On Sat, 10 Jan 2015 19:39:19 -0800
Philip Guenther <[email protected]> wrote:
> On Mon, 5 Jan 2015, Helg wrote:
> > The man page for LOCK(9) says that if the kernel option LOCKDEBUG is
> > enabled, additional facilities are provided to assist in determining
> > deadlock occurrences.
> >
> > I created a copy of /sys/arch/amd64/conf/GENERIC and added option
> > LOCKDEBUG. Executing config and then make clean && make results in
> > warnings like:
> >
> > implicit declaration of function '__mp_lock'
> >
> > Adding includes for <sys/mplock.h> in the offending files resolves the
> > problem but this just doesn't seem right.
> >
> > Does anyone have any suggestions?
>
> Yeah, don't use it. It used to be a lot more when there were still traces
> of the original "simplelocks" in the tree, but the code to do more with
> LOCKDEBUG was ripped out as those no-ops were felt to be more misleading
> than helpful.
Thanks. I figured as much when I started to look deeper into the
implementation of lockinit and lockmgr. These are now just legacy
wrappers for rwlock functions. Removing LOCKDEBUG makes sense to me.
>
> It's dead, Jim, let's bury LOCKDEBUG.
>
> oks?
>
>
> Philip
>
> Index: sys/arch/i386/i386/trap.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/i386/i386/trap.c,v
> retrieving revision 1.119
> diff -u -p -r1.119 trap.c
> --- sys/arch/i386/i386/trap.c 2 Dec 2014 18:13:10 -0000 1.119
> +++ sys/arch/i386/i386/trap.c 11 Jan 2015 03:33:48 -0000
> @@ -381,11 +381,6 @@ trap(struct trapframe *frame)
> case T_PAGEFLT: /* allow page faults in kernel mode */
> if (p == 0 || p->p_addr == 0)
> goto we_re_toast;
> -#ifdef LOCKDEBUG
> - /* If we page-fault while in scheduler, we're doomed. */
> - if (__mp_lock_held(&sched_lock))
> - goto we_re_toast;
> -#endif
>
> pcb = &p->p_addr->u_pcb;
> #if 0
> Index: sys/sys/sched.h
> ===================================================================
> RCS file: /cvs/src/sys/sys/sched.h,v
> retrieving revision 1.37
> diff -u -p -r1.37 sched.h
> --- sys/sys/sched.h 17 Oct 2014 01:51:39 -0000 1.37
> +++ sys/sys/sched.h 11 Jan 2015 03:33:48 -0000
> @@ -183,7 +183,7 @@ void remrunqueue(struct proc *);
> yield(); \
> } while (0)
>
> -#if defined(MULTIPROCESSOR) || defined(LOCKDEBUG)
> +#if defined(MULTIPROCESSOR)
> #include <sys/lock.h>
>
> /*
> @@ -215,7 +215,7 @@ do {
> \
> splx(s); \
> } while (/* CONSTCOND */ 0)
>
> -#else /* ! MULTIPROCESSOR || LOCKDEBUG */
> +#else /* ! MULTIPROCESSOR */
>
> #define SCHED_ASSERT_LOCKED() splassert(IPL_SCHED);
> #define SCHED_ASSERT_UNLOCKED() /* nothing */
> @@ -225,7 +225,7 @@ do {
> \
> #define SCHED_LOCK(s) s = splsched()
> #define SCHED_UNLOCK(s) splx(s)
>
> -#endif /* MULTIPROCESSOR || LOCKDEBUG */
> +#endif /* MULTIPROCESSOR */
>
> #endif /* _KERNEL */
> #endif /* _SYS_SCHED_H_ */
> Index: share/man/man9/lock.9
> ===================================================================
> RCS file: /cvs/src/share/man/man9/lock.9,v
> retrieving revision 1.22
> diff -u -p -r1.22 lock.9
> --- share/man/man9/lock.9 9 Jul 2014 14:16:10 -0000 1.22
> +++ share/man/man9/lock.9 11 Jan 2015 03:33:48 -0000
> @@ -57,10 +57,6 @@ single process.
> It also allows upgrading a shared-access lock to an
> exclusive-access lock, as well as downgrading an exclusive-access lock
> to a shared-access lock.
> -.Pp
> -If the kernel option LOCKDEBUG is enabled, additional facilities
> -are provided to record additional lock information.
> -These facilities are provided to assist in determining deadlock occurrences.
> .Sh FUNCTIONS
> The functions which operate on locks are:
> .Bl -tag -width Ds
--
Helg <[email protected]>
