HADOOP-10808. Remove unused native code for munlock. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1609509 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -391,6 +391,8 @@ Release 2.6.0 - UNRELEASED
 
   IMPROVEMENTS
 
+    HADOOP-10808. Remove unused native code for munlock. (cnauroth)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/NativeIO.java

@@ -292,8 +292,6 @@ public class NativeIO {
 
     static native void mlock_native(
         ByteBuffer buffer, long len) throws NativeIOException;
-    static native void munlock_native(
-        ByteBuffer buffer, long len) throws NativeIOException;
 
     /**
      * Locks the provided direct ByteBuffer into memory, preventing it from
@@ -312,23 +310,6 @@ public class NativeIO {
       }
       mlock_native(buffer, len);
     }
-
-    /**
-     * Unlocks a locked direct ByteBuffer, allowing it to swap out of memory.
-     * This is a no-op if the ByteBuffer was not previously locked.
-     * 
-     * See the munlock(2) man page for more information.
-     * 
-     * @throws NativeIOException
-     */
-    public static void munlock(ByteBuffer buffer, long len)
-        throws IOException {
-      assertCodeLoaded();
-      if (!buffer.isDirect()) {
-        throw new IOException("Cannot munlock a non-direct ByteBuffer");
-      }
-      munlock_native(buffer, len);
-    }
     
     /**
      * Unmaps the block from memory. See munmap(2).

hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/io/nativeio/NativeIO.c

@@ -404,34 +404,6 @@ Java_org_apache_hadoop_io_nativeio_NativeIO_00024POSIX_mlock_1native(
 #endif
 }
 
-/**
- * public static native void munlock_native(
- *   ByteBuffer buffer, long offset);
- *
- * The "00024" in the function name is an artifact of how JNI encodes
- * special characters. U+0024 is '$'.
- */
-JNIEXPORT void JNICALL
-Java_org_apache_hadoop_io_nativeio_NativeIO_00024POSIX_munlock_1native(
-  JNIEnv *env, jclass clazz,
-  jobject buffer, jlong len)
-{
-#ifdef UNIX
-  void* buf = (void*)(*env)->GetDirectBufferAddress(env, buffer);
-  PASS_EXCEPTIONS(env);
-
-  if (munlock(buf, len)) {
-    CHECK_DIRECT_BUFFER_ADDRESS(buf);
-    throw_ioe(env, errno);
-  }
-#endif
-
-#ifdef WINDOWS
-  THROW(env, "java/io/IOException",
-    "The function POSIX.munlock_native() is not supported on Windows");
-#endif
-}
-
 #ifdef __FreeBSD__
 static int toFreeBSDFlags(int flags)
 {

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/nativeio/TestNativeIO.java

@@ -607,8 +607,8 @@ public class TestNativeIO {
         sum += mapbuf.get(i);
       }
       assertEquals("Expected sums to be equal", bufSum, sum);
-      // munlock the buffer
-      NativeIO.POSIX.munlock(mapbuf, fileSize);
+      // munmap the buffer, which also implicitly unlocks it
+      NativeIO.POSIX.munmap(mapbuf);
     } finally {
       if (channel != null) {
         channel.close();