Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/g1/heapRegionSeq.hpp @ 20337:1f1d373cd044
8038423: G1: Decommit memory within heap
Summary: Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.
Reviewed-by: mgerdin, brutisso, jwilhelm
author | tschatzl |
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date | Thu, 21 Aug 2014 11:47:10 +0200 |
parents | 6701abbc4441 |
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20336:6701abbc4441 | 20337:1f1d373cd044 |
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24 | 24 |
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP | 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
27 | 27 |
28 #include "gc_implementation/g1/g1BiasedArray.hpp" | 28 #include "gc_implementation/g1/g1BiasedArray.hpp" |
29 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp" | |
29 #include "gc_implementation/g1/heapRegionSet.hpp" | 30 #include "gc_implementation/g1/heapRegionSet.hpp" |
30 | 31 |
31 class HeapRegion; | 32 class HeapRegion; |
32 class HeapRegionClosure; | 33 class HeapRegionClosure; |
33 class FreeRegionList; | 34 class FreeRegionList; |
35 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { | 36 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { |
36 protected: | 37 protected: |
37 virtual HeapRegion* default_value() const { return NULL; } | 38 virtual HeapRegion* default_value() const { return NULL; } |
38 }; | 39 }; |
39 | 40 |
40 // This class keeps track of the region metadata (i.e., HeapRegion | 41 // This class keeps track of the actual heap memory, auxiliary data |
41 // instances). They are kept in the _regions array in address | 42 // and its metadata (i.e., HeapRegion instances) and the list of free regions. |
42 // order. A region's index in the array corresponds to its index in | 43 // |
43 // the heap (i.e., 0 is the region at the bottom of the heap, 1 is | 44 // This allows maximum flexibility for deciding what to commit or uncommit given |
44 // the one after it, etc.). Two regions that are consecutive in the | 45 // a request from outside. |
45 // array should also be adjacent in the address space (i.e., | 46 // |
46 // region(i).end() == region(i+1).bottom(). | 47 // HeapRegions are kept in the _regions array in address order. A region's |
48 // index in the array corresponds to its index in the heap (i.e., 0 is the | |
49 // region at the bottom of the heap, 1 is the one after it, etc.). Two | |
50 // regions that are consecutive in the array should also be adjacent in the | |
51 // address space (i.e., region(i).end() == region(i+1).bottom(). | |
47 // | 52 // |
48 // We create a HeapRegion when we commit the region's address space | 53 // We create a HeapRegion when we commit the region's address space |
49 // for the first time. When we uncommit the address space of a | 54 // for the first time. When we uncommit the address space of a |
50 // region we retain the HeapRegion to be able to re-use it in the | 55 // region we retain the HeapRegion to be able to re-use it in the |
51 // future (in case we recommit it). | 56 // future (in case we recommit it). |
52 // | 57 // |
53 // We keep track of three lengths: | 58 // We keep track of three lengths: |
54 // | 59 // |
55 // * _committed_length (returned by length()) is the number of currently | 60 // * _num_committed (returned by length()) is the number of currently |
56 // committed regions. | 61 // committed regions. These may not be contiguous. |
57 // * _allocated_length (not exposed outside this class) is the | 62 // * _allocated_heapregions_length (not exposed outside this class) is the |
58 // number of regions for which we have HeapRegions. | 63 // number of regions+1 for which we have HeapRegions. |
59 // * max_length() returns the maximum number of regions the heap can have. | 64 // * max_length() returns the maximum number of regions the heap can have. |
60 // | 65 // |
61 // and maintain that: _committed_length <= _allocated_length <= max_length() | |
62 | 66 |
63 class HeapRegionSeq: public CHeapObj<mtGC> { | 67 class HeapRegionSeq: public CHeapObj<mtGC> { |
64 friend class VMStructs; | 68 friend class VMStructs; |
65 | 69 |
66 G1HeapRegionTable _regions; | 70 G1HeapRegionTable _regions; |
67 | 71 |
68 ReservedSpace _reserved; | 72 G1RegionToSpaceMapper* _heap_mapper; |
69 VirtualSpace _storage; | 73 G1RegionToSpaceMapper* _prev_bitmap_mapper; |
74 G1RegionToSpaceMapper* _next_bitmap_mapper; | |
