src/hotspot/share/gc/shared/threadLocalAllocBuffer.inline.hpp

*** 51,60 ****
--- 51,81 ----
      return obj;
    }
    return NULL;
  }
  
+ inline bool ThreadLocalAllocBuffer::undo_allocate(HeapWord* obj, size_t size) {
+   invariants();
+ 
+   // The object might not be allocated in this TLAB
+   if (contains(obj, size)) {
+     return false;
+   }
+ 
+   HeapWord* const prev_top = top() - size;
+ 
+   // The object might not be the last allocated in this TLAB
+   if (prev_top != obj) {
+     return false;
+   }
+ 
+   set_top(prev_top);
+ 
+   invariants();
+   return true;
+ }
+ 
  inline size_t ThreadLocalAllocBuffer::compute_size(size_t obj_size) {
    // Compute the size for the new TLAB.
    // The "last" tlab may be smaller to reduce fragmentation.
    // unsafe_max_tlab_alloc is just a hint.
    const size_t available_size = Universe::heap()->unsafe_max_tlab_alloc(myThread()) /