On Thu, Aug 12, 2021, Ben Gardon wrote: > On Wed, Aug 11, 2021 at 10:07 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > > > Set the min_level for the TDP iterator at the root level when zapping all > > SPTEs so that the _iterator_ only processes top-level SPTEs. Zapping a > > non-leaf SPTE will recursively zap all its children, thus there is no > > need for the iterator to attempt to step down. This avoids rereading all > > the top-level SPTEs after they are zapped by causing try_step_down() to > > short-circuit. > > > > Cc: Ben Gardon <bgardon@xxxxxxxxxx> > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > This change looks functionally correct, but I'm not sure it's worth > adding more code special cased on zap-all for what seems like a small > performance improvement in a context which shouldn't be particularly > performance sensitive. Yeah, I was/am on the fence too, I almost included a blurb in the cover letter saying as much. I'll do that for v2 and let Paolo decide. Thanks! > Change is a correct optimization though and it's not much extra code, > so I'm happy to give a: > Reviewed-by: Ben Gardon <bgardon@xxxxxxxxxx>
