From 9233ddb49172677be6e2687a0eaed2592658f848 Mon Sep 17 00:00:00 2001
From: Alex Buynytskyy <alexbuy@google.com>
Date: Thu, 1 Dec 2022 11:42:22 -0800
Subject: [PATCH 1/2] Further async settings write optimizations.

Bug: 252726591
Test: presubmit
Change-Id: Ie08130539adefa71f95bebab65c60ff30eb83d26
---
 .../java/com/android/server/pm/Settings.java  | 34 +++++++++++++------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/services/core/java/com/android/server/pm/Settings.java b/services/core/java/com/android/server/pm/Settings.java
index 4aba01637abf2..f9d0108c862a7 100644
--- a/services/core/java/com/android/server/pm/Settings.java
+++ b/services/core/java/com/android/server/pm/Settings.java
@@ -5613,8 +5613,7 @@ public final class Settings implements Watchable, Snappable {
 
         // Low-priority handlers running on SystemBg thread.
         private final Handler mAsyncHandler = new MyHandler();
-        private final Handler mPersistenceHandler = new Handler(
-                BackgroundThread.getHandler().getLooper());
+        private final Handler mPersistenceHandler = new PersistenceHandler();
 
         private final Object mLock = new Object();
 
@@ -5761,20 +5760,22 @@ public final class Settings implements Watchable, Snappable {
                 @NonNull WatchedArrayMap<String, SharedUserSetting> sharedUsers,
                 @Nullable Handler pmHandler, @NonNull Object pmLock,
                 boolean sync) {
-            final int version;
-            final String fingerprint;
-            final boolean isLegacyPermissionStateStale;
             synchronized (mLock) {
                 mAsyncHandler.removeMessages(userId);
                 mWriteScheduled.delete(userId);
-
-                version = mVersions.get(userId, INITIAL_VERSION);
-                fingerprint = mFingerprints.get(userId);
-                isLegacyPermissionStateStale = mIsLegacyPermissionStateStale;
-                mIsLegacyPermissionStateStale = false;
             }
 
             Runnable writer = () -> {
+                final int version;
+                final String fingerprint;
+                final boolean isLegacyPermissionStateStale;
+                synchronized (mLock) {
+                    version = mVersions.get(userId, INITIAL_VERSION);
+                    fingerprint = mFingerprints.get(userId);
+                    isLegacyPermissionStateStale = mIsLegacyPermissionStateStale;
+                    mIsLegacyPermissionStateStale = false;
+                }
+
                 final RuntimePermissionsState runtimePermissions;
                 synchronized (pmLock) {
                     if (sync || isLegacyPermissionStateStale) {
@@ -5823,7 +5824,7 @@ public final class Settings implements Watchable, Snappable {
                 }
                 if (pmHandler != null) {
                     // Async version.
-                    mPersistenceHandler.post(() -> writePendingStates());
+                    mPersistenceHandler.obtainMessage(userId).sendToTarget();
                 } else {
                     // Sync version.
                     writePendingStates();
@@ -6099,6 +6100,17 @@ public final class Settings implements Watchable, Snappable {
                 }
             }
         }
+
+        private final class PersistenceHandler extends Handler {
+            PersistenceHandler() {
+                super(BackgroundThread.getHandler().getLooper());
+            }
+
+            @Override
+            public void handleMessage(Message message) {
+                writePendingStates();
+            }
+        }
     }
 
     /**

From f0bbf0d66807bac62f9ee491b653c9be4b914481 Mon Sep 17 00:00:00 2001
From: Alex Buynytskyy <alexbuy@google.com>
Date: Fri, 2 Dec 2022 16:17:56 -0800
Subject: [PATCH 2/2] Increase the default period to allow for more async
 writes.

Bug: 252726591
Test: presubmit
Change-Id: I652a101fac05dfc588b0cb02e77c6ddba8c593d4
---
 services/core/java/com/android/server/pm/Settings.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/pm/Settings.java b/services/core/java/com/android/server/pm/Settings.java
index f9d0108c862a7..ef67676ce4aed 100644
--- a/services/core/java/com/android/server/pm/Settings.java
+++ b/services/core/java/com/android/server/pm/Settings.java
@@ -5594,8 +5594,8 @@ public final class Settings implements Watchable, Snappable {
     }
 
     private static final class RuntimePermissionPersistence {
-        // 200-400ms delay to avoid monopolizing PMS lock when written for multiple users.
-        private static final long WRITE_PERMISSIONS_DELAY_MILLIS = 300;
+        // 700-1300ms delay to avoid monopolizing PMS lock when written for multiple users.
+        private static final long WRITE_PERMISSIONS_DELAY_MILLIS = 1000;
         private static final double WRITE_PERMISSIONS_DELAY_JITTER = 0.3;
 
         private static final long MAX_WRITE_PERMISSIONS_DELAY_MILLIS = 2000;