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Commit db5dec27 authored by Filip Gruszczynski's avatar Filip Gruszczynski
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Improve relaunch merging in activity thread. 

To reduce the number of times that we load resources based on
configuration changes ActivityThread employs an optimization
strategy that merges relaunch operations. If it receives a
relaunch request why one is already queued, it will just update
the queued request instead of creating a new one. Unfortunately
this breaks the guarantee of executing lifecycle events in the
order they were received.

Consider following scenario of requestes from Activity Manager:
1) relaunch the activity in not resumed state;
2) resume the activity;
3) relaunch the activity in resumed state.

The Activity Thread can process these commands in following order:
1) receive the request to relaunch in not resumed state;
2) receive the request to resume the activity;
3) receive the request to resumed state, update the exisiting
request;
4) execute the request to relaunch in resume state;
5) execute the request to resume.

This causes the activity to perform resume twice.

Since we need the merging of relaunch operations for performance
reasons, we need to introduce a secondary mechanism for ordering
of lifecycle requests. Relaunching, pausing, stopping and resuming
receive a sequence number based on when the request was received. If
the last executed sequence number is higher then the operations
sequence number then the operation will be dropped.

In the above scenario the sequence number would be:
1) request to relaunch not resumed receives seq + 0;
2) request to resume receives seq + 1;
3) request to relaunch resumed receives seq + 2;
4) execution of of request to relaunch resumed set current sequence
number to seq + 2;
5) since seq + 1 < seq + 2, then the execution of request to resume
is prevented.

Bug: 24806374

Change-Id: Ia520dd1aa215827d4172a9891a7cc01db2ce627e
parent b52b1805

core/java/android/app/ActivityThread.java

+124 −25
Original line number Diff line number Diff line
@@ -101,11 +101,13 @@ import android.view.WindowManagerGlobal; 
import android.renderscript.RenderScriptCacheDir;

import android.security.keystore.AndroidKeyStoreProvider;



import com.android.internal.annotations.GuardedBy;

import com.android.internal.app.IVoiceInteractor;

import com.android.internal.content.ReferrerIntent;

import com.android.internal.os.BinderInternal;

import com.android.internal.os.RuntimeInit;

import com.android.internal.os.SamplingProfilerIntegration;

import com.android.internal.os.SomeArgs;

import com.android.internal.util.FastPrintWriter;

import com.android.org.conscrypt.OpenSSLSocketImpl;

import com.android.org.conscrypt.TrustedCertificateStore;
@@ -163,6 +165,7 @@ public final class ActivityThread { 
    private static final boolean DEBUG_SERVICE = false;

    private static final boolean DEBUG_MEMORY_TRIM = false;

    private static final boolean DEBUG_PROVIDER = false;

    private static final boolean DEBUG_ORDER = false;

    private static final long MIN_TIME_BETWEEN_GCS = 5*1000;

    private static final int SQLITE_MEM_RELEASED_EVENT_LOG_TAG = 75003;

    private static final int LOG_AM_ON_PAUSE_CALLED = 30021;
@@ -175,6 +178,10 @@ public final class ActivityThread { 
    /** Type for IActivityManager.serviceDoneExecuting: done stopping (destroying) service */

    public static final int SERVICE_DONE_EXECUTING_STOP = 2;



    // Details for pausing activity.

    private static final int USER_LEAVING = 1;

    private static final int DONT_REPORT = 2;



    private ContextImpl mSystemContext;



    static IPackageManager sPackageManager;
@@ -231,6 +238,12 @@ public final class ActivityThread { 
    final ArrayList<ActivityClientRecord> mRelaunchingActivities

            = new ArrayList<ActivityClientRecord>();

    Configuration mPendingConfiguration = null;

    // Because we merge activity relaunch operations we can't depend on the ordering provided by

    // the handler messages. We need to introduce secondary ordering mechanism, which will allow

    // us to drop certain events, if we know that they happened before relaunch we already executed.

