On Tue, Aug 10, 2021 at 02:20:08PM -0700, Andi Kleen wrote: > Also I agree with your suggestion that we should get the slow path out of > the zone locks/interrupt disable region. That should be easy enough and is > an obvious improvement. I also agree that the slow-path needs to be outside of the memory allocator locks. But I think this conflicts with the concept of accepting memory in 2MB chunks even if allocation size is smaller. Given some kernel code allocated 2 pages and the allocator path starts to validate the whole 2MB page the memory is on, then there are potential races to take into account. Either some other code path allocates memory from that page and returns it before validation is finished or we end up with double validation. Returning unvalidated memory is a guest-problem and double validation will cause security issues for SNP guests. Regards, Joerg
