On Mon 28-09-20 13:53:58, Zi Yan wrote: > From: Zi Yan <z...@nvidia.com> > > Hi all, > > This patchset adds support for 1GB PUD THP on x86_64. It is on top of > v5.9-rc5-mmots-2020-09-18-21-23. It is also available at: > https://github.com/x-y-z/linux-1gb-thp/tree/1gb_thp_v5.9-rc5-mmots-2020-09-18-21-23 > > Other than PUD THP, we had some discussion on generating THPs and contiguous > physical memory via a synchronous system call [0]. I am planning to send out a > separate patchset on it later, since I feel that it can be done independently > of > PUD THP support.
While the technical challenges for the kernel implementation can be discussed before the user API is decided I believe we cannot simply add something now and then decide about a proper interface. I have raised few basic questions we should should find answers for before the any interface is added. Let me copy them here for easier reference - THP allocation time - #PF and/or madvise context - lazy/sync instantiation - huge page sizes controllable by the userspace? - aggressiveness - how hard to try - internal fragmentation - allow to create THPs on sparsely or unpopulated ranges - do we need some sort of access control or privilege check as some THPs would be a really scarce (like those that require pre-reservation). -- Michal Hocko SUSE Labs
