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Commit 465e3b71 authored by Zim's avatar Zim
Browse files

Extend AnrController to improve ANR dialog controls 

I5431d22bd8faa75e3deab1960a2f721784f98d42 introduced a basic ANR
controller interface to allow services within the system_server
register to delay the ANR dialog during an ANR.

Some limitations of that interface were:
1. No way to cancel the ANR dialog if the normal function of the app
resumed during the delay
2. The AnrController#getAnrDelay method was serving a dual purpose of
returning the delay and showing an interim UI
3. The interim UI might live within an updatable mainline
module, hence forcing the system_server to block (asynchronously) on
the 'getter' for the binder call.

This cl addresses the problems above with the following new
methods on AnrController: onAnrDelayStarted and onAnrDelayCompleted.

These methods provide a clearer interface for the following reasons:
1. onAnrDelayCompleted will return a boolean value to indicate whether
the ANR dialog should still be shown after the delay
2. onAnrDelayStarted is a more explicit API that can be called
asynchronously without blocking to notify external components to show
an interim UI
3. The existing getAnrDelay can be handled completely within the
system_server without blocking on an external binder call

See design (2a) in go/transcoding-anrs for more details

Test: Manual
Bug: 170486601
Change-Id: Idb9190a0e6014ce64bf1412c26f6ae03f97e922d
parent 59536a1e

core/java/android/app/AnrController.java

+23 −1
Original line number Diff line number Diff line
@@ -23,7 +23,29 @@ package android.app; 
public interface AnrController {

    /**

     * Returns the delay in milliseconds for an ANR dialog that is about to be shown for

     * {@code packageName}.

     * {@code packageName} with {@code uid}.

     *

     * Implementations should only return a positive value if they actually expect the

     * {@code packageName} to be delayed due to them.



     * If there are multiple controllers registered, the controller with the max delay will

     * be selected and will receive an {@link #onAnrDelayStarted} callback at the start of the

     * delay and an {@link #onAnrDelayCompleted} at the end of the delay.

     */

    long getAnrDelayMillis(String packageName, int uid);



    /**

     * Notifies the controller at the start of the ANR dialog delay for {@code packageName} with

     * {@code uid}. The controller can decide to show a progress UI after this notification.

     */

    void onAnrDelayStarted(String packageName, int uid);



    /**

     * Notifies the controller at the end of the ANR dialog delay for {@code packageName} with

     * {@code uid}.

     *

     * @return whether the ANR dialog should be shown or cancelled. {@code true} if the

     * ANR dialog should be shown, {@code false} if it should be cancelled.

     */

    boolean onAnrDelayCompleted(String packageName, int uid);

}

services/core/java/com/android/server/StorageManagerService.java

+24 −8
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ import android.annotation.Nullable; 
import android.annotation.UserIdInt;

import android.app.ActivityManager;

import android.app.ActivityManagerInternal;

import android.app.AnrController;

import android.app.AppOpsManager;

import android.app.IActivityManager;

import android.app.KeyguardManager;
@@ -938,14 +939,29 @@ class StorageManagerService extends IStorageManager.Stub 


        if (transcodeEnabled) {

            LocalServices.getService(ActivityManagerInternal.class)

                    .registerAnrController((packageName, uid) -> {

                        try {

                            return mStorageSessionController.getAnrDelayMillis(packageName, uid);

                        } catch (ExternalStorageServiceException e) {

                            Log.e(TAG, "Failed to get ANR delay for " + packageName, e);

                            return 0;

                .registerAnrController(new ExternalStorageServiceAnrController());

        }

                    });

    }



    // TODO(b/170486601): Check transcoding status based on events pushed from the MediaProvider

    private class ExternalStorageServiceAnrController implements AnrController {

        @Override

        public long getAnrDelayMillis(String packageName, int uid) {

            int delay = SystemProperties.getInt("sys.fuse.transcode_anr_delay", 0);

            Log.d(TAG, "getAnrDelayMillis: " + packageName + ". Delaying for " + delay + "ms");

            return delay;

        }



        @Override

        public void onAnrDelayStarted(String packageName, int uid) {

            Log.d(TAG, "onAnrDelayStarted: " + packageName);

        }



        @Override

        public boolean onAnrDelayCompleted(String packageName, int uid) {

            boolean show = SystemProperties.getBoolean("sys.fuse.transcode_anr_dialog_show", true);

            Log.d(TAG, "onAnrDelayCompleted: " + packageName + ". Show: " + show);

            return show;

