-#define VM_BEHAVIOR_DEFAULT ((vm_behavior_t) 0) /* default */
-#define VM_BEHAVIOR_RANDOM ((vm_behavior_t) 1) /* random */
-#define VM_BEHAVIOR_SEQUENTIAL ((vm_behavior_t) 2) /* forward sequential */
-#define VM_BEHAVIOR_RSEQNTL ((vm_behavior_t) 3) /* reverse sequential */
-#define VM_BEHAVIOR_WILLNEED ((vm_behavior_t) 4) /* will need in near future */
-#define VM_BEHAVIOR_DONTNEED ((vm_behavior_t) 5) /* dont need in near future */
+/*
+ * The following behaviors affect the memory region's future behavior
+ * and are stored in the VM map entry data structure.
+ */
+#define VM_BEHAVIOR_DEFAULT ((vm_behavior_t) 0) /* default */
+#define VM_BEHAVIOR_RANDOM ((vm_behavior_t) 1) /* random */
+#define VM_BEHAVIOR_SEQUENTIAL ((vm_behavior_t) 2) /* forward sequential */
+#define VM_BEHAVIOR_RSEQNTL ((vm_behavior_t) 3) /* reverse sequential */
+
+/*
+ * The following "behaviors" affect the memory region only at the time of the
+ * call and are not stored in the VM map entry.
+ */
+#define VM_BEHAVIOR_WILLNEED ((vm_behavior_t) 4) /* will need in near future */
+#define VM_BEHAVIOR_DONTNEED ((vm_behavior_t) 5) /* dont need in near future */
+#define VM_BEHAVIOR_FREE ((vm_behavior_t) 6) /* free memory without write-back */
+#define VM_BEHAVIOR_ZERO_WIRED_PAGES ((vm_behavior_t) 7) /* zero out the wired pages of an entry if it is being deleted without unwiring them first */
+#define VM_BEHAVIOR_REUSABLE ((vm_behavior_t) 8)
+#define VM_BEHAVIOR_REUSE ((vm_behavior_t) 9)
+#define VM_BEHAVIOR_CAN_REUSE ((vm_behavior_t) 10)
+#define VM_BEHAVIOR_PAGEOUT ((vm_behavior_t) 11)