Backport 8c6d12250b524c0f4ee25dbbc6fe959581b7617b

Author: rgithubli

test/jdk/java/nio/channels/FileChannel/directio/DirectIOTest.java

@@ -27,11 +27,13 @@
  * @summary Test for ExtendedOpenOption.DIRECT flag
  * @requires (os.family == "linux" | os.family == "aix")
  * @library /test/lib
+ * @modules java.base/sun.nio.ch:+open java.base/java.io:+open
  * @build jdk.test.lib.Platform
  * @run main/native DirectIOTest
  */
 
 import java.io.*;
+import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.channels.*;
@@ -47,10 +49,25 @@
 public class DirectIOTest {
 
     private static final int BASE_SIZE = 4096;
+    private static final int TRIES = 3;
+
+    public static int getFD(FileChannel channel) throws Exception {
+        Field fFdFd = channel.getClass().getDeclaredField("fd");
+        fFdFd.setAccessible(true);
+        FileDescriptor fd = (FileDescriptor) fFdFd.get(channel);
+
+        Field fFd = FileDescriptor.class.getDeclaredField("fd");
+        fFd.setAccessible(true);
+        return fFd.getInt(fd);
+    }
+
+    private static void testWrite(Path p, long blockSize) throws Exception {
+        try (FileChannel fc = FileChannel.open(p,
+                StandardOpenOption.READ,
+                StandardOpenOption.WRITE,
+                ExtendedOpenOption.DIRECT)) {
+            int fd = getFD(fc);
 
-    private static int testWrite(Path p, long blockSize) throws Exception {
-        try (FileChannel fc = FileChannel.open(p, StandardOpenOption.WRITE,
-             ExtendedOpenOption.DIRECT)) {
             int bs = (int)blockSize;
             int size = Math.max(BASE_SIZE, bs);
             int alignment = bs;
@@ -60,22 +77,55 @@ private static int testWrite(Path p, long blockSize) throws Exception {
             for (int j = 0; j < size; j++) {
                 src.put((byte)0);
             }
-            src.flip();
-            fc.write(src);
-            return size;
+
+            // If there is AV or other FS tracing software, it may cache the file
+            // contents on first access, even though we have asked for DIRECT here.
+            // Do several attempts to make test more resilient.
+
+            for (int t = 0; t < TRIES; t++) {
+                flushFileCache(size, fd);
+                src.flip();
+                fc.position(0);
+                fc.write(src);
+                if (!isFileInCache(size, fd)) {
+                    return;
+                }
+            }
+
+            throw new RuntimeException("DirectIO is not working properly with " +
+                                       "write. File still exists in cache!");
         }
     }
 
-    private static int testRead(Path p, long blockSize) throws Exception {
-        try (FileChannel fc = FileChannel.open(p, ExtendedOpenOption.DIRECT)) {
+    private static void testRead(Path p, long blockSize) throws Exception {
+        try (FileChannel fc = FileChannel.open(p,
+                StandardOpenOption.READ,
+                ExtendedOpenOption.DIRECT)) {
+            int fd = getFD(fc);
+
             int bs = (int)blockSize;
             int size = Math.max(BASE_SIZE, bs);
             int alignment = bs;
             ByteBuffer dest = ByteBuffer.allocateDirect(size + alignment - 1)
                                         .alignedSlice(alignment);
             assert dest.capacity() != 0;
-            fc.read(dest);
-            return size;
+
+            // If there is AV or other FS tracing software, it may cache the file
+            // contents on first access, even though we have asked for DIRECT here.
+            // Do several attempts to make test more resilient.
+
+            for (int t = 0; t < TRIES; t++) {
+                flushFileCache(size, fd);
+                dest.clear();
+                fc.position(0);
+                fc.read(dest);
+                if (!isFileInCache(size, fd)) {
+                    return;
+                }
+            }
+
+            throw new RuntimeException("DirectIO is not working properly with " +
+                                       "read. File still exists in cache!");
         }
     }
 
