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src/share/vm/gc/g1/heapRegionType.hpp

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  27 
  28 #include "memory/allocation.hpp"
  29 
  30 #define hrt_assert_is_valid(tag) \
  31   assert(is_valid((tag)), err_msg("invalid HR type: %u", (uint) (tag)))
  32 
  33 class HeapRegionType VALUE_OBJ_CLASS_SPEC {
  34 private:
  35   // We encode the value of the heap region type so the generation can be
  36   // determined quickly. The tag is split into two parts:
  37   //
  38   //   major type (young, humongous)                         : top N-1 bits
  39   //   minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit
  40   //
  41   // If there's need to increase the number of minor types in the
  42   // future, we'll have to increase the size of the latter and hence
  43   // decrease the size of the former.
  44   //
  45   // 0000 0 [ 0] Free
  46   //
  47   // 0001 0      Young Mask
  48   // 0001 0 [ 2] Eden
  49   // 0001 1 [ 3] Survivor
  50   //
  51   // 0010 0      Humongous Mask
  52   // 0010 0 [ 4] Starts Humongous
  53   // 0010 1 [ 5] Continues Humongous

  54   //
  55   // 01000 [ 8] Old


  56   typedef enum {
  57     FreeTag               = 0,
  58 
  59     YoungMask             = 2,
  60     EdenTag               = YoungMask,
  61     SurvTag               = YoungMask + 1,
  62 
  63     HumongousMask         = 4,
  64     StartsHumongousTag    = HumongousMask,
  65     ContinuesHumongousTag = HumongousMask + 1,




  66 
  67     OldTag                = 8
  68   } Tag;
  69 
  70   volatile Tag _tag;
  71 
  72   static bool is_valid(Tag tag);
  73 
  74   Tag get() const {
  75     hrt_assert_is_valid(_tag);
  76     return _tag;
  77   }
  78 
  79   // Sets the type to 'tag'.
  80   void set(Tag tag) {
  81     hrt_assert_is_valid(tag);
  82     hrt_assert_is_valid(_tag);
  83     _tag = tag;
  84   }
  85 
  86   // Sets the type to 'tag', expecting the type to be 'before'. This
  87   // is available for when we want to add sanity checking to the type


  91     hrt_assert_is_valid(before);
  92     hrt_assert_is_valid(_tag);
  93     assert(_tag == before,
  94            err_msg("HR tag: %u, expected: %u new tag; %u", _tag, before, tag));
  95     _tag = tag;
  96   }
  97 
  98 public:
  99   // Queries
 100 
 101   bool is_free() const { return get() == FreeTag; }
 102 
 103   bool is_young()    const { return (get() & YoungMask) != 0; }
 104   bool is_eden()     const { return get() == EdenTag;  }
 105   bool is_survivor() const { return get() == SurvTag;  }
 106 
 107   bool is_humongous()           const { return (get() & HumongousMask) != 0;   }
 108   bool is_starts_humongous()    const { return get() == StartsHumongousTag;    }
 109   bool is_continues_humongous() const { return get() == ContinuesHumongousTag; }
 110 
 111   bool is_old() const { return get() == OldTag; }






 112 
 113   // Setters
 114 
 115   void set_free() { set(FreeTag); }
 116 
 117   void set_eden()        { set_from(EdenTag, FreeTag); }
 118   void set_eden_pre_gc() { set_from(EdenTag, SurvTag); }
 119   void set_survivor()    { set_from(SurvTag, FreeTag); }
 120 
 121   void set_starts_humongous()    { set_from(StartsHumongousTag,    FreeTag); }
 122   void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); }
 123 
 124   void set_old() { set(OldTag); }


 125 
 126   // Misc
 127 
 128   const char* get_str() const;
 129   const char* get_short_str() const;
 130 
 131   HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); }
 132 };
 133 
 134 #endif // SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP


