Re: Idle Function Not Getting Called

[Chris Vine <chris cvine freeserve co uk>]

On Sat, 12 Sep 2009 00:18:59 -0400 (EDT)
Marshall Lake <mlake mlake net> wrote:
[snip]
> I can't find a non-commercial deadlock checker for Linux.  I agree
> that the multi-threaded facet of the code is causing my problem but
> so far I'm having trouble using breakpoints/debug code to isolate the
> exact cause.
>
> The mutex locks/unlocks are only in a secondary thread and an idle 
> function.  I assume there's no problems with idle functions using
> mutexes?

There is no problem provided that any mutex acquired by the idle
function does not block (it immediately acquires), or if it does block
then it only does so transiently.  If the secondary thread undertakes a
lengthy operation holding a lock which the idle function may also want
to acquire, then there is a bottleneck in the code.  If at the same
time the secondary thread is waiting for the idle handler to complete,
there is a deadlock.

The important point in looking at out-of-order locking (or other
locking issues) is that the idle handler runs in the thread in which the
main program loop runs, not the thread which called g_idle_add()/
g_idle_add_full(), and that it runs at a time not of that calling
thread's choosing.

Chris