1 /*
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  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
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  24 
  25 #ifndef SHARE_VM_GC_G1_G1MEMORYPOOL_HPP
  26 #define SHARE_VM_GC_G1_G1MEMORYPOOL_HPP
  27 
  28 #include "gc/g1/g1MonitoringSupport.hpp"
  29 #include "services/memoryPool.hpp"
  30 #include "services/memoryUsage.hpp"
  31 
  32 // This file contains the three classes that represent the memory
  33 // pools of the G1 spaces: G1EdenPool, G1SurvivorPool, and
  34 // G1OldGenPool. In G1, unlike our other GCs, we do not have a
  35 // physical space for each of those spaces. Instead, we allocate
  36 // regions for all three spaces out of a single pool of regions (that
  37 // pool basically covers the entire heap). As a result, the eden,
  38 // survivor, and old gen are considered logical spaces in G1, as each
  39 // is a set of non-contiguous regions. This is also reflected in the
  40 // way we map them to memory pools here. The easiest way to have done
  41 // this would have been to map the entire G1 heap to a single memory
  42 // pool. However, it's helpful to show how large the eden and survivor
  43 // get, as this does affect the performance and behavior of G1. Which
  44 // is why we introduce the three memory pools implemented here.
  45 //
  46 // See comments in g1MonitoringSupport.hpp for additional details
  47 // on this model.
  48 //
  49 
  50 class G1CollectedHeap;
  51 
  52 // This class is shared by the three G1 memory pool classes
  53 // (G1EdenPool, G1SurvivorPool, G1OldGenPool).
  54 class G1MemoryPoolSuper : public CollectedMemoryPool {
  55 protected:
  56   const static size_t _undefined_max = (size_t) -1;
  57   G1MonitoringSupport* _g1mm;
  58 
  59   // Would only be called from subclasses.
  60   G1MemoryPoolSuper(G1CollectedHeap* g1h,
  61                     const char* name,
  62                     size_t init_size,
  63                     size_t max_size,
  64                     bool support_usage_threshold);
  65 };
  66 
  67 // Memory pool that represents the G1 eden.
  68 class G1EdenPool : public G1MemoryPoolSuper {
  69 public:
  70   G1EdenPool(G1CollectedHeap* g1h);
  71 
  72   size_t used_in_bytes() {
  73     return _g1mm->eden_space_used();
  74   }
  75   size_t max_size() const {
  76     return _undefined_max;
  77   }
  78   MemoryUsage get_memory_usage();
  79 };
  80 
  81 // Memory pool that represents the G1 survivor.
  82 class G1SurvivorPool : public G1MemoryPoolSuper {
  83 public:
  84   G1SurvivorPool(G1CollectedHeap* g1h);
  85 
  86   size_t used_in_bytes() {
  87     return _g1mm->survivor_space_used();
  88   }
  89   size_t max_size() const {
  90     return _undefined_max;
  91   }
  92   MemoryUsage get_memory_usage();
  93 };
  94 
  95 // Memory pool that represents the G1 old gen.
  96 class G1OldGenPool : public G1MemoryPoolSuper {
  97 public:
  98   G1OldGenPool(G1CollectedHeap* g1h);
  99 
 100   size_t used_in_bytes() {
 101     return _g1mm->old_space_used();
 102   }
 103   size_t max_size() const {
 104     return _g1mm->old_gen_max();
 105   }
 106   MemoryUsage get_memory_usage();
 107 };
 108 
 109 #endif // SHARE_VM_GC_G1_G1MEMORYPOOL_HPP