Throttle package session async write requests (288dc8fe) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/pm/PackageInstallerService.java

+21 −21

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@ import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
		import static org.xmlpull.v1.XmlPullParser.START_TAG;

		import android.Manifest;
		import android.annotation.NonNull;
		import android.app.ActivityManager;
		import android.app.AppGlobals;
		import android.app.AppOpsManager;
		@@ -88,6 +89,7 @@ import com.android.server.SystemConfig;
		import com.android.server.SystemService;
		import com.android.server.SystemServiceManager;
		import com.android.server.pm.parsing.PackageParser2;
		import com.android.server.pm.utils.RequestThrottle;

		import libcore.io.IoUtils;

		@@ -220,6 +222,14 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		}
		}

		@NonNull
		private final RequestThrottle mSettingsWriteRequest = new RequestThrottle(IoThread.getHandler(),
		() -> {
		synchronized (mSessions) {
		return writeSessionsLocked();
		}
		});

		public PackageInstallerService(Context context, PackageManagerService pm,
		Supplier<PackageParser2> apexParserSupplier) {
		mContext = context;
		@@ -275,7 +285,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements

		// Invalid sessions might have been marked while parsing. Re-write the database with
		// the updated information.
		writeSessionsLocked();
		mSettingsWriteRequest.runNow();

		}
		}
		@@ -464,7 +474,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		}

		@GuardedBy("mSessions")
		private void writeSessionsLocked() {
		private boolean writeSessionsLocked() {
		if (LOGD) Slog.v(TAG, "writeSessionsLocked()");

		FileOutputStream fos = null;
		@@ -483,28 +493,20 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		out.endDocument();

		mSessionsFile.finishWrite(fos);
		return true;
		} catch (IOException e) {
		if (fos != null) {
		mSessionsFile.failWrite(fos);
		}
		}

		return false;
		}

		private File buildAppIconFile(int sessionId) {
		return new File(mSessionsDir, "app_icon." + sessionId + ".png");
		}

		private void writeSessionsAsync() {
		IoThread.getHandler().post(new Runnable() {
		@Override
		public void run() {
		synchronized (mSessions) {
		writeSessionsLocked();
		}
		}
		});
		}

		@Override
		public int createSession(SessionParams params, String installerPackageName,
		String callingAttributionTag, int userId) {
		@@ -764,7 +766,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements

		mCallbacks.notifySessionCreated(session.sessionId, session.userId);

		writeSessionsAsync();
		mSettingsWriteRequest.schedule();
		return sessionId;
		}

		@@ -1374,7 +1376,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		class InternalCallback {
		public void onSessionBadgingChanged(PackageInstallerSession session) {
		mCallbacks.notifySessionBadgingChanged(session.sessionId, session.userId);
		writeSessionsAsync();
		mSettingsWriteRequest.schedule();
		}

		public void onSessionActiveChanged(PackageInstallerSession session, boolean active) {
		@@ -1389,7 +1391,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements

		public void onStagedSessionChanged(PackageInstallerSession session) {
		session.markUpdated();
		writeSessionsAsync();
		mSettingsWriteRequest.schedule();
		if (mOkToSendBroadcasts && !session.isDestroyed()) {
		// we don't scrub the data here as this is sent only to the installer several
		// privileged system packages
		@@ -1419,7 +1421,7 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		appIconFile.delete();
		}

		writeSessionsLocked();
		mSettingsWriteRequest.runNow();
		}
		}
		});
		@@ -1428,16 +1430,14 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements
		public void onSessionPrepared(PackageInstallerSession session) {
		// We prepared the destination to write into; we want to persist
		// this, but it's not critical enough to block for.
		writeSessionsAsync();
		mSettingsWriteRequest.schedule();
		}

		public void onSessionSealedBlocking(PackageInstallerSession session) {
		// It's very important that we block until we've recorded the
		// session as being sealed, since we never want to allow mutation
		// after sealing.
		synchronized (mSessions) {
		writeSessionsLocked();
		}
		mSettingsWriteRequest.runNow();
		}
		}
		}

services/core/java/com/android/server/pm/utils/RequestThrottle.java

0 → 100644

+154 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2021 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.server.pm.utils;

		import android.annotation.NonNull;
		import android.os.Handler;

		import com.android.server.IoThread;

		import java.util.concurrent.atomic.AtomicInteger;
		import java.util.function.Supplier;

