1 /*
2 * Copyright (c) 2014, 2018, 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/bitset.hpp"
26 #include "jfr/leakprofiler/chains/bfsClosure.hpp"
27 #include "jfr/leakprofiler/chains/dfsClosure.hpp"
28 #include "jfr/leakprofiler/chains/edge.hpp"
29 #include "jfr/leakprofiler/chains/edgeStore.hpp"
30 #include "jfr/leakprofiler/chains/edgeQueue.hpp"
31 #include "jfr/leakprofiler/utilities/granularTimer.hpp"
32 #include "jfr/leakprofiler/utilities/unifiedOop.hpp"
33 #include "logging/log.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/access.inline.hpp"
36 #include "utilities/align.hpp"
37
38 BFSClosure::BFSClosure(EdgeQueue* edge_queue, EdgeStore* edge_store, BitSet* mark_bits) :
39 _edge_queue(edge_queue),
40 _edge_store(edge_store),
41 _mark_bits(mark_bits),
42 _current_parent(NULL),
43 _current_frontier_level(0),
44 _next_frontier_idx(0),
45 _prev_frontier_idx(0),
46 _dfs_fallback_idx(0),
47 _use_dfs(false) {
48 }
49
50 static void log_frontier_level_summary(size_t level,
51 size_t high_idx,
52 size_t low_idx,
53 size_t edge_size) {
54 const size_t nof_edges_in_frontier = high_idx - low_idx;
55 log_trace(jfr, system)(
56 "BFS front: " SIZE_FORMAT " edges: " SIZE_FORMAT " size: " SIZE_FORMAT " [KB]",
57 level,
58 nof_edges_in_frontier,
59 (nof_edges_in_frontier * edge_size) / K
60 );
61 }
62
63 void BFSClosure::log_completed_frontier() const {
64 log_frontier_level_summary(_current_frontier_level,
65 _next_frontier_idx,
66 _prev_frontier_idx,
67 _edge_queue->sizeof_edge());
68 }
69
70 void BFSClosure::log_dfs_fallback() const {
71 const size_t edge_size = _edge_queue->sizeof_edge();
72 // first complete summary for frontier in progress
73 log_frontier_level_summary(_current_frontier_level,
74 _next_frontier_idx,
75 _prev_frontier_idx,
76 edge_size);
77
78 // and then also complete the last frontier
79 log_frontier_level_summary(_current_frontier_level + 1,
80 _edge_queue->bottom(),
81 _next_frontier_idx,
82 edge_size);
83
84 // additional information about DFS fallover
85 log_trace(jfr, system)(
86 "BFS front: " SIZE_FORMAT " filled edge queue at edge: " SIZE_FORMAT,
87 _current_frontier_level,
88 _dfs_fallback_idx
89 );
90
91 const size_t nof_dfs_completed_edges = _edge_queue->bottom() - _dfs_fallback_idx;
92 log_trace(jfr, system)(
93 "DFS to complete " SIZE_FORMAT " edges size: " SIZE_FORMAT " [KB]",
94 nof_dfs_completed_edges,
95 (nof_dfs_completed_edges * edge_size) / K
96 );
97 }
98
99 void BFSClosure::process() {
100
101 process_root_set();
102 process_queue();
103 }
104
105 void BFSClosure::process_root_set() {
106 for (size_t idx = _edge_queue->bottom(); idx < _edge_queue->top(); ++idx) {
107 const Edge* edge = _edge_queue->element_at(idx);
108 assert(edge->parent() == NULL, "invariant");
109 process(edge->reference(), edge->pointee());
110 }
111 }
112
113 void BFSClosure::process(const oop* reference, const oop pointee) {
114 closure_impl(reference, pointee);
115 }
116 void BFSClosure::closure_impl(const oop* reference, const oop pointee) {
117 assert(reference != NULL, "invariant");
118 assert(UnifiedOop::dereference(reference) == pointee, "invariant");
119
120 if (GranularTimer::is_finished()) {
121 return;
122 }
123
124 if (_use_dfs) {
125 assert(_current_parent != NULL, "invariant");
126 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, _current_parent);
127 return;
128 }
129
130 if (!_mark_bits->is_marked(pointee)) {
131 _mark_bits->mark_obj(pointee);
132 // is the pointee a sample object?
