This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


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

Jamie Lokier writes ("Re: [Xen-devel] Re: [Qemu-devel] [PATCH 01/13] Handle 
terminating signals."):
> Ian Jackson wrote:
> > 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.

Yes.  Err, I'm not sure what effect that will have in Anthony's patch
but it probably wouldn't be good.

As I say I haven't managed to reproduce this other than in a full
qemu-dm tree (from qemu-xen).

So it may be that it is because of something I did or something the
qemu-xen code does - although it seems hard to imagine how it could
break the signal mask in the helper thread given that that thread runs
entirely glibc code, except when a signal is being delivered (and of
course the signal mask is saved and restored for signal delivery).


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>