src/share/vm/gc/shared/collectedHeap.cpp

@@ -36,10 +36,11 @@
 #include "logging/log.hpp"
 #include "memory/metaspace.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/instanceMirrorKlass.hpp"
 #include "oops/oop.inline.hpp"
+#include "runtime/heapMonitoring.hpp"
 #include "runtime/init.hpp"
 #include "runtime/thread.inline.hpp"
 #include "services/heapDumper.hpp"
 
 

@@ -294,10 +295,31 @@
   }
 }
 #endif
 
 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
+  // We can come here for three reasons:
+  //  - We either really did fill the tlab.
+  //  - We pretended to everyone we did and we want to sample.
+  //  - Both of the above reasons are true at the same time.
+  if (HeapMonitoring::enabled()) {
+    if (thread->tlab().should_sample()) {
+      // The tlab could still have space after this sample.
+      thread->tlab().set_back_actual_end();
+
+      // Try to allocate again: it could work now.
+      HeapWord* obj = thread->tlab().allocate(size);
+      if (obj != NULL) {
+        // Object got allocated, sample it now.
+        HeapMonitoring::object_alloc_do_sample(thread,
+                                               reinterpret_cast<oopDesc*>(obj),
+                                               size);
+        thread->tlab().pick_next_sample();
+        return obj;
+      }
+    }
+  }
 
   // Retain tlab and allocate object in shared space if
   // the amount free in the tlab is too large to discard.
   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
     thread->tlab().record_slow_allocation(size);

@@ -334,10 +356,20 @@
     size_t hdr_size = oopDesc::header_size();
     Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
 #endif // ASSERT
   }
   thread->tlab().fill(obj, obj + size, new_tlab_size);
+
+  if (HeapMonitoring::enabled()) {
+    if (thread->tlab().should_sample()) {
+      HeapMonitoring::object_alloc_do_sample(thread,
+                                             reinterpret_cast<oopDesc*>(obj),
+                                             size);
+    }
+    // Always pick a next sample here.
+    thread->tlab().pick_next_sample();
+  }
   return obj;
 }
 
 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
   MemRegion deferred = thread->deferred_card_mark();