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src/hotspot/share/gc/g1/g1InCSetState.hpp

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rev 52675 : 8213890: Implementation of JEP 344: Abortable Mixed Collections for G1
Reviewed-by:
Contributed-by: erik.helin@oracle.com, stefan.johansson@oracle.com


  39   // favor smaller types, so we use the smallest usable type there.
  40 #ifdef SPARC
  41   #define CSETSTATE_FORMAT INTPTR_FORMAT
  42   typedef intptr_t in_cset_state_t;
  43 #else
  44   #define CSETSTATE_FORMAT "%d"
  45   typedef int8_t in_cset_state_t;
  46 #endif
  47  private:
  48   in_cset_state_t _value;
  49  public:
  50   enum {
  51     // Selection of the values were driven to micro-optimize the encoding and
  52     // frequency of the checks.
  53     // The most common check is whether the region is in the collection set or not,
  54     // this encoding allows us to use an > 0 check.
  55     // The positive values are encoded in increasing generation order, which
  56     // makes getting the next generation fast by a simple increment. They are also
  57     // used to index into arrays.
  58     // The negative values are used for objects requiring various special cases,
  59     // for example eager reclamation of humongous objects.

  60     Humongous    = -1,    // The region is humongous
  61     NotInCSet    =  0,    // The region is not in the collection set.
  62     Young        =  1,    // The region is in the collection set and a young region.
  63     Old          =  2,    // The region is in the collection set and an old region.
  64     Num
  65   };
  66 
  67   InCSetState(in_cset_state_t value = NotInCSet) : _value(value) {
  68     assert(is_valid(), "Invalid state %d", _value);
  69   }
  70 
  71   in_cset_state_t value() const        { return _value; }
  72 
  73   void set_old()                       { _value = Old; }
  74 
  75   bool is_in_cset_or_humongous() const { return is_in_cset() || is_humongous(); }
  76   bool is_in_cset() const              { return _value > NotInCSet; }
  77 
  78   bool is_humongous() const            { return _value == Humongous; }
  79   bool is_young() const                { return _value == Young; }
  80   bool is_old() const                  { return _value == Old; }

  81 
  82 #ifdef ASSERT
  83   bool is_default() const              { return _value == NotInCSet; }
  84   bool is_valid() const                { return (_value >= Humongous) && (_value < Num); }
  85   bool is_valid_gen() const            { return (_value >= Young && _value <= Old); }
  86 #endif
  87 };
  88 
  89 // Instances of this class are used for quick tests on whether a reference points
  90 // into the collection set and into which generation or is a humongous object
  91 //
  92 // Each of the array's elements indicates whether the corresponding region is in
  93 // the collection set and if so in which generation, or a humongous region.
  94 //
  95 // We use this to speed up reference processing during young collection and
  96 // quickly reclaim humongous objects. For the latter, by making a humongous region
  97 // succeed this test, we sort-of add it to the collection set. During the reference
  98 // iteration closures, when we see a humongous region, we then simply mark it as
  99 // referenced, i.e. live.
 100 class G1InCSetStateFastTestBiasedMappedArray : public G1BiasedMappedArray<InCSetState> {
 101  protected:
 102   InCSetState default_value() const { return InCSetState::NotInCSet; }
 103  public:






 104   void set_humongous(uintptr_t index) {
 105     assert(get_by_index(index).is_default(),
 106            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 107     set_by_index(index, InCSetState::Humongous);
 108   }
 109 
 110   void clear_humongous(uintptr_t index) {
 111     set_by_index(index, InCSetState::NotInCSet);
 112   }
 113 
 114   void set_in_young(uintptr_t index) {
 115     assert(get_by_index(index).is_default(),
 116            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 117     set_by_index(index, InCSetState::Young);
 118   }
 119 
 120   void set_in_old(uintptr_t index) {
 121     assert(get_by_index(index).is_default(),
 122            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 123     set_by_index(index, InCSetState::Old);