		/**
		* Loose throttle latest behavior for success/fail requests, with options to schedule or force a
		* request through. Throttling is implicit and not configurable. This means requests are dispatched
		* to the {@link Handler} immediately when received, and only batched while waiting on the next
		* message execution or running request.
		*
		* This also means there is no explicit debouncing. Implicit debouncing is available through the
		* same runtime delays in the {@link Handler} instance and the request execution, where multiple
		* requests prior to the execution point are collapsed.
		*
		* Callers provide a {@link Handler} with which to schedule tasks on. This may be a highly
		* contentious thread like {@link IoThread#getHandler()}, but note that there are no guarantees
		* that the request will be handled before the system server dies. Ideally callers should handle
		* re-initialization from stale state with no consequences to the user.
		*
		* This class will retry requests if they don't succeed, as provided by a true/false response from
		* the block provided to run the request. This uses an exponential backoff mechanism, assuming that
		* state write should be attempted immediately, but not retried so heavily as to potentially block
		* other system server callers. Exceptions are not considered and will not result in a retry if
		* thrown from inside the block. Caller should wrap with try-catch and rollback and transaction
		* state before returning false to signal a retry.
		*
		* The caller is strictly responsible for data synchronization, as this class will not synchronize
		* the request block, potentially running it multiple times or on multiple threads simultaneously
		* if requests come in asynchronously.
		*/
		public class RequestThrottle {

		private static final int DEFAULT_RETRY_MAX_ATTEMPTS = 5;
		private static final int DEFAULT_DELAY_MS = 1000;
		private static final int DEFAULT_BACKOFF_BASE = 2;

		private final AtomicInteger mLastRequest = new AtomicInteger(0);
		private final AtomicInteger mLastCommitted = new AtomicInteger(-1);

		private final int mMaxAttempts;
		private final int mFirstDelay;
		private final int mBackoffBase;

		private final AtomicInteger mCurrentRetry = new AtomicInteger(0);

		@NonNull
		private final Handler mHandler;

		@NonNull
		private final Supplier<Boolean> mBlock;

		@NonNull
		private final Runnable mRunnable;

		/**
		* @see #RequestThrottle(Handler, int, int, int, Supplier)
		*/
		public RequestThrottle(@NonNull Handler handler, @NonNull Supplier<Boolean> block) {
		this(handler, DEFAULT_RETRY_MAX_ATTEMPTS, DEFAULT_DELAY_MS, DEFAULT_BACKOFF_BASE,
		block);
		}

		/**
		* Backoff timing is calculated as firstDelay * (backoffBase ^ retryAttempt).
		*
		* @param handler Representing the thread to run the provided block.
		* @param block The action to run when scheduled, returning whether or not the request was
		* successful. Note that any thrown exceptions will be ignored and not
		* retried, since it's not easy to tell how destructive or retry-able an
		* exception is.
		* @param maxAttempts Number of times to re-attempt any single request.
		* @param firstDelay The first delay used after the initial attempt.
		* @param backoffBase The base of the backoff calculation, where retry attempt count is the
		* exponent.
		*/
		public RequestThrottle(@NonNull Handler handler, int maxAttempts, int firstDelay,
		int backoffBase, @NonNull Supplier<Boolean> block) {
		mHandler = handler;
		mBlock = block;
		mMaxAttempts = maxAttempts;
		mFirstDelay = firstDelay;
		mBackoffBase = backoffBase;
		mRunnable = this::runInternal;
		}

		/**
		* Schedule the intended action on the provided {@link Handler}.
		*/
		public void schedule() {
		// To avoid locking the Handler twice by pre-checking hasCallbacks, instead just queue
		// the Runnable again. It will no-op if the request has already been written to disk.
		mLastRequest.incrementAndGet();
		mHandler.post(mRunnable);
		}

		/**
		* Run the intended action immediately on the calling thread. Note that synchronization and
		* deadlock between threads is not handled. This will immediately call the request block, and
		* also potentially schedule a retry. The caller must not block itself.
		*
		* @return true if the write succeeded or the last request was already written
		*/
		public boolean runNow() {
		mLastRequest.incrementAndGet();
		return runInternal();
		}

		private boolean runInternal() {
		int lastRequest = mLastRequest.get();
		int lastCommitted = mLastCommitted.get();
		if (lastRequest == lastCommitted) {
		return true;
		}

		if (mBlock.get()) {
		mCurrentRetry.set(0);
		mLastCommitted.set(lastRequest);
		return true;
		} else {
		int currentRetry = mCurrentRetry.getAndIncrement();
		if (currentRetry < mMaxAttempts) {
		long nextDelay =
		(long) (mFirstDelay * Math.pow(mBackoffBase, currentRetry));
		mHandler.postDelayed(mRunnable, nextDelay);
		} else {
		mCurrentRetry.set(0);
		}

		return false;
		}
		}
		}

services/tests/PackageManagerServiceTests/unit/src/com/android/server/pm/test/install/RequestThrottleTest.kt

0 → 100644

+219 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2021 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.server.pm.test.install

		import com.android.server.pm.utils.RequestThrottle
		import com.android.server.testutils.TestHandler
		import com.google.common.collect.Range
		import com.google.common.truth.LongSubject
		import com.google.common.truth.Truth.assertThat
		import org.junit.Before
		import org.junit.Test
		import java.util.concurrent.CountDownLatch
		import java.util.concurrent.CyclicBarrier
		import java.util.concurrent.TimeUnit
		import java.util.concurrent.atomic.AtomicBoolean
		import java.util.concurrent.atomic.AtomicInteger
		import java.util.concurrent.atomic.AtomicLong

		class RequestThrottleTest {

		private val counter = AtomicInteger(0)

		private val handler = TestHandler(null)

