--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/OptimisticTypesPersistence.java Mon Sep 01 17:34:37 2014 +0400
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/OptimisticTypesPersistence.java Wed Sep 03 14:33:34 2014 +0200
@@ -31,9 +31,11 @@
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
+import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.file.Files;
+import java.nio.file.Path;
import java.security.AccessController;
import java.security.MessageDigest;
import java.security.PrivilegedAction;
@@ -41,6 +43,14 @@
import java.util.Base64;
import java.util.Date;
import java.util.Map;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Function;
+import java.util.function.IntFunction;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
import jdk.nashorn.internal.codegen.types.Type;
import jdk.nashorn.internal.runtime.Context;
import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData;
@@ -49,30 +59,66 @@
import jdk.nashorn.internal.runtime.options.Options;
/**
- * Static utility that encapsulates persistence of decompilation information for functions. Normally, the type info
- * persistence feature is enabled and operates in an operating-system specific per-user cache directory. You can
- * override the directory by specifying it in the {@code nashorn.typeInfo.cacheDir} directory. Also, you can disable the
- * type info persistence altogether by specifying the {@code nashorn.typeInfo.disabled} system property.
+ * Static utility that encapsulates persistence of type information for functions compiled with optimistic
+ * typing. With this feature enabled, when a JavaScript function is recompiled because it gets deoptimized,
+ * the type information for deoptimization is stored in a cache file. If the same function is compiled in a
+ * subsequent JVM invocation, the type information is used for initial compilation, thus allowing the system
+ * to skip a lot of intermediate recompilations and immediately emit a version of the code that has its
+ * optimistic types at (or near) the steady state.
+ * </p><p>
+ * Normally, the type info persistence feature is disabled. When the {@code nashorn.typeInfo.maxFiles} system
+ * property is specified with a value greater than 0, it is enabled and operates in an operating-system
+ * specific per-user cache directory. You can override the directory by specifying it in the
+ * {@code nashorn.typeInfo.cacheDir} directory. The maximum number of files is softly enforced by a task that
+ * cleans up the directory periodically on a separate thread. It is run after some delay after a new file is
+ * added to the cache. The default delay is 20 seconds, and can be set using the
+ * {@code nashorn.typeInfo.cleanupDelaySeconds} system property. You can also specify the word
+ * {@code unlimited} as the value for {@code nashorn.typeInfo.maxFiles} in which case the type info cache is
+ * allowed to grow without limits.
*/
public final class OptimisticTypesPersistence {
+ // Default is 0, for disabling the feature when not specified. A reasonable default when enabled is
+ // dependent on the application; setting it to e.g. 20000 is probably good enough for most uses and will
+ // usually cap the cache directory to about 80MB presuming a 4kB filesystem allocation unit. There is one
+ // file per JavaScript function.
+ private static final int DEFAULT_MAX_FILES = 0;
+ // Constants for signifying that the cache should not be limited
+ private static final int UNLIMITED_FILES = -1;
+ // Maximum number of files that should be cached on disk. The maximum will be softly enforced.
+ private static final int MAX_FILES = getMaxFiles();
+ // Number of seconds to wait between adding a new file to the cache and running a cleanup process
+ private static final int DEFAULT_CLEANUP_DELAY = 20;
+ private static final int CLEANUP_DELAY = Math.max(0, Options.getIntProperty(
+ "nashorn.typeInfo.cleanupDelaySeconds", DEFAULT_CLEANUP_DELAY));
// The name of the default subdirectory within the system cache directory where we store type info.
private static final String DEFAULT_CACHE_SUBDIR_NAME = "com.oracle.java.NashornTypeInfo";
// The directory where we cache type info
- private static final File cacheDir = createCacheDir();
+ private static final File baseCacheDir = createBaseCacheDir();
+ private static final File cacheDir = createCacheDir(baseCacheDir);
// In-process locks to make sure we don't have a cross-thread race condition manipulating any file.
private static final Object[] locks = cacheDir == null ? null : createLockArray();
-
// Only report one read/write error every minute
private static final long ERROR_REPORT_THRESHOLD = 60000L;
private static volatile long lastReportedError;
-
+ private static final AtomicBoolean scheduledCleanup;
+ private static final Timer cleanupTimer;
+ static {
+ if (baseCacheDir == null || MAX_FILES == UNLIMITED_FILES) {
+ scheduledCleanup = null;
+ cleanupTimer = null;
+ } else {
+ scheduledCleanup = new AtomicBoolean();
+ cleanupTimer = new Timer(true);
+ }
+ }
/**
- * Retrieves an opaque descriptor for the persistence location for a given function. It should be passed to
- * {@link #load(Object)} and {@link #store(Object, Map)} methods.
