8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 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). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP 27 28 class HeapRegion; 29 class HeapRegionClosure; 30 class FreeRegionList; 31 32 // This class keeps track of the region metadata (i.e., HeapRegion 33 // instances). They are kept in the _regions array in address 34 // order. A region's index in the array corresponds to its index in 35 // the heap (i.e., 0 is the region at the bottom of the heap, 1 is 36 // the one after it, etc.). Two regions that are consecutive in the 37 // array should also be adjacent in the address space (i.e., 38 // region(i).end() == region(i+1).bottom(). 39 // 40 // We create a HeapRegion when we commit the region's address space 41 // for the first time. When we uncommit the address space of a 42 // region we retain the HeapRegion to be able to re-use it in the 43 // future (in case we recommit it). 44 // 45 // We keep track of three lengths: 46 // 47 // * _length (returned by length()) is the number of currently 48 // committed regions. 49 // * _allocated_length (not exposed outside this class) is the 50 // number of regions for which we have HeapRegions. 51 // * _max_length (returned by max_length()) is the maximum number of 52 // regions the heap can have. 53 // 54 // and maintain that: _length <= _allocated_length <= _max_length 55 56 class HeapRegionSeq: public CHeapObj<mtGC> { 57 friend class VMStructs; 58 59 // The array that holds the HeapRegions. 60 HeapRegion** _regions; 61 62 // Version of _regions biased to address 0 63 HeapRegion** _regions_biased; 64 65 // The number of regions committed in the heap. 66 uint _length; 67 68 // The address of the first reserved word in the heap. 69 HeapWord* _heap_bottom; 70 71 // The address of the last reserved word in the heap - 1. 72 HeapWord* _heap_end; 73 74 // The log of the region byte size. 75 uint _region_shift; 76 77 // A hint for which index to start searching from for humongous 78 // allocations. 79 uint _next_search_index; 80 81 // The number of regions for which we have allocated HeapRegions for. 82 uint _allocated_length; 83 84 // The maximum number of regions in the heap. 85 uint _max_length; 86 87 // Find a contiguous set of empty regions of length num, starting 88 // from the given index. 89 uint find_contiguous_from(uint from, uint num); 90 91 // Map a heap address to a biased region index. Assume that the 92 // address is valid. 93 inline uintx addr_to_index_biased(HeapWord* addr) const; 94 95 void increment_allocated_length() { 96 assert(_allocated_length < _max_length, "pre-condition"); 97 _allocated_length++; 98 } 99 100 void increment_length() { 101 assert(_length < _max_length, "pre-condition"); 102 _length++; 103 } 104 105 void decrement_length() { 106 assert(_length > 0, "pre-condition"); 107 _length--; 108 } 109 110 public: 111 // Empty contructor, we'll initialize it with the initialize() method. 112 HeapRegionSeq() { } 113 114 void initialize(HeapWord* bottom, HeapWord* end, uint max_length); 115 116 // Return the HeapRegion at the given index. Assume that the index 117 // is valid. 118 inline HeapRegion* at(uint index) const; 119 120 // If addr is within the committed space return its corresponding 121 // HeapRegion, otherwise return NULL. 122 inline HeapRegion* addr_to_region(HeapWord* addr) const; 123 124 // Return the HeapRegion that corresponds to the given 125 // address. Assume the address is valid. 126 inline HeapRegion* addr_to_region_unsafe(HeapWord* addr) const; 127 128 // Return the number of regions that have been committed in the heap. 129 uint length() const { return _length; } 130 131 // Return the maximum number of regions in the heap. 132 uint max_length() const { return _max_length; } 133 134 // Expand the sequence to reflect that the heap has grown from 135 // old_end to new_end. Either create new HeapRegions, or re-use 136 // existing ones, and return them in the given list. Returns the 137 // memory region that covers the newly-created regions. If a 138 // HeapRegion allocation fails, the result memory region might be 139 // smaller than the desired one. 140 MemRegion expand_by(HeapWord* old_end, HeapWord* new_end, 141 FreeRegionList* list); 142 143 // Return the number of contiguous regions at the end of the sequence 144 // that are available for allocation. 145 uint free_suffix(); 146 147 // Find a contiguous set of empty regions of length num and return 148 // the index of the first region or G1_NULL_HRS_INDEX if the 149 // search was unsuccessful. 