--- a/src/hotspot/os/windows/os_windows.cpp	Thu May 03 14:10:08 2018 +0200
+++ b/src/hotspot/os/windows/os_windows.cpp	Thu May 03 08:07:20 2018 -0400
@@ -365,6 +365,39 @@
   return sz;
 }
 
+bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
+  MEMORY_BASIC_INFORMATION minfo;
+  committed_start = NULL;
+  committed_size = 0;
+  address top = start + size;
+  const address start_addr = start;
+  while (start < top) {
+    VirtualQuery(start, &minfo, sizeof(minfo));
+    if ((minfo.State & MEM_COMMIT) == 0) {  // not committed
+      if (committed_start != NULL) {
+        break;
+      }
+    } else {  // committed
+      if (committed_start == NULL) {
+        committed_start = start;
+      }
+      size_t offset = start - (address)minfo.BaseAddress;
+      committed_size += minfo.RegionSize - offset;
+    }
+    start = (address)minfo.BaseAddress + minfo.RegionSize;
+  }
+
+  if (committed_start == NULL) {
+    assert(committed_size == 0, "Sanity");
+    return false;
+  } else {
+    assert(committed_start >= start_addr && committed_start < top, "Out of range");
+    // current region may go beyond the limit, trim to the limit
+    committed_size = MIN2(committed_size, size_t(top - committed_start));
+    return true;
+  }
+}
+
 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
   const struct tm* time_struct_ptr = localtime(clock);
   if (time_struct_ptr != NULL) {