    // This represents the order of receiving the request from AM.

    @GuardedBy("mResourcesManager")

    int mLifecycleSeq = 0;



    private final ResourcesManager mResourcesManager;
@@ -319,6 +332,14 @@ public final class ActivityThread { 
        WindowManager mPendingRemoveWindowManager;

        boolean mPreserveWindow;



        // Set for relaunch requests, indicates the order number of the relaunch operation, so it

        // can be compared with other lifecycle operations.

        int relaunchSeq = 0;



        // Can only be accessed from the UI thread. This represents the latest processed message

        // that is related to lifecycle events/

        int lastProcessedSeq = 0;



        ActivityClientRecord() {

            parent = null;

            embeddedID = null;
@@ -592,18 +613,25 @@ public final class ActivityThread { 


        public final void schedulePauseActivity(IBinder token, boolean finished,

                boolean userLeaving, int configChanges, boolean dontReport) {

            int seq = getLifecycleSeq();

            if (DEBUG_ORDER) Slog.d(TAG, "pauseActivity " + ActivityThread.this

                    + " operation received seq: " + seq);

            sendMessage(

                    finished ? H.PAUSE_ACTIVITY_FINISHING : H.PAUSE_ACTIVITY,

                    token,

                    (userLeaving ? 1 : 0) | (dontReport ? 2 : 0),

                    configChanges);

                    (userLeaving ? USER_LEAVING : 0) | (dontReport ? DONT_REPORT : 0),

                    configChanges,

                    seq);

        }



        public final void scheduleStopActivity(IBinder token, boolean showWindow,

                int configChanges) {

            int seq = getLifecycleSeq();

            if (DEBUG_ORDER) Slog.d(TAG, "stopActivity " + ActivityThread.this

                    + " operation received seq: " + seq);

            sendMessage(

                showWindow ? H.STOP_ACTIVITY_SHOW : H.STOP_ACTIVITY_HIDE,

                token, 0, configChanges);

                token, 0, configChanges, seq);

        }



        public final void scheduleWindowVisibility(IBinder token, boolean showWindow) {
@@ -618,8 +646,11 @@ public final class ActivityThread { 


        public final void scheduleResumeActivity(IBinder token, int processState,

                boolean isForward, Bundle resumeArgs) {

            int seq = getLifecycleSeq();

            if (DEBUG_ORDER) Slog.d(TAG, "resumeActivity " + ActivityThread.this

                    + " operation received seq: " + seq);

            updateProcessState(processState, false);

            sendMessage(H.RESUME_ACTIVITY, token, isForward ? 1 : 0);

            sendMessage(H.RESUME_ACTIVITY, token, isForward ? 1 : 0, 0, seq);

        }



        public final void scheduleSendResult(IBinder token, List<ResultInfo> results) {
@@ -1245,6 +1276,12 @@ public final class ActivityThread { 
        }

    }



    private int getLifecycleSeq() {

        synchronized (mResourcesManager) {

            return mLifecycleSeq++;

        }

    }



    private class H extends Handler {

        public static final int LAUNCH_ACTIVITY         = 100;

        public static final int PAUSE_ACTIVITY          = 101;
@@ -1373,29 +1410,34 @@ public final class ActivityThread { 
                    handleRelaunchActivity(r);

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                } break;

                case PAUSE_ACTIVITY:

                case PAUSE_ACTIVITY: {

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause");

                    handlePauseActivity((IBinder)msg.obj, false, (msg.arg1&1) != 0, msg.arg2,

                            (msg.arg1&2) != 0);

                    SomeArgs args = (SomeArgs) msg.obj;

                    handlePauseActivity((IBinder) args.arg1, false,

                            (args.argi1 & USER_LEAVING) != 0, args.argi2,

                            (args.argi1 & DONT_REPORT) != 0, args.argi3);

                    maybeSnapshot();

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                    break;

                case PAUSE_ACTIVITY_FINISHING:

