On Tue 29-11-22 14:08:34, Johannes Weiner wrote: [...] > Short of further restricting the pages that can be moved, I don't see > how we can get rid of the cgroup locks in rmap after all. :( :( > We can try limiting move candidates to present ptes. But maybe it's > indeed time to deprecate the legacy charge moving altogether, and get > rid of the entire complication. > > Hugh, Shakeel, Michal, what do you think? I do agree with Hugh that going part way will likely not solve the general maintenance burden. I am OK with dropping the functionality but we should at least add a big fat warning if anybody wants to enable memory.move_charge_at_immigrate. If there are any workload which absolutely depend on the feature (which would make them impossible to migrate to v2 btw) then we want to hear about that and address in some way. An incremental deprecation by limiting to present ptes sounds like this semantic change might get overlooked for an extended time. -- Michal Hocko SUSE Labs
