Side note (and maybe this was obvious to people already): I would suggest
that the "limiting" not be done the way fork() is limited ("return EAGAIN
if you go over a limit") but be done as a per-task counting semaphore
(down() on submit, up() on fibril exit).
So we should limit these to basically have some maximum concurrency
factor, but rather than consider it an error to go over it, we'd just cap
the concurrency by default, so that people can freely use asynchronous
interfaces without having to always worry about what happens if their
resources run out..
However, that also implies that we should probably add a "flags" parameter
to "async_submit()" and have a FIBRIL_IMMEDIATE flag (or a timeout) or
something to tell the kernel to rather return EAGAIN than wait. Sometimes
you don't want to block just because you already have too much work.
Hmm?
Linus
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