75 G1RegionToSpaceMapper* _bot_mapper; | |
76 G1RegionToSpaceMapper* _cardtable_mapper; | |
77 G1RegionToSpaceMapper* _card_counts_mapper; | |
70 | 78 |
71 FreeRegionList _free_list; | 79 FreeRegionList _free_list; |
80 | |
81 // Each bit in this bitmap indicates that the corresponding region is available | |
82 // for allocation. | |
83 BitMap _available_map; | |
72 | 84 |
73 // The number of regions committed in the heap. | 85 // The number of regions committed in the heap. |
74 uint _num_committed; | 86 uint _num_committed; |
75 | 87 |
76 // Internal only. The highest heap region +1 we allocated a HeapRegion instance for. | 88 // Internal only. The highest heap region +1 we allocated a HeapRegion instance for. |
77 uint _allocated_heapregions_length; | 89 uint _allocated_heapregions_length; |
78 | 90 |
79 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); } | 91 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); } |
80 HeapWord* heap_top() const { return heap_bottom() + _num_committed * HeapRegion::GrainWords; } | |
81 HeapWord* heap_end() const {return _regions.end_address_mapped(); } | 92 HeapWord* heap_end() const {return _regions.end_address_mapped(); } |
82 | 93 |
83 void make_regions_available(uint index, uint num_regions = 1); | 94 void make_regions_available(uint index, uint num_regions = 1); |
84 | 95 |
85 // Pass down commit calls to the VirtualSpace. | 96 // Pass down commit calls to the VirtualSpace. |
90 void update_committed_space(HeapWord* old_end, HeapWord* new_end); | 101 void update_committed_space(HeapWord* old_end, HeapWord* new_end); |
91 // Calculate the starting region for each worker during parallel iteration so | 102 // Calculate the starting region for each worker during parallel iteration so |
92 // that they do not all start from the same region. | 103 // that they do not all start from the same region. |
93 uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const; | 104 uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const; |
94 | 105 |
106 // Find a contiguous set of empty or uncommitted regions of length num and return | |
107 // the index of the first region or G1_NO_HRS_INDEX if the search was unsuccessful. | |
108 // If only_empty is true, only empty regions are considered. | |
109 // Searches from bottom to top of the heap, doing a first-fit. | |
110 uint find_contiguous(size_t num, bool only_empty); | |
95 // Finds the next sequence of unavailable regions starting from start_idx. Returns the | 111 // Finds the next sequence of unavailable regions starting from start_idx. Returns the |
96 // length of the sequence found. If this result is zero, no such sequence could be found, | 112 // length of the sequence found. If this result is zero, no such sequence could be found, |
97 // otherwise res_idx indicates the start index of these regions. | 113 // otherwise res_idx indicates the start index of these regions. |
98 uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const; | 114 uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const; |
99 // Finds the next sequence of empty regions starting from start_idx, going backwards in | 115 // Finds the next sequence of empty regions starting from start_idx, going backwards in |
100 // the heap. Returns the length of the sequence found. If this value is zero, no | 116 // the heap. Returns the length of the sequence found. If this value is zero, no |
101 // sequence could be found, otherwise res_idx contains the start index of this range. | 117 // sequence could be found, otherwise res_idx contains the start index of this range. |
102 uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const; | 118 uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const; |
119 // Allocate a new HeapRegion for the given index. | |
120 HeapRegion* new_heap_region(uint hrs_index); | |
103 #ifdef ASSERT | 121 #ifdef ASSERT |
104 public: | 122 public: |
105 bool is_free(HeapRegion* hr) const; | 123 bool is_free(HeapRegion* hr) const; |
106 #endif | 124 #endif |
107 // Returns whether the given region is available for allocation. | 125 // Returns whether the given region is available for allocation. |
108 bool is_available(uint region) const; | 126 bool is_available(uint region) const; |
109 | 127 |
110 // Allocate a new HeapRegion for the given index. | |
111 HeapRegion* new_heap_region(uint hrs_index); | |
112 public: | 128 public: |
