Reland "Reland "[tracing] Use trace thread for gpu process to initialize tracing""

This is a reland of commit 972bef57b3
No change was made. LUCI Bisection misdiagnosed this CL as the
culprit of ASAN failures.

Original change's description:
> Reland "[tracing] Use trace thread for gpu process to initialize tracing"
>
> This is a reland of commit 44d8036a9d
>
> Previous CL was reverted because PostDelayedTask is dropped when
> Linux/ChromeOS sandboxing procedure stops the running thread. Such tasks
> need to be reposted. There're several places that PostDelayedTask to the
> trace_thread:
> - Some are through the PerfettoTaskRunner, that can be tracked easily.
> - One is directly posted by ConnectProducerSocketViaMojo, needs to be
>   special treated.
>
> This CL:
> - For trace_startup.h/.cc, add option to start tracing using the
>   trace_thread, and set will_trace_thread_restart to true on linux and
>   chromeos.
> - For perfetto_traced_process.h/.cc, postpone system tracing producer
>   socket connection to after sandbox entrance on linux & chromeos.
> - For perfetto_task_runner.h/.cc, store delayed tasks and post them when
>   internal taks_runner is reset.
>
> Original change's description:
> > [tracing] Use trace thread for gpu process to initialize tracing
> >
> > For non-zygote child gpu thread, start the trace thread in
> > ContentMainRunnerImpl() directly.
> >
> > For zygote child gpu thread, start the trace thread in RunZygote after
> > zygote fork and featurelist init.
> >
> > For Linux & ChromeOS, stop and restart the trace thread when entering
> > sandbox. Restarting trace thread has a caveat that delayed tasks would
> > will be lost unless we save them.
> >
> > This is [3/?] CL of enabling tracing prior to sandboxing.
> >
> > Bug: 380411640
> > Change-Id: I89fa94f63a709de0e3da4f8759098c9fff813bee
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6180639
> > Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> > Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
> > Commit-Queue: Kramer Ge <fangzhoug@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1428704}
>
> Bug: 380411640, b/401194534
> Change-Id: I0f9172e48ee601f0236d84b0d8f784a11bd3d61a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6462335
> Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
> Commit-Queue: Kramer Ge <fangzhoug@chromium.org>
> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> Reviewed-by: Zhenyao Mo <zmo@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1451893}

Bug: 380411640, b/401194534
Change-Id: I32d42c00b0645783f00898ddc5167d655d773246
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6495650
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Auto-Submit: Kramer Ge <fangzhoug@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1453740}

services/tracing/public/cpp/perfetto/perfetto_traced_process.cc

@@ -108,7 +108,7 @@ void ConnectProducerSocketViaMojo(perfetto::CreateSocketCallback cb,
 
 // Wrapper for |ConnectProducerSocketViaMojo| to be used as a function pointer.
 void ConnectProducerSocketAsync(perfetto::CreateSocketCallback cb) {
-  ConnectProducerSocketViaMojo(std::move(cb), base::Milliseconds(100));
+  PerfettoTracedProcess::Get().DeferOrConnectProducerSocket(std::move(cb));
 }
 #endif
 
@@ -171,19 +171,22 @@ void PerfettoTracedProcess::DataSourceBase::ResetTaskRunner(
   GetDataSourceTaskRunner() = task_runner;
 }
 
-// static
 void PerfettoTracedProcess::RestartThreadInSandbox() {
-  base::Thread* trace_thread = PerfettoTracedProcess::GetTraceThread();
-  if (trace_thread->StartWithOptions(
-          base::Thread::Options(base::MessagePumpType::IO, 0))) {
-    DETACH_FROM_SEQUENCE(PerfettoTracedProcess::Get().sequence_checker_);
-    PerfettoTracedProcess::Get().task_runner_ = trace_thread->task_runner();
-    PerfettoTracedProcess::Get().platform_->ResetTaskRunner(
-        trace_thread->task_runner());
-    DataSourceBase::ResetTaskRunner(trace_thread->task_runner());
-    PerfettoTracedProcess::Get().tracing_backend_->DetachFromMuxerSequence();
-    CustomEventRecorder::GetInstance()->DetachFromSequence();
+  CHECK(trace_process_thread_->StartWithOptions(
+      base::Thread::Options(base::MessagePumpType::IO, 0)));
+  DETACH_FROM_SEQUENCE(sequence_checker_);
+  task_runner_ = trace_process_thread_->task_runner();
+  platform_->ResetTaskRunner(trace_process_thread_->task_runner());
+  DataSourceBase::ResetTaskRunner(trace_process_thread_->task_runner());
+  tracing_backend_->DetachFromMuxerSequence();
+  CustomEventRecorder::GetInstance()->DetachFromSequence();
+  will_trace_thread_restart_ = false;
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  if (system_tracing_producer_socket_cb_) {
+    task_runner_->PostTask(FROM_HERE,
+                           std::move(system_tracing_producer_socket_cb_));
   }
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
 }
 
