--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp Tue Nov 14 11:33:23 2017 +0100
@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) 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.hpp"
+#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
+#include "gc/g1/g1FullCollector.hpp"
+#include "gc/g1/g1FullGCCompactionPoint.hpp"
+#include "gc/g1/g1FullGCMarker.hpp"
+#include "gc/g1/g1FullGCOopClosures.inline.hpp"
+#include "gc/g1/g1FullGCPrepareTask.hpp"
+#include "gc/g1/g1HotCardCache.hpp"
+#include "gc/g1/heapRegion.inline.hpp"
+#include "gc/shared/gcTraceTime.inline.hpp"
+#include "gc/shared/referenceProcessor.hpp"
+#include "logging/log.hpp"
+#include "utilities/ticks.inline.hpp"
+
+bool G1FullGCPrepareTask::G1CalculatePointersClosure::doHeapRegion(HeapRegion* hr) {
+ if (hr->is_humongous()) {
+ oop obj = oop(hr->humongous_start_region()->bottom());
+ if (_bitmap->is_marked(obj)) {
+ if (hr->is_starts_humongous()) {
+ obj->forward_to(obj);
+ }
+ } else {
+ free_humongous_region(hr);
+ }
+ } else if (!hr->is_pinned()) {
+ prepare_for_compaction(hr);
+ }
+
+ // Reset data structures not valid after Full GC.
+ reset_region_metadata(hr);
+
+ return false;
+}
+
+G1FullGCPrepareTask::G1FullGCPrepareTask(G1FullCollector* collector) :
+ G1FullGCTask("G1 Prepare Compact Task", collector),
+ _hrclaimer(collector->workers()),
+ _freed_regions(false) {
+}
+
+void G1FullGCPrepareTask::set_freed_regions() {
+ if (!_freed_regions) {
+ _freed_regions = true;
+ }
+}
+
+bool G1FullGCPrepareTask::has_freed_regions() {
+ return _freed_regions;
+}
+
+void G1FullGCPrepareTask::work(uint worker_id) {
+ Ticks start = Ticks::now();
+ G1FullGCCompactionPoint* compaction_point = collector()->compaction_point(worker_id);
+ G1CalculatePointersClosure closure(collector()->mark_bitmap(), compaction_point);
+ G1CollectedHeap::heap()->heap_region_par_iterate_from_start(&closure, &_hrclaimer);
+
+ // Update humongous region sets
+ closure.update_sets();
+ compaction_point->update();
+
+ // Check if any regions was freed by this worker and store in task.
+ if (closure.freed_regions()) {
+ set_freed_regions();
+ }
+ log_task("Prepare compaction task", worker_id, start);
+}
+
+G1FullGCPrepareTask::G1CalculatePointersClosure::G1CalculatePointersClosure(G1CMBitMap* bitmap,
+ G1FullGCCompactionPoint* cp) :
+ _g1h(G1CollectedHeap::heap()),
+ _bitmap(bitmap),
+ _cp(cp),
+ _humongous_regions_removed(0) { }
+
+void G1FullGCPrepareTask::G1CalculatePointersClosure::free_humongous_region(HeapRegion* hr) {
+ FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep");
+
+ hr->set_containing_set(NULL);
+ _humongous_regions_removed++;
+
+ _g1h->free_humongous_region(hr, &dummy_free_list, false /* skip_remset */);
+ prepare_for_compaction(hr);
+ dummy_free_list.remove_all();
+}
+
+void G1FullGCPrepareTask::G1CalculatePointersClosure::reset_region_metadata(HeapRegion* hr) {
+ hr->reset_gc_time_stamp();
+ hr->rem_set()->clear();
+
+ _g1h->g1_barrier_set()->clear(MemRegion(hr->bottom(), hr->end()));
+
+ if (_g1h->g1_hot_card_cache()->use_cache()) {
+ _g1h->g1_hot_card_cache()->reset_card_counts(hr);
+ }
+}
+
+G1FullGCPrepareTask::G1PrepareCompactLiveClosure::G1PrepareCompactLiveClosure(G1FullGCCompactionPoint* cp) :
+ _cp(cp) { }
+
+size_t G1FullGCPrepareTask::G1PrepareCompactLiveClosure::apply(oop object) {
+ size_t size = object->size();
+ _cp->forward(object, size);
+ return size;
+}
+
+size_t G1FullGCPrepareTask::G1RePrepareClosure::apply(oop obj) {
+ // We only re-prepare objects forwarded within the current region, so
+ // skip objects that are already forwarded to another region.
