Index: sys/amd64/vmm/intel/ept.c
===================================================================
--- sys/amd64/vmm/intel/ept.c	(revision 331013)
+++ sys/amd64/vmm/intel/ept.c	(working copy)
@@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
+#include <sys/proc.h>
 #include <sys/types.h>
 #include <sys/systm.h>
 #include <sys/smp.h>
Index: sys/amd64/vmm/intel/vmcs.c
===================================================================
--- sys/amd64/vmm/intel/vmcs.c	(revision 331013)
+++ sys/amd64/vmm/intel/vmcs.c	(working copy)
@@ -34,6 +34,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/proc.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
 #include <sys/pcpu.h>
Index: sys/amd64/vmm/intel/vmx_genassym.c
===================================================================
--- sys/amd64/vmm/intel/vmx_genassym.c	(revision 331013)
+++ sys/amd64/vmm/intel/vmx_genassym.c	(working copy)
@@ -32,6 +32,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/proc.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/assym.h>
Index: sys/dev/cxgbe/t4_mp_ring.c
===================================================================
--- sys/dev/cxgbe/t4_mp_ring.c	(revision 331013)
+++ sys/dev/cxgbe/t4_mp_ring.c	(working copy)
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/counter.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
+#include <sys/proc.h>
 #include <machine/cpu.h>
 
 #include "t4_mp_ring.h"
Index: sys/dev/hyperv/vmbus/vmbus.c
===================================================================
--- sys/dev/hyperv/vmbus/vmbus.c	(revision 331013)
+++ sys/dev/hyperv/vmbus/vmbus.c	(working copy)
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/mutex.h>
+#include <sys/proc.h>
 #include <sys/smp.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
Index: sys/dev/ow/owc_gpiobus.c
===================================================================
--- sys/dev/ow/owc_gpiobus.c	(revision 331013)
+++ sys/dev/ow/owc_gpiobus.c	(working copy)
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/mutex.h>
+#include <sys/proc.h>
 
 #ifdef FDT
 #include <dev/fdt/fdt_common.h>
Index: sys/kern/kern_switch.c
===================================================================
--- sys/kern/kern_switch.c	(revision 331013)
+++ sys/kern/kern_switch.c	(working copy)
@@ -188,71 +188,29 @@ choosethread(void)
 	return (td);
 }
 
-/*
- * Kernel thread preemption implementation.  Critical sections mark
- * regions of code in which preemptions are not allowed.
- *
- * It might seem a good idea to inline critical_enter() but, in order
- * to prevent instructions reordering by the compiler, a __compiler_membar()
- * would have to be used here (the same as sched_pin()).  The performance
- * penalty imposed by the membar could, then, produce slower code than
- * the function call itself, for most cases.
- */
 void
-critical_enter(void)
+critical_exit_owepreempt(struct thread *td)
 {
-	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);
-}
-
-void
-critical_exit(void)
-{
-	struct thread *td;
 	int flags;
 
-	td = curthread;
-	KASSERT(td->td_critnest != 0,
-	    ("critical_exit: td_critnest == 0"));
+	if (kdb_active)
+		return;
 
-	if (td->td_critnest == 1) {
-		td->td_critnest = 0;
-
-		/*
-		 * Interrupt handlers execute critical_exit() on
-		 * leave, and td_owepreempt may be left set by an
-		 * interrupt handler only when td_critnest > 0.  If we
-		 * are decrementing td_critnest from 1 to 0, read
-		 * td_owepreempt after decrementing, to not miss the
-		 * preempt.  Disallow compiler to reorder operations.
-		 */
-		__compiler_membar();
-		if (td->td_owepreempt && !kdb_active) {
-			/*
-			 * Microoptimization: we committed to switch,
-			 * disable preemption in interrupt handlers
-			 * while spinning for the thread lock.
-			 */
-			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
-		td->td_critnest--;
-
-	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);
+	/*
+	 * Microoptimization: we committed to switch,
+	 * disable preemption in interrupt handlers
+	 * while spinning for the thread lock.
+	 */
+	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);
 }
 
 /************************************************************************
Index: sys/net/if_var.h
===================================================================
--- sys/net/if_var.h	(revision 331013)
+++ sys/net/if_var.h	(working copy)
@@ -73,6 +73,7 @@ struct	netmap_adapter;
 
 #ifdef _KERNEL
 #include <sys/mbuf.h>		/* ifqueue only? */
+#include <sys/proc.h>
 #include <sys/buf_ring.h>
 #include <net/vnet.h>
 #endif /* _KERNEL */
Index: sys/net/mp_ring.c
===================================================================
--- sys/net/mp_ring.c	(revision 331013)
+++ sys/net/mp_ring.c	(working copy)
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/malloc.h>
+#include <sys/proc.h>
 #include <machine/cpu.h>
 
