Index: sys/vm/vm_radix.c
===================================================================
--- sys/vm/vm_radix.c	(revision 252252)
+++ sys/vm/vm_radix.c	(working copy)
@@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
+#include <sys/ktr.h>
 #include <sys/vmmeter.h>
 
 #include <vm/uma.h>
@@ -365,6 +366,9 @@ vm_radix_insert(struct vm_radix *rtree, vm_page_t
 
 	index = page->pindex;
 
+	CTR3(KTR_DEBUG, "%s: rtree %p, insert page %p", __func__, rtree,
+	    page);
+
 	/*
 	 * The owner of record for root is not really important because it
 	 * will never be used.
@@ -677,6 +681,9 @@ vm_radix_remove(struct vm_radix *rtree, vm_pindex_
 	vm_page_t m;
 	int i, slot;
 
+	CTR3(KTR_DEBUG, "%s: rtree %p, index %ld", __func__, rtree,
+	    index);
+
 	rnode = vm_radix_getroot(rtree);
 	if (vm_radix_isleaf(rnode)) {
 		m = vm_radix_topage(rnode);
Index: sys/sys/ktr.h
===================================================================
--- sys/sys/ktr.h	(revision 252252)
+++ sys/sys/ktr.h	(working copy)
@@ -75,6 +75,7 @@
 #define	KTR_INET6	0x10000000		/* IPv6 stack */
 #define	KTR_SCHED	0x20000000		/* Machine parsed sched info. */
 #define	KTR_BUF		0x40000000		/* Buffer cache */
+#define	KTR_DEBUG	0x80000000
 #define	KTR_ALL		0x7fffffff
 
 /* Trace classes to compile in */