OptimisticTypesPersistence.java revision 1093:3fa7d5c6ed92
1/* 2 * Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25package jdk.nashorn.internal.codegen; 26 27import java.io.BufferedInputStream; 28import java.io.BufferedOutputStream; 29import java.io.DataInputStream; 30import java.io.DataOutputStream; 31import java.io.File; 32import java.io.FileInputStream; 33import java.io.FileOutputStream; 34import java.io.IOException; 35import java.io.InputStream; 36import java.net.URL; 37import java.nio.file.Files; 38import java.nio.file.Path; 39import java.security.AccessController; 40import java.security.MessageDigest; 41import java.security.PrivilegedAction; 42import java.text.SimpleDateFormat; 43import java.util.Base64; 44import java.util.Date; 45import java.util.Map; 46import java.util.Timer; 47import java.util.TimerTask; 48import java.util.concurrent.TimeUnit; 49import java.util.concurrent.atomic.AtomicBoolean; 50import java.util.function.Function; 51import java.util.function.IntFunction; 52import java.util.function.Predicate; 53import java.util.stream.Stream; 54import jdk.nashorn.internal.codegen.types.Type; 55import jdk.nashorn.internal.runtime.Context; 56import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData; 57import jdk.nashorn.internal.runtime.Source; 58import jdk.nashorn.internal.runtime.logging.DebugLogger; 59import jdk.nashorn.internal.runtime.options.Options; 60 61/** 62 * Static utility that encapsulates persistence of type information for functions compiled with optimistic 63 * typing. With this feature enabled, when a JavaScript function is recompiled because it gets deoptimized, 64 * the type information for deoptimization is stored in a cache file. If the same function is compiled in a 65 * subsequent JVM invocation, the type information is used for initial compilation, thus allowing the system 66 * to skip a lot of intermediate recompilations and immediately emit a version of the code that has its 67 * optimistic types at (or near) the steady state. 68 * </p><p> 69 * Normally, the type info persistence feature is disabled. When the {@code nashorn.typeInfo.maxFiles} system 70 * property is specified with a value greater than 0, it is enabled and operates in an operating-system 71 * specific per-user cache directory. You can override the directory by specifying it in the 72 * {@code nashorn.typeInfo.cacheDir} directory. The maximum number of files is softly enforced by a task that 73 * cleans up the directory periodically on a separate thread. It is run after some delay after a new file is 74 * added to the cache. The default delay is 20 seconds, and can be set using the 75 * {@code nashorn.typeInfo.cleanupDelaySeconds} system property. You can also specify the word 76 * {@code unlimited} as the value for {@code nashorn.typeInfo.maxFiles} in which case the type info cache is 77 * allowed to grow without limits. 78 */ 79public final class OptimisticTypesPersistence { 80 // Default is 0, for disabling the feature when not specified. A reasonable default when enabled is 81 // dependent on the application; setting it to e.g. 20000 is probably good enough for most uses and will 82 // usually cap the cache directory to about 80MB presuming a 4kB filesystem allocation unit. There is one 83 // file per JavaScript function. 84 private static final int DEFAULT_MAX_FILES = 0; 85 // Constants for signifying that the cache should not be limited 86 private static final int UNLIMITED_FILES = -1; 87 // Maximum number of files that should be cached on disk. The maximum will be softly enforced. 