src/hotspot/share/gc/shared/memAllocator.cpp

rev 52132 : 8201655: Add thread-enabled support for the Heap Sampling
Summary:
Reviewed-by:

@@ -30,10 +30,12 @@
 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
 #include "memory/universe.hpp"
 #include "oops/arrayOop.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiExport.hpp"
+#include "prims/jvmtiEventController.inline.hpp"
+#include "prims/jvmtiThreadState.inline.hpp"
 #include "runtime/sharedRuntime.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/thread.inline.hpp"
 #include "services/lowMemoryDetector.hpp"
 #include "utilities/align.hpp"

@@ -181,19 +183,41 @@
     _thread->check_for_valid_safepoint_state(true);
   }
 }
 #endif
 
+static bool thread_enabled_for_one_jvmti_env() {
+  JavaThread *thread  = JavaThread::current();
+  JvmtiThreadState *state = thread->jvmti_thread_state();
+  if (state == NULL) {
+    return false;
+  }
+
+  JvmtiEnvThreadStateIterator it(state);
+  for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
+    if (ets->is_enabled(JVMTI_EVENT_SAMPLED_OBJECT_ALLOC)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
   // support for JVMTI VMObjectAlloc event (no-op if not enabled)
   JvmtiExport::vm_object_alloc_event_collector(obj());
 
   if (!JvmtiExport::should_post_sampled_object_alloc()) {
     // Sampling disabled
     return;
   }
 
+  // Sampling is enabled for at least one thread, is it this one?
+  if (!thread_enabled_for_one_jvmti_env()) {
+    return;
+  }
+
   if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
     // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
     // or expands it due to taking a sampler induced slow path.
     return;
   }