142 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* heap, bool activate)
143 : MarkScope(activate), _sh(heap), _n_workers_done_with_threads(0)
144 {
145 if (_active) {
146 _sh->register_strong_roots_scope(this);
147 _sh->change_strong_roots_parity();
148 // Zero the claimed high water mark in the StringTable
149 StringTable::clear_parallel_claimed_index();
150 }
151 }
152
153 SharedHeap::StrongRootsScope::~StrongRootsScope() {
154 if (_active) {
155 _sh->unregister_strong_roots_scope(this);
156 }
157 }
158
159 Monitor* SharedHeap::StrongRootsScope::_lock = new Monitor(Mutex::leaf, "StrongRootsScope lock", false);
160
161 void SharedHeap::StrongRootsScope::mark_worker_done_with_threads(uint n_workers) {
162 // The Thread work barrier is only needed by G1.
163 // No need to use the barrier if this is single-threaded code.
164 if (UseG1GC && n_workers > 0) {
165 uint new_value = (uint)Atomic::add(1, &_n_workers_done_with_threads);
166 if (new_value == n_workers) {
167 // This thread is last. Notify the others.
168 MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
169 _lock->notify_all();
170 }
171 }
172 }
173
174 void SharedHeap::StrongRootsScope::wait_until_all_workers_done_with_threads(uint n_workers) {
175 // No need to use the barrier if this is single-threaded code.
176 if (n_workers > 0 && (uint)_n_workers_done_with_threads != n_workers) {
177 MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
178 while ((uint)_n_workers_done_with_threads != n_workers) {
179 _lock->wait(Mutex::_no_safepoint_check_flag, 0, false);
180 }
181 }
182 }
183
184 void SharedHeap::process_roots(bool activate_scope,
185 ScanningOption so,
186 OopClosure* strong_roots,
187 OopClosure* weak_roots,
188 CLDClosure* strong_cld_closure,
189 CLDClosure* weak_cld_closure,
190 CodeBlobClosure* code_roots) {
191 StrongRootsScope srs(this, activate_scope);
192
193 // General roots.
194 assert(_strong_roots_parity != 0, "must have called prologue code");
195 assert(code_roots != NULL, "code root closure should always be set");
196 // _n_termination for _process_strong_tasks should be set up stream
197 // in a method not running in a GC worker. Otherwise the GC worker
198 // could be trying to change the termination condition while the task
199 // is executing in another GC worker.
200
201 // Iterating over the CLDG and the Threads are done early to allow G1 to
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142 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* heap, bool activate)
143 : MarkScope(activate), _sh(heap), _n_workers_done_with_threads(0)
144 {
145 if (_active) {
146 _sh->register_strong_roots_scope(this);
147 _sh->change_strong_roots_parity();
148 // Zero the claimed high water mark in the StringTable
149 StringTable::clear_parallel_claimed_index();
150 }
151 }
152
153 SharedHeap::StrongRootsScope::~StrongRootsScope() {
154 if (_active) {
155 _sh->unregister_strong_roots_scope(this);
156 }
157 }
158
159 Monitor* SharedHeap::StrongRootsScope::_lock = new Monitor(Mutex::leaf, "StrongRootsScope lock", false);
160
161 void SharedHeap::StrongRootsScope::mark_worker_done_with_threads(uint n_workers) {
162 #if INCLUDE_ALL_GCS
163 // The Thread work barrier is only needed by G1 Class Unloading.
164 // No need to use the barrier if this is single-threaded code.
165 if (UseG1GC && G1ClassUnloadingEnabled && n_workers > 0) {
166 uint new_value = (uint)Atomic::add(1, &_n_workers_done_with_threads);
167 if (new_value == n_workers) {
168 // This thread is last. Notify the others.
169 MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
170 _lock->notify_all();
171 }
172 }
173 #endif
174 }
175
176 void SharedHeap::StrongRootsScope::wait_until_all_workers_done_with_threads(uint n_workers) {
177 #if INCLUDE_ALL_GCS
178 assert(UseG1GC, "Currently only used by G1");
179 assert(G1ClassUnloadingEnabled, "Currently only needed when doing G1 Class Unloading");
180
181 // No need to use the barrier if this is single-threaded code.
182 if (n_workers > 0 && (uint)_n_workers_done_with_threads != n_workers) {
183 MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
184 while ((uint)_n_workers_done_with_threads != n_workers) {
185 _lock->wait(Mutex::_no_safepoint_check_flag, 0, false);
186 }
187 }
188 #endif
189 }
190
191 void SharedHeap::process_roots(bool activate_scope,
192 ScanningOption so,
193 OopClosure* strong_roots,
194 OopClosure* weak_roots,
195 CLDClosure* strong_cld_closure,
196 CLDClosure* weak_cld_closure,
197 CodeBlobClosure* code_roots) {
198 StrongRootsScope srs(this, activate_scope);
199
200 // General roots.
201 assert(_strong_roots_parity != 0, "must have called prologue code");
202 assert(code_roots != NULL, "code root closure should always be set");
203 // _n_termination for _process_strong_tasks should be set up stream
204 // in a method not running in a GC worker. Otherwise the GC worker
205 // could be trying to change the termination condition while the task
206 // is executing in another GC worker.
207
208 // Iterating over the CLDG and the Threads are done early to allow G1 to
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