On Thu, 2021-05-06 at 15:29 +0000, Sean Christopherson wrote: > On Thu, May 06, 2021, Kai Huang wrote: > > On Wed, 2021-05-05 at 09:11 -0700, Ben Gardon wrote: > > > It would probably also be worth putting a comment on pf_fixed so that > > > people in the future know what it's supposed to mean and we don't get > > > into archeology, reverse engineering the meaning of the stat again. > > > > It seems the legacy MMU code path is a better place to add the comment to explain when > > pf_fixed should be increased. However I am not sure whether it is necessary for this > > patch (and I confess I found it's hard to explain why to increase pf_fixed in case of > > emulation :)). Or perhaps Sean can write a patch to add comment to legacy MMU :) > > Ya, I think it makes sense to hold off on documenting the existing behavior in > the TDP MMU. As is often the case in KVM, just because KVM has always done > something one way, doesn't mean it's correct/ideal. But, bikeshedding over what > faults exactly should count towards pf_fixed is best left to a separate patch. > > > I ended up with below, by adding a comment in TDP MMU saying "to make it consistent with > > legacy MMU...", and in the commit message, I put a lore link of this discussion, since I > > found Sean's explanation is quite useful. When people are interested in, they can do a git > > blame and find the commit msg of this change -- although it is not as straightforward as > > having comment directly. > > > > Is this OK to you? > > > > And Sean? > > Yep, works for me. Thanks!
