1 /*
2 * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24 #include "precompiled.hpp"
25 #include "jfr/leakprofiler/chains/bfsClosure.hpp"
26 #include "jfr/leakprofiler/chains/dfsClosure.hpp"
27 #include "jfr/leakprofiler/chains/edge.hpp"
28 #include "jfr/leakprofiler/chains/edgeStore.hpp"
29 #include "jfr/leakprofiler/chains/edgeQueue.hpp"
30 #include "jfr/leakprofiler/chains/jfrbitset.hpp"
31 #include "jfr/leakprofiler/utilities/granularTimer.hpp"
32 #include "jfr/leakprofiler/utilities/unifiedOopRef.inline.hpp"
33 #include "logging/log.hpp"
34 #include "memory/iterator.inline.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/access.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "utilities/align.hpp"
39
40 BFSClosure::BFSClosure(EdgeQueue* edge_queue, EdgeStore* edge_store, JFRBitSet* mark_bits) :
41 _edge_queue(edge_queue),
42 _edge_store(edge_store),
43 _mark_bits(mark_bits),
44 _current_parent(NULL),
45 _current_frontier_level(0),
46 _next_frontier_idx(0),
47 _prev_frontier_idx(0),
48 _dfs_fallback_idx(0),
49 _use_dfs(false) {
50 }
51
52 static void log_frontier_level_summary(size_t level,
53 size_t high_idx,
54 size_t low_idx,
55 size_t edge_size) {
56 const size_t nof_edges_in_frontier = high_idx - low_idx;
57 log_trace(jfr, system)(
58 "BFS front: " SIZE_FORMAT " edges: " SIZE_FORMAT " size: " SIZE_FORMAT " [KB]",
59 level,
60 nof_edges_in_frontier,
61 (nof_edges_in_frontier * edge_size) / K
62 );
63 }
64
65 void BFSClosure::log_completed_frontier() const {
66 log_frontier_level_summary(_current_frontier_level,
67 _next_frontier_idx,
68 _prev_frontier_idx,
69 _edge_queue->sizeof_edge());
70 }
71
72 void BFSClosure::log_dfs_fallback() const {
73 const size_t edge_size = _edge_queue->sizeof_edge();
74 // first complete summary for frontier in progress
75 log_frontier_level_summary(_current_frontier_level,
76 _next_frontier_idx,
77 _prev_frontier_idx,
78 edge_size);
79
80 // and then also complete the last frontier
81 log_frontier_level_summary(_current_frontier_level + 1,
82 _edge_queue->bottom(),
83 _next_frontier_idx,
84 edge_size);
85
86 // additional information about DFS fallover
87 log_trace(jfr, system)(
88 "BFS front: " SIZE_FORMAT " filled edge queue at edge: " SIZE_FORMAT,
89 _current_frontier_level,
90 _dfs_fallback_idx
91 );
92
93 const size_t nof_dfs_completed_edges = _edge_queue->bottom() - _dfs_fallback_idx;
94 log_trace(jfr, system)(
95 "DFS to complete " SIZE_FORMAT " edges size: " SIZE_FORMAT " [KB]",
96 nof_dfs_completed_edges,
97 (nof_dfs_completed_edges * edge_size) / K
98 );
99 }
100
101 void BFSClosure::process() {
102 process_root_set();
103 process_queue();
104 }
105
106 void BFSClosure::process_root_set() {
107 for (size_t idx = _edge_queue->bottom(); idx < _edge_queue->top(); ++idx) {
108 const Edge* edge = _edge_queue->element_at(idx);
109 assert(edge->parent() == NULL, "invariant");
110 process(edge->reference(), edge->pointee());
111 }
112 }
113
114 void BFSClosure::process(UnifiedOopRef reference, const oop pointee) {
115 closure_impl(reference, pointee);
116 }
117 void BFSClosure::closure_impl(UnifiedOopRef reference, const oop pointee) {
118 assert(!reference.is_null(), "invariant");
119 assert(reference.dereference() == pointee, "invariant");
120
121 if (GranularTimer::is_finished()) {
122 return;
123 }
124
125 if (_use_dfs) {
126 assert(_current_parent != NULL, "invariant");
127 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, _current_parent);
128 return;
129 }
130
131 if (!_mark_bits->is_marked(pointee)) {
132 _mark_bits->mark_obj(pointee);
133 // is the pointee a sample object?