+ * Retrieves an opaque descriptor for the persistence location for a given function. It should be passed
+ * to {@link #load(Object)} and {@link #store(Object, Map)} methods.
* @param source the source where the function comes from
* @param functionId the unique ID number of the function within the source
- * @param paramTypes the types of the function parameters (as persistence is per parameter type specialization).
+ * @param paramTypes the types of the function parameters (as persistence is per parameter type
+ * specialization).
* @return an opaque descriptor for the persistence location. Can be null if persistence is disabled.
*/
public static Object getLocationDescriptor(final Source source, final int functionId, final Type[] paramTypes) {
@@ -82,7 +128,8 @@
final StringBuilder b = new StringBuilder(48);
// Base64-encode the digest of the source, and append the function id.
b.append(source.getDigest()).append('-').append(functionId);
- // Finally, if this is a parameter-type specialized version of the function, add the parameter types to the file name.
+ // Finally, if this is a parameter-type specialized version of the function, add the parameter types
+ // to the file name.
if(paramTypes != null && paramTypes.length > 0) {
b.append('-');
for(final Type t: paramTypes) {
@@ -118,6 +165,11 @@
@Override
public Void run() {
synchronized(getFileLock(file)) {
+ if (!file.exists()) {
+ // If the file already exists, we aren't increasing the number of cached files, so
+ // don't schedule cleanup.
+ scheduleCleanup();
+ }
try (final FileOutputStream out = new FileOutputStream(file)) {
out.getChannel().lock(); // lock exclusive
final DataOutputStream dout = new DataOutputStream(new BufferedOutputStream(out));
@@ -174,19 +226,19 @@
}
}
- private static File createCacheDir() {
- if(Options.getBooleanProperty("nashorn.typeInfo.disabled")) {
+ private static File createBaseCacheDir() {
+ if(MAX_FILES == 0 || Options.getBooleanProperty("nashorn.typeInfo.disabled")) {
return null;
}
try {
- return createCacheDirPrivileged();
+ return createBaseCacheDirPrivileged();
} catch(final Exception e) {
getLogger().warning("Failed to create cache dir", e);
return null;
}
}
- private static File createCacheDirPrivileged() {
+ private static File createBaseCacheDirPrivileged() {
return AccessController.doPrivileged(new PrivilegedAction<File>() {
@Override
public File run() {
@@ -195,14 +247,35 @@
if(explicitDir != null) {
dir = new File(explicitDir);
} else {
- // When no directory is explicitly specified, get an operating system specific cache directory,
- // and create "com.oracle.java.NashornTypeInfo" in it.
+ // When no directory is explicitly specified, get an operating system specific cache
+ // directory, and create "com.oracle.java.NashornTypeInfo" in it.
final File systemCacheDir = getSystemCacheDir();
dir = new File(systemCacheDir, DEFAULT_CACHE_SUBDIR_NAME);
if (isSymbolicLink(dir)) {
return null;
}
}
+ return dir;
+ }
+ });
+ }
+
+ private static File createCacheDir(final File baseDir) {
+ if (baseDir == null) {
+ return null;
+ }
+ try {
+ return createCacheDirPrivileged(baseDir);
+ } catch(final Exception e) {
+ getLogger().warning("Failed to create cache dir", e);
+ return null;
+ }
+ }
+
+ private static File createCacheDirPrivileged(final File baseDir) {
+ return AccessController.doPrivileged(new PrivilegedAction<File>() {
+ @Override
+ public File run() {
final String versionDirName;
try {
versionDirName = getVersionDirName();
@@ -210,12 +283,12 @@
getLogger().warning("Failed to calculate version dir name", e);
return null;
}
- final File versionDir = new File(dir, versionDirName);
+ final File versionDir = new File(baseDir, versionDirName);
if (isSymbolicLink(versionDir)) {
return null;
}
versionDir.mkdirs();
- if(versionDir.isDirectory()) {
+ if (versionDir.isDirectory()) {
getLogger().info("Optimistic type persistence directory is " + versionDir);
return versionDir;
}
@@ -235,12 +308,12 @@
// Mac OS X stores caches in ~/Library/Caches
return new File(new File(System.getProperty("user.home"), "Library"), "Caches");
} else if(os.startsWith("Windows")) {
- // On Windows, temp directory is the best approximation of a cache directory, as its contents persist across
- // reboots and various cleanup utilities know about it. java.io.tmpdir normally points to a user-specific
- // temp directory, %HOME%\LocalSettings\Temp.
