From 34eb9ca577d78524b992d2af367e23ce89a9f034 Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Thu, 18 Nov 2021 15:23:23 -0800
Subject: SF: Introduce background task executor

Extract logic to execute work outside of the main thread
from TransactionCallbackInvoker so we can reuse the
thread for other tasks that are not critical to drawing.

Bug: 206380307
Test: presubmit
Change-Id: I8128d2f333e3aab5639cd1200e820de39f0b3191
---
 .../surfaceflinger/TransactionCallbackInvoker.cpp  | 39 +++-------------------
 1 file changed, 5 insertions(+), 34 deletions(-)

(limited to 'services/surfaceflinger/TransactionCallbackInvoker.cpp')

diff --git a/services/surfaceflinger/TransactionCallbackInvoker.cpp b/services/surfaceflinger/TransactionCallbackInvoker.cpp
index f3d46ea061..b705d9cf7b 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.cpp
+++ b/services/surfaceflinger/TransactionCallbackInvoker.cpp
@@ -24,6 +24,7 @@
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
 #include "TransactionCallbackInvoker.h"
+#include "BackgroundExecutor.h"
 
 #include <cinttypes>
 
@@ -49,31 +50,6 @@ static bool containsOnCommitCallbacks(const std::vector<CallbackId>& callbacks)
     return !callbacks.empty() && callbacks.front().type == CallbackId::Type::ON_COMMIT;
 }
 
-TransactionCallbackInvoker::TransactionCallbackInvoker() {
-    mThread = std::thread([&]() {
-          std::unique_lock lock(mCallbackThreadMutex);
-
-        while (mKeepRunning) {
-          while (mCallbackThreadWork.size() > 0) {
-              mCallbackThreadWork.front()();
-              mCallbackThreadWork.pop();
-          }
-          mCallbackConditionVariable.wait(lock);
-        }
-    });
-}
-
-TransactionCallbackInvoker::~TransactionCallbackInvoker() {
-    {
-          std::unique_lock lock(mCallbackThreadMutex);
-          mKeepRunning = false;
-          mCallbackConditionVariable.notify_all();
-    }
-    if (mThread.joinable()) {
-        mThread.join();
-    }
-}
-
 void TransactionCallbackInvoker::addEmptyTransaction(const ListenerCallbacks& listenerCallbacks) {
     auto& [listener, callbackIds] = listenerCallbacks;
     auto& transactionStatsDeque = mCompletedTransactions[listener];
@@ -242,15 +218,10 @@ void TransactionCallbackInvoker::sendCallbacks(bool onCommitOnly) {
                 // keep it as an IBinder due to consistency reasons: if we
                 // interface_cast at the IPC boundary when reading a Parcel,
                 // we get pointers that compare unequal in the SF process.
-                {
-                    std::unique_lock lock(mCallbackThreadMutex);
-                    mCallbackThreadWork.push(
-                        [stats = std::move(listenerStats)]() {
-                          interface_cast<ITransactionCompletedListener>(stats.listener)
-                              ->onTransactionCompleted(stats);
-                    });
-                    mCallbackConditionVariable.notify_all();
-                }
+                BackgroundExecutor::getInstance().execute([stats = std::move(listenerStats)]() {
+                    interface_cast<ITransactionCompletedListener>(stats.listener)
+                            ->onTransactionCompleted(stats);
+                });
             }
         }
         completedTransactionsItr++;
-- 
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