+ oop forwarded_to = obj->forwardee();
+ if (forwarded_to != NULL && !_current->is_in(forwarded_to)) {
+ return obj->size();
+ }
+
+ // Get size and forward.
+ size_t size = obj->size();
+ _cp->forward(obj, size);
+
+ return size;
+}
+
+void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction_work(G1FullGCCompactionPoint* cp,
+ HeapRegion* hr) {
+ G1PrepareCompactLiveClosure prepare_compact(cp);
+ hr->set_compaction_top(hr->bottom());
+ hr->apply_to_marked_objects(_bitmap, &prepare_compact);
+}
+
+void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction(HeapRegion* hr) {
+ if (!_cp->is_initialized()) {
+ hr->set_compaction_top(hr->bottom());
+ _cp->initialize(hr, true);
+ }
+ // Add region to the compaction queue and prepare it.
+ _cp->add(hr);
+ prepare_for_compaction_work(_cp, hr);
+}
+
+void G1FullGCPrepareTask::prepare_serial_compaction() {
+ GCTraceTime(Debug, gc, phases) debug("Phase 2: Prepare Serial Compaction", collector()->scope()->timer());
+ // At this point we know that no regions were completely freed by
+ // the parallel compaction. That means that the last region of
+ // all compaction queues still have data in them. We try to compact
+ // these regions in serial to avoid a premature OOM.
+ for (uint i = 0; i < collector()->workers(); i++) {
+ G1FullGCCompactionPoint* cp = collector()->compaction_point(i);
+ if (cp->has_regions()) {
+ collector()->serial_compaction_point()->add(cp->remove_last());
+ }
+ }
+
+ // Update the forwarding information for the regions in the serial
+ // compaction point.
+ G1FullGCCompactionPoint* cp = collector()->serial_compaction_point();
+ for (GrowableArrayIterator<HeapRegion*> it = cp->regions()->begin(); it != cp->regions()->end(); ++it) {
+ HeapRegion* current = *it;
+ if (!cp->is_initialized()) {
+ // Initialize the compaction point. Nothing more is needed for the first heap region
+ // since it is already prepared for compaction.
+ cp->initialize(current, false);
+ } else {
+ assert(!current->is_humongous(), "Should be no humongous regions in compaction queue");
+ G1RePrepareClosure re_prepare(cp, current);
+ current->set_compaction_top(current->bottom());
+ current->apply_to_marked_objects(collector()->mark_bitmap(), &re_prepare);
+ }
+ }
+ cp->update();
+}
+
+void G1FullGCPrepareTask::G1CalculatePointersClosure::update_sets() {
+ // We'll recalculate total used bytes and recreate the free list
+ // at the end of the GC, so no point in updating those values here.
+ _g1h->remove_from_old_sets(0, _humongous_regions_removed);
+}
+
+bool G1FullGCPrepareTask::G1CalculatePointersClosure::freed_regions() {
+ if (_humongous_regions_removed > 0) {
+ // Free regions from dead humongous regions.
+ return true;
+ }
+
+ if (!_cp->has_regions()) {
+ // No regions in queue, so no free ones either.
+ return false;
+ }
+
+ if (_cp->current_region() != _cp->regions()->last()) {
+ // The current region used for compaction is not the last in the
+ // queue. That means there is at least one free region in the queue.
+ return true;
+ }
+
+ // No free regions in the queue.
+ return false;
+}