WebAssembly support?

[jedisct1]

Is WebAssembly a target mimalloc may eventually support?

WebAssembly doesn't have mmap(); only a single, linear memory segment that can grow. Allocating memory from the host must be done in a way similar to sbrk(2) as in the good old days.

Is it something mimalloc could do?

[daanx]

Yes, we want to see a WASM backend (especially since I am working towards supporting algebraic effects in WASM). I didn't study the full implications yet, but in principle it should be quite easy to extend mimalloc to use an sbrk like interface. The https://github.com/microsoft/mimalloc/blob/master/src/os.c source contains the OS interface but basically mimalloc just gets 4MiB chunks from the OS using whatever is available. Of course, some functionality would become noops, like guard pages or page resets, but that makes sense in a WASM environment.

[jedisct1]

Preliminary port to WebAssembly/WASI here: https://github.com/jedisct1/mimalloc

[daanx]

That is crazy fast! I'll look at it later when I have more time but this is great :-)

[daanx]

I'll close this now that there is a pull request #32