From 61db88fc8b4a5729d9ce6bc1b7bfaac5c09c8f90 Mon Sep 17 00:00:00 2001
From: Adam Lesinski <adamlesinski@google.com>
Date: Wed, 1 Jul 2015 15:05:07 -0700
Subject: [PATCH] BatteryStats: Remove isolated UIDs from /proc/uid_cputime
 when they are not in use anymore

Bug:22225933
Change-Id: I384a3c37ad45af981cca5fc3e92643da948d48d0
---
 .../android/internal/os/BatteryStatsImpl.java | 20 +++++++++-
 .../server/am/BatteryStatsService.java        | 37 +++++++++++++++----
 2 files changed, 47 insertions(+), 10 deletions(-)

diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index 8b4b99422a4d4..f4211895031b1 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -183,6 +183,7 @@ public final class BatteryStatsImpl extends BatteryStats {
     public interface ExternalStatsSync {
         void scheduleSync(String reason);
         void scheduleWifiSync(String reason);
+        void scheduleCpuSyncDueToRemovedUid(int uid);
     }
 
     public final MyHandler mHandler;
@@ -2522,13 +2523,28 @@ public final class BatteryStatsImpl extends BatteryStats {
         mIsolatedUids.put(isolatedUid, appUid);
     }
 
-    public void removeIsolatedUidLocked(int isolatedUid, int appUid) {
+    /**
+     * Schedules a read of the latest cpu times before removing the isolated UID.
+     * @see #removeIsolatedUidLocked(int)
+     */
+    public void scheduleRemoveIsolatedUidLocked(int isolatedUid, int appUid) {
         int curUid = mIsolatedUids.get(isolatedUid, -1);
         if (curUid == appUid) {
-            mIsolatedUids.delete(isolatedUid);
+            if (mExternalSync != null) {
+                mExternalSync.scheduleCpuSyncDueToRemovedUid(isolatedUid);
+            }
         }
     }
 
+    /**
+     * This should only be called after the cpu times have been read.
+     * @see #scheduleRemoveIsolatedUidLocked(int, int)
+     */
+    public void removeIsolatedUidLocked(int isolatedUid) {
+        mIsolatedUids.delete(isolatedUid);
+        mKernelUidCpuTimeReader.removeUid(isolatedUid);
+    }
+
     public int mapUid(int uid) {
         int isolated = mIsolatedUids.get(uid, -1);
         return isolated > 0 ? isolated : uid;
diff --git a/services/core/java/com/android/server/am/BatteryStatsService.java b/services/core/java/com/android/server/am/BatteryStatsService.java
index 6cc1b115572bf..ab47f763d7f3b 100644
--- a/services/core/java/com/android/server/am/BatteryStatsService.java
+++ b/services/core/java/com/android/server/am/BatteryStatsService.java
@@ -41,6 +41,7 @@ import android.os.WorkSource;
 import android.telephony.DataConnectionRealTimeInfo;
 import android.telephony.SignalStrength;
 import android.telephony.TelephonyManager;
+import android.util.IntArray;
 import android.util.Slog;
 
 import android.util.TimeUtils;
@@ -82,6 +83,7 @@ public final class BatteryStatsService extends IBatteryStats.Stub
         public static final int MSG_SYNC_EXTERNAL_STATS = 1;
         public static final int MSG_WRITE_TO_DISK = 2;
         private int mUpdateFlags = 0;
+        private IntArray mUidsToRemove = new IntArray();
 
         public BatteryStatsHandler(Looper looper) {
             super(looper);
@@ -98,6 +100,15 @@ public final class BatteryStatsService extends IBatteryStats.Stub
                         mUpdateFlags = 0;
                     }
                     updateExternalStats((String)msg.obj, updateFlags);
+                    synchronized (this) {
+                        synchronized (mStats) {
+                            final int numUidsToRemove = mUidsToRemove.size();
+                            for (int i = 0; i < numUidsToRemove; i++) {
+                                mStats.removeIsolatedUidLocked(mUidsToRemove.get(i));
+                            }
+                        }
+                        mUidsToRemove.clear();
+                    }
                     break;
 
                 case MSG_WRITE_TO_DISK:
@@ -111,22 +122,32 @@ public final class BatteryStatsService extends IBatteryStats.Stub
 
         @Override
         public void scheduleSync(String reason) {
-            scheduleSyncImpl(reason, UPDATE_ALL);
+            synchronized (this) {
+                scheduleSyncLocked(reason, UPDATE_ALL);
+            }
         }
 
         @Override
         public void scheduleWifiSync(String reason) {
-            scheduleSyncImpl(reason, UPDATE_WIFI);
+            synchronized (this) {
+                scheduleSyncLocked(reason, UPDATE_WIFI);
+            }
         }
 
-        private void scheduleSyncImpl(String reason, int updateFlags) {
+        @Override
+        public void scheduleCpuSyncDueToRemovedUid(int uid) {
             synchronized (this) {
-                if (mUpdateFlags == 0) {
-                    sendMessage(Message.obtain(this, MSG_SYNC_EXTERNAL_STATS, reason));
-                }
-                mUpdateFlags |= updateFlags;
+                scheduleSyncLocked("remove-uid", UPDATE_CPU);
+                mUidsToRemove.add(uid);
             }
         }
+
+        private void scheduleSyncLocked(String reason, int updateFlags) {
+            if (mUpdateFlags == 0) {
+                sendMessage(Message.obtain(this, MSG_SYNC_EXTERNAL_STATS, reason));
+            }
+            mUpdateFlags |= updateFlags;
+        }
     }
 
     BatteryStatsService(File systemDir, Handler handler) {
@@ -220,7 +241,7 @@ public final class BatteryStatsService extends IBatteryStats.Stub
 
     void removeIsolatedUid(int isolatedUid, int appUid) {
         synchronized (mStats) {
-            mStats.removeIsolatedUidLocked(isolatedUid, appUid);
+            mStats.scheduleRemoveIsolatedUidLocked(isolatedUid, appUid);
         }
     }