--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/leakprofiler/chains/pathToGcRootsOperation.cpp Sat Aug 24 14:30:27 2019 +0200
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2019, 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/shared/collectedHeap.hpp"
+#include "jfr/leakprofiler/leakProfiler.hpp"
+#include "jfr/leakprofiler/chains/bfsClosure.hpp"
+#include "jfr/leakprofiler/chains/bitset.hpp"
+#include "jfr/leakprofiler/chains/dfsClosure.hpp"
+#include "jfr/leakprofiler/chains/edge.hpp"
+#include "jfr/leakprofiler/chains/edgeQueue.hpp"
+#include "jfr/leakprofiler/chains/edgeStore.hpp"
+#include "jfr/leakprofiler/chains/objectSampleMarker.hpp"
+#include "jfr/leakprofiler/chains/rootSetClosure.hpp"
+#include "jfr/leakprofiler/chains/edgeStore.hpp"
+#include "jfr/leakprofiler/chains/objectSampleMarker.hpp"
+#include "jfr/leakprofiler/chains/pathToGcRootsOperation.hpp"
+#include "jfr/leakprofiler/checkpoint/eventEmitter.hpp"
+#include "jfr/leakprofiler/checkpoint/objectSampleCheckpoint.hpp"
+#include "jfr/leakprofiler/sampling/objectSample.hpp"
+#include "jfr/leakprofiler/sampling/objectSampler.hpp"
+#include "jfr/leakprofiler/utilities/granularTimer.hpp"
+#include "logging/log.hpp"
+#include "memory/universe.hpp"
+
+#include "oops/oop.inline.hpp"
+#include "runtime/safepoint.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+PathToGcRootsOperation::PathToGcRootsOperation(ObjectSampler* sampler, EdgeStore* edge_store, int64_t cutoff, bool emit_all) :
+ _sampler(sampler),_edge_store(edge_store), _cutoff_ticks(cutoff), _emit_all(emit_all) {}
+
+/* The EdgeQueue is backed by directly managed virtual memory.
+ * We will attempt to dimension an initial reservation
+ * in proportion to the size of the heap (represented by heap_region).
+ * Initial memory reservation: 5% of the heap OR at least 32 Mb
+ * Commit ratio: 1 : 10 (subject to allocation granularties)
+ */
+static size_t edge_queue_memory_reservation(const MemRegion& heap_region) {
+ const size_t memory_reservation_bytes = MAX2(heap_region.byte_size() / 20, 32*M);
+ assert(memory_reservation_bytes >= (size_t)32*M, "invariant");
+ return memory_reservation_bytes;
+}
+
+static size_t edge_queue_memory_commit_size(size_t memory_reservation_bytes) {
+ const size_t memory_commit_block_size_bytes = memory_reservation_bytes / 10;
+ assert(memory_commit_block_size_bytes >= (size_t)3*M, "invariant");
+ return memory_commit_block_size_bytes;
+}
+
+static void log_edge_queue_summary(const EdgeQueue& edge_queue) {
+ log_trace(jfr, system)("EdgeQueue reserved size total: " SIZE_FORMAT " [KB]", edge_queue.reserved_size() / K);
+ log_trace(jfr, system)("EdgeQueue edges total: " SIZE_FORMAT, edge_queue.top());
+ log_trace(jfr, system)("EdgeQueue liveset total: " SIZE_FORMAT " [KB]", edge_queue.live_set() / K);
+ if (edge_queue.reserved_size() > 0) {
+ log_trace(jfr, system)("EdgeQueue commit reserve ratio: %f\n",
+ ((double)edge_queue.live_set() / (double)edge_queue.reserved_size()));
+ }
+}
+
+void PathToGcRootsOperation::doit() {
+ assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+ assert(_cutoff_ticks > 0, "invariant");
+
+ // The bitset used for marking is dimensioned as a function of the heap size
+ const MemRegion heap_region = Universe::heap()->reserved_region();
+ BitSet mark_bits(heap_region);
+
+ // The edge queue is dimensioned as a fraction of the heap size
+ const size_t edge_queue_reservation_size = edge_queue_memory_reservation(heap_region);
+ EdgeQueue edge_queue(edge_queue_reservation_size, edge_queue_memory_commit_size(edge_queue_reservation_size));
+
+ // The initialize() routines will attempt to reserve and allocate backing storage memory.
+ // Failure to accommodate will render root chain processing impossible.
+ // As a fallback on failure, just write out the existing samples, flat, without chains.
+ if (!(mark_bits.initialize() && edge_queue.initialize())) {
+ log_warning(jfr)("Unable to allocate memory for root chain processing");
+ return;
+ }
+
+ // Save the original markWord for the potential leak objects,
+ // to be restored on function exit
+ ObjectSampleMarker marker;
+ if (ObjectSampleCheckpoint::save_mark_words(_sampler, marker, _emit_all) == 0) {
+ // no valid samples to process
+ return;
+ }
+
+ // Necessary condition for attempting a root set iteration
+ Universe::heap()->ensure_parsability(false);
+
+ BFSClosure bfs(&edge_queue, _edge_store, &mark_bits);
+ RootSetClosure<BFSClosure> roots(&bfs);
+
+ GranularTimer::start(_cutoff_ticks, 1000000);
+ roots.process();
+ if (edge_queue.is_full()) {
+ // Pathological case where roots don't fit in queue
+ // Do a depth-first search, but mark roots first
+ // to avoid walking sideways over roots
+ DFSClosure::find_leaks_from_root_set(_edge_store, &mark_bits);
+ } else {
+ bfs.process();
+ }
+ GranularTimer::stop();
+ log_edge_queue_summary(edge_queue);
+
+ // Emit old objects including their reference chains as events
+ EventEmitter emitter(GranularTimer::start_time(), GranularTimer::end_time());
+ emitter.write_events(_sampler, _edge_store, _emit_all);
+}