Speed up NetworkPolicy thread during user creation

Network Policy Manager makes a ton of calls to
UsageStats.isAppIdle, which in turn tries to get
the network scorer and results in a lot of calls to
PackageManager. Caching the network scorer reduces a
lot of the lock contention with PackageManager.

Also, caching calls to check for an app's internet
permission.

Handler for USER_ADDED broadcast reduced in wallclock
duration from 2+ seconds to 114ms.

Bug: 156582823
Test: atest UserLifecycleTests#createAndStartUser
Test: atest AppStandbyTests
Change-Id: I369f9c129ca8a13016e00b1bec2776111fa04513

1 files changed, 24 insertions, 2 deletions

diff --git a/apex/jobscheduler/service/java/com/android/server/usage/AppStandbyController.java b/apex/jobscheduler/service/java/com/android/server/usage/AppStandbyController.java
index 280a6870a5e1..8b5602bc7cd9 100644
--- a/apex/jobscheduler/service/java/com/android/server/usage/AppStandbyController.java
+++ b/apex/jobscheduler/service/java/com/android/server/usage/AppStandbyController.java
@@ -90,6 +90,7 @@ import android.os.Process;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.SystemClock;
+import android.os.Trace;
 import android.os.UserHandle;
 import android.provider.Settings.Global;
 import android.telephony.TelephonyManager;
@@ -238,6 +239,14 @@ public class AppStandbyController implements AppStandbyInternal {
 
     private final CountDownLatch mAdminDataAvailableLatch = new CountDownLatch(1);
 
+    // Cache the active network scorer queried from the network scorer service
+    private volatile String mCachedNetworkScorer = null;
+    // The last time the network scorer service was queried
+    private volatile long mCachedNetworkScorerAtMillis = 0L;
+    // How long before querying the network scorer again. During this time, subsequent queries will
+    // get the cached value
+    private static final long NETWORK_SCORER_CACHE_DURATION_MILLIS = 5000L;
+
     // Messages for the handler
     static final int MSG_INFORM_LISTENERS = 3;
     static final int MSG_FORCE_IDLE_STATE = 4;
@@ -1154,6 +1163,8 @@ public class AppStandbyController implements AppStandbyInternal {
             return new int[0];
         }
 
+        Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "getIdleUidsForUser");
+
         final long elapsedRealtime = mInjector.elapsedRealtime();
 
         List<ApplicationInfo> apps;
@@ -1189,6 +1200,7 @@ public class AppStandbyController implements AppStandbyInternal {
                 uidStates.setValueAt(index, value + 1 + (idle ? 1<<16 : 0));
             }
         }
+
         if (DEBUG) {
             Slog.d(TAG, "getIdleUids took " + (mInjector.elapsedRealtime() - elapsedRealtime));
         }
@@ -1210,6 +1222,8 @@ public class AppStandbyController implements AppStandbyInternal {
             }
         }
 
+        Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
+
         return res;
     }
 
@@ -1576,8 +1590,16 @@ public class AppStandbyController implements AppStandbyInternal {
     }
 
     private boolean isActiveNetworkScorer(String packageName) {
-        String activeScorer = mInjector.getActiveNetworkScorer();
-        return packageName != null && packageName.equals(activeScorer);
+        // Validity of network scorer cache is limited to a few seconds. Fetch it again
+        // if longer since query.
+        // This is a temporary optimization until there's a callback mechanism for changes to network scorer.
+        final long now = SystemClock.elapsedRealtime();
+        if (mCachedNetworkScorer == null
+                || mCachedNetworkScorerAtMillis < now - NETWORK_SCORER_CACHE_DURATION_MILLIS) {
+            mCachedNetworkScorer = mInjector.getActiveNetworkScorer();
+            mCachedNetworkScorerAtMillis = now;
+        }
+        return packageName != null && packageName.equals(mCachedNetworkScorer);
     }
 
     private void informListeners(String packageName, int userId, int bucket, int reason,