IMO strict memory accounting misses the point. It can ensure that all allocated pages fits to VM (or return error during allocation), but more pragmatic memory

IMO strict memory accounting misses the point. It can ensure that all allocated pages fits to VM (or return error during allocation), but more pragmatic memory constraint is whether working set of pages (including code/mmap-based pages) fits in physical RAM. If that is not satisfied, system/application crawls to a halt due to page thrashing and some kind of OOM killer is needed. And that may happen even if strict memory accounting is satisfied.