3702e81d30
Testing so far with recent Wasmtime has not been able to show the need for avoiding the process-wide mmap lock in real-world use-cases. As such, the technique of using an anonymous file and ftruncate() to extend it seems unnecessary; instead, memfd can always use anonymous zeroed memory for heap backing where the CoW image is not present, and mprotect() to extend the heap limit by changing page protections.