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

rev 50392 : JEP 331

*** 364,373 ****
--- 364,393 ----
    }
  }
  #endif
  
  HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
+   HeapWord* obj = NULL;
+ 
+   // In assertion mode, check that there was a sampling collector present
+   // in the stack. This enforces checking that no path is without a sampling
+   // collector.
+   // Only check if the sampler could actually sample something in this call path.
+   assert(!JvmtiExport::should_post_sampled_object_alloc()
+          || !JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample()
+          || thread->heap_sampler().sampling_collector_present(),
+          "Sampling collector not present.");
+ 
+   if (ThreadHeapSampler::enabled()) {
+     // Try to allocate the sampled object from TLAB, it is possible a sample
+     // point was put and the TLAB still has space.
+     obj = thread->tlab().allocate_sampled_object(size);
+ 
+     if (obj != NULL) {
+       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);
*** 386,396 ****
  
    // Allocate a new TLAB requesting new_tlab_size. Any size
    // between minimal and new_tlab_size is accepted.
    size_t actual_tlab_size = 0;
    size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
!   HeapWord* obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
    if (obj == NULL) {
      assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
             min_tlab_size, new_tlab_size, actual_tlab_size);
      return NULL;
    }
--- 406,416 ----
  
    // Allocate a new TLAB requesting new_tlab_size. Any size
    // between minimal and new_tlab_size is accepted.
    size_t actual_tlab_size = 0;
    size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
!   obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
    if (obj == NULL) {
      assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
             min_tlab_size, new_tlab_size, actual_tlab_size);
      return NULL;
    }
*** 410,419 ****
--- 430,447 ----
      // any concurrent GC thread.
      size_t hdr_size = oopDesc::header_size();
      Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
  #endif // ASSERT
    }
+ 
+   // Send the thread information about this allocation in case a sample is
+   // requested.
+   if (ThreadHeapSampler::enabled()) {
+     size_t tlab_bytes_since_last_sample = thread->tlab().bytes_since_last_sample_point();
+     thread->heap_sampler().check_for_sampling(obj, size, tlab_bytes_since_last_sample);
+   }
+ 
    thread->tlab().fill(obj, obj + size, actual_tlab_size);
    return obj;
  }
  
  size_t CollectedHeap::max_tlab_size() const {