src/hotspot/share/gc/g1/g1FromCardCache.hpp

rev 50098 : [mq]: 8202842-g1-footprint-regressions

*** 1,7 ****
  /*
!  * Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 29,39 ****
  #include "utilities/ostream.hpp"
  
  // G1FromCardCache remembers the most recently processed card on the heap on
  // a per-region and per-thread basis.
  class G1FromCardCache : public AllStatic {
!  private:
    // Array of card indices. Indexed by heap region (rows) and thread (columns) to minimize
    // thread contention.
    // This order minimizes the time to clear all entries for a given region during region
    // freeing. I.e. a single clear of a single memory area instead of multiple separate
    // accesses with a large stride per region.
--- 29,39 ----
  #include "utilities/ostream.hpp"
  
  // G1FromCardCache remembers the most recently processed card on the heap on
  // a per-region and per-thread basis.
  class G1FromCardCache : public AllStatic {
! private:
    // Array of card indices. Indexed by heap region (rows) and thread (columns) to minimize
    // thread contention.
    // This order minimizes the time to clear all entries for a given region during region
    // freeing. I.e. a single clear of a single memory area instead of multiple separate
    // accesses with a large stride per region.
*** 47,59 ****
      assert(worker_id < _max_workers, "Worker_id %u is larger than maximum %u", worker_id, _max_workers);
      assert(region_idx < _max_regions, "Region_idx %u is larger than maximum %u", region_idx, _max_regions);
    }
  #endif
  
!  public:
!   static const uintptr_t InvalidCard = UINTPTR_MAX;
  
    static void clear(uint region_idx);
  
    // Returns true if the given card is in the cache at the given location, or
    // replaces the card at that location and returns false.
    static bool contains_or_replace(uint worker_id, uint region_idx, uintptr_t card) {
--- 47,62 ----
      assert(worker_id < _max_workers, "Worker_id %u is larger than maximum %u", worker_id, _max_workers);
      assert(region_idx < _max_regions, "Region_idx %u is larger than maximum %u", region_idx, _max_regions);
    }
  #endif
  
!   // This card index indicates "no card for that entry" yet. This allows us to use the OS
!   // lazy backing of memory with zero-filled pages to avoid initial actual memory use.
!   // This means that the heap must not contain card zero.
!   static const uintptr_t InvalidCard = 0;
  
+ public:
    static void clear(uint region_idx);
  
    // Returns true if the given card is in the cache at the given location, or
    // replaces the card at that location and returns false.
    static bool contains_or_replace(uint worker_id, uint region_idx, uintptr_t card) {