On Wed, Apr 12, 2023 at 08:10:33PM +0900, Kyungsan Kim wrote: > Pinning and plubbability is mutual exclusive so it can not happen at the same time. > What we argue is ZONE_EXMEM does not "confine movability". an allocation context can determine the movability attribute. > Even one unmovable allocation will make the entire CXL DRAM unpluggable. > When you see ZONE_EXMEM just on movable/unmoable aspect, we think it is the same with ZONE_NORMAL, > but ZONE_EXMEM works on an extended memory, as of now CXL DRAM. > > Then why ZONE_EXMEM is, ZONE_EXMEM considers not only the pluggability aspect, but CXL identifier for user/kenelspace API, > the abstraction of multiple CXL DRAM channels, and zone unit algorithm for CXL HW characteristics. > The last one is potential at the moment, though. > > As mentioned in ZONE_EXMEM thread, we are preparing slides to explain experiences and proposals. > It it not final version now[1]. > [1] https://github.com/OpenMPDK/SMDK/wiki/93.-%5BLSF-MM-BPF-TOPIC%5D-SMDK-inspired-MM-changes-for-CXL The problem is that you're starting out with a solution. Tell us what your requirements are, at a really high level, then walk us through why ZONE_EXMEM is the best way to satisfy those requirements. Also, those slides are terrible. Even at 200% zoom, the text is tiny. There is no MAP_NORMAL argument to mmap(), there are no GFP flags to sys_mmap() and calling mmap() does not typically cause alloc_page() to be called. I'm not sure that putting your thoughts onto slides is making them any better organised.