133 if (NULL == pointee->mark()) {
134 add_chain(reference, pointee);
135 }
136
137 // if we are processinig initial root set, don't add to queue
138 if (_current_parent != NULL) {
139 assert(_current_parent->distance_to_root() == _current_frontier_level, "invariant");
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(const oop* reference, const oop pointee) {
150 assert(pointee != NULL, "invariant");
151 assert(NULL == pointee->mark(), "invariant");
152
153 const size_t length = _current_parent == NULL ? 1 : _current_parent->distance_to_root() + 2;
154 ResourceMark rm;
155 Edge* const chain = NEW_RESOURCE_ARRAY(Edge, length);
156 size_t idx = 0;
157 chain[idx++] = Edge(NULL, reference);
158 // aggregate from breadth-first search
159 const Edge* current = _current_parent;
160 while (current != NULL) {
161 chain[idx++] = Edge(NULL, current->reference());
162 current = current->parent();
163 }
164 assert(length == idx, "invariant");
165 _edge_store->add_chain(chain, length);
166 }
167
168 void BFSClosure::dfs_fallback() {
169 assert(_edge_queue->is_full(), "invariant");
170 _use_dfs = true;
171 _dfs_fallback_idx = _edge_queue->bottom();
172 while (!_edge_queue->is_empty()) {
173 const Edge* edge = _edge_queue->remove();
174 if (edge->pointee() != NULL) {
175 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, edge);
176 }
177 }
178 }
179
180 void BFSClosure::process_queue() {
181 assert(_current_frontier_level == 0, "invariant");
182 assert(_next_frontier_idx == 0, "invariant");
183 assert(_prev_frontier_idx == 0, "invariant");
184
185 _next_frontier_idx = _edge_queue->top();
186 while (!is_complete()) {
187 iterate(_edge_queue->remove()); // edge_queue.remove() increments bottom
188 }
189 }
190
191 void BFSClosure::step_frontier() const {
192 log_completed_frontier();
193 ++_current_frontier_level;
194 _prev_frontier_idx = _next_frontier_idx;
195 _next_frontier_idx = _edge_queue->top();
196 }
197
198 bool BFSClosure::is_complete() const {
199 if (_edge_queue->bottom() < _next_frontier_idx) {
200 return false;
201 }
202 if (_edge_queue->bottom() > _next_frontier_idx) {
203 // fallback onto DFS as part of processing the frontier
204 assert(_dfs_fallback_idx >= _prev_frontier_idx, "invariant");
205 assert(_dfs_fallback_idx < _next_frontier_idx, "invariant");
206 log_dfs_fallback();
207 return true;
208 }
209 assert(_edge_queue->bottom() == _next_frontier_idx, "invariant");
210 if (_edge_queue->is_empty()) {
211 return true;
212 }
213 step_frontier();
214 return false;
215 }
216
217 void BFSClosure::iterate(const Edge* parent) {
218 assert(parent != NULL, "invariant");
219 const oop pointee = parent->pointee();
220 assert(pointee != NULL, "invariant");
221 _current_parent = parent;
222 pointee->oop_iterate(this);
223 }
224
225 void BFSClosure::do_oop(oop* ref) {
226 assert(ref != NULL, "invariant");
227 assert(is_aligned(ref, HeapWordSize), "invariant");
228 const oop pointee = *ref;
229 if (pointee != NULL) {
230 closure_impl(ref, pointee);
231 }
232 }
233
234 void BFSClosure::do_oop(narrowOop* ref) {
235 assert(ref != NULL, "invariant");
236 assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
237 const oop pointee = RawAccess<>::oop_load(ref);
238 if (pointee != NULL) {
239 closure_impl(UnifiedOop::encode(ref), pointee);
240 }
241 }