On Fri, Aug 31, 2018 at 12:12:48PM +0100, Will Deacon wrote: > On Fri, Aug 31, 2018 at 12:49:45PM +0200, Peter Zijlstra wrote: > > On Fri, Aug 31, 2018 at 08:32:34PM +1000, Nicholas Piggin wrote: > > > Oh gee, I suppose. powerpc hash is kind of interesting because it's > > > crazy, Aneesh knows that code a lot better than I do. radix modulo > > > some minor details of exact instructions is fairly like x86 > > > > The whole TLB broadcast vs explicit IPIs is a fairly big difference in > > my book. > > > > Anyway, have you guys tried the explicit IPI approach? Depending on how > > IPIs are routed vs broadcasts it might save a little bus traffic. No > > point in getting all CPUs to process the TLBI when there's only a hand > > full that really need it. > > > > OTOH, I suppose the broadcast thing has been optimized to death on the > > hardware side, so who knows.. > > You also can't IPI an IOMMU or a GPU ;)
Oh, right you are. I suppose that is why x86-iommu is using those mmu_notifiers.
