9936 atomic ops in syscall_mstate() induce significant overhead
9942 zone secflags are not initialized correctly

@@ -371,10 +371,23 @@
 
 #if !defined(ARRAY_SIZE)
 #define ARRAY_SIZE(x)   (sizeof (x) / sizeof (x[0]))
 #endif
 
+/*
+ * Add a value to a uint64_t that saturates at UINT64_MAX instead of wrapping
+ * around.
+ */
+#define UINT64_OVERFLOW_ADD(val, add) \
+        ((val) > ((val) + (add)) ? (UINT64_MAX) : ((val) + (add)))
+
+/*
+ * Convert to an int64, saturating at INT64_MAX.
+ */
+#define UINT64_OVERFLOW_TO_INT64(uval) \
+        (((uval) > INT64_MAX) ? INT64_MAX : (int64_t)(uval))
+
 #ifdef  __cplusplus
 }
 #endif
 
 #endif  /* _SYS_SYSMACROS_H */