Reduce lock contention in ContextImpl
Use double-check pattern.
Don't use same lock for dir creation work and for resources work.
Bug: 259323318
Change-Id: I4da7e00f1e87d15bb22701a602beeae965b61a32
diff --git a/core/java/android/app/ContextImpl.java b/core/java/android/app/ContextImpl.java
index af56cb4..831c298 100644
--- a/core/java/android/app/ContextImpl.java
+++ b/core/java/android/app/ContextImpl.java
@@ -272,10 +272,17 @@
@UnsupportedAppUsage
private Context mOuterContext;
+
+ private final Object mThemeLock = new Object();
+
@UnsupportedAppUsage
+ @GuardedBy("mThemeLock")
private int mThemeResource = 0;
+
@UnsupportedAppUsage
+ @GuardedBy("mThemeLock")
private Resources.Theme mTheme = null;
+
@UnsupportedAppUsage
private PackageManager mPackageManager;
private Context mReceiverRestrictedContext = null;
@@ -288,7 +295,6 @@
private ContentCaptureOptions mContentCaptureOptions = null;
- private final Object mSync = new Object();
/**
* Indicates this {@link Context} can not handle UI components properly and is not associated
* with a {@link Display} instance.
@@ -340,21 +346,18 @@
*/
private boolean mOwnsToken = false;
- @GuardedBy("mSync")
- private File mDatabasesDir;
- @GuardedBy("mSync")
- @UnsupportedAppUsage
- private File mPreferencesDir;
- @GuardedBy("mSync")
- private File mFilesDir;
- @GuardedBy("mSync")
- private File mCratesDir;
- @GuardedBy("mSync")
- private File mNoBackupFilesDir;
- @GuardedBy("mSync")
- private File mCacheDir;
- @GuardedBy("mSync")
- private File mCodeCacheDir;
+ private final Object mDirsLock = new Object();
+ private volatile File mDatabasesDir;
+ @UnsupportedAppUsage private volatile File mPreferencesDir;
+ private volatile File mFilesDir;
+ private volatile File mCratesDir;
+ private volatile File mNoBackupFilesDir;
+ private volatile File[] mExternalFilesDirs;
+ private volatile File[] mObbDirs;
+ private volatile File mCacheDir;
+ private volatile File mCodeCacheDir;
+ private volatile File[] mExternalCacheDirs;
+ private volatile File[] mExternalMediaDirs;
// The system service cache for the system services that are cached per-ContextImpl.
@UnsupportedAppUsage
@@ -458,7 +461,7 @@
@Override
public void setTheme(int resId) {
- synchronized (mSync) {
+ synchronized (mThemeLock) {
if (mThemeResource != resId) {
mThemeResource = resId;
initializeTheme();
@@ -468,14 +471,14 @@
@Override
public int getThemeResId() {
- synchronized (mSync) {
+ synchronized (mThemeLock) {
return mThemeResource;
}
}
@Override
public Resources.Theme getTheme() {
- synchronized (mSync) {
+ synchronized (mThemeLock) {
if (mTheme != null) {
return mTheme;
}
@@ -488,6 +491,7 @@
}
}
+ @GuardedBy("mThemeLock")
private void initializeTheme() {
if (mTheme == null) {
mTheme = mResources.newTheme();
@@ -731,12 +735,18 @@
@UnsupportedAppUsage
private File getPreferencesDir() {
- synchronized (mSync) {
- if (mPreferencesDir == null) {
- mPreferencesDir = new File(getDataDir(), "shared_prefs");
+ File localPreferencesDir = mPreferencesDir;
+ if (localPreferencesDir == null) {
+ synchronized (mDirsLock) {
+ localPreferencesDir = mPreferencesDir;
+ if (localPreferencesDir == null) {
+ localPreferencesDir = new File(getDataDir(), "shared_prefs");
+ ensurePrivateDirExists(localPreferencesDir);
+ mPreferencesDir = localPreferencesDir;
+ }
}
- return ensurePrivateDirExists(mPreferencesDir);
}
+ return localPreferencesDir;
}
@Override
@@ -778,16 +788,16 @@
/**
* Common-path handling of app data dir creation
*/
- private static File ensurePrivateDirExists(File file) {
- return ensurePrivateDirExists(file, 0771, -1, null);
+ private static void ensurePrivateDirExists(File file) {
+ ensurePrivateDirExists(file, 0771, -1, null);
}
- private static File ensurePrivateCacheDirExists(File file, String xattr) {
+ private static void ensurePrivateCacheDirExists(File file, String xattr) {
