Merge "Reduce impact of RenderThread in system_server" into oc-dev

4 files changed, 52 insertions, 5 deletions

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index e76ffb1b2e10..5283924d590c 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -13407,8 +13407,12 @@ public class ActivityManagerService extends IActivityManager.Stub
     public void setRenderThread(int tid) {
         synchronized (this) {
             ProcessRecord proc;
+            int pid = Binder.getCallingPid();
+            if (pid == Process.myPid()) {
+                demoteSystemServerRenderThread(tid);
+                return;
+            }
             synchronized (mPidsSelfLocked) {
-                int pid = Binder.getCallingPid();
                 proc = mPidsSelfLocked.get(pid);
                 if (proc != null && proc.renderThreadTid == 0 && tid > 0) {
                     // ensure the tid belongs to the process
@@ -13441,6 +13445,16 @@ public class ActivityManagerService extends IActivityManager.Stub
         }
     }
 
+    /**
+     * We only use RenderThread in system_server to store task snapshots to the disk, which should
+     * happen in the background. Thus, demote render thread from system_server to a lower priority.
+     *
+     * @param tid the tid of the RenderThread
+     */
+    private void demoteSystemServerRenderThread(int tid) {
+        setThreadPriority(tid, Process.THREAD_PRIORITY_BACKGROUND);
+    }
+
     @Override
     public int setVrMode(IBinder token, boolean enabled, ComponentName packageName) {
         if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_VR_MODE)) {
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotController.java b/services/core/java/com/android/server/wm/TaskSnapshotController.java
index b79173cf77e5..1bbe1d0c9a93 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotController.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotController.java
@@ -275,6 +275,15 @@ class TaskSnapshotController {
         mPersister.removeObsoleteFiles(persistentTaskIds, runningUserIds);
     }
 
+    /**
+     * Temporarily pauses/unpauses persisting of task snapshots.
+     *
+     * @param paused Whether task snapshot persisting should be paused.
+     */
+    void setPersisterPaused(boolean paused) {
+        mPersister.setPaused(paused);
+    }
+
     void dump(PrintWriter pw, String prefix) {
         mCache.dump(pw, prefix);
     }
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
index e5c7a72c78bc..028707004773 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
@@ -60,6 +60,8 @@ class TaskSnapshotPersister {
     private final ArrayDeque<WriteQueueItem> mWriteQueue = new ArrayDeque<>();
     @GuardedBy("mLock")
     private boolean mQueueIdling;
+    @GuardedBy("mLock")
+    private boolean mPaused;
     private boolean mStarted;
     private final Object mLock = new Object();
     private final DirectoryResolver mDirectoryResolver;
@@ -127,6 +129,15 @@ class TaskSnapshotPersister {
         }
     }
 
+    void setPaused(boolean paused) {
+        synchronized (mLock) {
+            mPaused = paused;
+            if (!paused) {
+                mLock.notifyAll();
+            }
+        }
+    }
+
     @TestApi
     void waitForQueueEmpty() {
         while (true) {
@@ -142,7 +153,9 @@ class TaskSnapshotPersister {
     @GuardedBy("mLock")
     private void sendToQueueLocked(WriteQueueItem item) {
         mWriteQueue.offer(item);
-        mLock.notifyAll();
+        if (!mPaused) {
+            mLock.notifyAll();
+        }
     }
 
     private File getDirectory(int userId) {
@@ -185,7 +198,11 @@ class TaskSnapshotPersister {
             while (true) {
                 WriteQueueItem next;
                 synchronized (mLock) {
-                    next = mWriteQueue.poll();
+                    if (mPaused) {
+                        next = null;
+                    } else {
+                        next = mWriteQueue.poll();
+                    }
                 }
                 if (next != null) {
                     next.write();
diff --git a/services/core/java/com/android/server/wm/WindowAnimator.java b/services/core/java/com/android/server/wm/WindowAnimator.java
index 067cc0905bd3..dd790a92323e 100644
--- a/services/core/java/com/android/server/wm/WindowAnimator.java
+++ b/services/core/java/com/android/server/wm/WindowAnimator.java
@@ -255,12 +255,19 @@ public class WindowAnimator {
             mWindowPlacerLocked.requestTraversal();
         }
 
-        if (mAnimating && !wasAnimating && Trace.isTagEnabled(Trace.TRACE_TAG_WINDOW_MANAGER)) {
-            Trace.asyncTraceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "animating", 0);
+        if (mAnimating && !wasAnimating) {
+
+            // Usually app transitions but quite a load onto the system already (with all the things
+            // happening in app), so pause task snapshot persisting to not increase the load.
+            mService.mTaskSnapshotController.setPersisterPaused(true);
+            if (Trace.isTagEnabled(Trace.TRACE_TAG_WINDOW_MANAGER)) {
+                Trace.asyncTraceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "animating", 0);
+            }
         }
 
         if (!mAnimating && wasAnimating) {
             mWindowPlacerLocked.requestTraversal();
+            mService.mTaskSnapshotController.setPersisterPaused(false);
             if (Trace.isTagEnabled(Trace.TRACE_TAG_WINDOW_MANAGER)) {
                 Trace.asyncTraceEnd(Trace.TRACE_TAG_WINDOW_MANAGER, "animating", 0);
             }