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

rev 4204 : 7163191: G1: introduce a "heap spanning table" abstraction
Summary: Add a heap spanning table and employ it for the heap region sequence table.
Reviewed-by:

*** 1763,1773 ****
      // Then propagate this update to the necessary data structures.
      HeapWord* new_end = (HeapWord*) _g1_storage.high();
      update_committed_space(old_end, new_end);
  
      FreeRegionList expansion_list("Local Expansion List");
!     MemRegion mr = _hrs.expand_by(old_end, new_end, &expansion_list);
      assert(mr.start() == old_end, "post-condition");
      // mr might be a smaller region than what was requested if
      // expand_by() was unable to allocate the HeapRegion instances
      assert(mr.end() <= new_end, "post-condition");
  
--- 1763,1773 ----
      // Then propagate this update to the necessary data structures.
      HeapWord* new_end = (HeapWord*) _g1_storage.high();
      update_committed_space(old_end, new_end);
  
      FreeRegionList expansion_list("Local Expansion List");
!     MemRegion mr = _hrs.expand_to(new_end, &expansion_list);
      assert(mr.start() == old_end, "post-condition");
      // mr might be a smaller region than what was requested if
      // expand_by() was unable to allocate the HeapRegion instances
      assert(mr.end() <= new_end, "post-condition");
  
*** 1818,1828 ****
    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",
--- 1818,1830 ----
    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;
!   HeapWord* desired_new_end =
!         (HeapWord*) _g1_storage.high() - (aligned_shrink_bytes / HeapWordSize);
!   MemRegion mr = _hrs.shrink_to(desired_new_end, &num_regions_deleted);
    HeapWord* old_end = (HeapWord*) _g1_storage.high();
    assert(mr.end() == old_end, "post-condition");
  
    ergo_verbose3(ErgoHeapSizing,
                  "shrink the heap",
*** 2037,2050 ****
    ReservedSpace g1_rs   = heap_rs.first_part(max_byte_size);
    _g1_reserved = MemRegion((HeapWord*)g1_rs.base(),
                             g1_rs.size()/HeapWordSize);
  
    _g1_storage.initialize(g1_rs, 0);
!   _g1_committed = MemRegion((HeapWord*)_g1_storage.low(), (size_t) 0);
    _hrs.initialize((HeapWord*) _g1_reserved.start(),
!                   (HeapWord*) _g1_reserved.end(),
!                   _expansion_regions);
  
    // 6843694 - ensure that the maximum region index can fit
    // in the remembered set structures.
    const uint max_region_idx = (1U << (sizeof(RegionIdx_t)*BitsPerByte-1)) - 1;
    guarantee((max_regions() - 1) <= max_region_idx, "too many regions");
--- 2039,2054 ----
    ReservedSpace g1_rs   = heap_rs.first_part(max_byte_size);
    _g1_reserved = MemRegion((HeapWord*)g1_rs.base(),
                             g1_rs.size()/HeapWordSize);
  
    _g1_storage.initialize(g1_rs, 0);
!   _g1_committed = MemRegion((HeapWord*) _g1_storage.low(), (size_t) 0);
    _hrs.initialize((HeapWord*) _g1_reserved.start(),
!                   (HeapWord*) _g1_reserved.end());
!   assert(_hrs.max_length() == _expansion_regions,
!          err_msg("max length: %u expansion regions: %u",
!                  _hrs.max_length(), _expansion_regions));
  
    // 6843694 - ensure that the maximum region index can fit
    // in the remembered set structures.
    const uint max_region_idx = (1U << (sizeof(RegionIdx_t)*BitsPerByte-1)) - 1;
    guarantee((max_regions() - 1) <= max_region_idx, "too many regions");