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_G1_HEAPREGIONMANAGER_HPP
26 #define SHARE_VM_GC_G1_HEAPREGIONMANAGER_HPP
27
28 #include "gc/g1/g1BiasedArray.hpp"
29 #include "gc/g1/g1RegionToSpaceMapper.hpp"
30 #include "gc/g1/heapRegionSet.hpp"
31 #include "services/memoryUsage.hpp"
32
33 class HeapRegion;
34 class HeapRegionClosure;
35 class HeapRegionClaimer;
36 class FreeRegionList;
37 class WorkGang;
38
39 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
40 protected:
41 virtual HeapRegion* default_value() const { return NULL; }
42 };
43
44 // This class keeps track of the actual heap memory, auxiliary data
45 // and its metadata (i.e., HeapRegion instances) and the list of free regions.
46 //
47 // This allows maximum flexibility for deciding what to commit or uncommit given
48 // a request from outside.
54 // address space (i.e., region(i).end() == region(i+1).bottom().
55 //
56 // We create a HeapRegion when we commit the region's address space
57 // for the first time. When we uncommit the address space of a
58 // region we retain the HeapRegion to be able to re-use it in the
59 // future (in case we recommit it).
60 //
61 // We keep track of three lengths:
62 //
63 // * _num_committed (returned by length()) is the number of currently
64 // committed regions. These may not be contiguous.
65 // * _allocated_heapregions_length (not exposed outside this class) is the
66 // number of regions+1 for which we have HeapRegions.
67 // * max_length() returns the maximum number of regions the heap can have.
68 //
69
70 class HeapRegionManager: public CHeapObj<mtGC> {
71 friend class VMStructs;
72 friend class HeapRegionClaimer;
73
74 G1HeapRegionTable _regions;
75
76 G1RegionToSpaceMapper* _heap_mapper;
77 G1RegionToSpaceMapper* _prev_bitmap_mapper;
78 G1RegionToSpaceMapper* _next_bitmap_mapper;
79 G1RegionToSpaceMapper* _bot_mapper;
80 G1RegionToSpaceMapper* _cardtable_mapper;
81 G1RegionToSpaceMapper* _card_counts_mapper;
82
83 FreeRegionList _free_list;
84
85 // Each bit in this bitmap indicates that the corresponding region is available
86 // for allocation.
87 CHeapBitMap _available_map;
88
89 // The number of regions committed in the heap.
90 uint _num_committed;
91
92 // Internal only. The highest heap region +1 we allocated a HeapRegion instance for.
93 uint _allocated_heapregions_length;
94
95 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }
96 HeapWord* heap_end() const {return _regions.end_address_mapped(); }
97
98 void make_regions_available(uint index, uint num_regions = 1, WorkGang* pretouch_gang = NULL);
99
100 // Pass down commit calls to the VirtualSpace.
101 void commit_regions(uint index, size_t num_regions = 1, WorkGang* pretouch_gang = NULL);
102 void uncommit_regions(uint index, size_t num_regions = 1);
103
104 // Notify other data structures about change in the heap layout.
105 void update_committed_space(HeapWord* old_end, HeapWord* new_end);
106
107 // Find a contiguous set of empty or uncommitted regions of length num and return
108 // the index of the first region or G1_NO_HRM_INDEX if the search was unsuccessful.
109 // If only_empty is true, only empty regions are considered.
110 // Searches from bottom to top of the heap, doing a first-fit.
111 uint find_contiguous(size_t num, bool only_empty);
112 // Finds the next sequence of unavailable regions starting from start_idx. Returns the
113 // length of the sequence found. If this result is zero, no such sequence could be found,
114 // otherwise res_idx indicates the start index of these regions.
115 uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const;
116 // Finds the next sequence of empty regions starting from start_idx, going backwards in
117 // the heap. Returns the length of the sequence found. If this value is zero, no
118 // sequence could be found, otherwise res_idx contains the start index of this range.
119 uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const;
120 // Allocate a new HeapRegion for the given index.
