G1: Use SoftMaxHeapSize to guide GC heuristics

          --- old/src/hotspot/share/gc/g1/g1HeapSizingPolicy.hpp
          +++ new/src/hotspot/share/gc/g1/g1HeapSizingPolicy.hpp

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  24   24  
  25   25  #ifndef SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP
  26   26  #define SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP
  27   27  
  28   28  #include "memory/allocation.hpp"
  29   29  
  30   30  class G1Analytics;
  31   31  class G1CollectedHeap;
  32   32  
  33   33  class G1HeapSizingPolicy: public CHeapObj<mtGC> {
  34   34    // MinOverThresholdForGrowth must be less than the number of recorded
  35   35    // pause times in G1Analytics, representing the minimum number of pause
  36   36    // time ratios that exceed GCTimeRatio before a heap expansion will be triggered.
  37   37    const static uint MinOverThresholdForGrowth = 4;

  38   38  
  39   39    const G1CollectedHeap* _g1h;
  40   40    const G1Analytics* _analytics;
  41   41  
  42   42    const uint _num_prev_pauses_for_heuristics;
  43   43    // Ratio check data for determining if heap growth is necessary.
  44   44    uint _ratio_over_threshold_count;
  45   45    double _ratio_over_threshold_sum;
  46   46    uint _pauses_since_start;
  47   47  
       48 +  // Mininum heap capacity after last concurrent mark
       49 +  size_t _minimum_desired_bytes_after_last_cm;
       50 +
  48   51  
  49   52  protected:
  50   53    G1HeapSizingPolicy(const G1CollectedHeap* g1h, const G1Analytics* analytics);
  51   54  public:
  52   55  
  53   56    // If an expansion would be appropriate, because recent GC overhead had
  54   57    // exceeded the desired limit, return an amount to expand by.
  55      -  virtual size_t expansion_amount();
       58 +  virtual size_t expansion_amount_after_young_collection();
       59 +  virtual size_t expansion_amount_after_concurrent_mark();
       60 +  virtual size_t shrink_amount_after_mixed_collections();
  56   61  
       62 +  // Calculate the target capacity based on used bytes and free ratio
       63 +  virtual size_t target_heap_capacity(size_t used_bytes,  uintx free_ratio);
  57   64    // Clear ratio tracking data used by expansion_amount().
  58   65    void clear_ratio_check_data();
  59   66  
  60   67    static G1HeapSizingPolicy* create(const G1CollectedHeap* g1h, const G1Analytics* analytics);
  61   68  };
  62   69  
  63   70  #endif // SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP
    

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