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 "classfile/javaClasses.hpp"
27 #include "classfile/stringTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc_implementation/shared/gcHeapSummary.hpp"
33 #include "gc_implementation/shared/gcTimer.hpp"
34 #include "gc_implementation/shared/gcTrace.hpp"
35 #include "gc_implementation/shared/gcTraceTime.hpp"
36 #include "gc_interface/collectedHeap.inline.hpp"
37 #include "memory/genCollectedHeap.hpp"
38 #include "memory/genMarkSweep.hpp"
39 #include "memory/genOopClosures.inline.hpp"
40 #include "memory/generation.inline.hpp"
41 #include "memory/modRefBarrierSet.hpp"
42 #include "memory/referencePolicy.hpp"
43 #include "memory/space.hpp"
44 #include "oops/instanceRefKlass.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "runtime/fprofiler.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "runtime/synchronizer.hpp"
50 #include "runtime/thread.inline.hpp"
51 #include "runtime/vmThread.hpp"
52 #include "utilities/copy.hpp"
53 #include "utilities/events.hpp"
54
55 void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, bool clear_all_softrefs) {
56 guarantee(level == 1, "We always collect both old and young.");
57 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
58
59 GenCollectedHeap* gch = GenCollectedHeap::heap();
60 #ifdef ASSERT
61 if (gch->collector_policy()->should_clear_all_soft_refs()) {
62 assert(clear_all_softrefs, "Policy should have been checked earlier");
63 }
64 #endif
65
66 // hook up weak ref data so it can be used during Mark-Sweep
67 assert(ref_processor() == NULL, "no stomping");
68 assert(rp != NULL, "should be non-NULL");
69 _ref_processor = rp;
70 rp->setup_policy(clear_all_softrefs);
71
72 GCTraceTime t1(GCCauseString("Full GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL, _gc_tracer->gc_id());
73
74 gch->trace_heap_before_gc(_gc_tracer);
75
76 // When collecting the permanent generation Method*s may be moving,
77 // so we either have to flush all bcp data or convert it into bci.
78 CodeCache::gc_prologue();
79
80 // Increment the invocation count
81 _total_invocations++;
82
83 // Capture heap size before collection for printing.
84 size_t gch_prev_used = gch->used();
85
86 // Capture used regions for each generation that will be
87 // subject to collection, so that card table adjustments can
88 // be made intelligently (see clear / invalidate further below).
89 gch->save_used_regions(level);
90
91 allocate_stacks();
92
93 mark_sweep_phase1(level, clear_all_softrefs);
94
95 mark_sweep_phase2();
96
97 // Don't add any more derived pointers during phase3
98 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
99 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
100
101 mark_sweep_phase3(level);
102
103 mark_sweep_phase4();
104
105 restore_marks();
106
107 // Set saved marks for allocation profiler (and other things? -- dld)
108 // (Should this be in general part?)
109 gch->save_marks();
110
111 deallocate_stacks();
112
113 // If compaction completely evacuated all generations younger than this
114 // one, then we can clear the card table. Otherwise, we must invalidate
115 // it (consider all cards dirty). In the future, we might consider doing
116 // compaction within generations only, and doing card-table sliding.
117 bool all_empty = true;
118 for (int i = 0; all_empty && i < level; i++) {
119 Generation* g = gch->get_gen(i);
120 all_empty = all_empty && gch->get_gen(i)->used() == 0;
121 }
122 GenRemSet* rs = gch->rem_set();
123 Generation* old_gen = gch->get_gen(level);
124 // Clear/invalidate below make use of the "prev_used_regions" saved earlier.
125 if (all_empty) {
126 // We've evacuated all generations below us.
127 rs->clear_into_younger(old_gen);
128 } else {
129 // Invalidate the cards corresponding to the currently used
130 // region and clear those corresponding to the evacuated region.
131 rs->invalidate_or_clear(old_gen);
132 }
133
134 CodeCache::gc_epilogue();
135 JvmtiExport::gc_epilogue();
136
137 if (PrintGC && !PrintGCDetails) {
138 gch->print_heap_change(gch_prev_used);
139 }
140
141 // refs processing: clean slate
142 _ref_processor = NULL;
143
144 // Update heap occupancy information which is used as
145 // input to soft ref clearing policy at the next gc.
146 Universe::update_heap_info_at_gc();
147
148 // Update time of last gc for all generations we collected
149 // (which currently is all the generations in the heap).
150 // We need to use a monotonically non-decreasing time in ms
151 // or we will see time-warp warnings and os::javaTimeMillis()
152 // does not guarantee monotonicity.