121 HeapRegion* new_heap_region(uint hrm_index);
122 #ifdef ASSERT
123 public:
124 bool is_free(HeapRegion* hr) const;
125 #endif
126 public:
127 // Empty constructor, we'll initialize it with the initialize() method.
128 HeapRegionManager();
129
130 void initialize(G1RegionToSpaceMapper* heap_storage,
131 G1RegionToSpaceMapper* prev_bitmap,
132 G1RegionToSpaceMapper* next_bitmap,
133 G1RegionToSpaceMapper* bot,
134 G1RegionToSpaceMapper* cardtable,
135 G1RegionToSpaceMapper* card_counts);
136
137 // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired
138 // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit
139 // the heap from the lowest address, this region (and its associated data
140 // structures) are available and we do not need to check further.
141 HeapRegion* get_dummy_region() { return new_heap_region(0); }
142
143 // Return the HeapRegion at the given index. Assume that the index
144 // is valid.
145 inline HeapRegion* at(uint index) const;
146
147 // Return the HeapRegion at the given index, NULL if the index
148 // is for an unavailable region.
149 inline HeapRegion* at_or_null(uint index) const;
150
151 // Returns whether the given region is available for allocation.
152 bool is_available(uint region) const;
153
154 // Return the next region (by index) that is part of the same
155 // humongous object that hr is part of.
156 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
157
158 // If addr is within the committed space return its corresponding
159 // HeapRegion, otherwise return NULL.
160 inline HeapRegion* addr_to_region(HeapWord* addr) const;
161
162 // Insert the given region into the free region list.
163 inline void insert_into_free_list(HeapRegion* hr);
164
165 // Insert the given region list into the global free region list.
166 void insert_list_into_free_list(FreeRegionList* list) {
167 _free_list.add_ordered(list);
168 }
169
170 HeapRegion* allocate_free_region(bool is_old) {
171 HeapRegion* hr = _free_list.remove_region(is_old);
172
173 if (hr != NULL) {
174 assert(hr->next() == NULL, "Single region should not have next");
175 assert(is_available(hr->hrm_index()), "Must be committed");
176 }
177 return hr;
178 }
179
180 inline void allocate_free_regions_starting_at(uint first, uint num_regions);
181
182 // Remove all regions from the free list.
183 void remove_all_free_regions() {
184 _free_list.remove_all();
185 }
186
187 // Return the number of committed free regions in the heap.
188 uint num_free_regions() const {
189 return _free_list.length();
190 }
191
192 size_t total_free_bytes() const {
193 return num_free_regions() * HeapRegion::GrainBytes;
194 }
195
196 // Return the number of available (uncommitted) regions.
197 uint available() const { return max_length() - length(); }
198
199 // Return the number of regions that have been committed in the heap.
200 uint length() const { return _num_committed; }
201
202 // Return the maximum number of regions in the heap.
203 uint max_length() const { return (uint)_regions.length(); }
204
205 MemoryUsage get_auxiliary_data_memory_usage() const;
206
207 MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); }
208
209 // Expand the sequence to reflect that the heap has grown. Either create new
210 // HeapRegions, or re-use existing ones. Returns the number of regions the
211 // sequence was expanded by. If a HeapRegion allocation fails, the resulting
212 // number of regions might be smaller than what's desired.
213 uint expand_by(uint num_regions, WorkGang* pretouch_workers);
214
215 // Makes sure that the regions from start to start+num_regions-1 are available
216 // for allocation. Returns the number of regions that were committed to achieve
217 // this.
218 uint expand_at(uint start, uint num_regions, WorkGang* pretouch_workers);
219
220 // Find a contiguous set of empty regions of length num. Returns the start index of
221 // that set, or G1_NO_HRM_INDEX.
222 uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); }
223 // Find a contiguous set of empty or unavailable regions of length num. Returns the
224 // start index of that set, or G1_NO_HRM_INDEX.
