Assign different oom score to visible apps based on layer ordering.

Pass oom score in kernel's full range [-1000,1000] to lmkd directly

bug: 21411311

Change-Id: I0cab2aa46269a716ea613025d3b84fe7d04404bb
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 7df50d5..bb1b6b8 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -5794,7 +5794,7 @@
         }
 
         boolean didSomething = killPackageProcessesLocked(packageName, appId, userId,
-                -100, callerWillRestart, true, doit, evenPersistent,
+                ProcessList.INVALID_ADJ, callerWillRestart, true, doit, evenPersistent,
                 packageName == null ? ("stop user " + userId) : ("stop " + packageName));
 
         if (mStackSupervisor.finishDisabledPackageActivitiesLocked(
@@ -6110,7 +6110,7 @@
         EventLog.writeEvent(EventLogTags.AM_PROC_BOUND, app.userId, app.pid, app.processName);
 
         app.makeActive(thread, mProcessStats);
-        app.curAdj = app.setAdj = -100;
+        app.curAdj = app.setAdj = ProcessList.INVALID_ADJ;
         app.curSchedGroup = app.setSchedGroup = Process.THREAD_GROUP_DEFAULT;
         app.forcingToForeground = null;
         updateProcessForegroundLocked(app, false, false);
@@ -18057,6 +18057,7 @@
 
         // Examine all activities if not already foreground.
         if (!foregroundActivities && activitiesSize > 0) {
+            int minLayer = ProcessList.VISIBLE_APP_LAYER_MAX;
             for (int j = 0; j < activitiesSize; j++) {
                 final ActivityRecord r = app.activities.get(j);
                 if (r.app != app) {
@@ -18077,6 +18078,12 @@
                     app.cached = false;
                     app.empty = false;
                     foregroundActivities = true;
+                    if (r.task != null && minLayer > 0) {
+                        final int layer = r.task.mLayerRank;
+                        if (layer >= 0 && minLayer > layer) {
+                            minLayer = layer;
+                        }
+                    }
                     break;
                 } else if (r.state == ActivityState.PAUSING || r.state == ActivityState.PAUSED) {
                     if (adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
@@ -18117,6 +18124,9 @@
                     }
                 }
             }
+            if (adj == ProcessList.VISIBLE_APP_ADJ) {
+                adj += minLayer;
+            }
         }
 
         if (adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
@@ -18326,11 +18336,11 @@
                                         && clientAdj < ProcessList.PERCEPTIBLE_APP_ADJ
                                         && adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
                                     adj = ProcessList.PERCEPTIBLE_APP_ADJ;
-                                } else if (clientAdj > ProcessList.VISIBLE_APP_ADJ) {
+                                } else if (clientAdj >= ProcessList.PERCEPTIBLE_APP_ADJ) {
                                     adj = clientAdj;
                                 } else {
                                     if (adj > ProcessList.VISIBLE_APP_ADJ) {
-                                        adj = ProcessList.VISIBLE_APP_ADJ;
+                                        adj = Math.max(clientAdj, ProcessList.VISIBLE_APP_ADJ);
                                     }
                                 }
                                 if (!client.cached) {
@@ -19368,6 +19378,8 @@
             uidRec.reset();
         }
 
+        mStackSupervisor.rankTaskLayersIfNeeded();
+
         mAdjSeq++;
         mNewNumServiceProcs = 0;
         mNewNumAServiceProcs = 0;
diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index a67c274..1721470 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -1378,6 +1378,20 @@
         return true;
     }
 
+    final int rankTaskLayers(int baseLayer) {
+        int layer = 0;
+        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
+            final TaskRecord task = mTaskHistory.get(taskNdx);
+            ActivityRecord r = task.topRunningActivityLocked();
+            if (r == null || r.finishing || !r.visible) {
+                task.mLayerRank = -1;
+            } else {
+                task.mLayerRank = baseLayer + layer++;
+            }
+        }
+        return layer;
+    }
+
     /**
      * Make sure that all activities that need to be visible (that is, they
      * currently can be seen by the user) actually are.
@@ -3784,6 +3798,7 @@
                 task.mLastTimeMoved *= -1;
             }
         }
+        mStackSupervisor.invalidateTaskLayers();
     }
 
     void moveHomeStackTaskToTop(int homeStackTaskType) {
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 2103b60..54ac58a 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -357,6 +357,9 @@
     // It will be calculated when the default display gets added.
     private int mDefaultMinimalSizeOfResizeableTask = -1;
 
