src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp

*** 306,325 ****
    assert_locked_or_safepoint(Heap_lock);
  
    size_t size = align_size_down(bytes, virtual_space()->alignment());
    if (size > 0) {
      assert_lock_strong(ExpandHeap_lock);
!     virtual_space()->shrink_by(bytes);
      post_resize();
  
      if (Verbose && PrintGC) {
        size_t new_mem_size = virtual_space()->committed_size();
!       size_t old_mem_size = new_mem_size + bytes;
        gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
                                           SIZE_FORMAT "K to "
                                           SIZE_FORMAT "K",
!                       name(), old_mem_size/K, bytes/K, new_mem_size/K);
      }
    }
  }
  
  void PSOldGen::resize(size_t desired_free_space) {
--- 306,325 ----
    assert_locked_or_safepoint(Heap_lock);
  
    size_t size = align_size_down(bytes, virtual_space()->alignment());
    if (size > 0) {
      assert_lock_strong(ExpandHeap_lock);
!     virtual_space()->shrink_by(size);
      post_resize();
  
      if (Verbose && PrintGC) {
        size_t new_mem_size = virtual_space()->committed_size();
!       size_t old_mem_size = new_mem_size + size;
        gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
                                           SIZE_FORMAT "K to "
                                           SIZE_FORMAT "K",
!                       name(), old_mem_size/K, size/K, new_mem_size/K);
      }
    }
  }
  
  void PSOldGen::resize(size_t desired_free_space) {
*** 495,499 ****
--- 495,522 ----
  void PSOldGen::record_spaces_top() {
    assert(ZapUnusedHeapArea, "Not mangling unused space");
    object_space()->set_top_for_allocations();
  }
  #endif
+ 
+ void PSOldGen::try_to_shrink_by(size_t shrink_bytes) {
+   if (shrink_bytes < MinHeapDeltaBytes ||
+       capacity_in_bytes() - shrink_bytes < _init_gen_size) {
+     return;
+   }
+ 
+   if (PrintGC) {
+     gclog_or_tty->print_cr(" Resizing old gen. shrink_bytes=%d", shrink_bytes);
+     gclog_or_tty->print("BEFORE: Old Gen: ");
+     gclog_or_tty->print("capacity : " SIZE_FORMAT ", ", capacity_in_bytes());
+     gclog_or_tty->print_cr("used : " SIZE_FORMAT ", " , used_in_bytes());
+   }
+ 
+   MutexLocker x(ExpandHeap_lock);
+   shrink(shrink_bytes);
+ 
+   if (PrintGC) {
+     gclog_or_tty->print("AFTER: Old Gen: ");
+     gclog_or_tty->print("capacity : " SIZE_FORMAT ", ", capacity_in_bytes());
+     gclog_or_tty->print_cr("used : " SIZE_FORMAT ", " , used_in_bytes());
+   }
+ }