 // static
@@ -200,8 +203,10 @@ PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstance() {
 }
 
 // static
-PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstanceWithThread() {
-  static base::NoDestructor<PerfettoTracedProcess> traced_process{};
+PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstanceWithThread(
+    bool will_trace_thread_restart) {
+  static base::NoDestructor<PerfettoTracedProcess> traced_process(
+      will_trace_thread_restart);
   return *traced_process;
 }
 
@@ -217,15 +222,18 @@ PerfettoTracedProcess& PerfettoTracedProcess::Get() {
   return *g_instance;
 }
 
-PerfettoTracedProcess::PerfettoTracedProcess()
+PerfettoTracedProcess::PerfettoTracedProcess(bool will_trace_thread_restart)
     : trace_process_thread_(std::make_unique<base::Thread>("PerfettoTrace")),
       task_runner_(trace_process_thread_->StartWithOptions(
                        base::Thread::Options(base::MessagePumpType::IO, 0))
                        ? trace_process_thread_->task_runner()
                        : nullptr),
-      platform_(
-          std::make_unique<base::tracing::PerfettoPlatform>(task_runner_)),
+      will_trace_thread_restart_(will_trace_thread_restart),
       tracing_backend_(std::make_unique<PerfettoTracingBackend>()) {
+  base::tracing::PerfettoPlatform::Options options{
+      .defer_delayed_tasks = will_trace_thread_restart_};
+  platform_ =
+      std::make_unique<base::tracing::PerfettoPlatform>(task_runner_, options);
   DETACH_FROM_SEQUENCE(sequence_checker_);
   CHECK_EQ(g_instance, nullptr);
   CHECK(task_runner_);
@@ -366,6 +374,20 @@ void PerfettoTracedProcess::SetupClientLibrary(bool enable_consumer) {
   CustomEventRecorder::GetInstance();
 }
 
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+void PerfettoTracedProcess::DeferOrConnectProducerSocket(
+    perfetto::CreateSocketCallback cb) {
+  CHECK(!system_tracing_producer_socket_cb_);
+  // Hold off the attempts to get socket fd until trace thread restarts.
+  if (will_trace_thread_restart_) {
+    system_tracing_producer_socket_cb_ = base::BindOnce(
+        ConnectProducerSocketViaMojo, cb, base::Milliseconds(100));
+  } else {
+    ConnectProducerSocketViaMojo(cb, base::Milliseconds(100));
+  }
+}
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
 void PerfettoTracedProcess::OnThreadPoolAvailable(bool enable_consumer) {
   thread_pool_started_ = true;
   SetupClientLibrary(enable_consumer);

services/tracing/public/cpp/perfetto/perfetto_traced_process.h

@@ -97,6 +97,9 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
     // By default, data source callbacks (e.g., Start/StopTracingImpl) are
     // called on PerfettoTracedProcess::GetTaskRunner()'s sequence. This method
     // allows overriding that task runner.
+    // Note: The task_runner's thread may stop and restart for Linux/ChromeOS
+    // sandboxing so the task_runner can change and delayed tasks posted to it
+    // may be silently dropped.
     virtual base::SequencedTaskRunner* GetTaskRunner();
 
     static void ResetTaskRunner(
@@ -152,8 +155,8 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
     perfetto::DataSourceConfig data_source_config_;
   };
 
-  // Restart the trace thread and replace the task_runner for tracing.
-  static void RestartThreadInSandbox();
+  // Restarts the trace thread and replaces the task_runner for tracing.
+  void RestartThreadInSandbox();
 
   // Returns the process-wide ptr to the trace thread, returns nullptr if the
   // task_runner for tracing is from the thread-pool.
@@ -161,7 +164,8 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
 