  39   // favor smaller types, so we use the smallest usable type there.
  40 #ifdef SPARC
  41   #define CSETSTATE_FORMAT INTPTR_FORMAT
  42   typedef intptr_t in_cset_state_t;
  43 #else
  44   #define CSETSTATE_FORMAT "%d"
  45   typedef int8_t in_cset_state_t;
  46 #endif
  47  private:
  48   in_cset_state_t _value;
  49  public:
  50   enum {
  51     // Selection of the values were driven to micro-optimize the encoding and
  52     // frequency of the checks.
  53     // The most common check is whether the region is in the collection set or not,
  54     // this encoding allows us to use an > 0 check.
  55     // The positive values are encoded in increasing generation order, which
  56     // makes getting the next generation fast by a simple increment. They are also
  57     // used to index into arrays.
  58     // The negative values are used for objects requiring various special cases,
  59     // for example eager reclamation of humongous objects or optional regions.
  60     Optional     = -2,    // The region is optional
  61     Humongous    = -1,    // The region is humongous
  62     NotInCSet    =  0,    // The region is not in the collection set.
  63     Young        =  1,    // The region is in the collection set and a young region.
  64     Old          =  2,    // The region is in the collection set and an old region.
  65     Num
  66   };
  67 
  68   InCSetState(in_cset_state_t value = NotInCSet) : _value(value) {
  69     assert(is_valid(), "Invalid state %d", _value);
  70   }
  71 
  72   in_cset_state_t value() const        { return _value; }
  73 
  74   void set_old()                       { _value = Old; }
  75 
  76   bool is_in_cset_or_humongous() const { return is_in_cset() || is_humongous(); }
  77   bool is_in_cset() const              { return _value > NotInCSet; }
  78 
  79   bool is_humongous() const            { return _value == Humongous; }
  80   bool is_young() const                { return _value == Young; }
  81   bool is_old() const                  { return _value == Old; }
  82   bool is_optional() const             { return _value == Optional; }
  83 
  84 #ifdef ASSERT
  85   bool is_default() const              { return _value == NotInCSet; }
  86   bool is_valid() const                { return (_value >= Optional) && (_value < Num); }
  87   bool is_valid_gen() const            { return (_value >= Young && _value <= Old); }
  88 #endif
  89 };
  90 
  91 // Instances of this class are used for quick tests on whether a reference points
  92 // into the collection set and into which generation or is a humongous object
  93 //
  94 // Each of the array's elements indicates whether the corresponding region is in
  95 // the collection set and if so in which generation, or a humongous region.
  96 //
  97 // We use this to speed up reference processing during young collection and
  98 // quickly reclaim humongous objects. For the latter, by making a humongous region
  99 // succeed this test, we sort-of add it to the collection set. During the reference
 100 // iteration closures, when we see a humongous region, we then simply mark it as
 101 // referenced, i.e. live.
 102 class G1InCSetStateFastTestBiasedMappedArray : public G1BiasedMappedArray<InCSetState> {
 103  protected:
 104   InCSetState default_value() const { return InCSetState::NotInCSet; }
 105  public:
 106   void set_optional(uintptr_t index) {
 107     assert(get_by_index(index).is_default(),
 108            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 109     set_by_index(index, InCSetState::Optional);
 110   }
 111 
 112   void set_humongous(uintptr_t index) {
 113     assert(get_by_index(index).is_default(),
 114            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 115     set_by_index(index, InCSetState::Humongous);
 116   }
 117 
 118   void clear_humongous(uintptr_t index) {
 119     set_by_index(index, InCSetState::NotInCSet);
 120   }
 121 
 122   void set_in_young(uintptr_t index) {
 123     assert(get_by_index(index).is_default(),
 124            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 125     set_by_index(index, InCSetState::Young);
 126   }
 127 
 128   void set_in_old(uintptr_t index) {
 129     assert(get_by_index(index).is_default(),
 130            "State at index " INTPTR_FORMAT " should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value());
 131     set_by_index(index, InCSetState::Old);
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