presumably PSE is important.) --Andy -- Andy Lutomirski AMA Capital Management, LLC -- 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/
