Merge "Another way to keep track number of foreground services in the device." into tm-qpr-dev

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

@@ -190,6 +190,7 @@ import java.util.Comparator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Predicate;
 
 public final class ActiveServices {
@@ -220,6 +221,11 @@ public final class ActiveServices {
                     | ServiceInfo.FOREGROUND_SERVICE_TYPE_CONNECTED_DEVICE
                     | ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION;
 
+    // Keep track of number of foreground services and number of apps that have foreground
+    // services in the device. This field is made to be directly accessed without holding AMS lock.
+    static final AtomicReference<Pair<Integer, Integer>> sNumForegroundServices =
+            new AtomicReference(new Pair<>(0, 0));
+
     // Foreground service is stopped for unknown reason.
     static final int FGS_STOP_REASON_UNKNOWN = 0;
     // Foreground service is stopped by app calling Service.stopForeground().
@@ -454,6 +460,7 @@ public final class ActiveServices {
         final ArrayList<ServiceRecord> mStartingBackground = new ArrayList<>();
 
         final ArrayMap<String, ActiveForegroundApp> mActiveForegroundApps = new ArrayMap<>();
+
         boolean mActiveForegroundAppsChanged;
 
         static final int MSG_BG_START_TIMEOUT = 1;
@@ -2025,6 +2032,7 @@ public final class ActiveServices {
                         logFGSStateChangeLocked(r,
                                 FrameworkStatsLog.FOREGROUND_SERVICE_STATE_CHANGED__STATE__ENTER,
                                 0, FGS_STOP_REASON_UNKNOWN);
+                        updateNumForegroundServicesLocked();
                     }
                     // Even if the service is already a FGS, we need to update the notification,
                     // so we need to call it again.
@@ -2116,6 +2124,7 @@ public final class ActiveServices {
                     mAm.updateLruProcessLocked(r.app, false, null);
                     updateServiceForegroundLocked(r.app.mServices, true);
                 }
+                updateNumForegroundServicesLocked();
             }
         }
     }
@@ -4784,6 +4793,7 @@ public final class ActiveServices {
         }
 
         smap.ensureNotStartingBackgroundLocked(r);
+        updateNumForegroundServicesLocked();
     }
 
     private void dropFgsNotificationStateLocked(ServiceRecord r) {
@@ -6975,6 +6985,10 @@ public final class ActiveServices {
                 fgsStopReasonToString(fgsStopReason));
     }
 
+    private void updateNumForegroundServicesLocked() {
+        sNumForegroundServices.set(mAm.mProcessList.getNumForegroundServices());
+    }
+
     boolean canAllowWhileInUsePermissionInFgsLocked(int callingPid, int callingUid,
             String callingPackage) {
         return shouldAllowFgsWhileInUsePermissionLocked(callingPackage, callingPid, callingUid,

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

@@ -814,12 +814,14 @@ public final class ProcessList {
                                                 < LmkdStatsReporter.KILL_OCCURRED_MSG_SIZE) {
                                             return false;
                                         }
-                                        Pair<Integer, Integer> temp = getNumForegroundServices();
+                                        // Note: directly access
-                                        final int totalForegroundServices = temp.first;
+                                        // ActiveServices.sNumForegroundServices, do not try to
-                                        final int procsWithForegroundServices = temp.second;
+                                        // hold AMS lock here, otherwise it is a potential deadlock.
+                                        Pair<Integer, Integer> foregroundServices =
+                                                ActiveServices.sNumForegroundServices.get();
                                         LmkdStatsReporter.logKillOccurred(inputData,
-                                                totalForegroundServices,
+                                                foregroundServices.first,
-                                                procsWithForegroundServices);
+                                                foregroundServices.second);
                                         return true;
                                     case LMK_STATE_CHANGED:
                                         if (receivedLen