There is no connection.

FreeBSD does page faults just like everybody else. Your process blocks until the memory is read in.

Sure it would be my pleasure. Kqueue allows a read request to be scheduled that is non-blocking on a page fault. Linux always blocks the thread executing read() on a page fault. This is still true using aio_read(), as all that does is run another thread to call read() which blocks. Which is great for small numbers of read requests but scales poorly.

And the bit from the paper that is relevant:

> A non kqueue-aware application using the asynchronous I/O (aio) facility starts an I/O request by issuing aio read() or aio write() The request then proceeds independently of the application, which must call aio error() repeatedly to check whether the request has completed, and then eventually call aio return() to collect the completion status of the request. The AIO filter replaces this polling model by allowing the user to register the aio request with a specified kqueue at the time the I/O request is issued, and an event is returned under the same conditions when aio error() would successfully return. This allows the application to issue an aio read() call, proceed with the main event loop, and then call aio return() when the kevent corresponding to the aio is returned from the kqueue, saving several system calls in the process.