--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,265 @@
+/*
+ * Copyright (c) 2001, 2017, 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/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1SATBCardTableModRefBS.inline.hpp"
+#include "gc/g1/heapRegion.hpp"
+#include "gc/g1/satbMarkQueue.hpp"
+#include "gc/shared/memset_with_concurrent_readers.hpp"
+#include "logging/log.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "runtime/thread.inline.hpp"
+
+G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(
+  MemRegion whole_heap,
+  const BarrierSet::FakeRtti& fake_rtti) :
+  CardTableModRefBS(whole_heap, fake_rtti.add_tag(BarrierSet::G1SATBCT))
+{ }
+
+void G1SATBCardTableModRefBS::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
+G1SATBCardTableModRefBS::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 G1SATBCardTableModRefBS::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
+  if (!dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+void G1SATBCardTableModRefBS::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
+  if (!dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+
+bool G1SATBCardTableModRefBS::mark_card_deferred(size_t card_index) {
+  jbyte val = _byte_map[card_index];
+  // It's already processed
+  if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
+    return false;
+  }
+
+  // Cached bit can be installed either on a clean card or on a claimed card.
+  jbyte new_val = val;
+  if (val == clean_card_val()) {
+    new_val = (jbyte)deferred_card_val();
+  } else {
+    if (val & claimed_card_val()) {
+      new_val = val | (jbyte)deferred_card_val();
+    }
+  }
+  if (new_val != val) {
+    Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
+  }
+  return true;
+}
+
+void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
+  jbyte *const first = byte_for(mr.start());
+  jbyte *const last = byte_after(mr.last());
+
+  memset_with_concurrent_readers(first, g1_young_gen, last - first);
+}
+
+#ifndef PRODUCT
+void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) {
+  verify_region(mr, g1_young_gen,  true);
+}
+#endif
+
+void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
+  // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.
+  MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
+  _card_table->clear(mr);
+}
+
+G1SATBCardTableLoggingModRefBS::
+G1SATBCardTableLoggingModRefBS(MemRegion whole_heap) :
+  G1SATBCardTableModRefBS(whole_heap, BarrierSet::FakeRtti(G1SATBCTLogging)),
+  _dcqs(JavaThread::dirty_card_queue_set()),
+  _listener()
+{
+  _listener.set_card_table(this);
+}
+
+void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) {
+  mapper->set_mapping_changed_listener(&_listener);
+
+  _byte_map_size = mapper->reserved().byte_size();
+
+  _guard_index = cards_required(_whole_heap.word_size()) - 1;
+  _last_valid_index = _guard_index - 1;
+
+  HeapWord* low_bound  = _whole_heap.start();
+  HeapWord* high_bound = _whole_heap.end();
+
+  _cur_covered_regions = 1;
+  _covered[0] = _whole_heap;
+
+  _byte_map = (jbyte*) mapper->reserved().start();
+  byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
+  assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
+  assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
+
+  log_trace(gc, barrier)("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: ");
+  log_trace(gc, barrier)("    &_byte_map[0]: " INTPTR_FORMAT "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
+                         p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));
+  log_trace(gc, barrier)("    byte_map_base: " INTPTR_FORMAT,  p2i(byte_map_base));
+}
+
+void
+G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
+                                                     oop new_val,
+                                                     bool release) {
+  volatile jbyte* byte = byte_for(field);
+  if (*byte == g1_young_gen) {
+    return;
+  }
+  OrderAccess::storeload();
+  if (*byte != dirty_card) {
+    *byte = dirty_card;
+    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
+G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr) {
+  volatile jbyte* byte = byte_for(mr.start());
+  jbyte* last_byte = byte_for(mr.last());
+  Thread* thr = Thread::current();
+    // skip all consecutive young cards
+  for (; byte <= last_byte && *byte == g1_young_gen; 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 == g1_young_gen) {
+          continue;
+        }
+        if (*byte != dirty_card) {
+          *byte = dirty_card;
+          jt->dirty_card_queue().enqueue(byte);
+        }
+      }
+    } else {
+      MutexLockerEx x(Shared_DirtyCardQ_lock,
+                      Mutex::_no_safepoint_check_flag);
+      for (; byte <= last_byte; byte++) {
+        if (*byte == g1_young_gen) {
+          continue;
+        }
+        if (*byte != dirty_card) {
+          *byte = dirty_card;
+          _dcqs.shared_dirty_card_queue()->enqueue(byte);
+        }
+      }
+    }
+  }
+}
+
+void G1SATBCardTableModRefBS::write_ref_nmethod_post(oop* dst, nmethod* nm) {
+  oop obj = oopDesc::load_heap_oop(dst);
+  if (obj != NULL) {
+    G1CollectedHeap* g1h = G1CollectedHeap::heap();
+    HeapRegion* hr = g1h->heap_region_containing(obj);
+    hr->add_strong_code_root(nm);
+  }
+}
+
+class G1EnsureLastRefToRegion : public OopClosure {
+  G1CollectedHeap* _g1h;
+  HeapRegion* _hr;
+  oop* _dst;
+
+  bool _value;
+public:
+  G1EnsureLastRefToRegion(G1CollectedHeap* g1h, HeapRegion* hr, oop* dst) :
+    _g1h(g1h), _hr(hr), _dst(dst), _value(true) {}
+
+  void do_oop(oop* p) {
+    if (_value && p != _dst) {
+      oop obj = oopDesc::load_heap_oop(p);
+      if (obj != NULL) {
+        HeapRegion* hr = _g1h->heap_region_containing(obj);
+        if (hr == _hr) {
+          // Another reference to the same region.
+          _value = false;
+        }
+      }
+    }
+  }
+  void do_oop(narrowOop* p) { ShouldNotReachHere(); }
+  bool value() const        { return _value;  }
+};
+
+void G1SATBCardTableModRefBS::write_ref_nmethod_pre(oop* dst, nmethod* nm) {
+  oop obj = oopDesc::load_heap_oop(dst);
+  if (obj != NULL) {
+    G1CollectedHeap* g1h = G1CollectedHeap::heap();
+    HeapRegion* hr = g1h->heap_region_containing(obj);
+    G1EnsureLastRefToRegion ensure_last_ref(g1h, hr, dst);
+    nm->oops_do(&ensure_last_ref);
+    if (ensure_last_ref.value()) {
+      // Last reference to this region, remove the nmethod from the rset.
+      hr->remove_strong_code_root(nm);
+    }
+  }
+}