153 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
154 gch->update_time_of_last_gc(now);
155
156 gch->trace_heap_after_gc(_gc_tracer);
157 }
158
159 void GenMarkSweep::allocate_stacks() {
160 GenCollectedHeap* gch = GenCollectedHeap::heap();
161 // Scratch request on behalf of oldest generation; will do no
162 // allocation.
163 ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0);
164
165 // $$$ To cut a corner, we'll only use the first scratch block, and then
166 // revert to malloc.
167 if (scratch != NULL) {
168 _preserved_count_max =
169 scratch->num_words * HeapWordSize / sizeof(PreservedMark);
170 } else {
171 _preserved_count_max = 0;
172 }
173
174 _preserved_marks = (PreservedMark*)scratch;
175 _preserved_count = 0;
176 }
177
178
179 void GenMarkSweep::deallocate_stacks() {
180 if (!UseG1GC) {
181 GenCollectedHeap* gch = GenCollectedHeap::heap();
182 gch->release_scratch();
183 }
184
185 _preserved_mark_stack.clear(true);
186 _preserved_oop_stack.clear(true);
187 _marking_stack.clear();
188 _objarray_stack.clear(true);
189 }
190
191 void GenMarkSweep::mark_sweep_phase1(int level,
192 bool clear_all_softrefs) {
193 // Recursively traverse all live objects and mark them
194 GCTraceTime tm("phase 1", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
195 trace(" 1");
196
197 GenCollectedHeap* gch = GenCollectedHeap::heap();
198
199 // Because follow_root_closure is created statically, cannot
200 // use OopsInGenClosure constructor which takes a generation,
201 // as the Universe has not been created when the static constructors
202 // are run.
203 follow_root_closure.set_orig_generation(gch->get_gen(level));
204
205 // Need new claim bits before marking starts.
206 ClassLoaderDataGraph::clear_claimed_marks();
207
208 gch->gen_process_roots(level,
209 false, // Younger gens are not roots.
210 true, // activate StrongRootsScope
211 SharedHeap::SO_None,
212 GenCollectedHeap::StrongRootsOnly,
213 &follow_root_closure,
214 &follow_root_closure,
215 &follow_cld_closure);
216
217 // Process reference objects found during marking
218 {
219 ref_processor()->setup_policy(clear_all_softrefs);
220 const ReferenceProcessorStats& stats =
221 ref_processor()->process_discovered_references(
222 &is_alive, &keep_alive, &follow_stack_closure, NULL, _gc_timer, _gc_tracer->gc_id());
223 gc_tracer()->report_gc_reference_stats(stats);
224 }
225
226 // This is the point where the entire marking should have completed.
227 assert(_marking_stack.is_empty(), "Marking should have completed");
228
257 //
258 // It is not required that we traverse spaces in the same order in
259 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
260 // tracking expects us to do so. See comment under phase4.
261
262 GenCollectedHeap* gch = GenCollectedHeap::heap();
263
264 GCTraceTime tm("phase 2", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
265 trace("2");
266
267 gch->prepare_for_compaction();
268 }
269
270 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure {
271 public:
272 void do_generation(Generation* gen) {
273 gen->adjust_pointers();
274 }
275 };
276
277 void GenMarkSweep::mark_sweep_phase3(int level) {
278 GenCollectedHeap* gch = GenCollectedHeap::heap();
279
280 // Adjust the pointers to reflect the new locations
281 GCTraceTime tm("phase 3", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
282 trace("3");
283
284 // Need new claim bits for the pointer adjustment tracing.
285 ClassLoaderDataGraph::clear_claimed_marks();
286
287 // Because the closure below is created statically, we cannot
288 // use OopsInGenClosure constructor which takes a generation,
289 // as the Universe has not been created when the static constructors
290 // are run.
291 adjust_pointer_closure.set_orig_generation(gch->get_gen(level));
292
293 gch->gen_process_roots(level,
294 false, // Younger gens are not roots.
