commit 3e40cddb03c7da6a33c781c67f3189e19b2a27a7
author Vishnu Nair <vishnun@google.com> Wed Jun 08 16:50:17 2022 -0700
committer Vishnu Nair <vishnun@google.com> Thu Jun 09 18:39:12 2022 -0700
tree 492d69803c273c0ed655676657adbb029d369b5c
parent 286f4f9e6c32c0b906eba7c103964aa55ba1f74a

LayerTraceGenerator: Fix layer deletion

Fixes a couple of issues with layer handle tracking which manifested
in the generated trace showing layers which were destroyed.
1. Destroyed handles were not written to proto correctly
2. When a handle was destroyed, it was removed from the tracing handle
to layer id map immediately. but we need to access this mapping in the
tracing thread when writing the transaction to proto.

Test: atest transactiontrace_testsuite
Bug: 235376060
Change-Id: I021be9a3864bdfc61422fc2f751f9bfd5e674059

services/surfaceflinger/Tracing/TransactionTracing.cpp

diff --git a/services/surfaceflinger/Tracing/TransactionTracing.cpp b/services/surfaceflinger/Tracing/TransactionTracing.cpp
index e53feca..af0594e 100644
--- a/services/surfaceflinger/Tracing/TransactionTracing.cpp
+++ b/services/surfaceflinger/Tracing/TransactionTracing.cpp
@@ -281,6 +281,14 @@
             }
         }
 
+        entryProto.mutable_removed_layer_handles()->Reserve(
+                static_cast<int32_t>(mRemovedLayerHandles.size()));
+        for (auto& [handle, layerId] : mRemovedLayerHandles) {
+            entryProto.mutable_removed_layer_handles()->Add(layerId);
+            mLayerHandles.erase(handle);
+        }
+        mRemovedLayerHandles.clear();
+
         std::string serializedProto;
         entryProto.SerializeToString(&serializedProto);
         entryProto.Clear();
@@ -288,13 +296,6 @@
         removedEntries.reserve(removedEntries.size() + entries.size());
         removedEntries.insert(removedEntries.end(), std::make_move_iterator(entries.begin()),
                               std::make_move_iterator(entries.end()));
-
-        entryProto.mutable_removed_layer_handles()->Reserve(
-                static_cast<int32_t>(mRemovedLayerHandles.size()));
-        for (auto& handle : mRemovedLayerHandles) {
-            entryProto.mutable_removed_layer_handles()->Add(handle);
-        }
-        mRemovedLayerHandles.clear();
     }
 
     proto::TransactionTraceEntry removedEntryProto;
@@ -355,9 +356,7 @@
         ALOGW("handle not found. %p", layerHandle);
         return;
     }
-
-    mRemovedLayerHandles.push_back(it->second);
-    mLayerHandles.erase(it);
+    mRemovedLayerHandles.emplace_back(layerHandle, it->second);
 }
 
 void TransactionTracing::tryPushToTracingThread() {
@@ -401,10 +400,15 @@
         }
     }
 
+    for (const int32_t removedLayerHandleId : removedEntry.removed_layer_handles()) {
+        mRemovedLayerHandlesAtStart.insert(removedLayerHandleId);
+    }
+
     // Clean up stale starting states since the layer has been removed and the buffer does not
     // contain any references to the layer.
     for (const int32_t removedLayerId : removedEntry.removed_layers()) {
         mStartingStates.erase(removedLayerId);
+        mRemovedLayerHandlesAtStart.erase(removedLayerId);
     }
 }
 
@@ -426,6 +430,12 @@
     transactionProto.set_vsync_id(0);
     transactionProto.set_post_time(mStartingTimestamp);
     entryProto->mutable_transactions()->Add(std::move(transactionProto));
+
+    entryProto->mutable_removed_layer_handles()->Reserve(
+            static_cast<int32_t>(mRemovedLayerHandlesAtStart.size()));
+    for (const int32_t removedLayerHandleId : mRemovedLayerHandlesAtStart) {
+        entryProto->mutable_removed_layer_handles()->Add(removedLayerHandleId);
+    }
 }
 
 proto::TransactionTraceFile TransactionTracing::writeToProto() {