Hi Christian, > > Emscripten's fiber does not support submitting coroutines to other > > threads. So this commit modifies hw/9pfs/coth.h to disable this behavior > > when compiled with Emscripten. > > The lack of being able to dispatch a coroutine to a worker thread is one > thing, however it would probably still make sense to use fibers in 9pfs as > replacement of its coroutines mechanism. > > In 9pfs coroutines are used to dispatch blocking fs I/O syscalls from main > thread to worker thread(s): > > https://wiki.qemu.org/Documentation/9p#Control_Flow > > If you just remove the coroutine code entirely, 9p server might hang for good, > and with it QEMU's main thread. > > By using fibers instead, it would not hang, as it seems as if I/O syscalls are > emulated in Emscripten, right?
Thank you for the feedback. Yes, it would be great if Emscripten's fiber could be used to address this limitation. Since Emscripten's fiber is cooperative, I believe a blocking code_block can still block the 9pfs server unless an explicit yield occurs within it. I'll continue exploring better solutions for this. Please let me know if I'm missing anything. > Missing > > errno = ENOTSUP; Sure, I'll fix this in the next version of the series. > Looks like you just copied the macOS errno translation code. That probably > doesn't make sense. Errno values differ between Emscripten and Linux, so conversion is required here. I've used the same mappings as macOS for now, but I'm happy to add more conversions if needed.
