Re: [PATCH v2 14/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC

From: Sean Christopherson
Date: Mon Dec 12 2022 - 13:12:16 EST


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.