On 10/24/2016 11:32 AM, David Nellans wrote: > On 10/24/2016 01:04 PM, Dave Hansen wrote: >> If you *really* don't want a "cdm" page to be migrated, then why isn't >> that policy set on the VMA in the first place? That would keep "cdm" >> pages from being made non-cdm. And, why would autonuma ever make a >> non-cdm page and migrate it in to cdm? There will be no NUMA access >> faults caused by the devices that are fed to autonuma. >> > Pages are desired to be migrateable, both into (starting cpu zone > movable->cdm) and out of (starting cdm->cpu zone movable) but only > through explicit migration, not via autonuma.
OK, and is there a reason that the existing mbind code plus NUMA policies fails to give you this behavior? Does autonuma somehow override strict NUMA binding? > other pages in the same > VMA should still be migrateable between CPU nodes via autonuma however. That's not the way the implementation here works, as I understand it. See the VM_CDM patch and my responses to it. > Its expected a lot of these allocations are going to end up in THPs. > I'm not sure we need to explicitly disallow hugetlbfs support but the > identified use case is definitely via THPs not tlbfs. I think THP and hugetlbfs are implementations, not use cases. :) Is it too hard to support hugetlbfs that we should complicate its code to exclude it from this type of memory? Why?
