src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

*** 1841,1877 ****
    size_t old_mem_size = _g1_storage.committed_size();
    size_t aligned_shrink_bytes =
      ReservedSpace::page_align_size_down(shrink_bytes);
    aligned_shrink_bytes = align_size_down(aligned_shrink_bytes,
                                           HeapRegion::GrainBytes);
!   uint num_regions_deleted = 0;
!   MemRegion mr = _hrs.shrink_by(aligned_shrink_bytes, &num_regions_deleted);
    HeapWord* old_end = (HeapWord*) _g1_storage.high();
!   assert(mr.end() == old_end, "post-condition");
  
    ergo_verbose3(ErgoHeapSizing,
                  "shrink the heap",
                  ergo_format_byte("requested shrinking amount")
                  ergo_format_byte("aligned shrinking amount")
                  ergo_format_byte("attempted shrinking amount"),
!                 shrink_bytes, aligned_shrink_bytes, mr.byte_size());
!   if (mr.byte_size() > 0) {
      if (_hr_printer.is_active()) {
!       HeapWord* curr = mr.end();
!       while (curr > mr.start()) {
          HeapWord* curr_end = curr;
          curr -= HeapRegion::GrainWords;
          _hr_printer.uncommit(curr, curr_end);
        }
-       assert(curr == mr.start(), "post-condition");
      }
  
!     _g1_storage.shrink_by(mr.byte_size());
!     HeapWord* new_end = (HeapWord*) _g1_storage.high();
!     assert(mr.start() == new_end, "post-condition");
! 
!     _expansion_regions += num_regions_deleted;
      update_committed_space(old_end, new_end);
      HeapRegionRemSet::shrink_heap(n_regions());
      g1_policy()->record_new_heap_size(n_regions());
    } else {
      ergo_verbose0(ErgoHeapSizing,
--- 1841,1876 ----
    size_t old_mem_size = _g1_storage.committed_size();
    size_t aligned_shrink_bytes =
      ReservedSpace::page_align_size_down(shrink_bytes);
    aligned_shrink_bytes = align_size_down(aligned_shrink_bytes,
                                           HeapRegion::GrainBytes);
!   uint num_regions_to_remove = (uint)(shrink_bytes / HeapRegion::GrainBytes);
! 
!   uint num_regions_removed = _hrs.shrink_by(num_regions_to_remove);
    HeapWord* old_end = (HeapWord*) _g1_storage.high();
!   size_t shrunk_bytes = num_regions_removed * HeapRegion::GrainBytes;
  
    ergo_verbose3(ErgoHeapSizing,
                  "shrink the heap",
                  ergo_format_byte("requested shrinking amount")
                  ergo_format_byte("aligned shrinking amount")
                  ergo_format_byte("attempted shrinking amount"),
!                 shrink_bytes, aligned_shrink_bytes, shrunk_bytes);
!   if (num_regions_removed > 0) {
!     _g1_storage.shrink_by(shrunk_bytes);
!     HeapWord* new_end = (HeapWord*) _g1_storage.high();
! 
      if (_hr_printer.is_active()) {
!       HeapWord* curr = old_end;
!       while (curr > new_end) {
          HeapWord* curr_end = curr;
          curr -= HeapRegion::GrainWords;
          _hr_printer.uncommit(curr, curr_end);
        }
      }
  
!     _expansion_regions += num_regions_removed;
      update_committed_space(old_end, new_end);
      HeapRegionRemSet::shrink_heap(n_regions());
      g1_policy()->record_new_heap_size(n_regions());
    } else {
      ergo_verbose0(ErgoHeapSizing,