107 uint index = length();
108
109 assert(index < _max_length, "otherwise we cannot expand further");
110 if (index == 0) {
111 // We have not allocated any regions so far
112 assert(next_bottom == _heap_bottom, "invariant");
113 } else {
114 // next_bottom should match the end of the last/previous region
115 assert(next_bottom == at(index - 1)->end(), "invariant");
116 }
117
118 if (index == _allocated_length) {
119 // We have to allocate a new HeapRegion.
120 HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom);
121 if (new_hr == NULL) {
122 // allocation failed, we bail out and return what we have done so far
123 return MemRegion(old_end, next_bottom);
124 }
125 assert(_regions[index] == NULL, "invariant");
126 _regions[index] = new_hr;
127 increment_length(&_allocated_length);
128 }
129 // Have to increment the length first, otherwise we will get an
130 // assert failure at(index) below.
131 increment_length(&_length);
132 HeapRegion* hr = at(index);
133 list->add_as_tail(hr);
134
135 next_bottom = hr->end();
136 }
137 assert(next_bottom == new_end, "post-condition");
138 return MemRegion(old_end, next_bottom);
139 }
140
141 uint HeapRegionSeq::free_suffix() {
142 uint res = 0;
143 uint index = length();
144 while (index > 0) {
145 index -= 1;
146 if (!at(index)->is_empty()) {
147 break;
148 }
149 res += 1;
150 }
151 return res;
184 hr_index = hr->hrs_index();
185 }
186
187 uint len = length();
188 for (uint i = hr_index; i < len; i += 1) {
189 bool res = blk->doHeapRegion(at(i));
190 if (res) {
191 blk->incomplete();
192 return;
193 }
194 }
195 for (uint i = 0; i < hr_index; i += 1) {
196 bool res = blk->doHeapRegion(at(i));
197 if (res) {
198 blk->incomplete();
199 return;
200 }
201 }
202 }
203
204 MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
205 uint* num_regions_deleted) {
206 // Reset this in case it's currently pointing into the regions that
207 // we just removed.
208 _next_search_index = 0;
209
210 assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
211 assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
212 assert(length() > 0, "the region sequence should not be empty");
213 assert(length() <= _allocated_length, "invariant");
214 assert(_allocated_length > 0, "we should have at least one region committed");
215
216 // around the loop, i will be the next region to be removed
217 uint i = length() - 1;
218 assert(i > 0, "we should never remove all regions");
219 // [last_start, end) is the MemRegion that covers the regions we will remove.
220 HeapWord* end = at(i)->end();
221 HeapWord* last_start = end;
222 *num_regions_deleted = 0;
223 while (shrink_bytes > 0) {
224 HeapRegion* cur = at(i);
225 // We should leave the humongous regions where they are.
226 if (cur->isHumongous()) break;
227 // We should stop shrinking if we come across a non-empty region.
228 if (!cur->is_empty()) break;
229
230 i -= 1;
231 *num_regions_deleted += 1;
232 shrink_bytes -= cur->capacity();
233 last_start = cur->bottom();
234 decrement_length(&_length);
235 // We will reclaim the HeapRegion. _allocated_length should be
236 // covering this index. So, even though we removed the region from
237 // the active set by decreasing _length, we still have it
238 // available in the future if we need to re-use it.