88 private static final int MAX_FILES = getMaxFiles(); 89 // Number of seconds to wait between adding a new file to the cache and running a cleanup process 90 private static final int DEFAULT_CLEANUP_DELAY = 20; 91 private static final int CLEANUP_DELAY = Math.max(0, Options.getIntProperty( 92 "nashorn.typeInfo.cleanupDelaySeconds", DEFAULT_CLEANUP_DELAY)); 93 // The name of the default subdirectory within the system cache directory where we store type info. 94 private static final String DEFAULT_CACHE_SUBDIR_NAME = "com.oracle.java.NashornTypeInfo"; 95 // The directory where we cache type info 96 private static final File baseCacheDir = createBaseCacheDir(); 97 private static final File cacheDir = createCacheDir(baseCacheDir); 98 // In-process locks to make sure we don't have a cross-thread race condition manipulating any file. 99 private static final Object[] locks = cacheDir == null ? null : createLockArray(); 100 // Only report one read/write error every minute 101 private static final long ERROR_REPORT_THRESHOLD = 60000L; 102 103 private static volatile long lastReportedError; 104 private static final AtomicBoolean scheduledCleanup; 105 private static final Timer cleanupTimer; 106 static { 107 if (baseCacheDir == null || MAX_FILES == UNLIMITED_FILES) { 108 scheduledCleanup = null; 109 cleanupTimer = null; 110 } else { 111 scheduledCleanup = new AtomicBoolean(); 112 cleanupTimer = new Timer(true); 113 } 114 } 115 /** 116 * Retrieves an opaque descriptor for the persistence location for a given function. It should be passed 117 * to {@link #load(Object)} and {@link #store(Object, Map)} methods. 118 * @param source the source where the function comes from 119 * @param functionId the unique ID number of the function within the source 120 * @param paramTypes the types of the function parameters (as persistence is per parameter type 121 * specialization). 122 * @return an opaque descriptor for the persistence location. Can be null if persistence is disabled. 123 */ 124 public static Object getLocationDescriptor(final Source source, final int functionId, final Type[] paramTypes) { 125 if(cacheDir == null) { 126 return null; 127 } 128 final StringBuilder b = new StringBuilder(48); 129 // Base64-encode the digest of the source, and append the function id. 130 b.append(source.getDigest()).append('-').append(functionId); 131 // Finally, if this is a parameter-type specialized version of the function, add the parameter types 132 // to the file name. 133 if(paramTypes != null && paramTypes.length > 0) { 134 b.append('-'); 135 for(final Type t: paramTypes) { 136 b.append(Type.getShortSignatureDescriptor(t)); 137 } 138 } 139 return new LocationDescriptor(new File(cacheDir, b.toString())); 140 } 141 142 private static final class LocationDescriptor { 143 private final File file; 144 145 LocationDescriptor(final File file) { 146 this.file = file; 147 } 148 } 149 150 151 /** 152 * Stores the map of optimistic types for a given function. 153 * @param locationDescriptor the opaque persistence location descriptor, retrieved by calling 154 * {@link #getLocationDescriptor(Source, int, Type[])}. 155 * @param optimisticTypes the map of optimistic types. 156 */ 157 @SuppressWarnings("resource") 158 public static void store(final Object locationDescriptor, final Map<Integer, Type> optimisticTypes) { 159 if(locationDescriptor == null || optimisticTypes.isEmpty()) { 160 return; 161 } 162 final File file = ((LocationDescriptor)locationDescriptor).file; 163 164 AccessController.doPrivileged(new PrivilegedAction<Void>() { 165 @Override 166 public Void run() { 167 synchronized(getFileLock(file)) { 168 if (!file.exists()) { 169 // If the file already exists, we aren't increasing the number of cached files, so 170 // don't schedule cleanup. 171 scheduleCleanup(); 172 } 173 try (final FileOutputStream out = new FileOutputStream(file)) { 174 out.getChannel().lock(); // lock exclusive 175 final DataOutputStream dout = new DataOutputStream(new BufferedOutputStream(out)); 176 Type.writeTypeMap(optimisticTypes, dout); 177 dout.flush(); 178 } catch(final Exception e) { 179 reportError("write", file, e); 180 } 181 } 182 return null; 183 } 184 }); 185 } 186 187 /** 188 * Loads the map of optimistic types for a given function. 