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Reduce lock contention on setting write.

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Context: go/pm-settings-persistence

0. The main issue is a background thread holding to 2 major and 1
   less-major locks for a long time.
1. Refactor Settings.writeStateForUser* not to take PMS lock in advance.
2. Add an option to move PMS-locked processing into PMS handler thread,
   executing on a big core with DEFAULT priority.
3. Make XML serialization use its own lock.
4. Move XML serialization + IO to background thread.
5. (separate CL) slightly optimize XML serialization. It's still an AI
   to move it to Fast/Binary serializers.

Bug: 220083428
Test: presubmit
Change-Id: I428d46d90c3ceef55a83358f5f3b2cddbce60efd
This commit is contained in:
Alex Buynytskyy
2022-04-21 21:08:15 +00:00
parent 06ac74c54f
commit 31c17f46f2
3 changed files with 120 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
services/core/java/com/android/server/pm/PackageManagerService.java
View File

@@ -1430,7 +1430,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
(i, pm) -> new Settings(Environment.getDataDirectory(),
RuntimePermissionsPersistence.createInstance(),
i.getPermissionManagerServiceInternal(),
domainVerificationService, lock),
domainVerificationService, backgroundHandler, lock),
(i, pm) -> AppsFilterImpl.create(i,
i.getLocalService(PackageManagerInternal.class)),
(i, pm) -> (PlatformCompat) ServiceManager.getService("platform_compat"),