239 assert(i > 0, "we should never remove all regions");
240 assert(length() > 0, "we should never remove all regions");
241 }
242 return MemRegion(last_start, end);
243 }
244
245 #ifndef PRODUCT
246 void HeapRegionSeq::verify_optional() {
247 guarantee(_length <= _allocated_length,
248 err_msg("invariant: _length: %u _allocated_length: %u",
249 _length, _allocated_length));
250 guarantee(_allocated_length <= _max_length,
251 err_msg("invariant: _allocated_length: %u _max_length: %u",
252 _allocated_length, _max_length));
253 guarantee(_next_search_index <= _length,
254 err_msg("invariant: _next_search_index: %u _length: %u",
255 _next_search_index, _length));
256
257 HeapWord* prev_end = _heap_bottom;
258 for (uint i = 0; i < _allocated_length; i += 1) {
259 HeapRegion* hr = _regions[i];
260 guarantee(hr != NULL, err_msg("invariant: i: %u", i));
261 guarantee(hr->bottom() == prev_end,
262 err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
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107 uint index = length();
108
109 assert(index < _max_length, "otherwise we cannot expand further");
110 if (index == 0) {
111 // We have not allocated any regions so far
112 assert(next_bottom == _heap_bottom, "invariant");
113 } else {
114 // next_bottom should match the end of the last/previous region
115 assert(next_bottom == at(index - 1)->end(), "invariant");
116 }
117
118 if (index == _allocated_length) {
119 // We have to allocate a new HeapRegion.
120 HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom);
121 if (new_hr == NULL) {
122 // allocation failed, we bail out and return what we have done so far
123 return MemRegion(old_end, next_bottom);
124 }
125 assert(_regions[index] == NULL, "invariant");
126 _regions[index] = new_hr;
127 increment_allocated_length();
128 }
129 // Have to increment the length first, otherwise we will get an
130 // assert failure at(index) below.
131 increment_length();
132 HeapRegion* hr = at(index);
133 list->add_as_tail(hr);
134
135 next_bottom = hr->end();
136 }
137 assert(next_bottom == new_end, "post-condition");
138 return MemRegion(old_end, next_bottom);
139 }
140
141 uint HeapRegionSeq::free_suffix() {
142 uint res = 0;
143 uint index = length();
144 while (index > 0) {
145 index -= 1;
146 if (!at(index)->is_empty()) {
147 break;
148 }
149 res += 1;
150 }
151 return res;
184 hr_index = hr->hrs_index();
185 }
186
187 uint len = length();
188 for (uint i = hr_index; i < len; i += 1) {
189 bool res = blk->doHeapRegion(at(i));
190 if (res) {
191 blk->incomplete();
192 return;
193 }
194 }
195 for (uint i = 0; i < hr_index; i += 1) {
196 bool res = blk->doHeapRegion(at(i));
197 if (res) {
198 blk->incomplete();
199 return;
200 }
201 }
202 }
203
204 uint HeapRegionSeq::shrink_by(uint num_regions_to_remove) {
205 // Reset this in case it's currently pointing into the regions that
206 // we just removed.
207 _next_search_index = 0;
208
209 assert(length() > 0, "the region sequence should not be empty");
210 assert(length() <= _allocated_length, "invariant");
211 assert(_allocated_length > 0, "we should have at least one region committed");
212 assert(num_regions_to_remove < length(), "We should never remove all regions");
213
214 uint i = 0;
215 for (; i < num_regions_to_remove; i++) {
216 HeapRegion* cur = at(length() - 1);
217
218 if (!cur->is_empty()) {
219 // We have to give up if the region can not be moved
220 break;
221 }
222 assert(!cur->isHumongous(), "Humongous regions should not be empty");
223
224 decrement_length();
225 }
226 return i;
227 }
228
229 #ifndef PRODUCT
230 void HeapRegionSeq::verify_optional() {
231 guarantee(_length <= _allocated_length,
232 err_msg("invariant: _length: %u _allocated_length: %u",
233 _length, _allocated_length));
234 guarantee(_allocated_length <= _max_length,
235 err_msg("invariant: _allocated_length: %u _max_length: %u",
236 _allocated_length, _max_length));
237 guarantee(_next_search_index <= _length,
238 err_msg("invariant: _next_search_index: %u _length: %u",
239 _next_search_index, _length));
240
241 HeapWord* prev_end = _heap_bottom;
242 for (uint i = 0; i < _allocated_length; i += 1) {
243 HeapRegion* hr = _regions[i];
244 guarantee(hr != NULL, err_msg("invariant: i: %u", i));
245 guarantee(hr->bottom() == prev_end,
246 err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
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