21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_G1ALLOCREGION_HPP
  26 #define SHARE_VM_GC_G1_G1ALLOCREGION_HPP
  27 
  28 #include "gc/g1/heapRegion.hpp"
  29 #include "gc/g1/g1EvacStats.hpp"
  30 #include "gc/g1/g1InCSetState.hpp"
  31 
  32 class G1CollectedHeap;
  33 
  34 // A class that holds a region that is active in satisfying allocation
  35 // requests, potentially issued in parallel. When the active region is
  36 // full it will be retired and replaced with a new one. The
  37 // implementation assumes that fast-path allocations will be lock-free
  38 // and a lock will need to be taken when the active region needs to be
  39 // replaced.
  40 
  41 class G1AllocRegion VALUE_OBJ_CLASS_SPEC {
  42 
  43 private:
  44   // The active allocating region we are currently allocating out
  45   // of. The invariant is that if this object is initialized (i.e.,
  46   // init() has been called and release() has not) then _alloc_region
  47   // is either an active allocating region or the dummy region (i.e.,
  48   // it can never be NULL) and this object can be used to satisfy
  49   // allocation requests. If this object is not initialized
  50   // (i.e. init() has not been called or release() has been called)
  51   // then _alloc_region is NULL and this object should not be used to
  52   // satisfy allocation requests (it was done this way to force the
  53   // correct use of init() and release()).
  54   HeapRegion* volatile _alloc_region;
  55 
  56   // It keeps track of the distinct number of regions that are used
  57   // for allocation in the active interval of this object, i.e.,
  58   // between a call to init() and a call to release(). The count
  59   // mostly includes regions that are freshly allocated, as well as
  60   // the region that is re-used using the set() method. This count can
  61   // be used in any heuristics that might want to bound how many

  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_G1ALLOCREGION_HPP
  26 #define SHARE_VM_GC_G1_G1ALLOCREGION_HPP
  27 
  28 #include "gc/g1/heapRegion.hpp"
  29 #include "gc/g1/g1EvacStats.hpp"
  30 #include "gc/g1/g1InCSetState.hpp"
  31 
  32 class G1CollectedHeap;
  33 
  34 // A class that holds a region that is active in satisfying allocation
  35 // requests, potentially issued in parallel. When the active region is
  36 // full it will be retired and replaced with a new one. The
  37 // implementation assumes that fast-path allocations will be lock-free
  38 // and a lock will need to be taken when the active region needs to be
  39 // replaced.
  40 
  41 class G1AllocRegion {
  42 
  43 private:
  44   // The active allocating region we are currently allocating out
  45   // of. The invariant is that if this object is initialized (i.e.,
  46   // init() has been called and release() has not) then _alloc_region
  47   // is either an active allocating region or the dummy region (i.e.,
  48   // it can never be NULL) and this object can be used to satisfy
  49   // allocation requests. If this object is not initialized
  50   // (i.e. init() has not been called or release() has been called)
  51   // then _alloc_region is NULL and this object should not be used to
  52   // satisfy allocation requests (it was done this way to force the
  53   // correct use of init() and release()).
  54   HeapRegion* volatile _alloc_region;
  55 
  56   // It keeps track of the distinct number of regions that are used
  57   // for allocation in the active interval of this object, i.e.,
  58   // between a call to init() and a call to release(). The count
  59   // mostly includes regions that are freshly allocated, as well as
  60   // the region that is re-used using the set() method. This count can
  61   // be used in any heuristics that might want to bound how many