177
services/core/java/com/android/server/pm/Settings.java
View File

@@ -360,6 +360,8 @@ public final class Settings implements Watchable, Snappable {
private static final String ATTR_VALUE = "value";
private static final String ATTR_FIRST_INSTALL_TIME = "first-install-time";
private final Handler mHandler;
private final PackageManagerTracedLock mLock;
@Watched(manual = true)
@@ -583,6 +585,8 @@ public final class Settings implements Watchable, Snappable {
"Settings.mInstallerPackages");
mKeySetManagerService = new KeySetManagerService(mPackages);
// Test-only handler working on background thread.
mHandler = new Handler(BackgroundThread.getHandler().getLooper());
mLock = new PackageManagerTracedLock();
mPackages.putAll(pkgSettings);
mAppIds = new AppIdSettingMap();
@@ -607,6 +611,7 @@ public final class Settings implements Watchable, Snappable {
Settings(File dataDir, RuntimePermissionsPersistence runtimePermissionsPersistence,
LegacyPermissionDataProvider permissionDataProvider,
@NonNull DomainVerificationManagerInternal domainVerificationManager,
@NonNull Handler handler,
@NonNull PackageManagerTracedLock lock) {
mPackages = new WatchedArrayMap<>();
mPackagesSnapshot =
@@ -620,6 +625,7 @@ public final class Settings implements Watchable, Snappable {
"Settings.mInstallerPackages");
mKeySetManagerService = new KeySetManagerService(mPackages);
mHandler = handler;
mLock = lock;
mAppIds = new AppIdSettingMap();
mPermissions = new LegacyPermissionSettings(lock);
@@ -627,10 +633,8 @@ public final class Settings implements Watchable, Snappable {
runtimePermissionsPersistence, new Consumer<Integer>() {
@Override
public void accept(Integer userId) {
synchronized (mLock) {
mRuntimePermissionsPersistence.writeStateForUserSync(userId,
mPermissionDataProvider, mPackages, mSharedUsers);
}
mRuntimePermissionsPersistence.writeStateForUser(userId,
mPermissionDataProvider, mPackages, mSharedUsers, mHandler, mLock);
}
});
mPermissionDataProvider = permissionDataProvider;
@@ -679,6 +683,7 @@ public final class Settings implements Watchable, Snappable {
// needed by the read-only methods. Note especially that the lock
// is not required because this clone is meant to support lock-free
// read-only methods.
mHandler = null;
mLock = null;
mRuntimePermissionsPersistence = r.mRuntimePermissionsPersistence;
mSettingsFilename = null;
@@ -5286,8 +5291,8 @@ public final class Settings implements Watchable, Snappable {
public void writePermissionStateForUserLPr(int userId, boolean sync) {
if (sync) {
mRuntimePermissionsPersistence.writeStateForUserSync(userId, mPermissionDataProvider,
mPackages, mSharedUsers);
mRuntimePermissionsPersistence.writeStateForUser(userId, mPermissionDataProvider,
mPackages, mSharedUsers, /*handler=*/null, mLock);
} else {
mRuntimePermissionsPersistence.writeStateForUserAsync(userId);
}
@@ -5373,9 +5378,14 @@ public final class Settings implements Watchable, Snappable {
private String mExtendedFingerprint;
@GuardedBy("mPersistenceLock")
private final RuntimePermissionsPersistence mPersistence;
private final Object mPersistenceLock = new Object();
private final Handler mHandler = new MyHandler();
// Low-priority handlers running on SystemBg thread.
private final Handler mAsyncHandler = new MyHandler();
private final Handler mPersistenceHandler = new Handler(
BackgroundThread.getHandler().getLooper());
private final Object mLock = new Object();
@@ -5398,6 +5408,11 @@ public final class Settings implements Watchable, Snappable {
// The mapping keys are user ids.
private final SparseBooleanArray mPermissionUpgradeNeeded = new SparseBooleanArray();
@GuardedBy("mLock")
// Staging area for states prepared to be written.
private final SparseArray<RuntimePermissionsState> mPendingStatesToWrite =
new SparseArray<>();
// This is a hack to allow this class to invoke a write using Settings's data structures,
// to facilitate moving to a finer scoped lock without a significant refactor.
private final Consumer<Integer> mInvokeWriteUserStateAsyncCallback;
@@ -5462,7 +5477,7 @@ public final class Settings implements Watchable, Snappable {
final long currentTimeMillis = SystemClock.uptimeMillis();
if (mWriteScheduled.get(userId)) {
mHandler.removeMessages(userId);
mAsyncHandler.removeMessages(userId);
// If enough time passed, write without holding off anymore.
final long lastNotWrittenMutationTimeMillis = mLastNotWrittenMutationTimesMillis
@@ -5471,7 +5486,7 @@ public final class Settings implements Watchable, Snappable {
- lastNotWrittenMutationTimeMillis;
if (timeSinceLastNotWrittenMutationMillis
>= MAX_WRITE_PERMISSIONS_DELAY_MILLIS) {
mHandler.obtainMessage(userId).sendToTarget();
mAsyncHandler.obtainMessage(userId).sendToTarget();
return;
}
@@ -5481,67 +5496,110 @@ public final class Settings implements Watchable, Snappable {
final long writeDelayMillis = Math.min(WRITE_PERMISSIONS_DELAY_MILLIS,
maxDelayMillis);
Message message = mHandler.obtainMessage(userId);
mHandler.sendMessageDelayed(message, writeDelayMillis);
Message message = mAsyncHandler.obtainMessage(userId);
mAsyncHandler.sendMessageDelayed(message, writeDelayMillis);
} else {
mLastNotWrittenMutationTimesMillis.put(userId, currentTimeMillis);
Message message = mHandler.obtainMessage(userId);
mHandler.sendMessageDelayed(message, WRITE_PERMISSIONS_DELAY_MILLIS);
Message message = mAsyncHandler.obtainMessage(userId);
mAsyncHandler.sendMessageDelayed(message, WRITE_PERMISSIONS_DELAY_MILLIS);
mWriteScheduled.put(userId, true);
}
}
}
public void writeStateForUserSync(int userId, @NonNull LegacyPermissionDataProvider
public void writeStateForUser(int userId, @NonNull LegacyPermissionDataProvider
legacyPermissionDataProvider,
@NonNull WatchedArrayMap<String, ? extends PackageStateInternal> packageStates,
@NonNull WatchedArrayMap<String, SharedUserSetting> sharedUsers) {
@NonNull WatchedArrayMap<String, SharedUserSetting> sharedUsers,
@Nullable Handler pmHandler, @NonNull Object pmLock) {
final int version;
final String fingerprint;
synchronized (mLock) {
mHandler.removeMessages(userId);
mAsyncHandler.removeMessages(userId);
mWriteScheduled.delete(userId);
legacyPermissionDataProvider.writeLegacyPermissionStateTEMP();
