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

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rev 49521 : [mq]: heap8
rev 49522 : [mq]: event_rebased

@@ -44,10 +44,18 @@
 void ThreadLocalAllocBuffer::clear_before_allocation() {
   _slow_refill_waste += (unsigned)remaining();
   make_parsable(true);   // also retire the TLAB
 }
 
+size_t ThreadLocalAllocBuffer::remaining() {
+  if (current_end() == NULL) {
+    return 0;
+  }
+
+  return pointer_delta(reserved_end(), top());
+}
+
 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
   global_stats()->initialize();
 
   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
     thread->tlab().accumulate_statistics();

@@ -106,28 +114,30 @@
 // Fills the current tlab with a dummy filler array to create
 // an illusion of a contiguous Eden and optionally retires the tlab.
 // Waste accounting should be done in caller as appropriate; see,
 // for example, clear_before_allocation().
 void ThreadLocalAllocBuffer::make_parsable(bool retire, bool zap) {
-  if (end() != NULL) {
+  if (current_end() != NULL) {
     invariants();
 
     if (retire) {
       myThread()->incr_allocated_bytes(used_bytes());
     }
 
-    CollectedHeap::fill_with_object(top(), hard_end(), retire && zap);
+    CollectedHeap::fill_with_object(top(), reserved_end(), retire && zap);
 
     if (retire || ZeroTLAB) {  // "Reset" the TLAB
       set_start(NULL);
       set_top(NULL);
       set_pf_top(NULL);
-      set_end(NULL);
+      set_current_end(NULL);
+      set_allocation_end(NULL);
     }
   }
   assert(!(retire || ZeroTLAB)  ||
-         (start() == NULL && end() == NULL && top() == NULL),
+         (start() == NULL && current_end() == NULL && top() == NULL &&
+          _allocation_end == NULL),
          "TLAB must be reset");
 }
 
 void ThreadLocalAllocBuffer::resize_all_tlabs() {
   if (ResizeTLAB) {

@@ -169,23 +179,29 @@
                                   HeapWord* top,
                                   size_t    new_size) {
   _number_of_refills++;
   print_stats("fill");
   assert(top <= start + new_size - alignment_reserve(), "size too small");
+
   initialize(start, top, start + new_size - alignment_reserve());
 
+  if (ThreadHeapSampler::enabled()) {
+    set_sample_end();
+  }
+
   // Reset amount of internal fragmentation
   set_refill_waste_limit(initial_refill_waste_limit());
 }
 
 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
                                         HeapWord* top,
                                         HeapWord* end) {
   set_start(start);
   set_top(top);
   set_pf_top(top);
-  set_end(end);
+  set_current_end(end);
+  set_allocation_end(end);
   invariants();
 }
 
 void ThreadLocalAllocBuffer::initialize() {
   initialize(NULL,                    // start

@@ -304,16 +320,50 @@
     p += oop(p)->size();
   }
   guarantee(p == top(), "end of last object must match end of space");
 }
 
+void ThreadLocalAllocBuffer::set_sample_end() {
+  size_t heap_words_remaining = pointer_delta(_current_end, _top);
+  size_t bytes_until_sample = myThread()->heap_sampler().bytes_until_sample();
+  size_t words_until_sample = bytes_until_sample / HeapWordSize;;
+
+  if (heap_words_remaining > words_until_sample) {
+    HeapWord* new_end = _top + words_until_sample;
+    set_current_end(new_end);
+    _bytes_since_last_sample_point = bytes_until_sample;
+  } else {
+    _bytes_since_last_sample_point = heap_words_remaining * HeapWordSize;;
+  }
+}
+
 Thread* ThreadLocalAllocBuffer::myThread() {
   return (Thread*)(((char *)this) +
                    in_bytes(start_offset()) -
                    in_bytes(Thread::tlab_start_offset()));
 }
 
+void ThreadLocalAllocBuffer::set_back_allocation_end() {
+  _current_end = _allocation_end;
+}
+
+HeapWord* ThreadLocalAllocBuffer::allocate_sampled_object(size_t size) {
+  Thread* thread = myThread();
+  thread->tlab().set_back_allocation_end();
+  HeapWord* result = thread->tlab().allocate(size);
+
+  if (result) {
+    thread->heap_sampler().check_for_sampling(result, size * HeapWordSize, _bytes_since_last_sample_point);
+    thread->tlab().set_sample_end();
+  }
+
+  return result;
+}
+
+HeapWord* ThreadLocalAllocBuffer::reserved_end() {
+  return _allocation_end + alignment_reserve();
+}
 
 GlobalTLABStats::GlobalTLABStats() :
   _allocating_threads_avg(TLABAllocationWeight) {
 
   initialize();
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