150 uint find_contiguous(uint num); 151 152 // Apply blk->doHeapRegion() on all committed regions in address order, | 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 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). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP 27 28 #include "gc_implementation/g1/g1BiasedArray.hpp" 29 30 class HeapRegion; 31 class HeapRegionClosure; 32 class FreeRegionList; 33 34 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { 35 protected: 36 virtual HeapRegion* default_value() const { return NULL; } 37 }; 38 39 // This class keeps track of the region metadata (i.e., HeapRegion 40 // instances). They are kept in the _regions array in address 41 // order. A region's index in the array corresponds to its index in 42 // the heap (i.e., 0 is the region at the bottom of the heap, 1 is 43 // the one after it, etc.). Two regions that are consecutive in the 44 // array should also be adjacent in the address space (i.e., 45 // region(i).end() == region(i+1).bottom(). 46 // 47 // We create a HeapRegion when we commit the region's address space 48 // for the first time. When we uncommit the address space of a 49 // region we retain the HeapRegion to be able to re-use it in the 50 // future (in case we recommit it). 51 // 52 // We keep track of three lengths: 53 // 54 // * _committed_length (returned by length()) is the number of currently 55 // committed regions. 56 // * _allocated_length (not exposed outside this class) is the 57 // number of regions for which we have HeapRegions. 58 // * max_length() returns the maximum number of regions the heap can have. 59 // 60 // and maintain that: _committed_length <= _allocated_length <= max_length() 61 62 class HeapRegionSeq: public CHeapObj<mtGC> { 63 friend class VMStructs; 64 65 G1HeapRegionTable _regions; 66 67 // The number of regions committed in the heap. 68 uint _committed_length; 69 70 // A hint for which index to start searching from for humongous 71 // allocations. 72 uint _next_search_index; 73 74 // The number of regions for which we have allocated HeapRegions for. 75 uint _allocated_length; 76 77 // Find a contiguous set of empty regions of length num, starting 78 // from the given index. 79 uint find_contiguous_from(uint from, uint num); 80 81 void increment_allocated_length() { 82 assert(_allocated_length < max_length(), "pre-condition"); 83 _allocated_length++; 84 } 85 86 void increment_length() { 87 assert(length() < max_length(), "pre-condition"); 88 _committed_length++; 89 } 90 91 void decrement_length() { 92 assert(length() > 0, "pre-condition"); 93 _committed_length--; 94 } 95 96 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); } 97 HeapWord* heap_end() const {return _regions.end_address_mapped(); } 98 99 public: 100 // Empty contructor, we'll initialize it with the initialize() method. 101 HeapRegionSeq() : _regions(), _committed_length(0), _next_search_index(0), _allocated_length(0) { } 102 103 void initialize(HeapWord* bottom, HeapWord* end); 104 105 // Return the HeapRegion at the given index. Assume that the index 106 // is valid. 107 inline HeapRegion* at(uint index) const; 108 109 // If addr is within the committed space return its corresponding 110 // HeapRegion, otherwise return NULL. 111 inline HeapRegion* addr_to_region(HeapWord* addr) const; 112 113 // Return the HeapRegion that corresponds to the given 114 // address. Assume the address is valid. 115 inline HeapRegion* addr_to_region_unsafe(HeapWord* addr) const; 116 117 // Return the number of regions that have been committed in the heap. 118 uint length() const { return _committed_length; } 119 120 // Return the maximum number of regions in the heap. 121 uint max_length() const { return (uint)_regions.length(); } 122 123 // Expand the sequence to reflect that the heap has grown from 124 // old_end to new_end. Either create new HeapRegions, or re-use 125 // existing ones, and return them in the given list. Returns the 126 // memory region that covers the newly-created regions. If a 127 // HeapRegion allocation fails, the result memory region might be 128 // smaller than the desired one. 129 MemRegion expand_by(HeapWord* old_end, HeapWord* new_end, 130 FreeRegionList* list); 131 132 // Return the number of contiguous regions at the end of the sequence 133 // that are available for allocation. 134 uint free_suffix(); 135 136 // Find a contiguous set of empty regions of length num and return 137 // the index of the first region or G1_NULL_HRS_INDEX if the 138 // search was unsuccessful. 139 uint find_contiguous(uint num); 140 141 // Apply blk->doHeapRegion() on all committed regions in address order, |