version = mVersions.get(userId, INITIAL_VERSION);
fingerprint = mFingerprints.get(userId);
}
int version = mVersions.get(userId, INITIAL_VERSION);
Runnable writer = () -> {
final RuntimePermissionsState runtimePermissions;
synchronized (pmLock) {
legacyPermissionDataProvider.writeLegacyPermissionStateTEMP();
String fingerprint = mFingerprints.get(userId);
Map<String, List<RuntimePermissionsState.PermissionState>> packagePermissions =
new ArrayMap<>();
int packagesSize = packageStates.size();
for (int i = 0; i < packagesSize; i++) {
String packageName = packageStates.keyAt(i);
PackageStateInternal packageState = packageStates.valueAt(i);
if (!packageState.hasSharedUser()) {
List<RuntimePermissionsState.PermissionState> permissions =
getPermissionsFromPermissionsState(
packageState.getLegacyPermissionState(), userId);
if (permissions.isEmpty()
&& !packageState.isInstallPermissionsFixed()) {
// Storing an empty state means the package is known to the
// system and its install permissions have been granted and fixed.
// If this is not the case, we should not store anything.
continue;
}
packagePermissions.put(packageName, permissions);
}
}
Map<String, List<RuntimePermissionsState.PermissionState>> packagePermissions =
new ArrayMap<>();
int packagesSize = packageStates.size();
for (int i = 0; i < packagesSize; i++) {
String packageName = packageStates.keyAt(i);
PackageStateInternal packageState = packageStates.valueAt(i);
if (!packageState.hasSharedUser()) {
Map<String, List<RuntimePermissionsState.PermissionState>>
sharedUserPermissions =
new ArrayMap<>();
final int sharedUsersSize = sharedUsers.size();
for (int i = 0; i < sharedUsersSize; i++) {
String sharedUserName = sharedUsers.keyAt(i);
SharedUserSetting sharedUserSetting = sharedUsers.valueAt(i);
List<RuntimePermissionsState.PermissionState> permissions =
getPermissionsFromPermissionsState(
packageState.getLegacyPermissionState(), userId);
if (permissions.isEmpty() && !packageState.isInstallPermissionsFixed()) {
// Storing an empty state means the package is known to the system and
// its install permissions have been granted and fixed. If this is not
// the case, we should not store anything.
continue;
}
packagePermissions.put(packageName, permissions);
sharedUserSetting.getLegacyPermissionState(), userId);
sharedUserPermissions.put(sharedUserName, permissions);
}
runtimePermissions = new RuntimePermissionsState(version,
fingerprint, packagePermissions, sharedUserPermissions);
}
Map<String, List<RuntimePermissionsState.PermissionState>> sharedUserPermissions =
new ArrayMap<>();
final int sharedUsersSize = sharedUsers.size();
for (int i = 0; i < sharedUsersSize; i++) {
String sharedUserName = sharedUsers.keyAt(i);
SharedUserSetting sharedUserSetting = sharedUsers.valueAt(i);
List<RuntimePermissionsState.PermissionState> permissions =
getPermissionsFromPermissionsState(
sharedUserSetting.getLegacyPermissionState(), userId);
sharedUserPermissions.put(sharedUserName, permissions);
synchronized (mLock) {
mPendingStatesToWrite.put(userId, runtimePermissions);
}
if (pmHandler != null) {
// Async version.
mPersistenceHandler.post(() -> writePendingStates());
} else {
// Sync version.
writePendingStates();
}
};
RuntimePermissionsState runtimePermissions = new RuntimePermissionsState(version,
fingerprint, packagePermissions, sharedUserPermissions);
if (pmHandler != null) {
// Async version, use pmHandler.
pmHandler.post(writer);
} else {
// Sync version, use caller's thread.
writer.run();
}
}
mPersistence.writeForUser(runtimePermissions, UserHandle.of(userId));
private void writePendingStates() {
while (true) {
final RuntimePermissionsState runtimePermissions;
final int userId;
synchronized (mLock) {
if (mPendingStatesToWrite.size() == 0) {
break;
}
userId = mPendingStatesToWrite.keyAt(0);
runtimePermissions = mPendingStatesToWrite.valueAt(0);
mPendingStatesToWrite.removeAt(0);
}
synchronized (mPersistenceLock) {
mPersistence.writeForUser(runtimePermissions, UserHandle.of(userId));
}
}
}
@@ -5563,7 +5621,7 @@ public final class Settings implements Watchable, Snappable {
private void onUserRemoved(int userId) {
synchronized (mLock) {
// Make sure we do not
mHandler.removeMessages(userId);
mAsyncHandler.removeMessages(userId);
mPermissionUpgradeNeeded.delete(userId);
mVersions.delete(userId);
@@ -5572,7 +5630,7 @@ public final class Settings implements Watchable, Snappable {
}
public void deleteUserRuntimePermissionsFile(int userId) {
synchronized (mLock) {
synchronized (mPersistenceLock) {
mPersistence.deleteForUser(UserHandle.of(userId));
}
}
@@ -5581,16 +5639,17 @@ public final class Settings implements Watchable, Snappable {
@NonNull WatchedArrayMap<String, PackageSetting> packageSettings,
@NonNull WatchedArrayMap<String, SharedUserSetting> sharedUsers,
@NonNull File userRuntimePermissionsFile) {
final RuntimePermissionsState runtimePermissions;
synchronized (mPersistenceLock) {
runtimePermissions = mPersistence.readForUser(UserHandle.of(userId));
}
if (runtimePermissions == null) {
readLegacyStateForUserSync(userId, userRuntimePermissionsFile, packageSettings,
sharedUsers);
writeStateForUserAsync(userId);
return;
}
synchronized (mLock) {
RuntimePermissionsState runtimePermissions = mPersistence.readForUser(UserHandle.of(
userId));
if (runtimePermissions == null) {
readLegacyStateForUserSync(userId, userRuntimePermissionsFile, packageSettings,
sharedUsers);
writeStateForUserAsync(userId);
return;
}
// If the runtime permissions file exists but the version is not set this is
// an upgrade from P->Q. Hence mark it with the special UPGRADE_VERSION.
int version = runtimePermissions.getVersion();

2
services/tests/servicestests/src/com/android/server/pm/PackageManagerSettingsTests.java
View File

@@ -1516,7 +1516,7 @@ public class PackageManagerSettingsTests {
private Settings makeSettings() {
return new Settings(InstrumentationRegistry.getContext().getFilesDir(),
mRuntimePermissionsPersistence, mPermissionDataProvider,
mDomainVerificationManager, new PackageManagerTracedLock());
mDomainVerificationManager, null, new PackageManagerTracedLock());
}
private void verifyKeySetMetaData(Settings settings)