Fix issue #2619247: Music sometimes stops playing when navigation talks

When a service transitions from foreground to background, we now push it
to the top of the LRU list.  Also fix the activity manager to take care
of killing processes if we go beyond a reasonable number of background
process to keep around.

Change-Id: Ic9f44c02af7a111ee6f1d06142386b301948bafe

1 files changed, 28 insertions, 9 deletions

diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 7e095b588a93..436bd17d0f80 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -315,6 +315,11 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
     // without empty apps being able to push them out of memory.
     static final int MIN_HIDDEN_APPS = 2;
     
+    // The maximum number of hidden processes we will keep around before
+    // killing them; this is just a control to not let us go too crazy with
+    // keeping around processes on devices with large amounts of RAM.
+    static final int MAX_HIDDEN_APPS = 15;
+    
     // We put empty content processes after any hidden processes that have
     // been idle for less than 30 seconds.
     static final long CONTENT_APP_IDLE_OFFSET = 30*1000;
@@ -8488,8 +8493,7 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                 }
                 int adj = proc.setAdj;
                 if (adj >= worstType) {
-                    Slog.w(TAG, "Killing " + reason + " : " + proc + " (adj "
-                            + adj + ")");
+                    Slog.w(TAG, "Killing " + proc + " (adj " + adj + "): " + reason);
                     EventLog.writeEvent(EventLogTags.AM_KILL, proc.pid,
                             proc.processName, adj, reason);
                     killed = true;
@@ -8904,9 +8908,10 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
             }
             if (app.pid > 0 && app.pid != MY_PID) {
                 handleAppCrashLocked(app);
-                Slog.i(ActivityManagerService.TAG, "Killing process "
-                        + app.processName
-                        + " (pid=" + app.pid + ") at user's request");
+                Slog.i(ActivityManagerService.TAG, "Killing "
+                        + app.processName + " (pid=" + app.pid + "): user's request");
+                EventLog.writeEvent(EventLogTags.AM_KILL, app.pid,
+                        app.processName, app.setAdj, "user's request after error");
                 Process.killProcess(app.pid);
             }
         }
@@ -10434,10 +10439,11 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
             if (!capp.persistent && capp.thread != null
                     && capp.pid != 0
                     && capp.pid != MY_PID) {
-                Slog.i(TAG, "Killing app " + capp.processName
-                        + " (pid " + capp.pid
-                        + ") because provider " + cpr.info.name
-                        + " is in dying process " + proc.processName);
+                Slog.i(TAG, "Kill " + capp.processName
+                        + " (pid " + capp.pid + "): provider " + cpr.info.name
+                        + " in dying process " + proc.processName);
+                EventLog.writeEvent(EventLogTags.AM_KILL, capp.pid,
+                        capp.processName, capp.setAdj, "dying provider " + proc.processName);
                 Process.killProcess(capp.pid);
             }
         }
@@ -11522,6 +11528,7 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                     if (r.isForeground) {
                         r.isForeground = false;
                         if (r.app != null) {
+                            updateLruProcessLocked(r.app, false, true);
                             updateServiceForegroundLocked(r.app, true);
                         }
                     }
@@ -14244,6 +14251,7 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
         int factor = (mLruProcesses.size()-4)/numSlots;
         if (factor < 1) factor = 1;
         int step = 0;
+        int numHidden = 0;
         
         // First try updating the OOM adjustment for each of the
         // application processes based on their current state.
@@ -14262,6 +14270,17 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                         curHiddenAdj++;
                     }
                 }
+                if (app.curAdj >= HIDDEN_APP_MIN_ADJ) {
+                    numHidden++;
+                    if (numHidden > MAX_HIDDEN_APPS) {
+                        Slog.i(TAG, "Kill " + app.processName
+                                + " (pid " + app.pid + "): hidden #" + numHidden
+                                + " beyond limit " + MAX_HIDDEN_APPS);
+                        EventLog.writeEvent(EventLogTags.AM_KILL, app.pid,
+                                app.processName, app.setAdj, "too many background");
+                        Process.killProcess(app.pid);
+                    }
+                }
             } else {
                 didOomAdj = false;
             }