On Mon, Dec 12, 2022 at 06:09:39PM +0000, Sean Christopherson wrote: > On Fri, Dec 09, 2022, Dave Hansen wrote: > > On 12/9/22 08:05, Kristen Carlson Accardi wrote: > > > Aside from that though, I don't think that killing enclaves makes sense > > > outside the context of cgroup limits. > > > > I think it makes a lot of sense in theory. Whatever situation we get > > into with a cgroup's EPC we can also get into with the whole system's EPC. > > > > *But*, it's orders of magnitude harder to hit on the whole system. > > ... > > > If someone wants to extend this OOM support to system-wide EPC later, then go > > ahead. But, I don't think it makes a lot of sense to invert this series for > > it. > > +1 from the peanut gallery. With VMM EPC oversubscription suport, no sane VMM > will oversubscribe VEPC pages. And for VA pages, supporting swap of VA pages is > likely a more userspace-friendly approach if system-wide EPC OOM is a concern. When swapping VA pages the topology of the VA page cache for swapped VA pages is the main question. It is compromise between how long swap-in and swap-out can take, and how generic solution it be, meaning how deep hierarchies you want to build, or is just a flat list of parent VA pages "good enough". Also, there's the question whether it should be a global cache, per cgroup and so forth. Implementing any solution is not overly complicated. Locking in these options is what puzzles me. BR, Jarkko