225 uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); }
226
227 HeapRegion* next_region_in_heap(const HeapRegion* r) const;
228
229 // Find the highest free or uncommitted region in the reserved heap,
230 // and if uncommitted, commit it. If none are available, return G1_NO_HRM_INDEX.
231 // Set the 'expanded' boolean true if a new region was committed.
232 uint find_highest_free(bool* expanded);
233
234 // Allocate the regions that contain the address range specified, committing the
235 // regions if necessary. Return false if any of the regions is already committed
236 // and not free, and return the number of regions newly committed in commit_count.
237 bool allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers);
238
239 // Apply blk->do_heap_region() on all committed regions in address order,
240 // terminating the iteration early if do_heap_region() returns true.
241 void iterate(HeapRegionClosure* blk) const;
242
243 void par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) const;
244
245 // Uncommit up to num_regions_to_remove regions that are completely free.
246 // Return the actual number of uncommitted regions.
247 uint shrink_by(uint num_regions_to_remove);
248
249 // Uncommit a number of regions starting at the specified index, which must be available,
250 // empty, and free.
251 void shrink_at(uint index, size_t num_regions);
252
253 void verify();
254
255 // Do some sanity checking.
256 void verify_optional() PRODUCT_RETURN;
257 };
258
259 // The HeapRegionClaimer is used during parallel iteration over heap regions,
260 // allowing workers to claim heap regions, gaining exclusive rights to these regions.
261 class HeapRegionClaimer : public StackObj {
262 uint _n_workers;
263 uint _n_regions;
264 volatile uint* _claims;
265
266 static const uint Unclaimed = 0;
267 static const uint Claimed = 1;
268
269 public:
270 HeapRegionClaimer(uint n_workers);
271 ~HeapRegionClaimer();
272
273 inline uint n_regions() const {
|
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_G1_HEAPREGIONMANAGER_HPP
26 #define SHARE_VM_GC_G1_HEAPREGIONMANAGER_HPP
27
28 #include "gc/g1/g1BiasedArray.hpp"
29 #include "gc/g1/g1CollectorPolicy.hpp"
30 #include "gc/g1/g1RegionToSpaceMapper.hpp"
31 #include "gc/g1/heapRegionSet.hpp"
32 #include "services/memoryUsage.hpp"
33
34 class HeapRegion;
35 class HeapRegionClosure;
36 class HeapRegionClaimer;
37 class FreeRegionList;
38 class WorkGang;
39
40 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
41 protected:
42 virtual HeapRegion* default_value() const { return NULL; }
43 };
44
45 // This class keeps track of the actual heap memory, auxiliary data
46 // and its metadata (i.e., HeapRegion instances) and the list of free regions.
47 //
48 // This allows maximum flexibility for deciding what to commit or uncommit given
49 // a request from outside.
55 // address space (i.e., region(i).end() == region(i+1).bottom().
56 //
57 // We create a HeapRegion when we commit the region's address space
58 // for the first time. When we uncommit the address space of a
59 // region we retain the HeapRegion to be able to re-use it in the
60 // future (in case we recommit it).
61 //
62 // We keep track of three lengths:
63 //
64 // * _num_committed (returned by length()) is the number of currently
65 // committed regions. These may not be contiguous.
66 // * _allocated_heapregions_length (not exposed outside this class) is the
67 // number of regions+1 for which we have HeapRegions.
68 // * max_length() returns the maximum number of regions the heap can have.
69 //
70
71 class HeapRegionManager: public CHeapObj<mtGC> {
72 friend class VMStructs;
73 friend class HeapRegionClaimer;
74
75 G1RegionToSpaceMapper* _prev_bitmap_mapper;
76 G1RegionToSpaceMapper* _next_bitmap_mapper;
77 G1RegionToSpaceMapper* _bot_mapper;
78 G1RegionToSpaceMapper* _cardtable_mapper;
79 G1RegionToSpaceMapper* _card_counts_mapper;
80
81 // Each bit in this bitmap indicates that the corresponding region is available
82 // for allocation.
83 CHeapBitMap _available_map;
84
85 // The number of regions committed in the heap.