 #if defined(__powerpc__) || defined(__mips__)
Index: sys/sys/buf_ring.h
===================================================================
--- sys/sys/buf_ring.h	(revision 331013)
+++ sys/sys/buf_ring.h	(working copy)
@@ -33,6 +33,7 @@
 #define	_SYS_BUF_RING_H_
 
 #include <machine/cpu.h>
+#include <sys/proc.h>
 
 #if defined(INVARIANTS) && !defined(DEBUG_BUFRING)
 #define DEBUG_BUFRING 1
Index: sys/sys/proc.h
===================================================================
--- sys/sys/proc.h	(revision 331013)
+++ sys/sys/proc.h	(working copy)
@@ -48,6 +48,7 @@
 #endif
 #include <sys/queue.h>
 #include <sys/_lock.h>
+#include <sys/ktr.h>
 #include <sys/lock_profile.h>
 #include <sys/_mutex.h>
 #include <sys/osd.h>
@@ -1107,7 +1108,6 @@ void	thread_unlink(struct thread *td);
 void	thread_unsuspend(struct proc *p);
 void	thread_wait(struct proc *p);
 struct thread	*thread_find(struct proc *p, lwpid_t tid);
-
 void	stop_all_proc(void);
 void	resume_all_proc(void);
 
@@ -1146,6 +1146,64 @@ td_softdep_cleanup(struct thread *td)
 		softdep_ast_cleanup(td);
 }
 
+/*
+ * Kernel thread preemption implementation.  Critical sections mark
+ * regions of code in which preemptions are not allowed.
+ */
+
+void	critical_exit_owepreempt(struct thread *td);
+
+static __inline void
+critical_enter(void)
+{
+	struct thread *td;
+
+	td = curthread;
+	td->td_critnest++;
+	__compiler_membar();
+
+	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);
+}
+
+static __inline void
+critical_exit(void)
+{
+	struct thread *td;
+
+	td = curthread;
+	KASSERT(td->td_critnest != 0,
+	    ("critical_exit: td_critnest == 0"));
+
+	if (td->td_critnest == 1) {
+		td->td_critnest = 0;
+
+		/*
+		 * Interrupt handlers execute critical_exit() on
+		 * leave, and td_owepreempt may be left set by an
+		 * interrupt handler only when td_critnest > 0.  If we
+		 * are decrementing td_critnest from 1 to 0, read
+		 * td_owepreempt after decrementing, to not miss the
+		 * preempt.  Disallow compiler to reorder operations.
+		 */
+		__compiler_membar();
+#if 1
+		if (td->td_owepreempt)
+			critical_exit_owepreempt(td);
+#endif
+	} else
+		td->td_critnest--;
+
+	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);
+}
+
+/*
+ * Assert that a thread is in critical(9) section.
+ */
+#define	CRITICAL_ASSERT(td)						\
+	KASSERT((td)->td_critnest >= 1, ("Not in critical section"));
+ 
 #endif	/* _KERNEL */
 
 #endif	/* !_SYS_PROC_H_ */
Index: sys/sys/systm.h
===================================================================
--- sys/sys/systm.h	(revision 331013)
+++ sys/sys/systm.h	(working copy)
@@ -119,12 +119,6 @@ void	kassert_panic(const char *fmt, ...)  __printf
 	    ((uintptr_t)&(var) & (sizeof(void *) - 1)) == 0, msg)
 
 /*
- * Assert that a thread is in critical(9) section.
- */
-#define	CRITICAL_ASSERT(td)						\
-	KASSERT((td)->td_critnest >= 1, ("Not in critical section"));
- 
-/*
  * If we have already panic'd and this is the thread that called
  * panic(), then don't block on any mutexes but silently succeed.
  * Otherwise, the kernel will deadlock since the scheduler isn't
@@ -214,8 +208,6 @@ void	vpanic(const char *, __va_list) __dead2 __pri
 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/x86/x86/x86_mem.c
===================================================================
--- sys/x86/x86/x86_mem.c	(revision 331013)
+++ sys/x86/x86/x86_mem.c	(working copy)
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/memrange.h>
+#include <sys/proc.h>
 #include <sys/smp.h>
 #include <sys/sysctl.h>
 
Index: sys/x86/xen/xen_intr.c
===================================================================
--- sys/x86/xen/xen_intr.c	(revision 331013)
+++ sys/x86/xen/xen_intr.c	(working copy)
@@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mutex.h>
 #include <sys/interrupt.h>
 #include <sys/pcpu.h>
+#include <sys/proc.h>
 #include <sys/smp.h>
 #include <sys/refcount.h>