Reduce transactions for acquiring and releasing provider

App may access a provider frequently in a short time.
(Without using ContentProviderClient to keep the connection)
Then there will have some overhead for the management of
provider reference. So with a delay to release the provider,
the app can reuse the existing holder within the retain time.

Also change removeContentProvider to a one-way method to reduce
the time spent on app's main thread. This should be safe because
originally the app can acquire provider from any thread.

The cold start time of calendar app can be reduced by ~20ms.

Test: AppLaunchTest
Bug: 123043091
Change-Id: I220cec3deab18b658f4102f7eb9f47599c7c4b7c

1 files changed, 7 insertions, 4 deletions

diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index b6e5754aa65f..143361f721d1 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -224,6 +224,12 @@ public final class ActivityThread extends ClientTransactionHandler {
     private static final boolean DEBUG_PROVIDER = false;
     public static final boolean DEBUG_ORDER = false;
     private static final long MIN_TIME_BETWEEN_GCS = 5*1000;
+    /**
+     * The delay to release the provider when it has no more references. It reduces the number of
+     * transactions for acquiring and releasing provider if the client accesses the provider
+     * frequently in a short time.
+     */
+    private static final long CONTENT_PROVIDER_RETAIN_TIME = 1000;
     private static final int SQLITE_MEM_RELEASED_EVENT_LOG_TAG = 75003;
 
     /** Type for IActivityManager.serviceDoneExecuting: anonymous operation */
@@ -6498,16 +6504,13 @@ public final class ActivityThread extends ClientTransactionHandler {
                 if (!prc.removePending) {
                     // Schedule the actual remove asynchronously, since we don't know the context
                     // this will be called in.
-                    // TODO: it would be nice to post a delayed message, so
-                    // if we come back and need the same provider quickly
-                    // we will still have it available.
                     if (DEBUG_PROVIDER) {
                         Slog.v(TAG, "releaseProvider: Enqueueing pending removal - "
                                 + prc.holder.info.name);
                     }
                     prc.removePending = true;
                     Message msg = mH.obtainMessage(H.REMOVE_PROVIDER, prc);
-                    mH.sendMessage(msg);
+                    mH.sendMessageDelayed(msg, CONTENT_PROVIDER_RETAIN_TIME);
                 } else {
                     Slog.w(TAG, "Duplicate remove pending of provider " + prc.holder.info.name);
                 }