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 // Allocation context associated with this alloc region. 57 AllocationContext_t _allocation_context; 58 59 // It keeps track of the distinct number of regions that are used 60 // for allocation in the active interval of this object, i.e., 61 // between a call to init() and a call to release(). The count 62 // mostly includes regions that are freshly allocated, as well as 63 // the region that is re-used using the set() method. This count can 64 // be used in any heuristics that might want to bound how many 65 // distinct regions this object can used during an active interval. 66 uint _count; 67 68 // When we set up a new active region we save its used bytes in this 69 // field so that, when we retire it, we can calculate how much space 70 // we allocated in it. 71 size_t _used_bytes_before; 72 73 // When true, indicates that allocate calls should do BOT updates. 74 const bool _bot_updates; 75 76 // Useful for debugging and tracing. 77 const char* _name; 78 122 // Returns the number of bytes that have been filled up during retire. 123 virtual size_t retire(bool fill_up); 124 125 // For convenience as subclasses use it. 126 static G1CollectedHeap* _g1h; 127 128 virtual HeapRegion* allocate_new_region(size_t word_size, bool force) = 0; 129 virtual void retire_region(HeapRegion* alloc_region, 130 size_t allocated_bytes) = 0; 131 132 G1AllocRegion(const char* name, bool bot_updates); 133 134 public: 135 static void setup(G1CollectedHeap* g1h, HeapRegion* dummy_region); 136 137 HeapRegion* get() const { 138 HeapRegion * hr = _alloc_region; 139 // Make sure that the dummy region does not escape this class. 140 return (hr == _dummy_region) ? NULL : hr; 141 } 142 143 void set_allocation_context(AllocationContext_t context) { _allocation_context = context; } 144 AllocationContext_t allocation_context() { return _allocation_context; } 145 146 uint count() { return _count; } 147 148 // The following two are the building blocks for the allocation method. 149 150 // First-level allocation: Should be called without holding a 151 // lock. It will try to allocate lock-free out of the active region, 152 // or return NULL if it was unable to. 153 inline HeapWord* attempt_allocation(size_t word_size); 154 // Perform an allocation out of the current allocation region, with the given 155 // minimum and desired size. Returns the actual size allocated (between 156 // minimum and desired size) in actual_word_size if the allocation has been 157 // successful. 158 // Should be called without holding a lock. It will try to allocate lock-free 159 // out of the active region, or return NULL if it was unable to. 160 inline HeapWord* attempt_allocation(size_t min_word_size, 161 size_t desired_word_size, 162 size_t* actual_word_size); 163 164 // Second-level allocation: Should be called while holding a | 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 62 // distinct regions this object can used during an active interval. 63 uint _count; 64 65 // When we set up a new active region we save its used bytes in this 66 // field so that, when we retire it, we can calculate how much space 67 // we allocated in it. 68 size_t _used_bytes_before; 69 70 // When true, indicates that allocate calls should do BOT updates. 71 const bool _bot_updates; 72 73 // Useful for debugging and tracing. 74 const char* _name; 75 119 // Returns the number of bytes that have been filled up during retire. 120 virtual size_t retire(bool fill_up); 121 122 // For convenience as subclasses use it. 123 static G1CollectedHeap* _g1h; 124 125 virtual HeapRegion* allocate_new_region(size_t word_size, bool force) = 0; 126 virtual void retire_region(HeapRegion* alloc_region, 127 size_t allocated_bytes) = 0; 128 129 G1AllocRegion(const char* name, bool bot_updates); 130 131 public: 132 static void setup(G1CollectedHeap* g1h, HeapRegion* dummy_region); 133 134 HeapRegion* get() const { 135 HeapRegion * hr = _alloc_region; 136 // Make sure that the dummy region does not escape this class. 137 return (hr == _dummy_region) ? NULL : hr; 138 } 139 140 uint count() { return _count; } 141 142 // The following two are the building blocks for the allocation method. 143 144 // First-level allocation: Should be called without holding a 145 // lock. It will try to allocate lock-free out of the active region, 146 // or return NULL if it was unable to. 147 inline HeapWord* attempt_allocation(size_t word_size); 148 // Perform an allocation out of the current allocation region, with the given 149 // minimum and desired size. Returns the actual size allocated (between 150 // minimum and desired size) in actual_word_size if the allocation has been 151 // successful. 152 // Should be called without holding a lock. It will try to allocate lock-free 153 // out of the active region, or return NULL if it was unable to. 154 inline HeapWord* attempt_allocation(size_t min_word_size, 155 size_t desired_word_size, 156 size_t* actual_word_size); 157 158 // Second-level allocation: Should be called while holding a |