On Thu, Aug 08, 2024 at 11:25:29AM -0400, Peter Xu wrote: > On Thu, Aug 08, 2024 at 10:47:28AM -0400, Michael S. Tsirkin wrote: > > On Thu, Aug 08, 2024 at 10:15:36AM -0400, Peter Xu wrote: > > > On Thu, Aug 08, 2024 at 07:12:14AM -0400, Michael S. Tsirkin wrote: > > > > This is too big of a hammer. People already use what you call "cross > > > > migrate" and have for years. We are not going to stop developing > > > > features just because someone suddenly became aware of some such bit. > > > > If you care, you will have to work to solve the problem properly - > > > > nacking half baked hacks is the only tool maintainers have to make > > > > people work on hard problems. > > > > > > IMHO this is totally different thing. It's not about proposing a new > > > feature yet so far, it's about how we should fix a breakage first. > > > > > > And that's why I think we should fix it even in the simple way first, then > > > we consider anything more benefitial from perf side without breaking > > > anything, which should be on top of that. > > > > > > Thanks, > > > > As I said, once the quick hack is merged people stop caring. > > IMHO it's not a hack. It's a proper fix to me to disable it by default for > now. > > OTOH, having it ON always even knowing it can break migration is a hack to > me, when we don't have anything else to guard the migration. It's a hack in the sense that it's specific to this option. But hack or not, it's the only way I have to make people work on a full solution. > > Mixing different kernel versions in migration is esoteric enough for > > this not to matter to most people. There's no rush I think, address > > it properly. > > Exactly mixing kernel versions will be tricky to users to identify, but > that's, AFAICT, exactly happening everywhere. We can't urge user to always > use the exact same kernels when we're talking about a VM cluster. That's > why I think allowing migration to work across those kernels matter. > > I will agree there's no rush iff RHEL9 kernel won't backport TAP at all, > otherwise this will trigger between y-stream after people upgrades partial > of the clusters. > > Thanks, > > -- > Peter Xu
