Add some tracing for release fences

* Fix FenceMonitor to cleanly teardown
* App-side tracing for BBQ release callbacks
* Trace future compleition in TxnCallbackInvoker

Bug: 360932099
Bug: 357762453
Flag: EXEMPT debugging
Test: builds
Test: perfetto
Change-Id: I188c04da1e249b672b428837c328568d9e7a1e66
diff --git a/libs/gui/FenceMonitor.cpp b/libs/gui/FenceMonitor.cpp
index 230c81a..e38f1a8 100644
--- a/libs/gui/FenceMonitor.cpp
+++ b/libs/gui/FenceMonitor.cpp
@@ -25,9 +25,18 @@
 namespace android::gui {
 
 FenceMonitor::FenceMonitor(const char* name) : mName(name), mFencesQueued(0), mFencesSignaled(0) {
-    std::thread thread(&FenceMonitor::loop, this);
-    pthread_setname_np(thread.native_handle(), mName);
-    thread.detach();
+    mThread = std::thread(&FenceMonitor::loop, this);
+}
+
+FenceMonitor::~FenceMonitor() {
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mStopped = true;
+        mCondition.notify_one();
+    }
+    if (mThread.joinable()) {
+        mThread.join();
+    }
 }
 
 void FenceMonitor::queueFence(const sp<Fence>& fence) {
@@ -35,24 +44,26 @@
 
     std::lock_guard<std::mutex> lock(mMutex);
     if (fence->getSignalTime() != Fence::SIGNAL_TIME_PENDING) {
-        snprintf(message, sizeof(message), "%s fence %u has signaled", mName, mFencesQueued);
+        snprintf(message, sizeof(message), "%s fence %u has signaled", mName.c_str(),
+                 mFencesQueued);
         ATRACE_NAME(message);
         // Need an increment on both to make the trace number correct.
         mFencesQueued++;
         mFencesSignaled++;
         return;
     }
-    snprintf(message, sizeof(message), "Trace %s fence %u", mName, mFencesQueued);
+    snprintf(message, sizeof(message), "Trace %s fence %u", mName.c_str(), mFencesQueued);
     ATRACE_NAME(message);
 
     mQueue.push_back(fence);
     mCondition.notify_one();
     mFencesQueued++;
-    ATRACE_INT(mName, int32_t(mQueue.size()));
+    ATRACE_INT(mName.c_str(), int32_t(mQueue.size()));
 }
 
 void FenceMonitor::loop() {
-    while (true) {
+    pthread_setname_np(pthread_self(), mName.c_str());
+    while (!mStopped) {
         threadLoop();
     }
 }
@@ -62,15 +73,18 @@
     uint32_t fenceNum;
     {
         std::unique_lock<std::mutex> lock(mMutex);
-        while (mQueue.empty()) {
+        while (mQueue.empty() && !mStopped) {
             mCondition.wait(lock);
         }
+        if (mStopped) {
+            return;
+        }
         fence = mQueue[0];
         fenceNum = mFencesSignaled;
     }
     {
         char message[64];
-        snprintf(message, sizeof(message), "waiting for %s %u", mName, fenceNum);
+        snprintf(message, sizeof(message), "waiting for %s %u", mName.c_str(), fenceNum);
         ATRACE_NAME(message);
 
         status_t result = fence->waitForever(message);
@@ -82,8 +96,8 @@
         std::lock_guard<std::mutex> lock(mMutex);
         mQueue.pop_front();
         mFencesSignaled++;
-        ATRACE_INT(mName, int32_t(mQueue.size()));
+        ATRACE_INT(mName.c_str(), int32_t(mQueue.size()));
     }
 }
 
-} // namespace android::gui
\ No newline at end of file
+} // namespace android::gui