203 MutexLockerEx x(Shared_DirtyCardQ_lock,
204 Mutex::_no_safepoint_check_flag);
205 for (; byte <= last_byte; byte++) {
206 if (*byte == g1_young_gen) {
207 continue;
208 }
209 if (*byte != dirty_card) {
210 *byte = dirty_card;
211 _dcqs.shared_dirty_card_queue()->enqueue(byte);
212 }
213 }
214 }
215 }
216 }
217
218 bool G1SATBCardTableModRefBS::is_in_young(oop obj) const {
219 volatile jbyte* p = byte_for((void*)obj);
220 return *p == g1_young_card_val();
221 }
222
223 void G1SATBCardTableLoggingModRefBS::flush_deferred_barriers(JavaThread* thread) {
224 CardTableModRefBS::flush_deferred_barriers(thread);
225 thread->satb_mark_queue().flush();
226 thread->dirty_card_queue().flush();
227 }
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203 MutexLockerEx x(Shared_DirtyCardQ_lock,
204 Mutex::_no_safepoint_check_flag);
205 for (; byte <= last_byte; byte++) {
206 if (*byte == g1_young_gen) {
207 continue;
208 }
209 if (*byte != dirty_card) {
210 *byte = dirty_card;
211 _dcqs.shared_dirty_card_queue()->enqueue(byte);
212 }
213 }
214 }
215 }
216 }
217
218 bool G1SATBCardTableModRefBS::is_in_young(oop obj) const {
219 volatile jbyte* p = byte_for((void*)obj);
220 return *p == g1_young_card_val();
221 }
222
223 void G1SATBCardTableLoggingModRefBS::on_thread_create(JavaThread* thread) {
224 // This method initializes the SATB and dirty card queues before a
225 // JavaThread is added to the Java thread list. Right now, we don't
226 // have to do anything to the dirty card queue (it should have been
227 // activated when the thread was created), but we have to activate
228 // the SATB queue if the thread is created while a marking cycle is
229 // in progress. The activation / de-activation of the SATB queues at
230 // the beginning / end of a marking cycle is done during safepoints
231 // so we have to make sure this method is called outside one to be
232 // able to safely read the active field of the SATB queue set. Right
233 // now, it is called just before the thread is added to the Java
234 // thread list in the Threads::add() method. That method is holding
235 // the Threads_lock which ensures we are outside a safepoint. We
236 // cannot do the obvious and set the active field of the SATB queue
237 // when the thread is created given that, in some cases, safepoints
238 // might happen between the JavaThread constructor being called and the
239 // thread being added to the Java thread list (an example of this is
240 // when the structure for the DestroyJavaVM thread is created).
241 assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");
242 assert(!thread->satb_mark_queue().is_active(), "SATB queue should not be active");
243 assert(thread->satb_mark_queue().is_empty(), "SATB queue should be empty");
244 assert(thread->dirty_card_queue().is_active(), "Dirty card queue should be active");
245
246 // If we are creating the thread during a marking cycle, we should
247 // set the active field of the SATB queue to true.
248 if (thread->satb_mark_queue_set().is_active()) {
249 thread->satb_mark_queue().set_active(true);
250 }
251 }
252
253 void G1SATBCardTableLoggingModRefBS::on_thread_destroy(JavaThread* thread) {
254 // Flush any deferred card marks, SATB buffers and dirty card queue buffers
255 CardTableModRefBS::on_thread_destroy(thread);
256 thread->satb_mark_queue().flush();
257 thread->dirty_card_queue().flush();
258 }
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