189 * @param locationDescriptor the opaque persistence location descriptor, retrieved by calling 190 * {@link #getLocationDescriptor(Source, int, Type[])}. 191 * @return the map of optimistic types, or null if persisted type information could not be retrieved. 192 */ 193 @SuppressWarnings("resource") 194 public static Map<Integer, Type> load(final Object locationDescriptor) { 195 if (locationDescriptor == null) { 196 return null; 197 } 198 final File file = ((LocationDescriptor)locationDescriptor).file; 199 return AccessController.doPrivileged(new PrivilegedAction<Map<Integer, Type>>() { 200 @Override 201 public Map<Integer, Type> run() { 202 try { 203 if(!file.isFile()) { 204 return null; 205 } 206 synchronized(getFileLock(file)) { 207 try (final FileInputStream in = new FileInputStream(file)) { 208 in.getChannel().lock(0, Long.MAX_VALUE, true); // lock shared 209 final DataInputStream din = new DataInputStream(new BufferedInputStream(in)); 210 return Type.readTypeMap(din); 211 } 212 } 213 } catch (final Exception e) { 214 reportError("read", file, e); 215 return null; 216 } 217 } 218 }); 219 } 220 221 private static void reportError(final String msg, final File file, final Exception e) { 222 final long now = System.currentTimeMillis(); 223 if(now - lastReportedError > ERROR_REPORT_THRESHOLD) { 224 getLogger().warning(String.format("Failed to %s %s", msg, file), e); 225 lastReportedError = now; 226 } 227 } 228 229 private static File createBaseCacheDir() { 230 if(MAX_FILES == 0 || Options.getBooleanProperty("nashorn.typeInfo.disabled")) { 231 return null; 232 } 233 try { 234 return createBaseCacheDirPrivileged(); 235 } catch(final Exception e) { 236 getLogger().warning("Failed to create cache dir", e); 237 return null; 238 } 239 } 240 241 private static File createBaseCacheDirPrivileged() { 242 return AccessController.doPrivileged(new PrivilegedAction<File>() { 243 @Override 244 public File run() { 245 final String explicitDir = System.getProperty("nashorn.typeInfo.cacheDir"); 246 final File dir; 247 if(explicitDir != null) { 248 dir = new File(explicitDir); 249 } else { 250 // When no directory is explicitly specified, get an operating system specific cache 251 // directory, and create "com.oracle.java.NashornTypeInfo" in it. 252 final File systemCacheDir = getSystemCacheDir(); 253 dir = new File(systemCacheDir, DEFAULT_CACHE_SUBDIR_NAME); 254 if (isSymbolicLink(dir)) { 255 return null; 256 } 257 } 258 return dir; 259 } 260 }); 261 } 262 263 private static File createCacheDir(final File baseDir) { 264 if (baseDir == null) { 265 return null; 266 } 267 try { 268 return createCacheDirPrivileged(baseDir); 269 } catch(final Exception e) { 270 getLogger().warning("Failed to create cache dir", e); 271 return null; 272 } 273 } 274 275 private static File createCacheDirPrivileged(final File baseDir) { 276 return AccessController.doPrivileged(new PrivilegedAction<File>() { 277 @Override 278 public File run() { 279 final String versionDirName; 280 try { 281 versionDirName = getVersionDirName(); 282 } catch(final Exception e) { 283 getLogger().warning("Failed to calculate version dir name", e); 284 return null; 285 } 286 final File versionDir = new File(baseDir, versionDirName); 287 if (isSymbolicLink(versionDir)) { 288 return null; 289 } 290 versionDir.mkdirs(); 291 if (versionDir.isDirectory()) { 292 getLogger().info("Optimistic type persistence directory is " + versionDir); 293 return versionDir; 294 } 295 getLogger().warning("Could not create optimistic type persistence directory " + versionDir); 296 return null; 297 } 298 }); 299 } 300 301 /** 302 * Returns an operating system specific root directory for cache files. 