Do not deliver notifications to frozen processes (57d4dd81) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/am/ActivityManagerService.java

+3 −2

Original line number	Diff line number	Diff line
		@@ -2075,7 +2075,8 @@ public class ActivityManagerService extends IActivityManager.Stub
		app.setPersistent(true);
		app.setPid(MY_PID);
		app.mState.setMaxAdj(ProcessList.SYSTEM_ADJ);
		app.makeActive(mSystemThread.getApplicationThread(), mProcessStats);
		app.makeActive(new ApplicationThreadDeferred(mSystemThread.getApplicationThread()),
		mProcessStats);
		app.mProfile.addHostingComponentType(HOSTING_COMPONENT_TYPE_SYSTEM);
		addPidLocked(app);
		updateLruProcessLocked(app, false, null);
		@@ -4871,7 +4872,7 @@ public class ActivityManagerService extends IActivityManager.Stub
		// Make app active after binding application or client may be running requests (e.g
		// starting activities) before it is ready.
		synchronized (mProcLock) {
		app.makeActive(thread, mProcessStats);
		app.makeActive(new ApplicationThreadDeferred(thread), mProcessStats);
		checkTime(startTime, "attachApplicationLocked: immediately after bindApplication");
		}
		app.setPendingFinishAttach(true);

services/core/java/com/android/server/am/ApplicationThreadDeferred.java

0 → 100644

+173 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 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.am;

		import static com.android.server.am.ActivityManagerDebugConfig.TAG_AM;
		import static com.android.server.am.ActivityManagerDebugConfig.TAG_WITH_CLASS_NAME;

		import android.annotation.IntDef;
		import android.app.IApplicationThread;
		import android.os.RemoteException;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.annotations.VisibleForTesting;

		import java.lang.annotation.Retention;
		import java.lang.annotation.RetentionPolicy;
		import java.util.Arrays;

		/**
		* A subclass of {@link IApplicationThread} that defers certain binder calls while the process is
		* paused (frozen). Any deferred calls are executed when the process is unpaused. In some cases,
		* multiple instances of deferred calls are collapsed into a single call when the process is
		* unpaused.
		*
		* {@hide}
		*/
		class ApplicationThreadDeferred extends ApplicationThreadFilter {

		static final String TAG = TAG_WITH_CLASS_NAME ? "ApplicationThreadDeferred" : TAG_AM;

		// The flag that enables the deferral behavior of this class. If the flag is disabled then
		// the class behaves exactly like an ApplicationThreadFilter.
		private static boolean deferBindersWhenPaused() {
		return Flags.deferBindersWhenPaused();
		}

		// The list of notifications that may be deferred.
		private static final int CLEAR_DNS_CACHE = 0;
		private static final int UPDATE_TIME_ZONE = 1;
		private static final int SCHEDULE_LOW_MEMORY = 2;
		private static final int UPDATE_HTTP_PROXY = 3;
		private static final int NOTIFICATION_COUNT = 4;

		@IntDef(value = {
		CLEAR_DNS_CACHE,
		UPDATE_TIME_ZONE,
		SCHEDULE_LOW_MEMORY,
		UPDATE_HTTP_PROXY
		})
		@Retention(RetentionPolicy.SOURCE)
		private @interface NotificationType {};

		private final Object mLock = new Object();

		// If this is true, notifications should be queued for later delivery. If this is false,
		// notifications should be delivered immediately.
		@GuardedBy("mLock")
		private boolean mPaused = false;

		// An operation is a lambda that throws an exception.
		private interface Operation {
		void run() throws RemoteException;
		}

		// The array of operations.
		@GuardedBy("mLock")
		private final Operation[] mOperations = new Operation[NOTIFICATION_COUNT];

		// The array of operations that actually pending right now.
		@GuardedBy("mLock")
		private final boolean[] mPending = new boolean[NOTIFICATION_COUNT];

		// When true, binder calls to paused processes will be deferred until the process is unpaused.
		private final boolean mDefer;

		/** Create an instance with a base thread and a deferral enable flag. */
		@VisibleForTesting
		public ApplicationThreadDeferred(IApplicationThread thread, boolean defer) {
		super(thread);

		mDefer = defer;

		mOperations[CLEAR_DNS_CACHE] = () -> { super.clearDnsCache(); };
		mOperations[UPDATE_TIME_ZONE] = () -> { super.updateTimeZone(); };
		mOperations[SCHEDULE_LOW_MEMORY] = () -> { super.scheduleLowMemory(); };
		mOperations[UPDATE_HTTP_PROXY] = () -> { super.updateHttpProxy(); };
		}