86 uint _num_committed;
87
88 // Internal only. The highest heap region +1 we allocated a HeapRegion instance for.
89 uint _allocated_heapregions_length;
90
91 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }
92 HeapWord* heap_end() const {return _regions.end_address_mapped(); }
93
94 // Pass down commit calls to the VirtualSpace.
95 void commit_regions(uint index, size_t num_regions = 1, WorkGang* pretouch_gang = NULL);
96
97 // Notify other data structures about change in the heap layout.
98 void update_committed_space(HeapWord* old_end, HeapWord* new_end);
99
100 // Find a contiguous set of empty or uncommitted regions of length num and return
101 // the index of the first region or G1_NO_HRM_INDEX if the search was unsuccessful.
102 // If only_empty is true, only empty regions are considered.
103 // Searches from bottom to top of the heap, doing a first-fit.
104 uint find_contiguous(size_t num, bool only_empty);
105 // Finds the next sequence of unavailable regions starting from start_idx. Returns the
106 // length of the sequence found. If this result is zero, no such sequence could be found,
107 // otherwise res_idx indicates the start index of these regions.
108 uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const;
109 // Finds the next sequence of empty regions starting from start_idx, going backwards in
110 // the heap. Returns the length of the sequence found. If this value is zero, no
111 // sequence could be found, otherwise res_idx contains the start index of this range.
112 uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const;
113
114 protected:
115 G1HeapRegionTable _regions;
116 G1RegionToSpaceMapper* _heap_mapper;
117 FreeRegionList _free_list;
118 void make_regions_available(uint index, uint num_regions = 1, WorkGang* pretouch_gang = NULL);
119 void uncommit_regions(uint index, size_t num_regions = 1);
120 // Allocate a new HeapRegion for the given index.
121 HeapRegion* new_heap_region(uint hrm_index);
122 #ifdef ASSERT
123 public:
124 bool is_free(HeapRegion* hr) const;
125 #endif
126 public:
127 // Empty constructor, we'll initialize it with the initialize() method.
128 HeapRegionManager();
129
130 static HeapRegionManager* create_manager(G1CollectedHeap* heap, CollectorPolicy* policy);
131
132 void initialize(G1RegionToSpaceMapper* heap_storage,
133 G1RegionToSpaceMapper* prev_bitmap,
134 G1RegionToSpaceMapper* next_bitmap,
135 G1RegionToSpaceMapper* bot,
136 G1RegionToSpaceMapper* cardtable,
137 G1RegionToSpaceMapper* card_counts);
138
139 // Prepare heap regions before and after full collection.
140 // Nothing to be done in this class.
141 virtual void prepare_for_full_collection_start() {}
142 virtual void prepare_for_full_collection_end() {}
143
144 // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired
145 // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit
146 // the heap from the lowest address, this region (and its associated data
147 // structures) are available and we do not need to check further.
148 virtual HeapRegion* get_dummy_region() { return new_heap_region(0); }
149
150 // Return the HeapRegion at the given index. Assume that the index
151 // is valid.
152 inline HeapRegion* at(uint index) const;
153
154 // Return the HeapRegion at the given index, NULL if the index
155 // is for an unavailable region.
156 inline HeapRegion* at_or_null(uint index) const;
157
158 // Returns whether the given region is available for allocation.
159 bool is_available(uint region) const;
160
161 // Return the next region (by index) that is part of the same
162 // humongous object that hr is part of.
163 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
164
165 // If addr is within the committed space return its corresponding
166 // HeapRegion, otherwise return NULL.
167 inline HeapRegion* addr_to_region(HeapWord* addr) const;
168
169 // Insert the given region into the free region list.
170 inline void insert_into_free_list(HeapRegion* hr);
171
172 // Insert the given region list into the global free region list.