                } break;

                case PAUSE_ACTIVITY_FINISHING: {

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause");

                    handlePauseActivity((IBinder)msg.obj, true, (msg.arg1&1) != 0, msg.arg2,

                            (msg.arg1&1) != 0);

                    SomeArgs args = (SomeArgs) msg.obj;

                    handlePauseActivity((IBinder) args.arg1, true, (args.argi1 & USER_LEAVING) != 0,

                            args.argi2, (args.argi1 & DONT_REPORT) != 0, args.argi3);

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                    break;

                case STOP_ACTIVITY_SHOW:

                } break;

                case STOP_ACTIVITY_SHOW: {

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop");

                    handleStopActivity((IBinder)msg.obj, true, msg.arg2);

                    SomeArgs args = (SomeArgs) msg.obj;

                    handleStopActivity((IBinder) args.arg1, true, args.argi2, args.argi3);

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                    break;

                case STOP_ACTIVITY_HIDE:

                } break;

                case STOP_ACTIVITY_HIDE: {

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop");

                    handleStopActivity((IBinder)msg.obj, false, msg.arg2);

                    SomeArgs args = (SomeArgs) msg.obj;

                    handleStopActivity((IBinder) args.arg1, false, args.argi2, args.argi3);

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                    break;

                } break;

                case SHOW_WINDOW:

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityShowWindow");

                    handleWindowVisibility((IBinder)msg.obj, true);
@@ -1408,7 +1450,9 @@ public final class ActivityThread { 
                    break;

                case RESUME_ACTIVITY:

                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityResume");

                    handleResumeActivity((IBinder) msg.obj, true, msg.arg1 != 0, true);

                    SomeArgs args = (SomeArgs) msg.obj;

                    handleResumeActivity((IBinder) args.arg1, true, args.argi1 != 0, true,

                            args.argi3);

                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                    break;

                case SEND_RESULT:
@@ -1587,6 +1631,10 @@ public final class ActivityThread { 
                    handleStopBinderTrackingAndDump((ParcelFileDescriptor) msg.obj);

                    break;

            }

            Object obj = msg.obj;

            if (obj instanceof SomeArgs) {

                ((SomeArgs) obj).recycle();

            }

            if (DEBUG_MESSAGES) Slog.v(TAG, "<<< done: " + codeToString(msg.what));

        }
@@ -2311,6 +2359,21 @@ public final class ActivityThread { 
        mH.sendMessage(msg);

    }



    private void sendMessage(int what, Object obj, int arg1, int arg2, int seq) {

        if (DEBUG_MESSAGES) Slog.v(

                TAG, "SCHEDULE " + mH.codeToString(what) + " arg1=" + arg1 + " arg2=" + arg2 +

                        "seq= " + seq);

        Message msg = Message.obtain();

        msg.what = what;

        SomeArgs args = SomeArgs.obtain();

        args.arg1 = obj;

        args.argi1 = arg1;

        args.argi2 = arg2;

        args.argi3 = seq;

        msg.obj = args;

        mH.sendMessage(msg);

    }



    final void scheduleContextCleanup(ContextImpl context, String who,

            String what) {

        ContextCleanupInfo cci = new ContextCleanupInfo();
@@ -2516,7 +2579,7 @@ public final class ActivityThread { 
            reportSizeConfigurations(r);

            Bundle oldState = r.state;

            handleResumeActivity(r.token, false, r.isForward,

                    !r.activity.mFinished && !r.startsNotResumed);

                    !r.activity.mFinished && !r.startsNotResumed, r.lastProcessedSeq);



            if (!r.activity.mFinished && r.startsNotResumed) {

                // The activity manager actually wants this one to start out
@@ -3216,14 +3279,19 @@ public final class ActivityThread { 
    }



    final void handleResumeActivity(IBinder token,

            boolean clearHide, boolean isForward, boolean reallyResume) {

            boolean clearHide, boolean isForward, boolean reallyResume, int seq) {

        ActivityClientRecord r = mActivities.get(token);

        if (!checkAndUpdateLifecycleSeq(seq, r, "resumeActivity")) {

            return;

