commit 9a803c3e842f0bd56b461cc7db912c2f4c09e39f
author Robert Carr <racarr@google.com> Thu Jan 14 16:57:58 2021 -0800
committer Robert Carr <racarr@google.com> Wed Feb 03 17:05:51 2021 -0800
tree 50f848015ba3652b72dde523ef9c3fde8b061ffc
parent c5515fccae31bcec3c9861512008e8684a0f173b

SurfaceFlinger: Emit TransactionCompleted callbacks directly.

Transaction complete callbacks (BLAST Buffer release callbacks), are
emitted from a TransactionCompletedThread. There's no clear reason
for this behavior, as the actual runtime is exceedingly minimal. This
opens us to scheduling delays when we call
TransactionCompletedThread.sendCallbacks. In this CL we both remove the
threaded nature of TransactionCompletedThread, and also take advantage
of it running on the main thread to reduce some unnecessary copying and
further reduce its runtime.

Bug: 176691195
Test: Existing tests pass
Change-Id: Ib1661df24c4a2ee39fc28c29a395158ce0ee7b7f

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e9b5875..a131118 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2195,8 +2195,8 @@
         }
     });
 
-    mTransactionCompletedThread.addPresentFence(mPreviousPresentFences[0]);
-    mTransactionCompletedThread.sendCallbacks();
+    mTransactionCallbackInvoker.addPresentFence(mPreviousPresentFences[0]);
+    mTransactionCallbackInvoker.sendCallbacks();
 
     if (display && display->isPrimary() && display->getPowerMode() == hal::PowerMode::ON &&
         presentFenceTime->isValid()) {
@@ -3547,8 +3547,8 @@
     // that listeners with SurfaceControls will start registration during setClientStateLocked
     // below.
     for (const auto& listener : listenerCallbacks) {
-        mTransactionCompletedThread.startRegistration(listener);
-        mTransactionCompletedThread.endRegistration(listener);
+        mTransactionCallbackInvoker.startRegistration(listener);
+        mTransactionCallbackInvoker.endRegistration(listener);
     }
 
     std::unordered_set<ListenerCallbacks, ListenerCallbacksHash> listenerCallbacksWithSurfaces;
@@ -3567,12 +3567,12 @@
     }
 
     for (const auto& listenerCallback : listenerCallbacksWithSurfaces) {
-        mTransactionCompletedThread.endRegistration(listenerCallback);
+        mTransactionCallbackInvoker.endRegistration(listenerCallback);
     }
 
     // If the state doesn't require a traversal and there are callbacks, send them now
     if (!(clientStateFlags & eTraversalNeeded) && hasListenerCallbacks) {
-        mTransactionCompletedThread.sendCallbacks();
+        mTransactionCallbackInvoker.sendCallbacks();
     }
     transactionFlags |= clientStateFlags;
 
@@ -3687,7 +3687,7 @@
     for (auto& listener : s.listeners) {
         // note that startRegistration will not re-register if the listener has
         // already be registered for a prior surface control
-        mTransactionCompletedThread.startRegistration(listener);
+        mTransactionCallbackInvoker.startRegistration(listener);
         listenerCallbacks.insert(listener);
     }
 
@@ -3700,7 +3700,7 @@
     }
     if (layer == nullptr) {
         for (auto& [listener, callbackIds] : s.listeners) {
-            mTransactionCompletedThread.registerUnpresentedCallbackHandle(
+            mTransactionCallbackInvoker.registerUnpresentedCallbackHandle(
                     new CallbackHandle(listener, callbackIds, s.surface));
         }
         return 0;