< prev index next >
src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.cpp
Print this page
@@ -218,10 +218,41 @@
bool G1SATBCardTableModRefBS::is_in_young(oop obj) const {
volatile jbyte* p = byte_for((void*)obj);
return *p == g1_young_card_val();
}
-void G1SATBCardTableLoggingModRefBS::flush_deferred_barriers(JavaThread* thread) {
- CardTableModRefBS::flush_deferred_barriers(thread);
+void G1SATBCardTableLoggingModRefBS::on_thread_attach(JavaThread* thread) {
+ // This method initializes the SATB and dirty card queues before a
+ // JavaThread is added to the Java thread list. Right now, we don't
+ // have to do anything to the dirty card queue (it should have been
+ // activated when the thread was created), but we have to activate
+ // the SATB queue if the thread is created while a marking cycle is
+ // in progress. The activation / de-activation of the SATB queues at
+ // the beginning / end of a marking cycle is done during safepoints
+ // so we have to make sure this method is called outside one to be
+ // able to safely read the active field of the SATB queue set. Right
+ // now, it is called just before the thread is added to the Java
+ // thread list in the Threads::add() method. That method is holding
+ // the Threads_lock which ensures we are outside a safepoint. We
+ // cannot do the obvious and set the active field of the SATB queue
+ // when the thread is created given that, in some cases, safepoints
+ // might happen between the JavaThread constructor being called and the
+ // thread being added to the Java thread list (an example of this is
+ // when the structure for the DestroyJavaVM thread is created).
+ assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");
+ assert(!thread->satb_mark_queue().is_active(), "SATB queue should not be active");
+ assert(thread->satb_mark_queue().is_empty(), "SATB queue should be empty");
+ assert(thread->dirty_card_queue().is_active(), "Dirty card queue should be active");
+
+ // If we are creating the thread during a marking cycle, we should
+ // set the active field of the SATB queue to true.
+ if (thread->satb_mark_queue_set().is_active()) {
+ thread->satb_mark_queue().set_active(true);
+ }
+}
+
+void G1SATBCardTableLoggingModRefBS::on_thread_detach(JavaThread* thread) {
+ // Flush any deferred card marks, SATB buffers and dirty card queue buffers
+ CardTableModRefBS::on_thread_detach(thread);
thread->satb_mark_queue().flush();
thread->dirty_card_queue().flush();
}
< prev index next >