Index: sys/fs/tmpfs/tmpfs_vnops.c
===================================================================
--- sys/fs/tmpfs/tmpfs_vnops.c	(revisione 233702)
+++ sys/fs/tmpfs/tmpfs_vnops.c	(copia locale)
@@ -514,7 +514,7 @@ tmpfs_mappedread(vm_object_t vobj, vm_object_t tob
 		goto nocache;
 
 	VM_OBJECT_LOCK(vobj);
-	if (vobj->cached_page_count == 0) {
+	if (vobj->resident_page_count == 0 && vobj->cached_page_count == 0) {
 		VM_OBJECT_UNLOCK(vobj);
 		goto nocache;
 	}
@@ -647,7 +647,7 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t to
 	}
 
 	VM_OBJECT_LOCK(vobj);
-	if (vobj->cached_page_count == 0) {
+	if (vobj->resident_page_count == 0 && vobj->cached_page_count == 0) {
 		VM_OBJECT_UNLOCK(vobj);
 		vpg = NULL;
 		goto nocache;
@@ -669,6 +669,20 @@ lookupvpg:
 		VM_OBJECT_UNLOCK(vobj);
 		error = uiomove_fromphys(&vpg, offset, tlen, uio);
 	} else {
+		vpg = vm_radix_lookup(&vobj->rtree, idx, VM_RADIX_RED);
+		CTR4(KTR_FLO, "%s: lookup page %p, object %p idx %ju",
+		    __func__, p, p->object, (uintmax_t)idx);
+		if (vpg != NULL && (vpg->flags & PG_CACHED) != 0) {
+			CTR4(KTR_FLO, "%s: try rem page %p, object %p, idx %ju",
+			    __func__, p, p->object, (uintmax_t)idx);
+			mtx_lock(&vm_page_queue_free_mtx);
+			if (vpg->object == vobj) {
+				CTR3(KTR_FLO, "%s: page %p, object %p",
+				    __func__, p, p->object);
+				vm_page_cache_free(vpg);
+			}
+			mtx_unlock(&vm_page_queue_free_mtx);
+		}
 		VM_OBJECT_UNLOCK(vobj);
 		vpg = NULL;
 	}
Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c	(revisione 233702)
+++ sys/vm/vm_pageout.c	(copia locale)
@@ -926,6 +926,8 @@ rescan0:
 			 * Clean pages can be placed onto the cache queue.
 			 * This effectively frees them.
 			 */
+			CTR3(KTR_FLO, "%s: insert page %p, object %p",
+			    __func__, m, m->object);
 			vm_page_cache(m);
 			--page_shortage;
 		} else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) {
@@ -1212,9 +1214,12 @@ unlock_and_continue:
 				if (object->ref_count == 0) {
 					KASSERT(!pmap_page_is_mapped(m),
 				    ("vm_pageout_scan: page %p is mapped", m));
-					if (m->dirty == 0)
+					if (m->dirty == 0) {
+						CTR3(KTR_FLO,
+						    "%s: insert page %p, object %p",
+						    __func__, m, m->object);
 						vm_page_cache(m);
-					else
+					} else
 						vm_page_deactivate(m);
 				} else {
 					vm_page_deactivate(m);
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c	(revisione 233702)
+++ sys/vm/vm_object.c	(copia locale)
@@ -73,6 +73,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mman.h>
 #include <sys/mount.h>
 #include <sys/kernel.h>
+#include <sys/ktr.h>
 #include <sys/sysctl.h>
 #include <sys/mutex.h>
 #include <sys/proc.h>		/* for curproc, pageproc */
@@ -176,8 +177,8 @@ vm_object_zdtor(void *mem, int size, void *arg)
 	    object));
 #endif
 	KASSERT(object->cached_page_count == 0,
-	    ("object %p has cached pages",
-	    object));
+	    ("object %p has %d cached pages",
+	    object, object->cached_page_count));
 	KASSERT(object->paging_in_progress == 0,
 	    ("object %p paging_in_progress = %d",
 	    object, object->paging_in_progress));
@@ -1510,8 +1511,11 @@ restart:
 		 */
 		if (p->flags & PG_CACHED) {
 			mtx_lock(&vm_page_queue_free_mtx);
-			if (p->object == backing_object)
+			if (p->object == backing_object) {
+				CTR3(KTR_FLO, "%s: page %p, object %p",
+				    __func__, p, p->object);
 				vm_page_cache_free(p);
+			}
 			mtx_unlock(&vm_page_queue_free_mtx);
 			continue;
