src: reduce platform worker barrier lifetime

Minor cleanup in the lifetime for the platform worker initialization
synchronization barrier.

PR-URL: #23419
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: ofrobots

src/node_platform.cc

@@ -167,17 +167,20 @@ class WorkerThreadsTaskRunner::DelayedTaskScheduler {
 };
 
 WorkerThreadsTaskRunner::WorkerThreadsTaskRunner(int thread_pool_size) {
-  Mutex::ScopedLock lock(platform_workers_mutex_);
-  pending_platform_workers_ = thread_pool_size;
+  Mutex platform_workers_mutex;
+  ConditionVariable platform_workers_ready;
+
+  Mutex::ScopedLock lock(platform_workers_mutex);
+  int pending_platform_workers = thread_pool_size;
 
   delayed_task_scheduler_.reset(
       new DelayedTaskScheduler(&pending_worker_tasks_));
   threads_.push_back(delayed_task_scheduler_->Start());
 
   for (int i = 0; i < thread_pool_size; i++) {
     PlatformWorkerData* worker_data = new PlatformWorkerData{
-      &pending_worker_tasks_, &platform_workers_mutex_,
-      &platform_workers_ready_, &pending_platform_workers_, i
+      &pending_worker_tasks_, &platform_workers_mutex,
+      &platform_workers_ready, &pending_platform_workers, i
     };
     std::unique_ptr<uv_thread_t> t { new uv_thread_t() };
     if (uv_thread_create(t.get(), PlatformWorkerThread,
@@ -189,8 +192,8 @@ WorkerThreadsTaskRunner::WorkerThreadsTaskRunner(int thread_pool_size) {
 
   // Wait for platform workers to initialize before continuing with the
   // bootstrap.
-  while (pending_platform_workers_ > 0) {
-    platform_workers_ready_.Wait(lock);
+  while (pending_platform_workers > 0) {
+    platform_workers_ready.Wait(lock);
   }
 }
 

src/node_platform.h

@@ -117,10 +117,6 @@ class WorkerThreadsTaskRunner {
   std::unique_ptr<DelayedTaskScheduler> delayed_task_scheduler_;
 
   std::vector<std::unique_ptr<uv_thread_t>> threads_;
-
-  Mutex platform_workers_mutex_;
-  ConditionVariable platform_workers_ready_;
-  int pending_platform_workers_;
 };
 
 class NodePlatform : public MultiIsolatePlatform {