[geogriffin]

Doesn't something like jemalloc basically give you this, but without pauses? Thread-local freelists for quick recycling of small allocations without synchronization.. funnily enough, jemalloc even uses some garbage collection mechanisms internally.

[steveklabnik]

I don't know a ton about jemalloc internals, but it is true that a lot of modern mallocs use some mechanisms similar to GCs. There's some pretty major constraint differences though.