 		} else if (p->object != backing_object)
@@ -1932,6 +1936,8 @@ restart:
 			if (p->flags & PG_CACHED) {
 				mtx_lock(&vm_page_queue_free_mtx);
 				if (p->object == object) {
+					CTR3(KTR_FLO, "%s: page %p, object %p",
+					    __func__, p, p->object);
 					vm_page_cache_free(p);
 					if (object->type == OBJT_VNODE &&
 					    object->cached_page_count == 0)
Index: sys/vm/vm_fault.c
===================================================================
--- sys/vm/vm_fault.c	(revisione 233703)
+++ sys/vm/vm_fault.c	(copia locale)
@@ -79,6 +79,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
+#include <sys/ktr.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/proc.h>
@@ -503,8 +504,12 @@ readrest:
 					pmap_remove_all(mt);
 					if (mt->dirty != 0)
 						vm_page_deactivate(mt);
-					else
+					else {
+						CTR3(KTR_FLO,
+						    "%s: insert page %p, object %p",
+						    __func__, mt, mt->object);
 						vm_page_cache(mt);
+					}
 					vm_page_unlock(mt);
 				}
 				ahead += behind;
Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c	(revisione 233702)
+++ sys/vm/vm_page.c	(copia locale)
@@ -85,6 +85,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/lock.h>
 #include <sys/kernel.h>
+#include <sys/ktr.h>
 #include <sys/limits.h>
 #include <sys/malloc.h>
 #include <sys/msgbuf.h>
@@ -1077,6 +1078,7 @@ vm_page_cache_rename(vm_page_t m, vm_object_t new_
 	 * If the insert fails we simply free the cached page.
 	 */
 	if (vm_radix_insert(&new_object->rtree, idx, m) != 0) {
+		CTR3(KTR_FLO, "%s: page %p, object %p", __func__, m, m->object);
 		vm_page_cache_free(m);
 		return;
 	}
Index: sys/vm/vm_contig.c
===================================================================
--- sys/vm/vm_contig.c	(revisione 233702)
+++ sys/vm/vm_contig.c	(copia locale)
@@ -69,6 +69,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mutex.h>
 #include <sys/proc.h>
 #include <sys/kernel.h>
+#include <sys/ktr.h>
 #include <sys/sysctl.h>
 #include <sys/vmmeter.h>
 #include <sys/vnode.h>
@@ -144,6 +145,8 @@ vm_contig_launder_page(vm_page_t m, vm_page_t *nex
 			return (0);
 		}
 	} else {
+		CTR3(KTR_FLO, "%s: insert page %p, object %p",
+		    __func__, m, m->object);
 		vm_page_cache(m);
 		vm_page_unlock(m);
 	}
Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(revisione 233702)
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(copia locale)
@@ -71,6 +71,7 @@
 #include <sys/sf_buf.h>
 #include <sys/sched.h>
 #include <sys/acl.h>
+#include <sys/ktr.h>
 #include <vm/vm_pageout.h>
 
 /*
@@ -343,8 +344,12 @@ page_lookup(vnode_t *vp, int64_t start, int64_t of
 				if (obj->cached_page_count != 0 &&
 				    (pp->flags & PG_CACHED) != 0) {
 					mtx_lock(&vm_page_queue_free_mtx);
-					if (pp->object == obj)
+					if (pp->object == obj) {
+						CTR3(KTR_FLO,
+						    "%s: page %p, object %p",
+						    __func__, pp, pp->object);
 						vm_page_cache_free(pp);
+					}
 					mtx_unlock(&vm_page_queue_free_mtx);
 				}
 				pp = NULL;
Index: sys/sys/ktr.h
===================================================================
--- sys/sys/ktr.h	(revisione 233702)
+++ sys/sys/ktr.h	(copia locale)
@@ -75,7 +75,8 @@
 #define	KTR_INET6	0x10000000		/* IPv6 stack */
 #define	KTR_SCHED	0x20000000		/* Machine parsed sched info. */
 #define	KTR_BUF		0x40000000		/* Buffer cache */
-#define	KTR_ALL		0x7fffffff
+#define	KTR_FLO		0x80000000
+#define	KTR_ALL		0xffffffff
 
 /* Trace classes to compile in */
 #ifdef KTR