> > The way I see it, each process has a single pool instance as the parent
> > for all the threads. Resetting or destroying that pool should
> effectively
> > kill all threads. What am I missing?
>
> As I see it, the problem is:
>
> [ Platforms with SAFE_ACCEPT == APR_SUCCESS rather than the lock don't
> apply here. ]
>
> All threads are stuck in the accept mutex except for one. It reads the
> POD. And, it is time to die. It sets workers_may_exit to 1. It then
> releases the accept mutex and exits. Another *child process* acquires
> the accept mutex. Depending upon how many child processes you have, it
> may take a while for all of the threads in the doomed child process to
> acquire the mutex, wake up, check workers_may_exit, release the mutex,
> and then exit. Only when all of the threads in the doomed child process
> are exited does any cleanup occur.
>
> These sibling threads are blocked until they receive the mutex. They
> aren't going to be going anywhere until the mutex is turned over to
> them. They can't check the value of workers_may_exit *until* they
> acquire the mutex. Condition variables help *somewhat*, but the
> problem is now of scope - you have an interprocess condition and a
> intraprocess condition to check. Does this work? I don't know.
>
> And, you can't kick the thread out of the mutex acquire (pthread_cancel
> or similar strategies don't cancel a mutex operation), so you are
> screwed.
Err, doesn't destruction of the mutex wake everyone up?
Oh, wait, does every process share the same mutex?
> And, destroying its parent pool does *NOT* destroy the thread.
> Look at the code again.
Well, it should, although it may not do so now.
> The only person that can call
> pthread_exit() is the actual thread itself. You can't call
> pthread_exit on behalf of another thread (i.e. from the thread that
> knows it is doomed or a cleanup thread). It just doesn't work like
> that.
>
> I just don't agree with Ryan's assessment here. But, it's possible
> I'm missing some major piece of code. -- justin
Could be I'm way off too.
Sander