		/** Create an instance with a base flag, using the system deferral enable flag. */
		public ApplicationThreadDeferred(IApplicationThread thread) {
		this(thread, deferBindersWhenPaused());
		}

		/** The process is being paused. Start deferring calls. */
		void onProcessPaused() {
		synchronized (mLock) {
		mPaused = true;
		}
		}

		/** The process is no longer paused. Drain any deferred calls. */
		void onProcessUnpaused() {
		synchronized (mLock) {
		mPaused = false;
		try {
		for (int i = 0; i < mOperations.length; i++) {
		if (mPending[i]) {
		mOperations[i].run();
		}
		}
		} catch (RemoteException e) {
		// Swallow the exception. The caller is not expecting it. Remote exceptions
		// happen if a has process died; there is no need to report it here.
		} finally {
		Arrays.fill(mPending, false);
		}
		}
		}

		/** The pause operation has been canceled. Drain any deferred calls. */
		void onProcessPausedCancelled() {
		onProcessUnpaused();
		}

		/**
		* If the thread is not paused, execute the operation. Otherwise, save it to the pending
		* list.
		*/
		private void execute(@NotificationType int tag) throws RemoteException {
		synchronized (mLock) {
		if (mPaused && mDefer) {
		mPending[tag] = true;
		return;
		}
		}
		// Outside the synchronization block to avoid contention.
		mOperations[tag].run();
		}

		@Override
		public void clearDnsCache() throws RemoteException {
		execute(CLEAR_DNS_CACHE);
		}

		@Override
		public void updateTimeZone() throws RemoteException {
		execute(UPDATE_TIME_ZONE);
		}

		@Override
		public void scheduleLowMemory() throws RemoteException {
		execute(SCHEDULE_LOW_MEMORY);
		}

		@Override
		public void updateHttpProxy() throws RemoteException {
		execute(UPDATE_HTTP_PROXY);
		}
		}

services/core/java/com/android/server/am/ApplicationThreadFilter.java

0 → 100644

+603 −0

File added.

Preview size limit exceeded, changes collapsed.

services/core/java/com/android/server/am/ProcessRecord.java

+8 −5

Original line number	Diff line number	Diff line
		@@ -151,7 +151,7 @@ class ProcessRecord implements WindowProcessListener {
		* (in which case we are in the process of launching the app).
		*/
		@CompositeRWLock({"mService", "mProcLock"})
		private IApplicationThread mThread;
		private ApplicationThreadDeferred mThread;

		/**
		* Instance of {@link #mThread} that will always meet the {@code oneway}
		@@ -737,15 +737,15 @@ class ProcessRecord implements WindowProcessListener {
		}

		@GuardedBy({"mService", "mProcLock"})
		public void makeActive(IApplicationThread thread, ProcessStatsService tracker) {
		public void makeActive(ApplicationThreadDeferred thread, ProcessStatsService tracker) {
		mProfile.onProcessActive(thread, tracker);
		mThread = thread;
		if (mPid == Process.myPid()) {
		mOnewayThread = new SameProcessApplicationThread(thread, FgThread.getHandler());
		mOnewayThread = new SameProcessApplicationThread(mThread, FgThread.getHandler());
		} else {
		mOnewayThread = thread;
		mOnewayThread = mThread;
		}
		mWindowProcessController.setThread(thread);
		mWindowProcessController.setThread(mThread);
		if (mWindowProcessController.useFifoUiScheduling()) {
		mService.mSpecifiedFifoProcesses.add(this);
		}
		@@ -1436,14 +1436,17 @@ class ProcessRecord implements WindowProcessListener {

		void onProcessFrozen() {
		mProfile.onProcessFrozen();
		if (mThread != null) mThread.onProcessPaused();
		}

		void onProcessUnfrozen() {
		if (mThread != null) mThread.onProcessUnpaused();
		mProfile.onProcessUnfrozen();
		mServices.onProcessUnfrozen();
		}

		void onProcessFrozenCancelled() {
		if (mThread != null) mThread.onProcessPausedCancelled();
		mServices.onProcessFrozenCancelled();
		}

services/core/java/com/android/server/am/flags.aconfig

+8 −0

Original line number	Diff line number	Diff line
		@@ -176,3 +176,11 @@ flag {
		bug: "330682397"
		is_fixed_read_only: true
		}

		flag {
		name: "defer_binders_when_paused"
		namespace: "system_performance"
		is_fixed_read_only: true
		description: "Defer submitting binder calls to paused processes."
		bug: "327038797"
		}