Who even uses jemalloc in 2026 anyway? (many major projects)
42 points by eatonphil
42 points by eatonphil
Jemalloc is used extensively for deploying Ruby applications as it fits well with how Ruby allocates memory. Most Ruby/Rails applications that switch to jemalloc see a meaningful decrease in total memory usage.
Indeed the article mentions it is installed by default in Docker images generated by Rails.
I still hope that we can move FreeBSD to snmalloc. I was using it in libc for a while and it performed better and had a bunch of useful security features (bounds-checked memcpy!) that are much harder to do with jemalloc. Oh, and libc was 20% smaller with snmalloc than jemalloc. Which was amusing given that people often complain that C++ produces larger binaries than C.
What's stopping FreeBSD from using it? Is it just that snmalloc is pre-1.0?
I presume the allocator interface is sufficiently small and well-defined that you can swap out allocators without causing compatibility problems, i.e., it's not a thorny technical reason preventing the switch.
We actually added compat interfaces for the jemalloc non-standard APIs, but then FreeBSD removed them. It’s mostly inertia: changing malloc is moderately high risk and no one cares quite enough to push it.
I was looking through the copyright notices for Valve's Deadlock, built on their Source 2 engine, and that uses both mimalloc and jemalloc. I thought that was interesting.