Kqueue event loop (*BSD, macOS) #14829
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We can't call EPOLL_CTL_MOD with EPOLLEXCLUSIVE. Let's disable it for now and see later if we can replace it with a pair of EPOLL_CTL_DEL and EPOLL_CTL_ADD.
Process.run sometimes hang forever after fork and before exec, because it tries to close a fd that requires to lock, but another thread may have already acquired the lock, while `fork` only duplicates the current thread (the other ones are not, and the forked process was left waiting for a mutex to be unlocked, which would never happen.
That required to allocate a Node for the interrupt event, which ain't a bad idea.
Extracts the generic parts of the event loop into an intermediary class between Crystal::EventLoop and Crystal::Epoll::EventLoop so we can reuse it to implement the event loop on other similar syscalls (poll, kqueue).
Sometimes we only want a pair of fds, and not IO::FileDescriptor objects.
For some reason specs fail with a fiber failing to raise an exception because `pthread_mutex_unlock` failed with EPERM while trying to dequeue the `Fiber#resume_event` from the event loop. Re-creating the thread mutex after fork seems to fix the issue.
This was referenced Jul 26, 2024
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Superseded by #14959 |
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Why settle with epoll (linux specific) when we can have epoll+kqueue and support all the implemented POSIX targets (albeit we should use event ports on Solaris)?
Extracts the generic parts of
Crystal::Epoll::EventLoopinto theCrystal::Eventednamespace. Only the event (de)registration into epoll/kqueue and the actual run loops are specific (+ how to interrupt + timeout precision).May have the same issue as the epoll event loop, with CI sometimes failing with a
pthread_mutex_unlockinCrystal::Evented::EventLoop#enqueueor#dequeuefailing with EPERM. I reproduced on FreeBSD but I can't anymore with the latest patches.Another shared issue is with
preview_mt: we callCrystal::Scheduler.enqueuewhich may be reentrant (fiber channel uses a PIPE).Tested on FreeBSD 14. CI says Darwin is working.
Supersedes (or follow up) #14814.