final int gid = UserHandle.getCacheAppGid(Process.myUid());
- return ensurePrivateDirExists(file, 02771, gid, xattr);
+ ensurePrivateDirExists(file, 02771, gid, xattr);
}
- private static File ensurePrivateDirExists(File file, int mode, int gid, String xattr) {
+ private static void ensurePrivateDirExists(File file, int mode, int gid, String xattr) {
if (!file.exists()) {
final String path = file.getAbsolutePath();
try {
@@ -815,17 +825,22 @@
}
}
}
- return file;
}
@Override
public File getFilesDir() {
- synchronized (mSync) {
- if (mFilesDir == null) {
- mFilesDir = new File(getDataDir(), "files");
+ File localFilesDir = mFilesDir;
+ if (localFilesDir == null) {
+ localFilesDir = mFilesDir;
+ synchronized (mDirsLock) {
+ if (localFilesDir == null) {
+ localFilesDir = new File(getDataDir(), "files");
+ ensurePrivateDirExists(localFilesDir);
+ mFilesDir = localFilesDir;
+ }
}
- return ensurePrivateDirExists(mFilesDir);
}
+ return localFilesDir;
}
@Override
@@ -835,25 +850,37 @@
final Path absoluteNormalizedCratePath = cratesRootPath.resolve(crateId)
.toAbsolutePath().normalize();
- synchronized (mSync) {
- if (mCratesDir == null) {
- mCratesDir = cratesRootPath.toFile();
+ File localCratesDir = mCratesDir;
+ if (localCratesDir == null) {
+ synchronized (mDirsLock) {
+ localCratesDir = mCratesDir;
+ if (localCratesDir == null) {
+ localCratesDir = cratesRootPath.toFile();
+ ensurePrivateDirExists(localCratesDir);
+ mCratesDir = localCratesDir;
+ }
}
- ensurePrivateDirExists(mCratesDir);
}
- File cratedDir = absoluteNormalizedCratePath.toFile();
- return ensurePrivateDirExists(cratedDir);
+ File crateDir = absoluteNormalizedCratePath.toFile();
+ ensurePrivateDirExists(crateDir);
+ return crateDir;
}
@Override
public File getNoBackupFilesDir() {
- synchronized (mSync) {
- if (mNoBackupFilesDir == null) {
- mNoBackupFilesDir = new File(getDataDir(), "no_backup");
+ File localNoBackupFilesDir = mNoBackupFilesDir;
+ if (localNoBackupFilesDir == null) {
+ synchronized (mDirsLock) {
+ localNoBackupFilesDir = mNoBackupFilesDir;
+ if (localNoBackupFilesDir == null) {
+ localNoBackupFilesDir = new File(getDataDir(), "no_backup");
+ ensurePrivateDirExists(localNoBackupFilesDir);
+ mNoBackupFilesDir = localNoBackupFilesDir;
+ }
}
- return ensurePrivateDirExists(mNoBackupFilesDir);
}
+ return localNoBackupFilesDir;
}
@Override
@@ -865,13 +892,24 @@
@Override
public File[] getExternalFilesDirs(String type) {
- synchronized (mSync) {
- File[] dirs = Environment.buildExternalStorageAppFilesDirs(getPackageName());
- if (type != null) {
- dirs = Environment.buildPaths(dirs, type);
+ File[] localExternalFilesDirs = mExternalFilesDirs;
+ if (localExternalFilesDirs == null) {
+ synchronized (mDirsLock) {
+ localExternalFilesDirs = mExternalFilesDirs;
+ if (localExternalFilesDirs == null) {
+ localExternalFilesDirs =
+ Environment.buildExternalStorageAppFilesDirs(getPackageName());
+ if (type != null) {
+ localExternalFilesDirs =
+ Environment.buildPaths(localExternalFilesDirs, type);
+ }
+ localExternalFilesDirs = ensureExternalDirsExistOrFilter(
+ localExternalFilesDirs, true /* tryCreateInProcess */);
+ mExternalFilesDirs = localExternalFilesDirs;
+ }
}
- return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
}
+ return localExternalFilesDirs;
}
@Override
@@ -883,30 +921,51 @@
@Override
public File[] getObbDirs() {
- synchronized (mSync) {
- File[] dirs = Environment.buildExternalStorageAppObbDirs(getPackageName());
- return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
+ File[] localObbDirs = mObbDirs;
+ if (mObbDirs == null) {
+ synchronized (mDirsLock) {
+ localObbDirs = mObbDirs;
+ if (localObbDirs == null) {
+ localObbDirs = Environment.buildExternalStorageAppObbDirs(getPackageName());
+ localObbDirs = ensureExternalDirsExistOrFilter(