		@Before
		fun resetValues() {
		handler.flush()
		counter.set(0)
		assertThat(counter.get()).isEqualTo(0)
		}

		@Test
		fun simpleThrottle() {
		val request = RequestThrottle(handler) {
		counter.incrementAndGet()
		true
		}

		fun sendRequests() {
		request.schedule()
		val thread = startThread { request.schedule() }
		request.schedule()
		thread.joinForTest()
		}

		sendRequests()
		handler.flush()
		assertThat(counter.get()).isEqualTo(1)

		sendRequests()
		handler.flush()
		assertThat(counter.get()).isEqualTo(2)
		}

		@Test
		fun exceptionInRequest() {
		val shouldThrow = AtomicBoolean(true)
		val request = RequestThrottle(handler) {
		if (shouldThrow.get()) {
		throw RuntimeException()
		}
		counter.incrementAndGet()
		true
		}

		fun sendRequests() {
		request.schedule()
		val thread = startThread { request.schedule() }
		request.schedule()
		thread.joinForTest()
		}

		sendRequests()
		try {
		handler.flush()
		} catch (ignored: Exception) {
		}
		assertThat(counter.get()).isEqualTo(0)

		shouldThrow.set(false)

		sendRequests()
		handler.flush()
		assertThat(counter.get()).isEqualTo(1)
		}

		@Test
		fun scheduleWhileRunning() {
		val latchForStartRequest = CountDownLatch(1)
		val latchForEndRequest = CountDownLatch(1)
		val request = RequestThrottle(handler) {
		latchForStartRequest.countDown()
		counter.incrementAndGet()
		latchForEndRequest.awaitForTest()
		true
		}

		// Schedule and block a request
		request.schedule()
		val handlerThread = startThread { handler.timeAdvance() }
		latchForStartRequest.awaitForTest()

		// Hit it with other requests
		request.schedule()
		(0..5).map { startThread { request.schedule() } }
		.forEach { it.joinForTest() }

		// Release everything
		latchForEndRequest.countDown()
		handlerThread.join()
		handler.flush()

		// Ensure another request was run after initial blocking request ends
		assertThat(counter.get()).isEqualTo(2)
		}

		@Test
		fun backoffRetry() {
		val time = AtomicLong(0)
		val handler = TestHandler(null) { time.get() }
		val returnValue = AtomicBoolean(false)
		val request = RequestThrottle(handler, 3, 1000, 2) {
		counter.incrementAndGet()
		returnValue.get()
		}

		request.schedule()

		handler.timeAdvance()
		handler.pendingMessages.apply {
		assertThat(size).isEqualTo(1)
		assertThat(single().sendTime).isAround(1000)
		}

		time.set(1000)
		handler.timeAdvance()
		handler.pendingMessages.apply {
		assertThat(size).isEqualTo(1)
		assertThat(single().sendTime).isAround(3000)
		}

		time.set(3000)
		handler.timeAdvance()
		handler.pendingMessages.apply {
		assertThat(size).isEqualTo(1)
		assertThat(single().sendTime).isAround(7000)
		}

		returnValue.set(true)
		time.set(7000)
		handler.timeAdvance()
		assertThat(handler.pendingMessages).isEmpty()

		// Ensure another request was run after initial blocking request ends
		assertThat(counter.get()).isEqualTo(4)
		}

		@Test
		fun forceWriteMultiple() {
		val request = RequestThrottle(handler) {
		counter.incrementAndGet()
		true
		}

		request.runNow()
		request.runNow()
		request.runNow()

		assertThat(counter.get()).isEqualTo(3)
		}

		@Test
		fun forceWriteNowWithoutSync() {
		// When forcing a write without synchronizing the request block, 2 instances will be run.
		// There is no test for "with sync" because any logic to avoid multiple runs is left
		// entirely up to the caller.

		val barrierForEndRequest = CyclicBarrier(2)
		val request = RequestThrottle(handler) {
		counter.incrementAndGet()
		barrierForEndRequest.awaitForTest()
		true
		}

		// Schedule and block a request
		request.schedule()
		val thread = startThread { handler.timeAdvance() }

		request.runNow()

		thread.joinForTest()

		assertThat(counter.get()).isEqualTo(2)
		}

		private fun CountDownLatch.awaitForTest() = assertThat(await(5, TimeUnit.SECONDS)).isTrue()
		private fun CyclicBarrier.awaitForTest() = await(5, TimeUnit.SECONDS)
		private fun Thread.joinForTest() = join(5000)

		private fun startThread(block: () -> Unit) = Thread { block() }.apply { start() }

		// Float math means time calculations are not exact, so use a loose range
		private fun LongSubject.isAround(value: Long, threshold: Long = 10) =
		isIn(Range.closed(value - threshold, value + threshold))
		}