svn commit: r218967 - head/sys/kern

[Alexander Best]

On Wed Feb 23 11, Kostik Belousov wrote:
> On Wed, Feb 23, 2011 at 12:56:25PM +0000, John Baldwin wrote:
> > Author: jhb
> > Date: Wed Feb 23 12:56:25 2011
> > New Revision: 218967
> > URL: http://svn.freebsd.org/changeset/base/218967
> > 
> > Log:
> >   Fix off-by-one error in check against max_threads_per_proc.
> >   
> >   Submitted by:	arundel
> >   MFC after:	1 week
> > 
> > Modified:
> >   head/sys/kern/kern_thr.c
> > 
> > Modified: head/sys/kern/kern_thr.c
> > ==============================================================================
> > --- head/sys/kern/kern_thr.c	Wed Feb 23 10:28:37 2011	(r218966)
> > +++ head/sys/kern/kern_thr.c	Wed Feb 23 12:56:25 2011	(r218967)
> > @@ -153,7 +153,7 @@ create_thread(struct thread *td, mcontex
> >  	p = td->td_proc;
> >  
> >  	/* Have race condition but it is cheap. */
> > -	if (p->p_numthreads >= max_threads_per_proc) {
> > +	if (p->p_numthreads > max_threads_per_proc) {
> >  		++max_threads_hits;
> >  		return (EPROCLIM);
> >  	}
> 
> I do not think there was off by one error. The create_thread() function
> is called to create new thread, and before the process thread counter
> is incremented in thread_link(). The old test tried to not allow more
> then max_threads_per_proc threads in a process, now it allows to
> create max_threads_per_proc.

doesn't the semantics of the term "maximum" imply that it's own value is also
valid?

if a sign says maximum weight 2000kg, does that mean that a weight of 2000kg is
invalid and the highest valid weight is 1999,999..kg?

cheers.
alex

> 
> My guess is that the reference to mentioned pthread_vfork_test failed
> because reporter set kern.threads.max_threads_per_proc to 100. The
> test actually tries to create 101 threads, 1 main + 100 new.

so the main process counts as 1 thread and for each pthread_create invokation
the thread number gets bumped up?

so with a process doing a single pthread_create() that would imply this process
is having a thread count of 2?

cheers.
alex

-- 
a13x