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Stop holding mProxyLock while downloading PAC script data.

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Holding PacManager#mProxyLock for long time eventually causes ANR when
launching new applications.

1. ActivityThread#handleBindApplication blocks until

   ActivityThread#handleBindApplication
   -> ConnectivityService#getProxyForNetwork()
   -> ConnectivityService#getDefaultProxy()

  obtains the lock of ConnectivityService#mProxyLock

2. ConnectivityService#mProxyLock can be held by
   ConnectivityService#setGlobalProxy() running on another thread until

   ConnectivityService#setGlobalProxy()
   -> ConnectivityService#sendProxyBroadcast()
   -> PacManager#setCurrentProxyScriptUrl()

  obtains the lock of PacManager#mProxyLock

3. Before the CL, PacManager#mProxyLock could be held by
   mPacDownloader#run() on mNetThread until downloading a PAC script
   completed.

The CL fixes the step 3 so that mPacDownloader#run does not keep the
lock of PacManager#mProxyLock. It eventually fixes long blocking at
ActivityThread#handleBindApplication and ANR when launching an
application.

Bug: 36317236
Test: Build succeeded
Merged-In: I864e41e1142178681f8f1b4fb7750d37e3ab2076
Change-Id: I864e41e1142178681f8f1b4fb7750d37e3ab2076
This commit is contained in:
Daichi Hirono
2017-03-17 09:12:12 +09:00
parent 58ba53bd53
commit ce522835ea
1 changed files with 19 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
services/core/java/com/android/server/connectivity/PacManager.java
View File

@ -15,6 +15,7 @@
*/
package com.android.server.connectivity;
import android.annotation.WorkerThread;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
@ -73,7 +74,7 @@ public class PacManager {
public static final String KEY_PROXY = "keyProxy";
private String mCurrentPac;
@GuardedBy("mProxyLock")
private Uri mPacUrl = Uri.EMPTY;
private volatile Uri mPacUrl = Uri.EMPTY;
private AlarmManager mAlarmManager;
@GuardedBy("mProxyLock")
@ -86,29 +87,34 @@ public class PacManager {
private int mCurrentDelay;
private int mLastPort;
private boolean mHasSentBroadcast;
private boolean mHasDownloaded;
private volatile boolean mHasSentBroadcast;
private volatile boolean mHasDownloaded;
private Handler mConnectivityHandler;
private int mProxyMessage;
/**
* Used for locking when setting mProxyService and all references to mPacUrl or mCurrentPac.
* Used for locking when setting mProxyService and all references to mCurrentPac.
*/
private final Object mProxyLock = new Object();
/**
* Runnable to download PAC script.
* The behavior relies on the assamption it always run on mNetThread to guarantee that the
* latest data fetched from mPacUrl is stored in mProxyService.
*/
private Runnable mPacDownloader = new Runnable() {
@Override
@WorkerThread
public void run() {
String file;
synchronized (mProxyLock) {
if (Uri.EMPTY.equals(mPacUrl)) return;
try {
file = get(mPacUrl);
} catch (IOException ioe) {
file = null;
Log.w(TAG, "Failed to load PAC file: " + ioe);
}
final Uri pacUrl = mPacUrl;
if (Uri.EMPTY.equals(pacUrl)) return;
try {
file = get(pacUrl);
} catch (IOException ioe) {
file = null;
Log.w(TAG, "Failed to load PAC file: " + ioe);
}
if (file != null) {
synchronized (mProxyLock) {
@ -171,9 +177,7 @@ public class PacManager {
// Allow to send broadcast, nothing to do.
return false;
}
synchronized (mProxyLock) {
mPacUrl = proxy.getPacFileUrl();
}
mPacUrl = proxy.getPacFileUrl();
mCurrentDelay = DELAY_1;
mHasSentBroadcast = false;
mHasDownloaded = false;