303 * @return an operating system specific root directory for cache files. 304 */ 305 private static File getSystemCacheDir() { 306 final String os = System.getProperty("os.name", "generic"); 307 if("Mac OS X".equals(os)) { 308 // Mac OS X stores caches in ~/Library/Caches 309 return new File(new File(System.getProperty("user.home"), "Library"), "Caches"); 310 } else if(os.startsWith("Windows")) { 311 // On Windows, temp directory is the best approximation of a cache directory, as its contents 312 // persist across reboots and various cleanup utilities know about it. java.io.tmpdir normally 313 // points to a user-specific temp directory, %HOME%\LocalSettings\Temp. 314 return new File(System.getProperty("java.io.tmpdir")); 315 } else { 316 // In other cases we're presumably dealing with a UNIX flavor (Linux, Solaris, etc.); "~/.cache" 317 return new File(System.getProperty("user.home"), ".cache"); 318 } 319 } 320 321 /** 322 * In order to ensure that changes in Nashorn code don't cause corruption in the data, we'll create a 323 * per-code-version directory. Normally, this will create the SHA-1 digest of the nashorn.jar. In case the classpath 324 * for nashorn is local directory (e.g. during development), this will create the string "dev-" followed by the 325 * timestamp of the most recent .class file. 326 * 327 * @return digest of currently running nashorn 328 * @throws Exception if digest could not be created 329 */ 330 public static String getVersionDirName() throws Exception { 331 final URL url = OptimisticTypesPersistence.class.getResource(""); 332 final String protocol = url.getProtocol(); 333 if (protocol.equals("jar")) { 334 // Normal deployment: nashorn.jar 335 final String jarUrlFile = url.getFile(); 336 final String filePath = jarUrlFile.substring(0, jarUrlFile.indexOf('!')); 337 final URL file = new URL(filePath); 338 try (final InputStream in = file.openStream()) { 339 final byte[] buf = new byte[128*1024]; 340 final MessageDigest digest = MessageDigest.getInstance("SHA-1"); 341 for(;;) { 342 final int l = in.read(buf); 343 if(l == -1) { 344 return Base64.getUrlEncoder().withoutPadding().encodeToString(digest.digest()); 345 } 346 digest.update(buf, 0, l); 347 } 348 } 349 } else if(protocol.equals("file")) { 350 // Development 351 final String fileStr = url.getFile(); 352 final String className = OptimisticTypesPersistence.class.getName(); 353 final int packageNameLen = className.lastIndexOf('.'); 354 final String dirStr = fileStr.substring(0, fileStr.length() - packageNameLen - 1); 355 final File dir = new File(dirStr); 356 return "dev-" + new SimpleDateFormat("yyyyMMdd-HHmmss").format(new Date(getLastModifiedClassFile( 357 dir, 0L))); 358 } else { 359 throw new AssertionError(); 360 } 361 } 362 363 private static long getLastModifiedClassFile(final File dir, final long max) { 364 long currentMax = max; 365 for(final File f: dir.listFiles()) { 366 if(f.getName().endsWith(".class")) { 367 final long lastModified = f.lastModified(); 368 if (lastModified > currentMax) { 369 currentMax = lastModified; 370 } 371 } else if (f.isDirectory()) { 372 final long lastModified = getLastModifiedClassFile(f, currentMax); 373 if (lastModified > currentMax) { 374 currentMax = lastModified; 375 } 376 } 377 } 378 return currentMax; 379 } 380 381 /** 382 * Returns true if the specified file is a symbolic link, and also logs a warning if it is. 383 * @param file the file 384 * @return true if file is a symbolic link, false otherwise. 