134 if (pointee->mark().is_marked()) {
135 add_chain(reference, pointee);
136 }
137
138 // if we are processinig initial root set, don't add to queue
139 if (_current_parent != NULL) {
140 _edge_queue->add(_current_parent, reference);
141 }
142
143 if (_edge_queue->is_full()) {
144 dfs_fallback();
145 }
146 }
147 }
148
149 void BFSClosure::add_chain(UnifiedOopRef reference, const oop pointee) {
150 assert(pointee != NULL, "invariant");
151 assert(pointee->mark().is_marked(), "invariant");
152 Edge leak_edge(_current_parent, reference);
153 _edge_store->put_chain(&leak_edge, _current_parent == NULL ? 1 : _current_frontier_level + 2);
154 }
155
156 void BFSClosure::dfs_fallback() {
157 assert(_edge_queue->is_full(), "invariant");
158 _use_dfs = true;
159 _dfs_fallback_idx = _edge_queue->bottom();
160 while (!_edge_queue->is_empty()) {
161 const Edge* edge = _edge_queue->remove();
162 if (edge->pointee() != NULL) {
163 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, edge);
164 }
165 }
166 }
167
168 void BFSClosure::process_queue() {
169 assert(_current_frontier_level == 0, "invariant");
170 assert(_next_frontier_idx == 0, "invariant");
171 assert(_prev_frontier_idx == 0, "invariant");
172
173 _next_frontier_idx = _edge_queue->top();
174 while (!is_complete()) {
175 iterate(_edge_queue->remove()); // edge_queue.remove() increments bottom
176 }
177 }
178
179 void BFSClosure::step_frontier() const {
180 log_completed_frontier();
181 ++_current_frontier_level;
182 _prev_frontier_idx = _next_frontier_idx;
183 _next_frontier_idx = _edge_queue->top();
184 }
185
186 bool BFSClosure::is_complete() const {
187 if (_edge_queue->bottom() < _next_frontier_idx) {
188 return false;
189 }
190 if (_edge_queue->bottom() > _next_frontier_idx) {
191 // fallback onto DFS as part of processing the frontier
192 assert(_dfs_fallback_idx >= _prev_frontier_idx, "invariant");
193 assert(_dfs_fallback_idx < _next_frontier_idx, "invariant");
194 log_dfs_fallback();
195 return true;
196 }
197 assert(_edge_queue->bottom() == _next_frontier_idx, "invariant");
198 if (_edge_queue->is_empty()) {
199 return true;
200 }
201 step_frontier();
202 return false;
203 }
204
205 void BFSClosure::iterate(const Edge* parent) {
206 assert(parent != NULL, "invariant");
207 const oop pointee = parent->pointee();
208 assert(pointee != NULL, "invariant");
209 _current_parent = parent;
210 pointee->oop_iterate(this);
211 }
212
213 void BFSClosure::do_oop(oop* ref) {
214 assert(ref != NULL, "invariant");
215 assert(is_aligned(ref, HeapWordSize), "invariant");
216 const oop pointee = HeapAccess<AS_NO_KEEPALIVE>::oop_load(ref);
217 if (pointee != NULL) {
218 closure_impl(UnifiedOopRef::encode_in_heap(ref), pointee);
219 }
220 }
221
222 void BFSClosure::do_oop(narrowOop* ref) {
223 assert(ref != NULL, "invariant");
224 assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
225 const oop pointee = HeapAccess<AS_NO_KEEPALIVE>::oop_load(ref);
226 if (pointee != NULL) {
227 closure_impl(UnifiedOopRef::encode_in_heap(ref), pointee);
228 }
229 }
230
231 void BFSClosure::do_root(UnifiedOopRef ref) {
232 assert(ref.dereference() != NULL, "pointee must not be null");
233 if (!_edge_queue->is_full()) {
234 _edge_queue->add(NULL, ref);
235 }
236 }