+ localObbDirs, true /* tryCreateInProcess */);
+ mObbDirs = localObbDirs;
+ }
+ }
}
+ return localObbDirs;
}
@Override
public File getCacheDir() {
- synchronized (mSync) {
- if (mCacheDir == null) {
- mCacheDir = new File(getDataDir(), "cache");
+ File localCacheDir = mCacheDir;
+ if (localCacheDir == null) {
+ synchronized (mDirsLock) {
+ localCacheDir = mCacheDir;
+ if (localCacheDir == null) {
+ localCacheDir = new File(getDataDir(), "cache");
+ ensurePrivateCacheDirExists(localCacheDir, XATTR_INODE_CACHE);
+ mCacheDir = localCacheDir;
+ }
}
- return ensurePrivateCacheDirExists(mCacheDir, XATTR_INODE_CACHE);
}
+ return localCacheDir;
}
@Override
public File getCodeCacheDir() {
- synchronized (mSync) {
- if (mCodeCacheDir == null) {
- mCodeCacheDir = getCodeCacheDirBeforeBind(getDataDir());
+ File localCodeCacheDir = mCodeCacheDir;
+ if (localCodeCacheDir == null) {
+ synchronized (mDirsLock) {
+ localCodeCacheDir = mCodeCacheDir;
+ if (localCodeCacheDir == null) {
+ localCodeCacheDir = getCodeCacheDirBeforeBind(getDataDir());
+ ensurePrivateCacheDirExists(localCodeCacheDir, XATTR_INODE_CODE_CACHE);
+ mCodeCacheDir = localCodeCacheDir;
+ }
}
- return ensurePrivateCacheDirExists(mCodeCacheDir, XATTR_INODE_CODE_CACHE);
}
+ return localCodeCacheDir;
}
/**
@@ -927,21 +986,37 @@
@Override
public File[] getExternalCacheDirs() {
- synchronized (mSync) {
- File[] dirs = Environment.buildExternalStorageAppCacheDirs(getPackageName());
- // We don't try to create cache directories in-process, because they need special
- // setup for accurate quota tracking. This ensures the cache dirs are always
- // created through StorageManagerService.
- return ensureExternalDirsExistOrFilter(dirs, false /* tryCreateInProcess */);
+ File[] localExternalCacheDirs = mExternalCacheDirs;
+ if (localExternalCacheDirs == null) {
+ synchronized (mDirsLock) {
+ localExternalCacheDirs = mExternalCacheDirs;
+ if (localExternalCacheDirs == null) {
+ localExternalCacheDirs =
+ Environment.buildExternalStorageAppCacheDirs(getPackageName());
+ localExternalCacheDirs = ensureExternalDirsExistOrFilter(
+ localExternalCacheDirs, false /* tryCreateInProcess */);
+ mExternalCacheDirs = localExternalCacheDirs;
+ }
+ }
}
+ return localExternalCacheDirs;
}
@Override
public File[] getExternalMediaDirs() {
- synchronized (mSync) {
- File[] dirs = Environment.buildExternalStorageAppMediaDirs(getPackageName());
- return ensureExternalDirsExistOrFilter(dirs, true /* tryCreateInProcess */);
+ File[] localExternalMediaDirs = mExternalMediaDirs;
+ if (localExternalMediaDirs == null) {
+ synchronized (mDirsLock) {
+ localExternalMediaDirs = mExternalMediaDirs;
+ if (localExternalMediaDirs == null) {
+ localExternalMediaDirs = Environment.buildExternalStorageAppMediaDirs(getPackageName());
+ localExternalMediaDirs = ensureExternalDirsExistOrFilter(
+ localExternalMediaDirs, true /* tryCreateInProcess */);
+ mExternalMediaDirs = localExternalMediaDirs;
+ }
+ }
}
+ return localExternalMediaDirs;
}
/**
@@ -1040,16 +1115,22 @@
}
private File getDatabasesDir() {
- synchronized (mSync) {
- if (mDatabasesDir == null) {
- if ("android".equals(getPackageName())) {
- mDatabasesDir = new File("/data/system");
- } else {
- mDatabasesDir = new File(getDataDir(), "databases");
+ File localDatabasesDir = mDatabasesDir;
+ if (localDatabasesDir == null) {
+ synchronized (mDirsLock) {
+ localDatabasesDir = mDatabasesDir;
+ if (localDatabasesDir == null) {
+ if ("android".equals(getPackageName())) {
+ localDatabasesDir = new File("/data/system");
+ } else {
+ localDatabasesDir = new File(getDataDir(), "databases");
+ }
+ ensurePrivateDirExists(localDatabasesDir);
+ mDatabasesDir = localDatabasesDir;
}
}
- return ensurePrivateDirExists(mDatabasesDir);
}
+ return localDatabasesDir;
}
@Override