385 */ 386 private static boolean isSymbolicLink(final File file) { 387 if (Files.isSymbolicLink(file.toPath())) { 388 getLogger().warning("Directory " + file + " is a symlink"); 389 return true; 390 } 391 return false; 392 } 393 394 private static Object[] createLockArray() { 395 final Object[] lockArray = new Object[Runtime.getRuntime().availableProcessors() * 2]; 396 for (int i = 0; i < lockArray.length; ++i) { 397 lockArray[i] = new Object(); 398 } 399 return lockArray; 400 } 401 402 private static Object getFileLock(final File file) { 403 return locks[(file.hashCode() & Integer.MAX_VALUE) % locks.length]; 404 } 405 406 private static DebugLogger getLogger() { 407 try { 408 return Context.getContext().getLogger(RecompilableScriptFunctionData.class); 409 } catch (final Exception e) { 410 e.printStackTrace(); 411 return DebugLogger.DISABLED_LOGGER; 412 } 413 } 414 415 private static void scheduleCleanup() { 416 if (MAX_FILES != UNLIMITED_FILES && scheduledCleanup.compareAndSet(false, true)) { 417 cleanupTimer.schedule(new TimerTask() { 418 @Override 419 public void run() { 420 scheduledCleanup.set(false); 421 try { 422 doCleanup(); 423 } catch (final IOException e) { 424 // Ignore it. While this is unfortunate, we don't have good facility for reporting 425 // this, as we're running in a thread that has no access to Context, so we can't grab 426 // a DebugLogger. 427 } 428 } 429 }, TimeUnit.SECONDS.toMillis(CLEANUP_DELAY)); 430 } 431 } 432 433 private static void doCleanup() throws IOException { 434 final Path[] files = getAllRegularFilesInLastModifiedOrder(); 435 final int nFiles = files.length; 436 final int filesToDelete = Math.max(0, nFiles - MAX_FILES); 437 int filesDeleted = 0; 438 for (int i = 0; i < nFiles && filesDeleted < filesToDelete; ++i) { 439 try { 440 Files.deleteIfExists(files[i]); 441 // Even if it didn't exist, we increment filesDeleted; it existed a moment earlier; something 442 // else deleted it for us; that's okay with us. 443 filesDeleted++; 444 } catch (final Exception e) { 445 // does not increase filesDeleted 446 } 447 files[i] = null; // gc eligible 448 } 449 } 450 451 private static Path[] getAllRegularFilesInLastModifiedOrder() throws IOException { 452 try (final Stream<Path> filesStream = Files.walk(baseCacheDir.toPath())) { 453 // TODO: rewrite below once we can use JDK8 syntactic constructs 454 return filesStream 455 .filter(new Predicate<Path>() { 456 @Override 457 public boolean test(final Path path) { 458 return !Files.isDirectory(path); 459 } 460 }) 461 .map(new Function<Path, PathAndTime>() { 462 @Override 463 public PathAndTime apply(final Path path) { 464 return new PathAndTime(path); 465 } 466 }) 467 .sorted() 468 .map(new Function<PathAndTime, Path>() { 469 @Override 470 public Path apply(final PathAndTime pathAndTime) { 471 return pathAndTime.path; 472 } 473 }) 474 .toArray(new IntFunction<Path[]>() { // Replace with Path::new 475 @Override 476 public Path[] apply(final int length) { 477 return new Path[length]; 478 } 479 }); 480 } 481 } 482 483 private static class PathAndTime implements Comparable<PathAndTime> { 484 private final Path path; 485 private final long time; 486 487 PathAndTime(final Path path) { 488 this.path = path; 489 this.time = getTime(path); 490 } 491 492 @Override 493 public int compareTo(final PathAndTime other) { 494 return Long.compare(time, other.time); 495 } 496 497 private static long getTime(final Path path) { 498 try { 499 return Files.getLastModifiedTime(path).toMillis(); 500 } catch (final IOException e) { 501 // All files for which we can't retrieve the last modified date will be considered oldest. 502 return -1L; 503 } 504 } 505 } 506 507 private static int getMaxFiles() { 508 final String str = Options.getStringProperty("nashorn.typeInfo.maxFiles", null); 509 if (str == null) { 510 return DEFAULT_MAX_FILES; 511 } else if ("unlimited".equals(str)) { 512 return UNLIMITED_FILES; 513 } 514 return Math.max(0, Integer.parseInt(str)); 515 } 516} 517