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src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp

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 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 #include "precompiled.hpp"
 26 #include "gc/g1/g1CollectedHeap.hpp"
 27 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 28 #include "gc/g1/g1FullCollector.inline.hpp"
 29 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 30 #include "gc/g1/g1FullGCMarker.hpp"
 31 #include "gc/g1/g1FullGCOopClosures.inline.hpp"
 32 #include "gc/g1/g1FullGCPrepareTask.hpp"
 33 #include "gc/g1/g1HotCardCache.hpp"
 34 #include "gc/g1/heapRegion.inline.hpp"
 35 #include "gc/shared/gcTraceTime.inline.hpp"
 36 #include "gc/shared/referenceProcessor.hpp"

 37 #include "logging/log.hpp"
 38 #include "memory/iterator.inline.hpp"
 39 #include "oops/oop.inline.hpp"
 40 #include "utilities/ticks.hpp"
 41 
 42 template<bool is_humongous>
 43 void G1FullGCPrepareTask::G1CalculatePointersClosure::free_pinned_region(HeapRegion* hr) {
 44   _regions_freed = true;
 45   if (is_humongous) {
 46     _g1h->free_humongous_region(hr, nullptr);
 47   } else {
 48     _g1h->free_region(hr, nullptr);
 49   }
 50   prepare_for_compaction(hr);
 51   _collector->set_invalid(hr->hrm_index());
 52 }
 53 
 54 bool G1FullGCPrepareTask::G1CalculatePointersClosure::do_heap_region(HeapRegion* hr) {
 55   bool force_not_compacted = false;
 56   if (should_compact(hr)) {

139 bool G1FullGCPrepareTask::G1CalculatePointersClosure::should_compact(HeapRegion* hr) {
140   if (hr->is_pinned()) {
141     return false;
142   }
143   size_t live_words = _collector->live_words(hr->hrm_index());
144   size_t live_words_threshold = _collector->scope()->region_compaction_threshold();
145   // High live ratio region will not be compacted.
146   return live_words <= live_words_threshold;
147 }
148 
149 void G1FullGCPrepareTask::G1CalculatePointersClosure::reset_region_metadata(HeapRegion* hr) {
150   hr->rem_set()->clear();
151   hr->clear_cardtable();
152 
153   G1HotCardCache* hcc = _g1h->hot_card_cache();
154   if (hcc->use_cache()) {
155     hcc->reset_card_counts(hr);
156   }
157 }
158 
159 G1FullGCPrepareTask::G1PrepareCompactLiveClosure::G1PrepareCompactLiveClosure(G1FullGCCompactionPoint* cp) :

160     _cp(cp) { }
161 
162 size_t G1FullGCPrepareTask::G1PrepareCompactLiveClosure::apply(oop object) {

163   size_t size = object->size();
164   _cp->forward(object, size);
165   return size;
166 }
167 
168 size_t G1FullGCPrepareTask::G1RePrepareClosure::apply(oop obj) {

169   // We only re-prepare objects forwarded within the current region, so
170   // skip objects that are already forwarded to another region.
171   oop forwarded_to = obj->forwardee();
172   if (forwarded_to != NULL && !_current->is_in(forwarded_to)) {
173     return obj->size();



174   }
175 
176   // Get size and forward.
177   size_t size = obj->size();
178   _cp->forward(obj, size);
179 
180   return size;
181 }
182 
183 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction_work(G1FullGCCompactionPoint* cp,
184                                                                                   HeapRegion* hr) {
185   G1PrepareCompactLiveClosure prepare_compact(cp);
186   hr->set_compaction_top(hr->bottom());
187   hr->apply_to_marked_objects(_bitmap, &prepare_compact);






188 }
189 
190 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction(HeapRegion* hr) {
191   if (!_cp->is_initialized()) {
192     hr->set_compaction_top(hr->bottom());
193     _cp->initialize(hr, true);
194   }
195   // Add region to the compaction queue and prepare it.
196   _cp->add(hr);
197   prepare_for_compaction_work(_cp, hr);
198 }
199 
200 void G1FullGCPrepareTask::prepare_serial_compaction() {