@@ -84,12 +134,8 @@ public static Path createTempFile() throws IOException {
             Paths.get(System.getProperty("test.dir", ".")), "test", null);
     }
 
-    private static boolean isFileInCache(int size, Path p) {
-        String path = p.toString();
-        return isFileInCache0(size, path);
-    }
-
-    private static native boolean isFileInCache0(int size, String path);
+    private static native boolean flushFileCache(int size, int fd);
+    private static native boolean isFileInCache(int size, int fd);
 
     public static void main(String[] args) throws Exception {
         Path p = createTempFile();
@@ -98,16 +144,8 @@ public static void main(String[] args) throws Exception {
         System.loadLibrary("DirectIO");
 
         try {
-            int size = testWrite(p, blockSize);
-            if (isFileInCache(size, p)) {
-                throw new RuntimeException("DirectIO is not working properly with "
-                    + "write. File still exists in cache!");
-            }
-            size = testRead(p, blockSize);
-            if (isFileInCache(size, p)) {
-                throw new RuntimeException("DirectIO is not working properly with "
-                    + "read. File still exists in cache!");
-            }
+            testWrite(p, blockSize);
+            testRead(p, blockSize);
         } finally {
             Files.delete(p);
         }

test/jdk/java/nio/channels/FileChannel/directio/libDirectIO.c

@@ -45,13 +45,27 @@ static void ThrowException(JNIEnv *env, const char *name, const char *msg) {
 
 /*
  * Class:     DirectIO
- * Method:    isFileInCache0
- * Signature: (ILjava/lang/String;)Z
+ * Method:    flushFileCache
+ * Signature: (II;)V
  */
-JNIEXPORT jboolean Java_DirectIOTest_isFileInCache0(JNIEnv *env,
+JNIEXPORT void Java_DirectIOTest_flushFileCache(JNIEnv *env,
                                                 jclass cls,
                                                 jint file_size,
-                                                jstring file_path) {
+                                                jint fd) {
+#ifdef __linux__
+    posix_fadvise(fd, 0, file_size, POSIX_FADV_DONTNEED);
+#endif
+}
+
+/*
+ * Class:     DirectIO
+ * Method:    isFileInCache
+ * Signature: (II;)Z
+ */
+JNIEXPORT jboolean Java_DirectIOTest_isFileInCache(JNIEnv *env,
+                                                jclass cls,
+                                                jint file_size,
+                                                jint fd) {
     void *f_mmap;
 #ifdef __linux__
     unsigned char *f_seg;
@@ -69,17 +83,10 @@ JNIEXPORT jboolean Java_DirectIOTest_isFileInCache0(JNIEnv *env,
     size_t index = (file_size + page_size - 1) /page_size;
     jboolean result = JNI_FALSE;
 
-    const char* path = (*env)->GetStringUTFChars(env, file_path, JNI_FALSE);
-
-    int fd = open(path, O_RDWR);
-
-    (*env)->ReleaseStringUTFChars(env, file_path, path);
-
     f_mmap = mmap(0, file_size, PROT_NONE, MAP_SHARED, fd, 0);
     if (f_mmap == MAP_FAILED) {
-        close(fd);
         ThrowException(env, "java/io/IOException",
-            "test of whether file exists in cache failed");
+            "test of whether file exists in cache failed: mmap failed");
     }
     f_seg = malloc(index);
     if (f_seg != NULL) {
@@ -95,9 +102,8 @@ JNIEXPORT jboolean Java_DirectIOTest_isFileInCache0(JNIEnv *env,
         free(f_seg);
     } else {
         ThrowException(env, "java/io/IOException",
-            "test of whether file exists in cache failed");
+            "test of whether file exists in cache failed: malloc failed");
     }
-    close(fd);
     munmap(f_mmap, file_size);
     return result;
 }