You can find them at the original motivation for removing jemalloc, 7 years ago: https://github.com/rust-lang/rust/issues/36963
Also it's not "glibc's allocator", it's the system allocator. If you're unhappy with glibc's, get that replaced.
> 1. Reliability - how is an alternate allocator less reliable?
Jemalloc had to be disabled on various platforms and architectures, there is no reason to think mimalloc or tcmalloc are any different.
The system allocator, while shit, is always there and functional, the project does not have to curate its availability across platforms.
> 2. Compatibility - again sounds like a FUD argument. How is compatibility reduced by swapping out the allocator?
It makes interactions with anything which does use the system allocator worse, and almost certainly fails to interact correctly with some of the more specialised system facilities (e.g. malloc.conf) or tooling (in rust, jemalloc as shipped did not work with valgrind).
> Also, most people aren’t writing hello world applications
Most people aren't writing applications bound on allocation throughput either
> so the default should probably be for a good allocator.
Probably not, no.
> I’d also note that having a dependency of the std runtime on glibc in the first place likely bloats your binary more than the specific allocator selected.
That makes no sense whatsoever. The libc is the system's and dynamically linked. And changing allocator does not magically unlink it.
> 4. Maintenance burden - I don’t really buy this argument.
It doesn't matter that you don't buy it. Having to ship, resync, debug, and curate (cf (1)) an allocator is a maintenance burden. With a system allocator, all the project does is ensure it calls the system allocators correctly, the rest is out of its purview.
