Date: Fri, 26 Oct 2007 15:24:51 -0400 From: John Baldwin <jhb@freebsd.org> To: Julian Elischer <julian@elischer.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, Julian Elischer <julian@freebsd.org>, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/sys kthread.h src/sys/kern kern_kthread.c Message-ID: <200710261524.51945.jhb@freebsd.org> In-Reply-To: <4722399E.3090209@elischer.org> References: <200710261703.l9QH3Nmt061137@repoman.freebsd.org> <200710261420.34168.jhb@freebsd.org> <4722399E.3090209@elischer.org>
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On Friday 26 October 2007 03:01:50 pm Julian Elischer wrote:
> John Baldwin wrote:
> > On Friday 26 October 2007 01:03:22 pm Julian Elischer wrote:
> >> julian 2007-10-26 17:03:22 UTC
> >>
> >> FreeBSD src repository
> >>
> >> Modified files:
> >> sys/sys kthread.h
> >> sys/kern kern_kthread.c
> >> Log:
> >> kthread_exit needs no stinkin argument.
> >
> > So an important property of the old kthread_exit() (now kproc_exit()) was
that
> > a kernel module could safely ensure that a kthread it created was out of
the
> > kernel module's text segment before returning from a module unload hook to
> > prevent kernel panics by sleeping on the proc pointer with the proc lock
like
> > so:
> >
> > mtx_lock(&mylock);
> > PROC_LOCK(p);
> > signal_death = 1;
> > mtx_unlock(&mylock);
> > msleep(p, &p->p_mtx, ...);
> > PROC_UNLOCK(p);
> >
> > And have the main thread do this:
> >
> > ...
> > mtx_lock(&mylock);
> > while (!signal_death) {
> > ... fetch work, may drop mylock...
> > }
> > mtx_unlock(&mylock);
> > kthread_exit(0);
>
> the kproc_exit still does..
>
> I didn't see any users of it in the code that I've switched to kthreads
> so far so I haven't added it to the kthread_exit() yet.
Ok. That needs to happen at some point so that more kprocs can be kthreads.
For example, ipmi(4) creates a kthread/kproc, so does random(4), fdc(4), and
I think ndis(4).
--
John Baldwin
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