        }



        // If we are getting ready to gc after going to the background, well

        // we are back active so skip it.

        unscheduleGcIdler();

        mSomeActivitiesChanged = true;



        // TODO Push resumeArgs into the activity for consideration

        ActivityClientRecord r = performResumeActivity(token, clearHide);

        r = performResumeActivity(token, clearHide);



        if (r != null) {

            final Activity a = r.activity;
@@ -3400,8 +3468,11 @@ public final class ActivityThread { 
    }



    private void handlePauseActivity(IBinder token, boolean finished,

            boolean userLeaving, int configChanges, boolean dontReport) {

            boolean userLeaving, int configChanges, boolean dontReport, int seq) {

        ActivityClientRecord r = mActivities.get(token);

        if (!checkAndUpdateLifecycleSeq(seq, r, "pauseActivity")) {

            return;

        }

        if (r != null) {

            //Slog.v(TAG, "userLeaving=" + userLeaving + " handling pause of " + r);

            if (userLeaving) {
@@ -3639,8 +3710,11 @@ public final class ActivityThread { 
        }

    }



    private void handleStopActivity(IBinder token, boolean show, int configChanges) {

    private void handleStopActivity(IBinder token, boolean show, int configChanges, int seq) {

        ActivityClientRecord r = mActivities.get(token);

        if (!checkAndUpdateLifecycleSeq(seq, r, "stopActivity")) {

            return;

        }

        r.activity.mConfigChangeFlags |= configChanges;



        StopInfo info = new StopInfo();
@@ -3669,6 +3743,20 @@ public final class ActivityThread { 
        mSomeActivitiesChanged = true;

    }



    private static boolean checkAndUpdateLifecycleSeq(int seq, ActivityClientRecord r,

            String action) {

        if (r == null) {

            return true;

        }

        if (seq < r.lastProcessedSeq) {

            if (DEBUG_ORDER) Slog.d(TAG, action + " for " + r + " ignored, because seq=" + seq

                    + " < mCurrentLifecycleSeq=" + r.lastProcessedSeq);

            return false;

        }

        r.lastProcessedSeq = seq;

        return true;

    }



    final void performRestartActivity(IBinder token) {

        ActivityClientRecord r = mActivities.get(token);

        if (r.stopped) {
@@ -4070,7 +4158,10 @@ public final class ActivityThread { 
                target.overrideConfig = overrideConfig;

            }

            target.pendingConfigChanges |= configChanges;

            target.relaunchSeq = getLifecycleSeq();

        }

        if (DEBUG_ORDER) Slog.d(TAG, "relaunchActivity " + ActivityThread.this

                + " operation received seq: " + target.relaunchSeq);

    }



    private void handleRelaunchActivity(ActivityClientRecord tmp) {
@@ -4115,6 +4206,12 @@ public final class ActivityThread { 
            }

        }



        if (tmp.lastProcessedSeq > tmp.relaunchSeq) {

            Slog.wtf(TAG, "For some reason target: " + tmp + " has lower sequence: "

                    + tmp.relaunchSeq + " than current sequence: " + tmp.lastProcessedSeq);

        } else {

            tmp.lastProcessedSeq = tmp.relaunchSeq;

        }

        if (tmp.createdConfig != null) {

            // If the activity manager is passing us its current config,

            // assume that is really what we want regardless of what we
@@ -4148,6 +4245,8 @@ public final class ActivityThread { 
        r.activity.mConfigChangeFlags |= configChanges;

        r.onlyLocalRequest = tmp.onlyLocalRequest;

        r.mPreserveWindow = tmp.mPreserveWindow;

        r.lastProcessedSeq = tmp.lastProcessedSeq;

        r.relaunchSeq = tmp.relaunchSeq;

        Intent currentIntent = r.activity.mIntent;



        r.activity.mChangingConfigurations = true;