> On Jun 25, 2019, at 8:35 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote: > > On Tue, Jun 25, 2019 at 7:39 PM Nadav Amit <namit@xxxxxxxxxx> wrote: >>> On Jun 25, 2019, at 2:40 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote: >>> >>> On 6/12/19 11:48 PM, Nadav Amit wrote: >>>> Support the new interface of flush_tlb_multi, which also flushes the >>>> local CPU's TLB, instead of flush_tlb_others that does not. This >>>> interface is more performant since it parallelize remote and local TLB >>>> flushes. >>>> >>>> The actual implementation of flush_tlb_multi() is almost identical to >>>> that of flush_tlb_others(). >>> >>> This confused me a bit. I thought we didn't support paravirtualized >>> flush_tlb_multi() from reading earlier in the series. >>> >>> But, it seems like that might be Xen-only and doesn't apply to KVM and >>> paravirtualized KVM has no problem supporting flush_tlb_multi(). Is >>> that right? It might be good to include some of that background in the >>> changelog to set the context. >> >> I’ll try to improve the change-logs a bit. There is no inherent reason for >> PV TLB-flushers not to implement their own flush_tlb_multi(). It is left >> for future work, and here are some reasons: >> >> 1. Hyper-V/Xen TLB-flushing code is not very simple >> 2. I don’t have a proper setup >> 3. I am lazy > > In the long run, I think that we're going to want a way for one CPU to > do a remote flush and then, with appropriate locking, update the > tlb_gen fields for the remote CPU. Getting this right may be a bit > nontrivial. What do you mean by “do a remote flush”?
