Re: [Xen-devel] Re: [Qemu-devel] [PATCH 01/13] Handle terminating signals.

[Jamie Lokier]

Ian Jackson wrote:
> Jamie Lokier writes ("Re: [Xen-devel] Re: [Qemu-devel] [PATCH 01/13] Handle 
> terminating signals."):
> > Leading to: why would (real) signals being used to collect AIO events
> > anyway, if you don't have signalfd()?  If you've got a helper thread,
> 
> If you use aio, glibc has a tendency to emulate it with thread(s).
> The helper thread I was referring to in my commit message is the
> glibc-created helper thread.  glibc appears (in strace) to do IO in
> this thread and then raises the signal you asked for (SIGUSR2 in
> qemu's case).

That observation implies Anthony's helper thread will not always
receive the SIGUSR2 signals - Glibc's thread may receive them instead.

So when the signalfd-emulation signal handler writes to the pipe, it
might block Glibc's AIO thread.  Is that ok, Anthony?

-- Jamie