Re: wake up io_uring_enter(...IORING_ENTER_GETEVENTS..) via eventfd

[Pavel Begunkov <asml.silence@gmail.com>]

Hi,

I'd love to help but don't have time at the moment. I'll take a look but
in a week, either send it to io-uring@vger.kernel.org. Jens deals with
such stuff lightning fast!

> io_uring application should be a single thread in my application which
> means a different thread wakes up io_uring_enter via eventfd. The issue is
> that io_uring_enter(fd, 0, min_complete, IORING_ENTER_GETEVENTS, 0) which
> is blocking doesn't get any poling event from eventfd_write when both
> functions are executed in different threads

Yeah, sounds strange. Did you try to do the same but without io_uring?
e.g. with write(2), select(2).

> 
> 
> here small example
> 
> https://gist.github.com/1Jo1/6496d1b8b6b363c301271340e2eab95b
> 
> 
> io_uring_enter will get a polling event if you move eventfd_write(efd,
> (eventfd_t) 1L) to the main thread,
> 
> I don't get it..probably I missed something, why can't I run both functions
> on different threads, any ideas what the cause might be?
> 
> 
> (Linux Kernel 5.7.10-201) liburing 0.6 & 0.7
> 
> ---
> Josef
> 

-- 
Pavel Begunkov