+ // On Windows, temp directory is the best approximation of a cache directory, as its contents
+ // persist across reboots and various cleanup utilities know about it. java.io.tmpdir normally
+ // points to a user-specific temp directory, %HOME%\LocalSettings\Temp.
return new File(System.getProperty("java.io.tmpdir"));
} else {
- // In all other cases we're presumably dealing with a UNIX flavor (Linux, Solaris, etc.); "~/.cache"
+ // In other cases we're presumably dealing with a UNIX flavor (Linux, Solaris, etc.); "~/.cache"
return new File(System.getProperty("user.home"), ".cache");
}
}
@@ -278,7 +351,8 @@
final int packageNameLen = className.lastIndexOf('.');
final String dirStr = fileStr.substring(0, fileStr.length() - packageNameLen - 1);
final File dir = new File(dirStr);
- return "dev-" + new SimpleDateFormat("yyyyMMdd-HHmmss").format(new Date(getLastModifiedClassFile(dir, 0L)));
+ return "dev-" + new SimpleDateFormat("yyyyMMdd-HHmmss").format(new Date(getLastModifiedClassFile(
+ dir, 0L)));
} else {
throw new AssertionError();
}
@@ -335,4 +409,108 @@
return DebugLogger.DISABLED_LOGGER;
}
}
+
+ private static void scheduleCleanup() {
+ if (MAX_FILES != UNLIMITED_FILES && scheduledCleanup.compareAndSet(false, true)) {
+ cleanupTimer.schedule(new TimerTask() {
+ @Override
+ public void run() {
+ scheduledCleanup.set(false);
+ try {
+ doCleanup();
+ } catch (final IOException e) {
+ // Ignore it. While this is unfortunate, we don't have good facility for reporting
+ // this, as we're running in a thread that has no access to Context, so we can't grab
+ // a DebugLogger.
+ }
+ }
+ }, TimeUnit.SECONDS.toMillis(CLEANUP_DELAY));
+ }
+ }
+
+ private static void doCleanup() throws IOException {
+ final long start = System.nanoTime();
+ final Path[] files = getAllRegularFilesInLastModifiedOrder();
+ final int nFiles = files.length;
+ final int filesToDelete = Math.max(0, nFiles - MAX_FILES);
+ int filesDeleted = 0;
+ for (int i = 0; i < nFiles && filesDeleted < filesToDelete; ++i) {
+ try {
+ Files.deleteIfExists(files[i]);
+ // Even if it didn't exist, we increment filesDeleted; it existed a moment earlier; something
+ // else deleted it for us; that's okay with us.
+ filesDeleted++;
+ } catch (final Exception e) {
+ // does not increase filesDeleted
+ }
+ files[i] = null; // gc eligible
+ };
+ final long duration = System.nanoTime() - start;
+ }
+
+ private static Path[] getAllRegularFilesInLastModifiedOrder() throws IOException {
+ try (final Stream<Path> filesStream = Files.walk(baseCacheDir.toPath())) {
+ // TODO: rewrite below once we can use JDK8 syntactic constructs
+ return filesStream
+ .filter(new Predicate<Path>() {
+ @Override
+ public boolean test(final Path path) {
+ return !Files.isDirectory(path);
+ };
+ })
+ .map(new Function<Path, PathAndTime>() {
+ @Override
+ public PathAndTime apply(final Path path) {
+ return new PathAndTime(path);
+ }
+ })
+ .sorted()
+ .map(new Function<PathAndTime, Path>() {
+ @Override
+ public Path apply(final PathAndTime pathAndTime) {
+ return pathAndTime.path;
+ }
+ })
+ .toArray(new IntFunction<Path[]>() { // Replace with Path::new
+ @Override
+ public Path[] apply(final int length) {
+ return new Path[length];
+ }
+ });
+ }
+ }
+
+ private static class PathAndTime implements Comparable<PathAndTime> {
+ private final Path path;
+ private final long time;
+
+ PathAndTime(final Path path) {
+ this.path = path;
+ this.time = getTime(path);
+ }
+
+ @Override
+ public int compareTo(final PathAndTime other) {
+ return Long.compare(time, other.time);
+ }
+
+ private static long getTime(final Path path) {
+ try {
+ return Files.getLastModifiedTime(path).toMillis();
+ } catch (IOException e) {
+ // All files for which we can't retrieve the last modified date will be considered oldest.
+ return -1L;
+ }
+ }
+ }
+
+ private static int getMaxFiles() {
+ final String str = Options.getStringProperty("nashorn.typeInfo.maxFiles", null);
+ if (str == null) {
+ return DEFAULT_MAX_FILES;
+ } else if ("unlimited".equals(str)) {
+ return UNLIMITED_FILES;
+ }
+ return Math.max(0, Integer.parseInt(str));
+ }
}