Index: sys/amd64/conf/GENERIC
===================================================================
--- sys/amd64/conf/GENERIC	(revisione 240513)
+++ sys/amd64/conf/GENERIC	(copia locale)
@@ -79,8 +79,8 @@ options 	KDB			# Enable kernel debugger support.
 options 	DDB			# Support DDB.
 options 	GDB			# Support remote GDB.
 options 	DEADLKRES		# Enable the deadlock resolver
-options 	INVARIANTS		# Enable calls of extra sanity checking
-options 	INVARIANT_SUPPORT	# Extra sanity checks of internal structures, required by INVARIANTS
+#options 	INVARIANTS		# Enable calls of extra sanity checking
+#options 	INVARIANT_SUPPORT	# Extra sanity checks of internal structures, required by INVARIANTS
 options 	WITNESS			# Enable checks to detect deadlocks and cycles
 options 	WITNESS_SKIPSPIN	# Don't run witness on spinlocks for speed
 options 	MALLOC_DEBUG_MAXZONES=8	# Separate malloc(9) zones
Index: sys/sys/systm.h
===================================================================
--- sys/sys/systm.h	(revisione 240513)
+++ sys/sys/systm.h	(copia locale)
@@ -171,11 +171,37 @@ void	g_waitidle(void);
 
 void	panic(const char *, ...) __dead2 __printflike(1, 2);
 
+void	_critical_enter(const char *, int);
+void	_critical_exit(const char *, int);
+void	_critical_exit_hard(struct thread *);
+
+#define	_critical_enter_fast() do {					\
+	curthread->td_critnest++;					\
+	__asm __volatile("" : : : "memory");				\
+} while (0)
+
+#define	_critical_exit_fast() do {					\
+	struct thread *__td;						\
+									\
+	__td = curthread;						\
+	__asm __volatile("" : : : "memory");				\
+	if (__td->td_critnest != 1)					\
+		__td->td_critnest--;					\
+	else								\
+		_critical_exit_hard(__td);				\
+} while (0)
+
+#if defined(INVARIANT_SUPPORT) || defined(INVARIANTS) || defined(KTR)
+#define	critical_enter()	_critical_enter(__FILE__, __LINE__)
+#define	critical_exit()		_critical_exit(__FILE__, __LINE__)
+#else
+#define	critical_enter()	_critical_enter_fast()
+#define	critical_exit()		_critical_exit_fast()
+#endif
+
 void	cpu_boot(int);
 void	cpu_flush_dcache(void *, size_t);
 void	cpu_rootconf(void);
-void	critical_enter(void);
-void	critical_exit(void);
 void	init_param1(void);
 void	init_param2(long physpages);
 void	init_static_kenv(char *, size_t);
Index: sys/kern/kern_switch.c
===================================================================
--- sys/kern/kern_switch.c	(revisione 240513)
+++ sys/kern/kern_switch.c	(copia locale)
@@ -178,47 +178,56 @@ retry:
  * regions of code in which preemptions are not allowed.
  */
 void
-critical_enter(void)
+_critical_enter(const char *file, int line)
 {
 	struct thread *td;
 
 	td = curthread;
 	td->td_critnest++;
-	CTR4(KTR_CRITICAL, "critical_enter by thread %p (%ld, %s) to %d", td,
-	    (long)td->td_proc->p_pid, td->td_name, td->td_critnest);
+	CTR6(KTR_CRITICAL, "critical_enter: thread %p (%ld, %s) to %d @ %s:%d",
+	    td, (long)td->td_proc->p_pid, td->td_name, td->td_critnest, file,
+	    line);
 }
 
 void
-critical_exit(void)
+_critical_exit(const char *file, int line)
 {
 	struct thread *td;
-	int flags;
 
 	td = curthread;
 	KASSERT(td->td_critnest != 0,
 	    ("critical_exit: td_critnest == 0"));
 
-	if (td->td_critnest == 1) {
-		td->td_critnest = 0;
-		if (td->td_owepreempt && !kdb_active) {
-			td->td_critnest = 1;
-			thread_lock(td);
-			td->td_critnest--;
-			flags = SW_INVOL | SW_PREEMPT;
-			if (TD_IS_IDLETHREAD(td))
-				flags |= SWT_IDLE;
-			else
-				flags |= SWT_OWEPREEMPT;
-			mi_switch(flags, NULL);
-			thread_unlock(td);
-		}
-	} else
+	if (td->td_critnest != 1)
 		td->td_critnest--;
+	else 
+		_critical_exit_hard(td);
 
-	CTR4(KTR_CRITICAL, "critical_exit by thread %p (%ld, %s) to %d", td,
-	    (long)td->td_proc->p_pid, td->td_name, td->td_critnest);
+	CTR6(KTR_CRITICAL, "critical_exit: thread %p (%ld, %s) to %d @ %s:%d",
+	    td, (long)td->td_proc->p_pid, td->td_name, td->td_critnest,
+	    file, line);
 }
 
+void
+_critical_exit_hard(struct thread *td)
+{
+	int flags;
+
+	td->td_critnest = 0;
+	if (td->td_owepreempt && !kdb_active) {
+		td->td_critnest = 1;
+		thread_lock(td);
+		td->td_critnest--;
+		flags = SW_INVOL | SW_PREEMPT;
+		if (TD_IS_IDLETHREAD(td))
+			flags |= SWT_IDLE;
+		else
+			flags |= SWT_OWEPREEMPT;
+		mi_switch(flags, NULL);
+		thread_unlock(td);
+	}
+}
+
 /************************************************************************
  * SYSTEM RUN QUEUE manipulations and tests				*
  ************************************************************************/
Index: sys/kern/subr_smp.c
===================================================================
--- sys/kern/subr_smp.c	(revisione 240513)
+++ sys/kern/subr_smp.c	(copia locale)
@@ -368,7 +368,7 @@ smp_rendezvous_action(void)
 	 * during this routine.
 	 */
 	td = curthread;
-	td->td_critnest++;
+	critical_enter();
 #ifdef INVARIANTS
 	owepreempt = td->td_owepreempt;
 #endif
Index: sys/kern/kern_rmlock.c
===================================================================
--- sys/kern/kern_rmlock.c	(revisione 240513)
+++ sys/kern/kern_rmlock.c	(copia locale)
@@ -351,10 +351,8 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker
 	tracker->rmp_thread = td;
 	tracker->rmp_rmlock = rm;
 
-	td->td_critnest++;	/* critical_enter(); */
+	critical_enter();
 
-	compiler_memory_barrier();
-
 	pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
 
 	rm_tracker_add(pc, tracker);
@@ -419,7 +417,7 @@ _rm_runlock(struct rmlock *rm, struct rm_priotrack
 	if (SCHEDULER_STOPPED())
 		return;
 
-	td->td_critnest++;	/* critical_enter(); */
+	critical_enter();
 	pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
 	rm_tracker_remove(pc, tracker);
 	td->td_critnest--;