--- old/src/java.base/share/classes/java/io/RandomAccessFile.java	2016-08-25 17:51:52.967564689 -0700
+++ new/src/java.base/share/classes/java/io/RandomAccessFile.java	2016-08-25 17:51:52.863564688 -0700
@@ -64,6 +64,8 @@
     private FileDescriptor fd;
     private volatile FileChannel channel;
     private boolean rw;
+    private boolean direct = false;
+    private int pageSize = -1;
 
     /**
      * The path of the referenced file
@@ -78,6 +80,7 @@
     private static final int O_SYNC =   4;
     private static final int O_DSYNC =  8;
     private static final int O_TEMPORARY =  16;
+    private static final int O_DIRECT = 32;
 
     /**
      * Creates a random access file stream to read from, and optionally
@@ -216,6 +219,11 @@
         int imode = -1;
         if (mode.equals("r"))
             imode = O_RDONLY;
+        else if (mode.equals("ro")) {
+            imode = O_RDONLY | O_DIRECT;
+            direct = true;
+            getPageSize();
+        }
         else if (mode.startsWith("rw")) {
             imode = O_RDWR;
             rw = true;
@@ -224,6 +232,11 @@
                     imode |= O_SYNC;
                 else if (mode.equals("rwd"))
                     imode |= O_DSYNC;
+                else if (mode.equals("rwo")) {
+                    imode |= O_DIRECT;
+                    direct = true;
+                    getPageSize();
+                }
                 else
                     imode = -1;
             }
@@ -233,8 +246,8 @@
         if (imode < 0)
             throw new IllegalArgumentException("Illegal mode \"" + mode
                                                + "\" must be one of "
-                                               + "\"r\", \"rw\", \"rws\","
-                                               + " or \"rwd\"");
+                                               + "\"r\", \"ro\", \"rw\", \"rws\", \"rwd\""
+                                               + " or \"rwo\"");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkRead(name);
@@ -338,6 +351,15 @@
         open0(name, mode);
     }
 
+    private native int getPageSize0();
+
+    private int getPageSize() {
+        if (pageSize == -1) {
+            pageSize = getPageSize0();
+        }
+        return this.pageSize;
+    }
+
     // 'Read' primitives
 
     /**
@@ -371,6 +393,15 @@
     private native int readBytes(byte b[], int off, int len) throws IOException;
 
     /**
+     * Reads a sub array as a sequence of bytes with DirectIO.
+     * @param b the buffer into which the data is read.
+     * @param off the start offset of the data.
+     * @param len the number of bytes to read.
+     * @exception IOException If an I/O error has occurred.
+     */
+    private native int readBytesD(byte b[], int off, int len) throws IOException;
+
+    /**
      * Reads up to {@code len} bytes of data from this file into an
      * array of bytes. This method blocks until at least one byte of input
      * is available.
@@ -396,6 +427,9 @@
      * {@code b.length - off}
      */
     public int read(byte b[], int off, int len) throws IOException {
+        if (direct) {
+            return readBytesD(b, off, len);
+        }
         return readBytes(b, off, len);
     }
 
@@ -419,6 +453,9 @@
      * @exception  NullPointerException If {@code b} is {@code null}.
      */
     public int read(byte b[]) throws IOException {
+        if (direct) {
+            return readBytesD(b, 0, b.length);
+        }
         return readBytes(b, 0, b.length);
     }
 
@@ -529,6 +566,15 @@
     private native void writeBytes(byte b[], int off, int len) throws IOException;
 
     /**
+     * Writes a sub array as a sequence of bytes with DirectIO.
+     * @param b the data to be written
+     * @param off the start offset in the data
+     * @param len the number of bytes that are written
+     * @exception IOException If an I/O error has occurred.
+     */
+    private native void writeBytesD(byte b[], int off, int len) throws IOException;
+
+    /**
      * Writes {@code b.length} bytes from the specified byte array
      * to this file, starting at the current file pointer.
      *
@@ -536,7 +582,16 @@
      * @exception  IOException  if an I/O error occurs.
      */
     public void write(byte b[]) throws IOException {
-        writeBytes(b, 0, b.length);
+        if (direct) {
+            if((b.length % pageSize != 0) && (getCurrentLocation() % pageSize != 0)) {
+                throw new IOException("In DirectIO mode, the IO size and start point "
+                                      + "must be aligned with kernel page size " + pageSize + " bytes!"); 
+            } else {
+                writeBytesD(b, 0, b.length);
+            }
+        } else {
+            writeBytes(b, 0, b.length);
+        }
     }
 
     /**
@@ -549,7 +604,16 @@
      * @exception  IOException  if an I/O error occurs.
      */
     public void write(byte b[], int off, int len) throws IOException {
-        writeBytes(b, off, len);
+        if (direct) {
+            if ((len % pageSize != 0) || (getCurrentLocation() % pageSize != 0)) {
+                throw new IOException("In DirectIO mode, the IO size and start point "
+                                      + "must be aligned with kernel page size " + pageSize + " bytes!");
+            } else {
+                writeBytesD(b, off, len);
+            }
+        } else {
+            writeBytes(b, off, len);
+        }
     }
 
     // 'Random access' stuff
@@ -587,6 +651,12 @@
 
     private native void seek0(long pos) throws IOException;
 
+    private long getCurrentLocation() throws IOException {
+        return getCurrentLocation0();
+    }
+
+    private native long getCurrentLocation0() throws IOException;
+
     /**
      * Returns the length of this file.
      *