diff --git a/src/hotspot/share/gc/g1/g1BarrierSet.cpp b/src/hotspot/share/gc/g1/g1BarrierSet.cpp new file mode 100644 index 0000000..a444109 --- /dev/null +++ b/src/hotspot/share/gc/g1/g1BarrierSet.cpp @@ -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 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(); +}