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

rev 5920 : 8035406: Improve data structure for Code Cache remembered sets
Summary: Change the code cache remembered sets data structure from a GrowableArray to a chunked list of nmethods. This makes the data structure more amenable to parallelization, and decreases freeing time.
Reviewed-by:
rev 5921 : 8027295: Free CSet takes ~50% of young pause time
Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set.
Reviewed-by:

*** 360,380 ****
  int**  OtherRegionsTable::_from_card_cache = NULL;
  size_t OtherRegionsTable::_from_card_cache_max_regions = 0;
  size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
  
  void OtherRegionsTable::init_from_card_cache(size_t max_regions) {
!   _from_card_cache_max_regions = max_regions;
  
    int n_par_rs = HeapRegionRemSet::num_par_rem_sets();
    _from_card_cache = NEW_C_HEAP_ARRAY(int*, n_par_rs, mtGC);
    for (int i = 0; i < n_par_rs; i++) {
!     _from_card_cache[i] = NEW_C_HEAP_ARRAY(int, max_regions, mtGC);
!     for (size_t j = 0; j < max_regions; j++) {
        _from_card_cache[i][j] = -1;  // An invalid value.
      }
    }
!   _from_card_cache_mem_size = n_par_rs * max_regions * sizeof(int);
  }
  
  void OtherRegionsTable::shrink_from_card_cache(size_t new_n_regs) {
    for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
      assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
--- 360,391 ----
  int**  OtherRegionsTable::_from_card_cache = NULL;
  size_t OtherRegionsTable::_from_card_cache_max_regions = 0;
  size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
  
  void OtherRegionsTable::init_from_card_cache(size_t max_regions) {
!   guarantee(_from_card_cache == NULL, "Should not call this multiple times");
  
+   // Pad rows to cache line sizes.
+   static const int ints_per_cache_line = DEFAULT_CACHE_LINE_SIZE / sizeof(int);
    int n_par_rs = HeapRegionRemSet::num_par_rem_sets();
+   _from_card_cache_max_regions = align_size_up(max_regions, ints_per_cache_line);
+ 
+   // Need to make sure that the arrays are aligned too. Allocate a suitably
+   // large array to be able to align its base address later. We do not store
+   // the old pointer as we never free that memory.
+   size_t num_ints_to_alloc = n_par_rs * _from_card_cache_max_regions + ints_per_cache_line - 1;
+   int* data = NEW_C_HEAP_ARRAY(int, num_ints_to_alloc, mtGC);
+   data = (int*) (align_size_up_((uintptr_t)data, DEFAULT_CACHE_LINE_SIZE));
+ 
    _from_card_cache = NEW_C_HEAP_ARRAY(int*, n_par_rs, mtGC);
    for (int i = 0; i < n_par_rs; i++) {
!     _from_card_cache[i] = data + i * _from_card_cache_max_regions;
!     for (size_t j = 0; j < _from_card_cache_max_regions; j++) {
        _from_card_cache[i][j] = -1;  // An invalid value.
      }
    }
!   _from_card_cache_mem_size = num_ints_to_alloc * sizeof(int);
  }
  
  void OtherRegionsTable::shrink_from_card_cache(size_t new_n_regs) {
    for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
      assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
*** 726,736 ****
    return PerRegionTable::fl_mem_size();
  }
  
  void OtherRegionsTable::clear_fcc() {
    size_t hrs_idx = hr()->hrs_index();
!   for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
      _from_card_cache[i][hrs_idx] = -1;
    }
  }
  
  void OtherRegionsTable::clear() {
--- 737,748 ----
    return PerRegionTable::fl_mem_size();
  }
  
  void OtherRegionsTable::clear_fcc() {
    size_t hrs_idx = hr()->hrs_index();
!   uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
!   for (uint i = 0; i < num_par_remsets; i++) {
      _from_card_cache[i][hrs_idx] = -1;
    }
  }
  
  void OtherRegionsTable::clear() {