Michal Hocko <mhocko@xxxxxxxx> writes: > On Thu 02-11-23 14:11:09, Huang, Ying wrote: >> Michal Hocko <mhocko@xxxxxxxx> writes: >> >> > On Wed 01-11-23 10:21:47, Huang, Ying wrote: >> >> Michal Hocko <mhocko@xxxxxxxx> writes: >> > [...] >> >> > Well, I am not convinced about that TBH. Sure it is probably a good fit >> >> > for this specific CXL usecase but it just doesn't fit into many others I >> >> > can think of - e.g. proportional use of those tiers based on the >> >> > workload - you get what you pay for. >> >> >> >> For "pay", per my understanding, we need some cgroup based >> >> per-memory-tier (or per-node) usage limit. The following patchset is >> >> the first step for that. >> >> >> >> https://lore.kernel.org/linux-mm/cover.1655242024.git.tim.c.chen@xxxxxxxxxxxxxxx/ >> > >> > Why do we need a sysfs interface if there are plans for cgroup API? >> >> They are for different target. The cgroup API proposed here is to >> constrain the DRAM usage in a system with DRAM and CXL memory. The less >> you pay, the less DRAM and more CXL memory you use. > > Right, but why the usage distribution requires its own interface and > cannot be combined with the access control part of it? Per my understanding, they are orthogonal. Weighted-interleave is a memory allocation policy, other memory allocation policies include local first, etc. Usage limit is to constrain the usage of specific memory types (e.g. DRAM) for a cgroup. It can be used together with local first policy and some other memory allocation policy. -- Best Regards, Huang, Ying