  27 
  28 #include "memory/allocation.hpp"
  29 
  30 #define hrt_assert_is_valid(tag) \
  31   assert(is_valid((tag)), err_msg("invalid HR type: %u", (uint) (tag)))
  32 
  33 class HeapRegionType VALUE_OBJ_CLASS_SPEC {
  34 private:
  35   // We encode the value of the heap region type so the generation can be
  36   // determined quickly. The tag is split into two parts:
  37   //
  38   //   major type (young, humongous)                         : top N-1 bits
  39   //   minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit
  40   //
  41   // If there's need to increase the number of minor types in the
  42   // future, we'll have to increase the size of the latter and hence
  43   // decrease the size of the former.
  44   //
  45   // 0000 0 [ 0] Free
  46   //
  47   // 0001 0 [ 2] Young Mask
  48   // 0001 0 [ 2] Eden
  49   // 0001 1 [ 3] Survivor
  50   //
  51   // 0010 0 [ 4] Humongous Mask
  52   // 0100 0 [ 8] Pinned Mask
  53   // 0110 0 [12] Starts Humongous
  54   // 0110 1 [13] Continues Humongous
  55   //
  56   // 1000 0 [16] Old Mask
  57   //
  58   // 1100 0 [24] Archive
  59   typedef enum {
  60     FreeTag               = 0,
  61 
  62     YoungMask             = 2,
  63     EdenTag               = YoungMask,
  64     SurvTag               = YoungMask + 1,
  65 
  66     HumongousMask         = 4,
  67     PinnedMask            = 8,
  68     StartsHumongousTag    = HumongousMask | PinnedMask,
  69     ContinuesHumongousTag = HumongousMask | PinnedMask + 1,
  70 
  71     OldMask               = 16,
  72     OldTag                = OldMask,
  73 
  74     ArchiveTag            = PinnedMask | OldMask
  75   } Tag;
  76 
  77   volatile Tag _tag;
  78 
  79   static bool is_valid(Tag tag);
  80 
  81   Tag get() const {
  82     hrt_assert_is_valid(_tag);
  83     return _tag;
  84   }
  85 
  86   // Sets the type to 'tag'.
  87   void set(Tag tag) {
  88     hrt_assert_is_valid(tag);
  89     hrt_assert_is_valid(_tag);
  90     _tag = tag;
  91   }
  92 
  93   // Sets the type to 'tag', expecting the type to be 'before'. This
  94   // is available for when we want to add sanity checking to the type


  98     hrt_assert_is_valid(before);
  99     hrt_assert_is_valid(_tag);
 100     assert(_tag == before,
 101            err_msg("HR tag: %u, expected: %u new tag; %u", _tag, before, tag));
 102     _tag = tag;
 103   }
 104 
 105 public:
 106   // Queries
 107 
 108   bool is_free() const { return get() == FreeTag; }
 109 
 110   bool is_young()    const { return (get() & YoungMask) != 0; }
 111   bool is_eden()     const { return get() == EdenTag;  }
 112   bool is_survivor() const { return get() == SurvTag;  }
 113 
 114   bool is_humongous()           const { return (get() & HumongousMask) != 0;   }
 115   bool is_starts_humongous()    const { return get() == StartsHumongousTag;    }
 116   bool is_continues_humongous() const { return get() == ContinuesHumongousTag; }
 117 
 118   bool is_archive() const { return get() == ArchiveTag; } 
 119 
 120   // is_old regions may or may not also be pinned
 121   bool is_old() const { return (get() & OldMask) != 0; }
 122 
 123   // is_pinned regions may be archive or humongous
 124   bool is_pinned() const { return (get() & PinnedMask) != 0; }
 125 
 126   // Setters
 127 
 128   void set_free() { set(FreeTag); }
 129 
 130   void set_eden()        { set_from(EdenTag, FreeTag); }
 131   void set_eden_pre_gc() { set_from(EdenTag, SurvTag); }
 132   void set_survivor()    { set_from(SurvTag, FreeTag); }
 133 
 134   void set_starts_humongous()    { set_from(StartsHumongousTag,    FreeTag); }
 135   void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); }
 136 
 137   void set_old() { set(OldTag); }
 138 
 139   void set_archive() { set_from(ArchiveTag, FreeTag); }
 140 
 141   // Misc
 142 
 143   const char* get_str() const;
 144   const char* get_short_str() const;
 145 
 146   HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); }
 147 };
 148 
 149 #endif // SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP
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