Re: Anomalies while handling p_nstopchild count

[christos%zoulas.com@localhost (Christos Zoulas)]

On Oct 10,  3:27pm, campbell+netbsd-tech-kern%mumble.net@localhost (Taylor R Campbell) wrote:
-- Subject: Re: Anomalies while handling p_nstopchild count

| proc_lock may be held by another thread even if the caller is
| guaranteed not to hold it.  The other thread may furthermore be
| waiting on p->p_lock, in which case acquiring p->p_lock here would
| lead to deadlock -- but mutex_tryenter would simply fail.
| 
| The optimization is to optimistically assume nobody else is holding
| proc_lock and do mutex_tryenter.  Otherwise, we back out and acquire
| both locks in the correct order.

Thanks, now I get it!

christos