--- old/src/os/windows/vm/os_windows.cpp	2017-07-20 17:44:51.984854600 -0700
+++ new/src/os/windows/vm/os_windows.cpp	2017-07-20 17:44:51.570317400 -0700
@@ -3113,6 +3113,65 @@
   UseLargePages = success;
 }
 
+// Helper function to create a temp file in the given directory
+int os::create_file_for_heap(const char* dir, size_t size) {
+
+  const char name_template[] = "/jvmheap.XXXXXX";
+
+  char *fullname = (char*)_alloca(strlen(dir) + sizeof(name_template));
+  (void)strcpy(fullname, dir);
+  (void)strcat(fullname, name_template);
+  os::native_path(fullname);
+
+  char *path = _mktemp(fullname);
+  if (path == NULL) {
+    return -1;
+  }
+
+  int fd = _open(path, O_RDWR | O_CREAT | O_TEMPORARY | O_EXCL, S_IWRITE | S_IREAD);
+
+  if (fd < 0) {
+    warning("Failure to create file %s for heap", path);
+    return -1;
+  }
+
+  return fd;
+}
+
+// if 'base' is not NULL, function will return NULL if it cannot get 'base'
+//
+char* os::map_memory_to_dax_file(char* base, size_t size, int fd) {
+  assert(fd != -1, "File descriptor is not valid");
+
+  HANDLE fh = (HANDLE)_get_osfhandle(fd);
+  HANDLE fileMapping = CreateFileMapping(fh, NULL, PAGE_READWRITE,
+                                         (DWORD)(size >> 32), (DWORD)(size & 0xFFFFFFFF), NULL);
+  if (fileMapping == NULL) {
+    if (GetLastError() == ERROR_DISK_FULL) {
+      vm_exit_during_initialization(err_msg("Could not allocate sufficient disk space for heap"));
+    } else {
+      vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
+    }
+
+    return NULL;
+  }
+
+  LPVOID addr = MapViewOfFileEx(fileMapping, FILE_MAP_WRITE, 0, 0, size, base);
+
+  CloseHandle(fileMapping);
+
+  return (char*)addr;
+}
+
+char* os::replace_existing_mapping_with_dax_file_mapping(char* base, size_t size, int fd) {
+  assert(fd != -1, "File descriptor is not valid");
+  assert(base != NULL, "base cannot be NULL");
+
+  release_memory(base, size);
+  return map_memory_to_dax_file(base, size, fd);
+
+}
+
 // On win32, one cannot release just a part of reserved memory, it's an
 // all or nothing deal.  When we split a reservation, we must break the
 // reservation into two reservations.
@@ -3129,10 +3188,26 @@
   }
 }
 
+char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) {
+  char* result = NULL;
+  if (file_desc != -1) {
+    result = map_memory_to_dax_file(addr, bytes, file_desc);
+    if (result != NULL) {
+      MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
+    }
+  } else {
+    result = pd_attempt_reserve_memory_at(bytes, addr);
+    if (result != NULL) {
+      MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
+    }
+  }
+  return result;
+}
+
 // Multiple threads can race in this code but it's not possible to unmap small sections of
 // virtual space to get requested alignment, like posix-like os's.
 // Windows prevents multiple thread from remapping over each other so this loop is thread-safe.
-char* os::reserve_memory_aligned(size_t size, size_t alignment) {
+char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) {
   assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
          "Alignment must be a multiple of allocation granularity (page size)");
   assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
@@ -3143,16 +3218,21 @@
   char* aligned_base = NULL;
 
   do {
-    char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
+    char* extra_base = os::reserve_memory(extra_size, NULL, alignment, file_desc);
     if (extra_base == NULL) {
       return NULL;
     }
     // Do manual alignment
     aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);
 
-    os::release_memory(extra_base, extra_size);
+    if (file_desc != -1) {
+      os::unmap_memory(extra_base, extra_size);
+    }
+    else {
+      os::release_memory(extra_base, extra_size);
+    }
 
-    aligned_base = os::reserve_memory(size, aligned_base);
+    aligned_base = os::reserve_memory(size, aligned_base, 0, file_desc);
 
   } while (aligned_base == NULL);
 
@@ -3195,7 +3275,7 @@
 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
   // Windows os::reserve_memory() fails of the requested address range is
   // not avilable.
-  return reserve_memory(bytes, requested_addr);
+  return reserve_memory(bytes, requested_addr, 0);
 }
 
 size_t os::large_page_size() {
@@ -4908,7 +4988,6 @@
   return base;
 }
 
-
 // Remap a block of memory.
 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
                           char *addr, size_t bytes, bool read_only,