Re: [Qemu-devel] qemu vl.c

[Anders]

>>>>>   Redundant timer rearm optimisation by Anders Melchiorsen.

> I'm merging qemu-cvs into the kvm repository now, and with this commit
> in, kvm will hang after about a minute.  Attaching to it with gdb or
> strace will cause it to resume, so this is very likely a missing signal
> problem.

That is clearly not good.

I still cannot see anything wrong with my patch. As fewer signals are
delivered now, it is possible that this change highlights some old race.
It is certainly also possible that my patch is all wrong, even if I am not
able to see it.


The next few days I will be travelling, but when I get back, I was
planning to address Pauls concern by adding

  qemu_rearm_alarm_timer(alarm_timer);

to the bottom of qemu_mod_timer().

If you feel like it, you can try that out. I am predicting that I will
have a hard time reproducing your hang, as I have only been testing with
kvm, and obviously not seen this problem yet.

(What I really plan to add is a rearm only if the new timer is added at
the head of the list, but the above should do for a test)


Cheers,
Anders.