        }

    }

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

+21 −1
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ import static com.android.server.wm.ActivityTaskManagerService.RELAUNCH_REASON_N 


import android.app.ActivityManager;

import android.app.ActivityOptions;

import android.app.AnrController;

import android.app.ApplicationErrorReport;

import android.app.ApplicationExitInfo;

import android.content.ActivityNotFoundException;
@@ -1058,7 +1059,26 @@ class AppErrors { 
                    Settings.Secure.ANR_SHOW_BACKGROUND, 0,

                    mService.mUserController.getCurrentUserId()) != 0;

            if (mService.mAtmInternal.canShowErrorDialogs() || showBackground) {

                AnrController anrController = errState.getDialogController().getAnrController();

                if (anrController == null) {

                    errState.getDialogController().showAnrDialogs(data);

                } else {

                    String packageName = proc.info.packageName;

                    int uid = proc.info.uid;

                    boolean showDialog = anrController.onAnrDelayCompleted(packageName, uid);



                    if (showDialog) {

                        Slog.d(TAG, "ANR delay completed. Showing ANR dialog for package: "

                                + packageName);

                        errState.getDialogController().showAnrDialogs(data);

                    } else {

                        Slog.d(TAG, "ANR delay completed. Cancelling ANR dialog for package: "

                                + packageName);

                        errState.setNotResponding(false);

                        errState.setNotRespondingReport(null);

                        errState.getDialogController().clearAnrDialogs();

                    }

                }

            } else {

                MetricsLogger.action(mContext, MetricsProto.MetricsEvent.ACTION_APP_ANR,

                        AppNotRespondingDialog.CANT_SHOW);

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

+21 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 


package com.android.server.am;



import android.annotation.Nullable;

import android.app.AnrController;

import android.app.Dialog;

import android.content.Context;
@@ -57,6 +59,13 @@ final class ErrorDialogController { 
    @GuardedBy("mProcLock")

    private AppWaitingForDebuggerDialog mWaitDialog;



    /**

     * ANR dialog controller

     */

    @GuardedBy("mProcLock")

    @Nullable

    private AnrController mAnrController;



    @GuardedBy("mProcLock")

    boolean hasCrashDialogs() {

        return mCrashDialogs != null;
@@ -118,6 +127,7 @@ final class ErrorDialogController { 
        }

        forAllDialogs(mAnrDialogs, Dialog::dismiss);

        mAnrDialogs = null;

        mAnrController = null;

    }



    @GuardedBy("mProcLock")
@@ -220,6 +230,17 @@ final class ErrorDialogController { 
        });

    }



    @GuardedBy("mProcLock")

    @Nullable

    AnrController getAnrController() {

        return mAnrController;

    }



    @GuardedBy("mProcLock")

    void setAnrController(AnrController controller) {

        mAnrController = controller;

    }



    /**

     * Helper function to collect contexts from crashed app located displays.

     *

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

+12 −4
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ import static com.android.server.am.ActivityManagerService.MY_PID; 
import static com.android.server.am.ProcessRecord.TAG;



import android.app.ActivityManager;

import android.app.AnrController;

import android.app.ApplicationErrorReport;

import android.app.ApplicationExitInfo;

import android.content.ComponentName;
@@ -418,10 +419,16 @@ class ProcessErrorStateRecord { 


        // Retrieve max ANR delay from AnrControllers without the mService lock since the

        // controllers might in turn call into apps

        long anrDialogDelayMs = mService.mActivityTaskManager.getMaxAnrDelayMillis(aInfo);

        if (aInfo != null && aInfo.packageName != null && anrDialogDelayMs > 0) {

            Slog.i(TAG, "Delaying ANR dialog for " + aInfo.packageName + " for " + anrDialogDelayMs

                    + "ms");

        AnrController anrController = mService.mActivityTaskManager.getAnrController(aInfo);

        long anrDialogDelayMs = 0;

        if (anrController != null) {

            String packageName = aInfo.packageName;

            int uid = aInfo.uid;

            anrDialogDelayMs = anrController.getAnrDelayMillis(packageName, uid);

            // Might execute an async binder call to a system app to show an interim

            // ANR progress UI

            anrController.onAnrDelayStarted(packageName, uid);

            Slog.i(TAG, "ANR delay of " + anrDialogDelayMs + "ms started for " + packageName);

        }



        synchronized (mService) {
@@ -440,6 +447,7 @@ class ProcessErrorStateRecord { 
                // Set the app's notResponding state, and look up the errorReportReceiver

                makeAppNotRespondingLSP(activityShortComponentName,

                        annotation != null ? "ANR " + annotation : "ANR", info.toString());

                mDialogController.setAnrController(anrController);

            }



            // Notify package manager service to possibly update package state