+    // Whether tasks have moved and we need to rank the tasks before next OOM scoring
+    private boolean mTaskLayersChanged = true;
+
     /**
      * Description of a request to start a new activity, which has been held
      * due to app switches being disabled.
@@ -3613,6 +3616,24 @@
         }
     }
 
+    void invalidateTaskLayers() {
+        mTaskLayersChanged = true;
+    }
+
+    void rankTaskLayersIfNeeded() {
+        if (!mTaskLayersChanged) {
+            return;
+        }
+        mTaskLayersChanged = false;
+        for (int displayNdx = 0; displayNdx < mActivityDisplays.size(); displayNdx++) {
+            final ArrayList<ActivityStack> stacks = mActivityDisplays.valueAt(displayNdx).mStacks;
+            int baseLayer = 0;
+            for (int stackNdx = stacks.size() - 1; stackNdx >= 0; --stackNdx) {
+                baseLayer += stacks.get(stackNdx).rankTaskLayers(baseLayer);
+            }
+        }
+    }
+
     void clearOtherAppTimeTrackers(AppTimeTracker except) {
         for (int displayNdx = mActivityDisplays.size() - 1; displayNdx >= 0; --displayNdx) {
             final ArrayList<ActivityStack> stacks = mActivityDisplays.valueAt(displayNdx).mStacks;
diff --git a/services/core/java/com/android/server/am/ProcessList.java b/services/core/java/com/android/server/am/ProcessList.java
index 0e24952..b49370b 100644
--- a/services/core/java/com/android/server/am/ProcessList.java
+++ b/services/core/java/com/android/server/am/ProcessList.java
@@ -49,19 +49,22 @@
 
     // OOM adjustments for processes in various states:
 
+    // Uninitialized value for any major or minor adj fields
+    static final int INVALID_ADJ = -10000;
+
     // Adjustment used in certain places where we don't know it yet.
     // (Generally this is something that is going to be cached, but we
     // don't know the exact value in the cached range to assign yet.)
-    static final int UNKNOWN_ADJ = 16;
+    static final int UNKNOWN_ADJ = 1001;
 
     // This is a process only hosting activities that are not visible,
     // so it can be killed without any disruption.
-    static final int CACHED_APP_MAX_ADJ = 15;
-    static final int CACHED_APP_MIN_ADJ = 9;
+    static final int CACHED_APP_MAX_ADJ = 906;
+    static final int CACHED_APP_MIN_ADJ = 900;
 
     // The B list of SERVICE_ADJ -- these are the old and decrepit
     // services that aren't as shiny and interesting as the ones in the A list.
-    static final int SERVICE_B_ADJ = 8;
+    static final int SERVICE_B_ADJ = 800;
 
     // This is the process of the previous application that the user was in.
     // This process is kept above other things, because it is very common to
@@ -69,34 +72,35 @@
     // task switch (toggling between the two top recent apps) as well as normal
     // UI flow such as clicking on a URI in the e-mail app to view in the browser,
     // and then pressing back to return to e-mail.
-    static final int PREVIOUS_APP_ADJ = 7;
+    static final int PREVIOUS_APP_ADJ = 700;
 
     // This is a process holding the home application -- we want to try
     // avoiding killing it, even if it would normally be in the background,
     // because the user interacts with it so much.
-    static final int HOME_APP_ADJ = 6;
+    static final int HOME_APP_ADJ = 600;
 
     // This is a process holding an application service -- killing it will not
     // have much of an impact as far as the user is concerned.
-    static final int SERVICE_ADJ = 5;
+    static final int SERVICE_ADJ = 500;
 
     // This is a process with a heavy-weight application.  It is in the
     // background, but we want to try to avoid killing it.  Value set in
     // system/rootdir/init.rc on startup.
-    static final int HEAVY_WEIGHT_APP_ADJ = 4;
+    static final int HEAVY_WEIGHT_APP_ADJ = 400;
 
     // This is a process currently hosting a backup operation.  Killing it
     // is not entirely fatal but is generally a bad idea.
-    static final int BACKUP_APP_ADJ = 3;
+    static final int BACKUP_APP_ADJ = 300;
 
     // This is a process only hosting components that are perceptible to the
     // user, and we really want to avoid killing them, but they are not
     // immediately visible. An example is background music playback.
-    static final int PERCEPTIBLE_APP_ADJ = 2;
+    static final int PERCEPTIBLE_APP_ADJ = 200;
 
     // This is a process only hosting activities that are visible to the
     // user, so we'd prefer they don't disappear.
-    static final int VISIBLE_APP_ADJ = 1;
+    static final int VISIBLE_APP_ADJ = 100;
+    static final int VISIBLE_APP_LAYER_MAX = PERCEPTIBLE_APP_ADJ - VISIBLE_APP_ADJ - 1;
 