113 // Empty constructor, we'll initialize it with the initialize() method. | 129 // Empty constructor, we'll initialize it with the initialize() method. |
114 HeapRegionSeq() : _regions(), _reserved(), _storage(), _num_committed(0), | 130 HeapRegionSeq() : _regions(), _heap_mapper(NULL), _num_committed(0), |
115 _free_list("Master Free List", new MasterFreeRegionListMtSafeChecker()), | 131 _next_bitmap_mapper(NULL), _prev_bitmap_mapper(NULL), _bot_mapper(NULL), |
116 _allocated_heapregions_length(0) | 132 _allocated_heapregions_length(0), _available_map(), |
133 _free_list("Free list", new MasterFreeRegionListMtSafeChecker()) | |
117 { } | 134 { } |
118 | 135 |
119 void initialize(ReservedSpace reserved); | 136 void initialize(G1RegionToSpaceMapper* heap_storage, |
137 G1RegionToSpaceMapper* prev_bitmap, | |
138 G1RegionToSpaceMapper* next_bitmap, | |
139 G1RegionToSpaceMapper* bot, | |
140 G1RegionToSpaceMapper* cardtable, | |
141 G1RegionToSpaceMapper* card_counts); | |
120 | 142 |
121 // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired | 143 // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired |
122 // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit | 144 // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit |
123 // the heap from the lowest address, this region (and its associated data | 145 // the heap from the lowest address, this region (and its associated data |
124 // structures) are available and we do not need to check further. | 146 // structures) are available and we do not need to check further. |
173 uint length() const { return _num_committed; } | 195 uint length() const { return _num_committed; } |
174 | 196 |
175 // Return the maximum number of regions in the heap. | 197 // Return the maximum number of regions in the heap. |
176 uint max_length() const { return (uint)_regions.length(); } | 198 uint max_length() const { return (uint)_regions.length(); } |
177 | 199 |
178 MemRegion committed() const { return MemRegion(heap_bottom(), heap_top()); } | |
179 | |
180 MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); } | 200 MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); } |
181 | 201 |
182 // Expand the sequence to reflect that the heap has grown. Either create new | 202 // Expand the sequence to reflect that the heap has grown. Either create new |
183 // HeapRegions, or re-use existing ones. Returns the number of regions the | 203 // HeapRegions, or re-use existing ones. Returns the number of regions the |
184 // sequence was expanded by. If a HeapRegion allocation fails, the resulting | 204 // sequence was expanded by. If a HeapRegion allocation fails, the resulting |
188 // Makes sure that the regions from start to start+num_regions-1 are available | 208 // Makes sure that the regions from start to start+num_regions-1 are available |
189 // for allocation. Returns the number of regions that were committed to achieve | 209 // for allocation. Returns the number of regions that were committed to achieve |
190 // this. | 210 // this. |
191 uint expand_at(uint start, uint num_regions); | 211 uint expand_at(uint start, uint num_regions); |
192 | 212 |
193 // Find a contiguous set of empty or uncommitted regions of length num and return | 213 // Find a contiguous set of empty regions of length num. Returns the start index of |
194 // the index of the first region or G1_NO_HRS_INDEX if the search was unsuccessful. | 214 // that set, or G1_NO_HRS_INDEX. |
195 // If only_empty is true, only empty regions are considered. | 215 uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); } |
196 // Searches from bottom to top of the heap, doing a first-fit. | 216 // Find a contiguous set of empty or unavailable regions of length num. Returns the |
197 uint find_contiguous(size_t num, bool only_empty); | 217 // start index of that set, or G1_NO_HRS_INDEX. |
218 uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); } | |
198 | 219 |
199 HeapRegion* next_region_in_heap(const HeapRegion* r) const; | 220 HeapRegion* next_region_in_heap(const HeapRegion* r) const; |
200 | 221 |
201 // Apply blk->doHeapRegion() on all committed regions in address order, | 222 // Apply blk->doHeapRegion() on all committed regions in address order, |
202 // terminating the iteration early if doHeapRegion() returns true. | 223 // terminating the iteration early if doHeapRegion() returns true. |