   // Creates the process-wide instance of the PerfettoTracedProcess.
   static PerfettoTracedProcess& MaybeCreateInstance();
-  static PerfettoTracedProcess& MaybeCreateInstanceWithThread();
+  static PerfettoTracedProcess& MaybeCreateInstanceWithThread(
+      bool will_trace_thread_restart);
   static PerfettoTracedProcess& MaybeCreateInstanceForTesting();
 
   // Returns the process-wide instance of the PerfettoTracedProcess.
@@ -228,11 +232,15 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
       const perfetto::TraceConfig& config,
       const perfetto::Tracing::SetupStartupTracingOpts& opts);
 
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  void DeferOrConnectProducerSocket(perfetto::CreateSocketCallback cb);
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
  private:
   friend class base::NoDestructor<PerfettoTracedProcess>;
 
   // Default constructor would create a dedicated thread for tracing
-  PerfettoTracedProcess();
+  explicit PerfettoTracedProcess(bool will_trace_thread_restart);
   explicit PerfettoTracedProcess(
       scoped_refptr<base::SequencedTaskRunner> task_runner);
 
@@ -261,6 +269,11 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
   std::unique_ptr<base::Thread> trace_process_thread_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
+  bool will_trace_thread_restart_ = false;
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  base::OnceClosure system_tracing_producer_socket_cb_;
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
   // Platform implementation for the Perfetto client library.
   std::unique_ptr<base::tracing::PerfettoPlatform> platform_;
   std::unique_ptr<PerfettoTracingBackend> tracing_backend_;

services/tracing/public/cpp/trace_startup.cc

@@ -46,17 +46,15 @@ using base::trace_event::TraceLog;
 }  // namespace
 
 bool g_tracing_initialized_after_featurelist = false;
+bool g_tracing_with_thread = false;
 
 bool IsTracingInitialized() {
   return g_tracing_initialized_after_featurelist;
 }
 
-void EnableStartupTracingIfNeeded() {
+void EnableStartupTracingIfNeeded(bool with_thread) {
   RegisterTracedValueProtoWriter();
 
-  // Create the PerfettoTracedProcess.
-  PerfettoTracedProcess::MaybeCreateInstance();
-
   // Initialize the client library's TrackRegistry to support trace points
   // during startup tracing. We don't setup the client library completely here
   // yet, because we don't have field trials loaded yet (which influence which
@@ -65,6 +63,20 @@ void EnableStartupTracingIfNeeded() {
   // setting up the client library?
   perfetto::internal::TrackRegistry::InitializeInstance();
 
+  // Create the PerfettoTracedProcess.
+  if (with_thread) {
+    g_tracing_with_thread = true;
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
+    PerfettoTracedProcess::MaybeCreateInstanceWithThread(
+        /*will_trace_thread_restart=*/true);
+#else
+    PerfettoTracedProcess::MaybeCreateInstanceWithThread(
+        /*will_trace_thread_restart=*/false);
+#endif
+  } else {
+    PerfettoTracedProcess::MaybeCreateInstance();
+  }
+
   // Ensure TraceLog is initialized first.
   // https://crbug.com/764357
   TraceLog::GetInstance();
@@ -105,7 +117,9 @@ void InitTracingPostFeatureList(bool enable_consumer) {
   DCHECK(base::FeatureList::GetInstance());
 
   // Create the PerfettoTracedProcess.
-  PerfettoTracedProcess::MaybeCreateInstance();
+  if (!g_tracing_with_thread) {
+    PerfettoTracedProcess::MaybeCreateInstance();
+  }
   PerfettoTracedProcess::Get().OnThreadPoolAvailable(enable_consumer);
 #if BUILDFLAG(IS_WIN)
   tracing::EnableETWExport();

services/tracing/public/cpp/trace_startup.h

@@ -35,7 +35,8 @@ bool COMPONENT_EXPORT(TRACING_CPP) IsTracingInitialized();
 // TODO(eseckler): Consider allocating the SMB in parent processes outside the
 // sandbox and supply it via the command line. Then, we can revert to call this
 // earlier and from fewer places again.
-void COMPONENT_EXPORT(TRACING_CPP) EnableStartupTracingIfNeeded();
+void COMPONENT_EXPORT(TRACING_CPP)
+    EnableStartupTracingIfNeeded(bool with_thread = false);
 
 // Enable startup tracing for the current process with the provided config. Sets
 // up ProducerClient and trace event and/or sampler profiler data sources, and