Move quiet mode operations to a separate thread

The setQuietModeEnabled method is often called asynchronously on a
background thread. This has been a reason for noticeable delays caused
when the system server background thread is busy. With this change, we
are moving the operation to a separte thread using a ThreadPoolExecutor
of size 1.

Test: Tested locally on device by adding logs and capturing pertto
traces
Bug: 303201022

Change-Id: I71faf0d11115e5fa4828632c28778d3add9e62f2

2 files changed, 27 insertions, 5 deletions

diff --git a/core/java/android/content/pm/multiuser.aconfig b/core/java/android/content/pm/multiuser.aconfig
index c7797c719e2c..7c5d3054c945 100644
--- a/core/java/android/content/pm/multiuser.aconfig
+++ b/core/java/android/content/pm/multiuser.aconfig
@@ -70,4 +70,11 @@ flag {
     namespace: "profile_experiences"
     description: "Add support for Private Space in resolver sheet"
     bug: "307515485"
+}
+
+flag {
+    name: "move_quiet_mode_operations_to_separate_thread"
+    namespace: "profile_experiences"
+    description: "Move the quiet mode operations, happening on a background thread today, to a separate thread."
+    bug: "320483504"
 }
\ No newline at end of file
diff --git a/services/core/java/com/android/server/pm/UserManagerService.java b/services/core/java/com/android/server/pm/UserManagerService.java
index 315c36f32479..9859e1aaa56f 100644
--- a/services/core/java/com/android/server/pm/UserManagerService.java
+++ b/services/core/java/com/android/server/pm/UserManagerService.java
@@ -180,6 +180,8 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
@@ -333,6 +335,8 @@ public class UserManagerService extends IUserManager.Stub {
 
     private final Handler mHandler;
 
+    private final ThreadPoolExecutor mInternalExecutor;
+
     private final File mUsersDir;
     private final File mUserListFile;
 
@@ -722,11 +726,20 @@ public class UserManagerService extends IUserManager.Stub {
     @VisibleForTesting
     void setQuietModeEnabledAsync(@UserIdInt int userId, boolean enableQuietMode,
             IntentSender target, @Nullable String callingPackage) {
-        // Call setQuietModeEnabled on bg thread to avoid ANR
-        BackgroundThread.getHandler().post(
-                () -> setQuietModeEnabled(userId, enableQuietMode, target,
-                        callingPackage)
-        );
+        if (android.multiuser.Flags.moveQuietModeOperationsToSeparateThread()) {
+            // Call setQuietModeEnabled on a separate thread. Calling this operation on the main
+            // thread can cause ANRs, posting on a BackgroundThread can result in delays
+            Slog.d(LOG_TAG, "Calling setQuietModeEnabled for user " + userId
+                    + " on a separate thread");
+            mInternalExecutor.execute(() -> setQuietModeEnabled(userId, enableQuietMode, target,
+                    callingPackage));
+        } else {
+            // Call setQuietModeEnabled on bg thread to avoid ANR
+            BackgroundThread.getHandler().post(
+                    () -> setQuietModeEnabled(userId, enableQuietMode, target,
+                            callingPackage)
+            );
+        }
     }
 
     /**
@@ -952,6 +965,8 @@ public class UserManagerService extends IUserManager.Stub {
         mPackagesLock = packagesLock;
         mUsers = users != null ? users : new SparseArray<>();
         mHandler = new MainHandler();
+        mInternalExecutor = new ThreadPoolExecutor(/* corePoolSize */ 0, /* maximumPoolSize */ 1,
+                /* keepAliveTime */ 1, TimeUnit.SECONDS, new LinkedBlockingQueue<>());
         mUserVisibilityMediator = new UserVisibilityMediator(mHandler);
         mUserDataPreparer = userDataPreparer;
         mUserTypes = UserTypeFactory.getUserTypes();