173 void insert_list_into_free_list(FreeRegionList* list) {
174 _free_list.add_ordered(list);
175 }
176
177 virtual HeapRegion* allocate_free_region(bool is_old) {
178 HeapRegion* hr = _free_list.remove_region(is_old);
179
180 if (hr != NULL) {
181 assert(hr->next() == NULL, "Single region should not have next");
182 assert(is_available(hr->hrm_index()), "Must be committed");
183 }
184 return hr;
185 }
186
187 inline void allocate_free_regions_starting_at(uint first, uint num_regions);
188
189 // Remove all regions from the free list.
190 void remove_all_free_regions() {
191 _free_list.remove_all();
192 }
193
194 // Return the number of committed free regions in the heap.
195 uint num_free_regions() const {
196 return _free_list.length();
197 }
198
199 size_t total_free_bytes() const {
200 return num_free_regions() * HeapRegion::GrainBytes;
201 }
202
203 // Return the number of available (uncommitted) regions.
204 uint available() const { return max_length() - length(); }
205
206 // Return the number of regions that have been committed in the heap.
207 uint length() const { return _num_committed; }
208
209 // Return the maximum number of regions in the heap.
210 uint max_length() const { return (uint)_regions.length(); }
211
212 // Return maximum number of regions that heap can expand to.
213 virtual uint max_expandable_length() const { return (uint)_regions.length(); }
214
215 MemoryUsage get_auxiliary_data_memory_usage() const;
216
217 MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); }
218
219 // Expand the sequence to reflect that the heap has grown. Either create new
220 // HeapRegions, or re-use existing ones. Returns the number of regions the
221 // sequence was expanded by. If a HeapRegion allocation fails, the resulting
222 // number of regions might be smaller than what's desired.
223 virtual uint expand_by(uint num_regions, WorkGang* pretouch_workers);
224
225 // Makes sure that the regions from start to start+num_regions-1 are available
226 // for allocation. Returns the number of regions that were committed to achieve
227 // this.
228 virtual uint expand_at(uint start, uint num_regions, WorkGang* pretouch_workers);
229
230 // Find a contiguous set of empty regions of length num. Returns the start index of
231 // that set, or G1_NO_HRM_INDEX.
232 virtual uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); }
233 // Find a contiguous set of empty or unavailable regions of length num. Returns the
234 // start index of that set, or G1_NO_HRM_INDEX.
235 virtual uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); }
236
237 HeapRegion* next_region_in_heap(const HeapRegion* r) const;
238
239 // Find the highest free or uncommitted region in the reserved heap,
240 // and if uncommitted, commit it. If none are available, return G1_NO_HRM_INDEX.
241 // Set the 'expanded' boolean true if a new region was committed.
242 virtual uint find_highest_free(bool* expanded);
243
244 // Allocate the regions that contain the address range specified, committing the
245 // regions if necessary. Return false if any of the regions is already committed
246 // and not free, and return the number of regions newly committed in commit_count.
247 bool allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers);
248
249 // Apply blk->do_heap_region() on all committed regions in address order,
250 // terminating the iteration early if do_heap_region() returns true.
251 void iterate(HeapRegionClosure* blk) const;
252
253 void par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) const;
254
255 // Uncommit up to num_regions_to_remove regions that are completely free.
256 // Return the actual number of uncommitted regions.
257 virtual uint shrink_by(uint num_regions_to_remove);
258
259 // Uncommit a number of regions starting at the specified index, which must be available,
260 // empty, and free.
261 void shrink_at(uint index, size_t num_regions);
262
263 virtual void verify();
264
265 // Do some sanity checking.
266 void verify_optional() PRODUCT_RETURN;
267 };
268
269 // The HeapRegionClaimer is used during parallel iteration over heap regions,
270 // allowing workers to claim heap regions, gaining exclusive rights to these regions.
271 class HeapRegionClaimer : public StackObj {
272 uint _n_workers;
273 uint _n_regions;
274 volatile uint* _claims;
275
276 static const uint Unclaimed = 0;
277 static const uint Claimed = 1;
278
279 public:
280 HeapRegionClaimer(uint n_workers);
281 ~HeapRegionClaimer();
282
283 inline uint n_regions() const {
|