On Tue, Aug 09, 2022, David Matlack wrote: > On Fri, Aug 5, 2022 at 4:30 PM Vipin Sharma <vipinsh@xxxxxxxxxx> wrote: > > Approach B: > > Ask page from the specific node on fault path with option to fallback > > to the original cache and default task policy. > > > > This is what Sean's rough patch looks like. > > This would definitely be a simpler approach but could increase the > amount of time a vCPU thread holds the MMU lock when handling a fault, > since KVM would start performing GFP_NOWAIT allocations under the > lock. So my preference would be to try the cache approach first and > see how complex it turns out to be. Ya, as discussed off-list, I don't like my idea either :-) The pfn and thus node information is available before mmu_lock is acquired, so I don't see any reason to defer the allocation other than to reduce the memory footprint, and that's a solvable problem one way or another.