295 true, // activate StrongRootsScope
296 SharedHeap::SO_AllCodeCache,
297 GenCollectedHeap::StrongAndWeakRoots,
298 &adjust_pointer_closure,
299 &adjust_pointer_closure,
300 &adjust_cld_closure);
301
302 gch->gen_process_weak_roots(&adjust_pointer_closure);
303
304 adjust_marks();
305 GenAdjustPointersClosure blk;
306 gch->generation_iterate(&blk, true);
307 }
308
309 class GenCompactClosure: public GenCollectedHeap::GenClosure {
310 public:
311 void do_generation(Generation* gen) {
312 gen->compact();
313 }
|
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 "classfile/javaClasses.hpp"
27 #include "classfile/stringTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc_implementation/shared/gcHeapSummary.hpp"
33 #include "gc_implementation/shared/gcTimer.hpp"
34 #include "gc_implementation/shared/gcTrace.hpp"
35 #include "gc_implementation/shared/gcTraceTime.hpp"
36 #include "gc_interface/collectedHeap.inline.hpp"
37 #include "memory/genCollectedHeap.hpp"
38 #include "memory/genMarkSweep.hpp"
39 #include "memory/genOopClosures.inline.hpp"
40 #include "memory/generation.hpp"
41 #include "memory/generation.inline.hpp"
42 #include "memory/modRefBarrierSet.hpp"
43 #include "memory/referencePolicy.hpp"
44 #include "memory/space.hpp"
45 #include "oops/instanceRefKlass.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "runtime/fprofiler.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/synchronizer.hpp"
51 #include "runtime/thread.inline.hpp"
52 #include "runtime/vmThread.hpp"
53 #include "utilities/copy.hpp"
54 #include "utilities/events.hpp"
55
56 void GenMarkSweep::invoke_at_safepoint(ReferenceProcessor* rp, bool clear_all_softrefs) {
57 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
58
59 GenCollectedHeap* gch = GenCollectedHeap::heap();
60 #ifdef ASSERT
61 if (gch->collector_policy()->should_clear_all_soft_refs()) {
62 assert(clear_all_softrefs, "Policy should have been checked earlier");
63 }
64 #endif
65
66 // hook up weak ref data so it can be used during Mark-Sweep
67 assert(ref_processor() == NULL, "no stomping");
68 assert(rp != NULL, "should be non-NULL");
69 _ref_processor = rp;
70 rp->setup_policy(clear_all_softrefs);
71
72 GCTraceTime t1(GCCauseString("Full GC", gch->gc_cause()), PrintGC && !PrintGCDetails, true, NULL, _gc_tracer->gc_id());
73
74 gch->trace_heap_before_gc(_gc_tracer);
75
76 // When collecting the permanent generation Method*s may be moving,
77 // so we either have to flush all bcp data or convert it into bci.
78 CodeCache::gc_prologue();
79
80 // Increment the invocation count
81 _total_invocations++;
82
83 // Capture heap size before collection for printing.
84 size_t gch_prev_used = gch->used();
85
86 // Capture used regions for each generation that will be
87 // subject to collection, so that card table adjustments can
88 // be made intelligently (see clear / invalidate further below).
89 gch->save_used_regions();
90
91 allocate_stacks();
92
93 mark_sweep_phase1(clear_all_softrefs);
94
95 mark_sweep_phase2();
96
97 // Don't add any more derived pointers during phase3
98 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
99 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
100
101 mark_sweep_phase3();
102
103 mark_sweep_phase4();
104
105 restore_marks();
106
107 // Set saved marks for allocation profiler (and other things? -- dld)
108 // (Should this be in general part?)
109 gch->save_marks();
110
111 deallocate_stacks();
112
113 // If compaction completely evacuated the young generation we can clear
114 // the card table. Otherwise, we must invalidate it (consider all cards dirty).
115 // In the future, we might consider doing compaction within generations only,
116 // and doing card-table sliding.
117 GenRemSet* rs = gch->rem_set();
118 Generation* old_gen = gch->old_gen();
119 // Clear/invalidate below make use of the "prev_used_regions" saved earlier.
120 if (gch->young_gen()->used() == 0) {
121 // We've evacuated all generations below us.
122 rs->clear_into_younger(old_gen);
123 } else {
124 // Invalidate the cards corresponding to the currently used
125 // region and clear those corresponding to the evacuated region.
126 rs->invalidate_or_clear(old_gen);
127 }
128
129 CodeCache::gc_epilogue();
130 JvmtiExport::gc_epilogue();
131
132 if (PrintGC && !PrintGCDetails) {
133 gch->print_heap_change(gch_prev_used);
134 }
135
136 // refs processing: clean slate
137 _ref_processor = NULL;
138
139 // Update heap occupancy information which is used as
140 // input to soft ref clearing policy at the next gc.
141 Universe::update_heap_info_at_gc();
142
143 // Update time of last gc for all generations we collected
144 // (which currently is all the generations in the heap).
145 // We need to use a monotonically non-decreasing time in ms
146 // or we will see time-warp warnings and os::javaTimeMillis()
147 // does not guarantee monotonicity.