     // This is the process running the current foreground app.  We'd really
     // rather not kill it!
@@ -104,18 +108,18 @@
 
     // This is a process that the system or a persistent process has bound to,
     // and indicated it is important.
-    static final int PERSISTENT_SERVICE_ADJ = -11;
+    static final int PERSISTENT_SERVICE_ADJ = -700;
 
     // This is a system persistent process, such as telephony.  Definitely
     // don't want to kill it, but doing so is not completely fatal.
-    static final int PERSISTENT_PROC_ADJ = -12;
+    static final int PERSISTENT_PROC_ADJ = -800;
 
     // The system process runs at the default adjustment.
-    static final int SYSTEM_ADJ = -16;
+    static final int SYSTEM_ADJ = -900;
 
     // Special code for native processes that are not being managed by the system (so
     // don't have an oom adj assigned by the system).
-    static final int NATIVE_ADJ = -17;
+    static final int NATIVE_ADJ = -1000;
 
     // Memory pages are 4K.
     static final int PAGE_SIZE = 4*1024;
@@ -159,7 +163,7 @@
     // These must be kept in sync with the definitions in lmkd.c
     //
     // LMK_TARGET <minfree> <minkillprio> ... (up to 6 pairs)
-    // LMK_PROCPRIO <pid> <prio>
+    // LMK_PROCPRIO <pid> <uid> <prio>
     // LMK_PROCREMOVE <pid>
     static final byte LMK_TARGET = 0;
     static final byte LMK_PROCPRIO = 1;
diff --git a/services/core/java/com/android/server/am/ProcessRecord.java b/services/core/java/com/android/server/am/ProcessRecord.java
index bd31a21..08203c55b 100644
--- a/services/core/java/com/android/server/am/ProcessRecord.java
+++ b/services/core/java/com/android/server/am/ProcessRecord.java
@@ -171,10 +171,10 @@
     boolean debugging;          // was app launched for debugging?
     boolean waitedForDebugger;  // has process show wait for debugger dialog?
     Dialog waitDialog;          // current wait for debugger dialog
-    
+
     String shortStringName;     // caching of toShortString() result.
     String stringName;          // caching of toString() result.
-    
+
     // These reports are generated & stored when an app gets into an error condition.
     // They will be "null" when all is OK.
     ActivityManager.ProcessErrorStateInfo crashingReport;
@@ -402,7 +402,7 @@
             }
         }
     }
-    
+
     ProcessRecord(BatteryStatsImpl _batteryStats, ApplicationInfo _info,
             String _processName, int _uid) {
         mBatteryStats = _batteryStats;
@@ -413,8 +413,8 @@
         processName = _processName;
         pkgList.put(_info.packageName, new ProcessStats.ProcessStateHolder(_info.versionCode));
         maxAdj = ProcessList.UNKNOWN_ADJ;
-        curRawAdj = setRawAdj = -100;
-        curAdj = setAdj = -100;
+        curRawAdj = setRawAdj = ProcessList.INVALID_ADJ;
+        curAdj = setAdj = ProcessList.INVALID_ADJ;
         persistent = false;
         removed = false;
         lastStateTime = lastPssTime = nextPssTime = SystemClock.uptimeMillis();
@@ -560,7 +560,7 @@
         toShortString(sb);
         return shortStringName = sb.toString();
     }
-    
+
     void toShortString(StringBuilder sb) {
         sb.append(pid);
         sb.append(':');
@@ -585,7 +585,7 @@
             }
         }
     }
-    
+
     public String toString() {
         if (stringName != null) {
             return stringName;
@@ -695,7 +695,7 @@
             pkgList.put(info.packageName, new ProcessStats.ProcessStateHolder(info.versionCode));
         }
     }
-    
+
     public String[] getPackageList() {
         int size = pkgList.size();
         if (size == 0) {
diff --git a/services/core/java/com/android/server/am/TaskRecord.java b/services/core/java/com/android/server/am/TaskRecord.java
index 1999f49..fe87a93 100644
--- a/services/core/java/com/android/server/am/TaskRecord.java
+++ b/services/core/java/com/android/server/am/TaskRecord.java
@@ -221,6 +221,10 @@
     // default minimal size.
     final int mMinimalSize;
 
+    // Ranking (from top) of this task among all visible tasks. (-1 means it's not visible)
+    // This number will be assigned when we evaluate OOM scores for all visible tasks.
+    int mLayerRank = -1;
+
     Configuration mOverrideConfig = Configuration.EMPTY;
 
     TaskRecord(ActivityManagerService service, int _taskId, ActivityInfo info, Intent _intent,