Re: [Tracker] [Patch] New CVS version

[Jamie McCracken <jamiemcc blueyonder co uk>]

Jamie McCracken wrote:
> Laurent Aguerreche wrote:
> > Le mardi 22 aoÃt 2006 Ã 10:39 +0100, Jamie McCracken a Ãcrit :
> > > Gergan Penkov wrote:
> > > > and trackerd does not exit, I haven't waited more than 5-10 minutes though.
> > > Rats - I thought I sussed this one!
> > >
> > > if it takes more then a few seconds to exit then its a deadlock on a 
> > > mutex. I guess I should unlock them all as a precaution when exiting. 
> > > Please try latest cvs again (I cannot replicate your problem mind you)
> > I found a case where it doesn't exit smoothly.
> >
> > What I found:
> >
> > in a thread, called thread1, tracker_log() is called to write "Watching
> > directory %s (total watches = %d)":
> > - g_print() to STDOUT, Ok;
> > - then,
> >   1/ lock()      <<====== important
> >   2/ open() on ~/.Tracker/tracker.log
> > - *BOOM*, user does a Ctrl+C, so this thread won't continue as
> > signal_handler() has been called and replaces prior code...
> > - now, tracker_log() is called to write "Received termination signal %d
> > so now exiting."
> > - g_print() to STDOUT, Ok;
> > - then,
> >   1/ lock()
> >   of course, it will wait for ever since this mutex is already locked
> > and won't be released...
> >
> > At the same time, other threads will want to log something so they will
> > be locked.
>
> Great thanks for that - it sure was a subtle one!
>
> The right thing to do here is not to tracker_log anything until the 
> second phase of the shutdown. (the resumption of code after the sig 
> handler will allow the code to continue to unlock the mutex).

Have now altered CVS to fix this.

Also had a stab at improving the exiting (mostly guesswork) and 
increasing thread sync speed.


--
Mr Jamie McCracken
http://jamiemcc.livejournal.com/