src/hotspot/share/trace/tracingExport.cpp

rev 49672 : 8200374: Add ThreadsSMRSupport::verify_hazard_pointer_scanned() to verify threads_do().
rev 49673 : Add missing NULL check; use proper lock-free get/set with TracingExport::_sampler_thread.
rev 49674 : Rename TracingExport::get_sampler_thread() to TracingExport::sampler_thread_acquire() and TracingExport::set_sampler_thread() to TracingExport::set_sampler_thread_with_lock(); set_sampler_thread_with_lock() uses Threads_lock toavoid conflicts with Thread-SMR scans.
rev 49675 : TracingExport::set_sampler_thread_with_lock() needs to verify assumptions and to use release_store().

*** 34,40 ****
  }
  
  void TracingExport::set_sampler_thread_with_lock(Thread* thread) {
    // Grab Threads_lock to avoid conflicts with Thread-SMR scans.
    MutexLocker ml(Threads_lock);
!   _sampler_thread = thread;
  }
--- 34,42 ----
  }
  
  void TracingExport::set_sampler_thread_with_lock(Thread* thread) {
    // Grab Threads_lock to avoid conflicts with Thread-SMR scans.
    MutexLocker ml(Threads_lock);
!   assert(thread == NULL || _sampler_thread == NULL, "_sampler_thread should not already be set.");
!   // To match with the lock-free load_acquire():
!   OrderAccess::release_store(&_sampler_thread, thread);
  }