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_SERVICES_G1MEMORYPOOL_HPP
  26 #define SHARE_VM_SERVICES_G1MEMORYPOOL_HPP
  27 
  28 #include "utilities/macros.hpp"
  29 #if INCLUDE_ALL_GCS
  30 #include "gc/g1/g1MonitoringSupport.hpp"
  31 #include "services/memoryPool.hpp"
  32 #include "services/memoryUsage.hpp"
  33 #endif // INCLUDE_ALL_GCS
  34 
  35 // This file contains the three classes that represent the memory
  36 // pools of the G1 spaces: G1EdenPool, G1SurvivorPool, and
  37 // G1OldGenPool. In G1, unlike our other GCs, we do not have a
  38 // physical space for each of those spaces. Instead, we allocate
  39 // regions for all three spaces out of a single pool of regions (that
  40 // pool basically covers the entire heap). As a result, the eden,
  41 // survivor, and old gen are considered logical spaces in G1, as each
  42 // is a set of non-contiguous regions. This is also reflected in the
  43 // way we map them to memory pools here. The easiest way to have done
  44 // this would have been to map the entire G1 heap to a single memory
  45 // pool. However, it's helpful to show how large the eden and survivor
  46 // get, as this does affect the performance and behavior of G1. Which
  47 // is why we introduce the three memory pools implemented here.
  48 //
  49 // See comments in g1MonitoringSupport.hpp for additional details
  50 // on this model.
  51 //
  52 
  53 // This class is shared by the three G1 memory pool classes
  54 // (G1EdenPool, G1SurvivorPool, G1OldGenPool).
  55 class G1MemoryPoolSuper : public CollectedMemoryPool {
  56 protected:
  57   const static size_t _undefined_max = (size_t) -1;
  58   G1MonitoringSupport* _g1mm;
  59 
  60   // Would only be called from subclasses.
  61   G1MemoryPoolSuper(G1CollectedHeap* g1h,
  62                     const char* name,
  63                     size_t init_size,
  64                     size_t max_size,
  65                     bool support_usage_threshold);
  66 };
  67 
  68 // Memory pool that represents the G1 eden.
  69 class G1EdenPool : public G1MemoryPoolSuper {
  70 public:
  71   G1EdenPool(G1CollectedHeap* g1h);
  72 
  73   size_t used_in_bytes() {
  74     return _g1mm->eden_space_used();
  75   }
  76   size_t max_size() const {
  77     return _undefined_max;
  78   }
  79   MemoryUsage get_memory_usage();
  80 };
  81 
  82 // Memory pool that represents the G1 survivor.
  83 class G1SurvivorPool : public G1MemoryPoolSuper {
  84 public:
  85   G1SurvivorPool(G1CollectedHeap* g1h);
  86 
  87   size_t used_in_bytes() {
  88     return _g1mm->survivor_space_used();
  89   }
  90   size_t max_size() const {
  91     return _undefined_max;
  92   }
  93   MemoryUsage get_memory_usage();
  94 };
  95 
  96 // Memory pool that represents the G1 old gen.
  97 class G1OldGenPool : public G1MemoryPoolSuper {
  98 public:
  99   G1OldGenPool(G1CollectedHeap* g1h);
 100 
 101   size_t used_in_bytes() {
 102     return _g1mm->old_space_used();
 103   }
 104   size_t max_size() const {
 105     return _g1mm->old_gen_max();
 106   }
 107   MemoryUsage get_memory_usage();
 108 };
 109 
 110 #endif // SHARE_VM_SERVICES_G1MEMORYPOOL_HPP