On 11/29/2011 02:01 PM, Avi Kivity wrote: > On 11/29/2011 01:56 PM, Xiao Guangrong wrote: > > On 11/29/2011 07:20 PM, Avi Kivity wrote: > > > > > > > We used to have a bitmap in a shadow page with a bit set for every slot > > > pointed to by the page. If we extend this to non-leaf pages (so, when > > > we set a bit, we propagate it through its parent_ptes list), then we do > > > the following on write fault: > > > > > > > > > Thanks for the detail. > > > > Um, propagating slot bit to parent ptes is little slow, especially, it > > is the overload for no Xwindow guests which is dirty logged only in the > > migration(i guess most linux guests are running on this mode and migration > > is not frequent). No? > > You need to propagate very infrequently. The first pte added to a page > will need to propagate, but the second (if from the same slot, which is > likely) will already have the bit set in the page, so we're assured it's > set in all its parents. btw, if you plan to work on this, let's agree on pseudocode/data structures first to minimize churn. I'll also want this documented in mmu.txt. Of course we can still end up with something different than planned, but let's at least try to think of the issues in advance. -- error compiling committee.c: too many arguments to function -- 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
