--- a/sqlite3.c
+++ b/sqlite3.c
@@ -40656,8 +40656,12 @@
 #if HAVE_MREMAP
     pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE);
     zErr = "mremap";
+#else
+#if defined(MAP_POPULATE)
+    pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED | MAP_POPULATE, h, nReuse);
 #else
     pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse);
+#endif
     if( pNew!=MAP_FAILED ){
       if( pNew!=pReq ){
         osMunmap(pNew, nNew - nReuse);
@@ -40676,7 +40676,11 @@
 
   /* If pNew is still NULL, try to create an entirely new mapping. */
   if( pNew==0 ){
+#if defined(MAP_POPULATE)
+    pNew = osMmap(0, nNew, flags, MAP_SHARED | MAP_POPULATE, h, 0);
+#else
     pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0);
+#endif
   }
 
   if( pNew==MAP_FAILED ){