201   GCTraceTime(Debug, gc, phases) debug("Phase 2: Prepare Serial Compaction", collector()->scope()->timer());
202   // At this point we know that no regions were completely freed by
203   // the parallel compaction. That means that the last region of
204   // all compaction queues still have data in them. We try to compact
205   // these regions in serial to avoid a premature OOM.
206   for (uint i = 0; i < collector()->workers(); i++) {
207     G1FullGCCompactionPoint* cp = collector()->compaction_point(i);
208     if (cp->has_regions()) {
209       collector()->serial_compaction_point()->add(cp->remove_last());
210     }
211   }
212 
213   // Update the forwarding information for the regions in the serial
214   // compaction point.
215   G1FullGCCompactionPoint* cp = collector()->serial_compaction_point();
216   for (GrowableArrayIterator<HeapRegion*> it = cp->regions()->begin(); it != cp->regions()->end(); ++it) {
217     HeapRegion* current = *it;
218     if (!cp->is_initialized()) {
219       // Initialize the compaction point. Nothing more is needed for the first heap region
220       // since it is already prepared for compaction.
221       cp->initialize(current, false);
222     } else {
223       assert(!current->is_humongous(), "Should be no humongous regions in compaction queue");
224       G1RePrepareClosure re_prepare(cp, current);
225       current->set_compaction_top(current->bottom());
226       current->apply_to_marked_objects(collector()->mark_bitmap(), &re_prepare);
227     }
228   }
229   cp->update();
230 }
231 








232 bool G1FullGCPrepareTask::G1CalculatePointersClosure::freed_regions() {
233   if (_regions_freed) {
234     return true;
235   }
236 
237   if (!_cp->has_regions()) {
238     // No regions in queue, so no free ones either.
239     return false;
240   }
241 
242   if (_cp->current_region() != _cp->regions()->last()) {
243     // The current region used for compaction is not the last in the
244     // queue. That means there is at least one free region in the queue.
245     return true;
246   }
247 
248   // No free regions in the queue.
249   return false;
250 }

 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 #include "precompiled.hpp"
 26 #include "gc/g1/g1CollectedHeap.hpp"
 27 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 28 #include "gc/g1/g1FullCollector.inline.hpp"
 29 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 30 #include "gc/g1/g1FullGCMarker.hpp"
 31 #include "gc/g1/g1FullGCOopClosures.inline.hpp"
 32 #include "gc/g1/g1FullGCPrepareTask.hpp"
 33 #include "gc/g1/g1HotCardCache.hpp"
 34 #include "gc/g1/heapRegion.inline.hpp"
 35 #include "gc/shared/gcTraceTime.inline.hpp"
 36 #include "gc/shared/referenceProcessor.hpp"
 37 #include "gc/shared/slidingForwarding.inline.hpp"
 38 #include "logging/log.hpp"
 39 #include "memory/iterator.inline.hpp"
 40 #include "oops/oop.inline.hpp"
 41 #include "utilities/ticks.hpp"
 42 
 43 template<bool is_humongous>
 44 void G1FullGCPrepareTask::G1CalculatePointersClosure::free_pinned_region(HeapRegion* hr) {
 45   _regions_freed = true;
 46   if (is_humongous) {
 47     _g1h->free_humongous_region(hr, nullptr);
 48   } else {
 49     _g1h->free_region(hr, nullptr);
 50   }
 51   prepare_for_compaction(hr);
 52   _collector->set_invalid(hr->hrm_index());
 53 }
 54 
 55 bool G1FullGCPrepareTask::G1CalculatePointersClosure::do_heap_region(HeapRegion* hr) {
 56   bool force_not_compacted = false;
 57   if (should_compact(hr)) {

140 bool G1FullGCPrepareTask::G1CalculatePointersClosure::should_compact(HeapRegion* hr) {
141   if (hr->is_pinned()) {
142     return false;
143   }
144   size_t live_words = _collector->live_words(hr->hrm_index());
145   size_t live_words_threshold = _collector->scope()->region_compaction_threshold();
146   // High live ratio region will not be compacted.
147   return live_words <= live_words_threshold;
148 }
149 
150 void G1FullGCPrepareTask::G1CalculatePointersClosure::reset_region_metadata(HeapRegion* hr) {
151   hr->rem_set()->clear();
152   hr->clear_cardtable();
153 
154   G1HotCardCache* hcc = _g1h->hot_card_cache();
155   if (hcc->use_cache()) {
156     hcc->reset_card_counts(hr);
157   }
158 }
159 
160 template <bool ALT_FWD>
161 G1FullGCPrepareTask::G1PrepareCompactLiveClosure<ALT_FWD>::G1PrepareCompactLiveClosure(G1FullGCCompactionPoint* cp) :
162     _cp(cp) { }
163 
164 template <bool ALT_FWD>
165 size_t G1FullGCPrepareTask::G1PrepareCompactLiveClosure<ALT_FWD>::apply(oop object) {
166   size_t size = object->size();
167   _cp->forward<ALT_FWD>(object, size);
168   return size;
169 }
170 
171 template <bool ALT_FWD>
172 size_t G1FullGCPrepareTask::G1RePrepareClosure<ALT_FWD>::apply(oop obj) {
173   // We only re-prepare objects forwarded within the current region, so
174   // skip objects that are already forwarded to another region.
175   if (SlidingForwarding::is_forwarded(obj)) {
176     oop forwarded_to = SlidingForwarding::forwardee<ALT_FWD>(obj);
177     assert(forwarded_to != NULL, "must have forwardee");
178     if (!_current->is_in(forwarded_to)) {
179       return obj->size();
180     }
181   }