148 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
149 gch->update_time_of_last_gc(now);
150
151 gch->trace_heap_after_gc(_gc_tracer);
152 }
153
154 void GenMarkSweep::allocate_stacks() {
155 GenCollectedHeap* gch = GenCollectedHeap::heap();
156 // Scratch request on behalf of oldest generation; will do no
157 // allocation.
158 ScratchBlock* scratch = gch->gather_scratch(gch->old_gen(), 0);
159
160 // $$$ To cut a corner, we'll only use the first scratch block, and then
161 // revert to malloc.
162 if (scratch != NULL) {
163 _preserved_count_max =
164 scratch->num_words * HeapWordSize / sizeof(PreservedMark);
165 } else {
166 _preserved_count_max = 0;
167 }
168
169 _preserved_marks = (PreservedMark*)scratch;
170 _preserved_count = 0;
171 }
172
173
174 void GenMarkSweep::deallocate_stacks() {
175 if (!UseG1GC) {
176 GenCollectedHeap* gch = GenCollectedHeap::heap();
177 gch->release_scratch();
178 }
179
180 _preserved_mark_stack.clear(true);
181 _preserved_oop_stack.clear(true);
182 _marking_stack.clear();
183 _objarray_stack.clear(true);
184 }
185
186 void GenMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
187 // Recursively traverse all live objects and mark them
188 GCTraceTime tm("phase 1", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
189 trace(" 1");
190
191 GenCollectedHeap* gch = GenCollectedHeap::heap();
192
193 // Because follow_root_closure is created statically, cannot
194 // use OopsInGenClosure constructor which takes a generation,
195 // as the Universe has not been created when the static constructors
196 // are run.
197 follow_root_closure.set_orig_generation(gch->old_gen());
198
199 // Need new claim bits before marking starts.
200 ClassLoaderDataGraph::clear_claimed_marks();
201
202 gch->gen_process_roots(Generation::Old,
203 false, // Younger gens are not roots.
204 true, // activate StrongRootsScope
205 SharedHeap::SO_None,
206 GenCollectedHeap::StrongRootsOnly,
207 &follow_root_closure,
208 &follow_root_closure,
209 &follow_cld_closure);
210
211 // Process reference objects found during marking
212 {
213 ref_processor()->setup_policy(clear_all_softrefs);
214 const ReferenceProcessorStats& stats =
215 ref_processor()->process_discovered_references(
216 &is_alive, &keep_alive, &follow_stack_closure, NULL, _gc_timer, _gc_tracer->gc_id());
217 gc_tracer()->report_gc_reference_stats(stats);
218 }
219
220 // This is the point where the entire marking should have completed.
221 assert(_marking_stack.is_empty(), "Marking should have completed");
222
251 //
252 // It is not required that we traverse spaces in the same order in
253 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
254 // tracking expects us to do so. See comment under phase4.
255
256 GenCollectedHeap* gch = GenCollectedHeap::heap();
257
258 GCTraceTime tm("phase 2", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
259 trace("2");
260
261 gch->prepare_for_compaction();
262 }
263
264 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure {
265 public:
266 void do_generation(Generation* gen) {
267 gen->adjust_pointers();
268 }
269 };
270
271 void GenMarkSweep::mark_sweep_phase3() {
272 GenCollectedHeap* gch = GenCollectedHeap::heap();
273
274 // Adjust the pointers to reflect the new locations
275 GCTraceTime tm("phase 3", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id());
276 trace("3");
277
278 // Need new claim bits for the pointer adjustment tracing.
279 ClassLoaderDataGraph::clear_claimed_marks();
280
281 // Because the closure below is created statically, we cannot
282 // use OopsInGenClosure constructor which takes a generation,
283 // as the Universe has not been created when the static constructors
284 // are run.
285 adjust_pointer_closure.set_orig_generation(gch->old_gen());
286
287 gch->gen_process_roots(Generation::Old,
288 false, // Younger gens are not roots.
289 true, // activate StrongRootsScope
290 SharedHeap::SO_AllCodeCache,
291 GenCollectedHeap::StrongAndWeakRoots,
292 &adjust_pointer_closure,
293 &adjust_pointer_closure,
294 &adjust_cld_closure);
295
296 gch->gen_process_weak_roots(&adjust_pointer_closure);
297
298 adjust_marks();
299 GenAdjustPointersClosure blk;
300 gch->generation_iterate(&blk, true);
301 }
302
303 class GenCompactClosure: public GenCollectedHeap::GenClosure {
304 public:
305 void do_generation(Generation* gen) {
306 gen->compact();
307 }
|