--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1BarrierSet.cpp	Tue Mar 06 08:36:44 2018 +0100
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/g1/g1BarrierSet.inline.hpp"
+#include "gc/g1/g1CardTable.inline.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/heapRegion.hpp"
+#include "gc/g1/satbMarkQueue.hpp"
+#include "logging/log.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/thread.inline.hpp"
+
+G1BarrierSet::G1BarrierSet(G1CardTable* card_table) :
+  CardTableModRefBS(card_table, BarrierSet::FakeRtti(BarrierSet::G1BarrierSet)),
+  _dcqs(JavaThread::dirty_card_queue_set())
+{ }
+
+void G1BarrierSet::enqueue(oop pre_val) {
+  // Nulls should have been already filtered.
+  assert(oopDesc::is_oop(pre_val, true), "Error");
+
+  if (!JavaThread::satb_mark_queue_set().is_active()) return;
+  Thread* thr = Thread::current();
+  if (thr->is_Java_thread()) {
+    JavaThread* jt = (JavaThread*)thr;
+    jt->satb_mark_queue().enqueue(pre_val);
+  } else {
+    MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
+    JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);
+  }
+}
+
+template <class T> void
+G1BarrierSet::write_ref_array_pre_work(T* dst, int count) {
+  if (!JavaThread::satb_mark_queue_set().is_active()) return;
+  T* elem_ptr = dst;
+  for (int i = 0; i < count; i++, elem_ptr++) {
+    T heap_oop = oopDesc::load_heap_oop(elem_ptr);
+    if (!oopDesc::is_null(heap_oop)) {
+      enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
+    }
+  }
+}
+
+void G1BarrierSet::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
+  if (!dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+
+void G1BarrierSet::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
+  if (!dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+
+void G1BarrierSet::write_ref_field_post_slow(volatile jbyte* byte) {
+  // In the slow path, we know a card is not young
+  assert(*byte != G1CardTable::g1_young_card_val(), "slow path invoked without filtering");
+  OrderAccess::storeload();
+  if (*byte != G1CardTable::dirty_card_val()) {
+    *byte = G1CardTable::dirty_card_val();
+    Thread* thr = Thread::current();
+    if (thr->is_Java_thread()) {
+      JavaThread* jt = (JavaThread*)thr;
+      jt->dirty_card_queue().enqueue(byte);
+    } else {
+      MutexLockerEx x(Shared_DirtyCardQ_lock,
+                      Mutex::_no_safepoint_check_flag);
+      _dcqs.shared_dirty_card_queue()->enqueue(byte);
+    }
+  }
+}
+
+void G1BarrierSet::invalidate(MemRegion mr) {
+  if (mr.is_empty()) {
+    return;
+  }
+  volatile jbyte* byte = _card_table->byte_for(mr.start());
+  jbyte* last_byte = _card_table->byte_for(mr.last());
+  Thread* thr = Thread::current();
+    // skip all consecutive young cards
+  for (; byte <= last_byte && *byte == G1CardTable::g1_young_card_val(); byte++);
+
+  if (byte <= last_byte) {
+    OrderAccess::storeload();
+    // Enqueue if necessary.
+    if (thr->is_Java_thread()) {
+      JavaThread* jt = (JavaThread*)thr;
+      for (; byte <= last_byte; byte++) {
+        if (*byte == G1CardTable::g1_young_card_val()) {
+          continue;
+        }
+        if (*byte != G1CardTable::dirty_card_val()) {
+          *byte = G1CardTable::dirty_card_val();
+          jt->dirty_card_queue().enqueue(byte);
+        }
+      }
+    } else {
+      MutexLockerEx x(Shared_DirtyCardQ_lock,
+                      Mutex::_no_safepoint_check_flag);
+      for (; byte <= last_byte; byte++) {
+        if (*byte == G1CardTable::g1_young_card_val()) {
+          continue;
+        }
+        if (*byte != G1CardTable::dirty_card_val()) {
+          *byte = G1CardTable::dirty_card_val();
+          _dcqs.shared_dirty_card_queue()->enqueue(byte);
+        }
+      }
+    }
+  }
+}
+
+void G1BarrierSet::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 G1BarrierSet::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();
+}