182   // Get size and forward.
183   size_t size = obj->size();
184   _cp->forward<ALT_FWD>(obj, size);
185 
186   return size;
187 }
188 
189 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction_work(G1FullGCCompactionPoint* cp,
190                                                                                   HeapRegion* hr) {
191   if (UseAltGCForwarding) {
192     G1PrepareCompactLiveClosure<true> prepare_compact(cp);
193     hr->set_compaction_top(hr->bottom());
194     hr->apply_to_marked_objects(_bitmap, &prepare_compact);
195   } else {
196     G1PrepareCompactLiveClosure<false> prepare_compact(cp);
197     hr->set_compaction_top(hr->bottom());
198     hr->apply_to_marked_objects(_bitmap, &prepare_compact);
199   }
200 }
201 
202 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction(HeapRegion* hr) {
203   if (!_cp->is_initialized()) {
204     hr->set_compaction_top(hr->bottom());
205     _cp->initialize(hr, true);
206   }
207   // Add region to the compaction queue and prepare it.
208   _cp->add(hr);
209   prepare_for_compaction_work(_cp, hr);
210 }
211 
212 template <bool ALT_FWD>
213 void G1FullGCPrepareTask::prepare_serial_compaction_impl() {
214   GCTraceTime(Debug, gc, phases) debug("Phase 2: Prepare Serial Compaction", collector()->scope()->timer());
215   // At this point we know that no regions were completely freed by
216   // the parallel compaction. That means that the last region of
217   // all compaction queues still have data in them. We try to compact
218   // these regions in serial to avoid a premature OOM.
219   for (uint i = 0; i < collector()->workers(); i++) {
220     G1FullGCCompactionPoint* cp = collector()->compaction_point(i);
221     if (cp->has_regions()) {
222       collector()->serial_compaction_point()->add(cp->remove_last());
223     }
224   }
225 
226   // Update the forwarding information for the regions in the serial
227   // compaction point.
228   G1FullGCCompactionPoint* cp = collector()->serial_compaction_point();
229   for (GrowableArrayIterator<HeapRegion*> it = cp->regions()->begin(); it != cp->regions()->end(); ++it) {
230     HeapRegion* current = *it;
231     if (!cp->is_initialized()) {
232       // Initialize the compaction point. Nothing more is needed for the first heap region
233       // since it is already prepared for compaction.
234       cp->initialize(current, false);
235     } else {
236       assert(!current->is_humongous(), "Should be no humongous regions in compaction queue");
237       G1RePrepareClosure<ALT_FWD> re_prepare(cp, current);
238       current->set_compaction_top(current->bottom());
239       current->apply_to_marked_objects(collector()->mark_bitmap(), &re_prepare);
240     }
241   }
242   cp->update();
243 }
244 
245 void G1FullGCPrepareTask::prepare_serial_compaction() {
246   if (UseAltGCForwarding) {
247     prepare_serial_compaction_impl<true>();
248   } else {
249     prepare_serial_compaction_impl<false>();
250   }
251 }
252 
253 bool G1FullGCPrepareTask::G1CalculatePointersClosure::freed_regions() {
254   if (_regions_freed) {
255     return true;
256   }
257 
258   if (!_cp->has_regions()) {
259     // No regions in queue, so no free ones either.
260     return false;
261   }
262 
263   if (_cp->current_region() != _cp->regions()->last()) {
264     // The current region used for compaction is not the last in the
265     // queue. That means there is at least one free region in the queue.
266     return true;
267   }
268 
269   // No free regions in the queue.
270   return false;
271 }
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