1 /*
2 * Copyright (c) 2014, 2019, 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 "memory/iterator.inline.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "utilities/align.hpp"
37
BFSClosure(EdgeQueue * edge_queue,EdgeStore * edge_store,BitSet * mark_bits)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
log_frontier_level_summary(size_t level,size_t high_idx,size_t low_idx,size_t edge_size)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 if (LogJFR && Verbose) tty->print_cr(
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
log_completed_frontier() const63 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
log_dfs_fallback() const70 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 if (LogJFR && Verbose) tty->print_cr(
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 if (LogJFR && Verbose) tty->print_cr(
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
process()99 void BFSClosure::process() {
100 process_root_set();
101 process_queue();
102 }
103
process_root_set()104 void BFSClosure::process_root_set() {
105 for (size_t idx = _edge_queue->bottom(); idx < _edge_queue->top(); ++idx) {
106 const Edge* edge = _edge_queue->element_at(idx);
107 assert(edge->parent() == NULL, "invariant");
108 process(edge->reference(), edge->pointee());
109 }
110 }
111
process(const oop * reference,const oop pointee)112 void BFSClosure::process(const oop* reference, const oop pointee) {
113 closure_impl(reference, pointee);
114 }
closure_impl(const oop * reference,const oop pointee)115 void BFSClosure::closure_impl(const oop* reference, const oop pointee) {
116 assert(reference != NULL, "invariant");
117 assert(UnifiedOop::dereference(reference) == pointee, "invariant");
118
119 if (GranularTimer::is_finished()) {
120 return;
121 }
122
123 if (_use_dfs) {
124 assert(_current_parent != NULL, "invariant");
125 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, _current_parent);
126 return;
127 }
128
129 if (!_mark_bits->is_marked(pointee)) {
130 _mark_bits->mark_obj(pointee);
131 // is the pointee a sample object?
132 if (NULL == pointee->mark()) {
133 add_chain(reference, pointee);
134 }
135
136 // if we are processinig initial root set, don't add to queue
137 if (_current_parent != NULL) {
138 _edge_queue->add(_current_parent, reference);
139 }
140
141 if (_edge_queue->is_full()) {
142 dfs_fallback();
143 }
144 }
145 }
146
add_chain(const oop * reference,const oop pointee)147 void BFSClosure::add_chain(const oop* reference, const oop pointee) {
148 assert(pointee != NULL, "invariant");
149 assert(NULL == pointee->mark(), "invariant");
150 Edge leak_edge(_current_parent, reference);
151 _edge_store->put_chain(&leak_edge, _current_parent == NULL ? 1 : _current_frontier_level + 2);
152 }
153
dfs_fallback()154 void BFSClosure::dfs_fallback() {
155 assert(_edge_queue->is_full(), "invariant");
156 _use_dfs = true;
157 _dfs_fallback_idx = _edge_queue->bottom();
158 while (!_edge_queue->is_empty()) {
159 const Edge* edge = _edge_queue->remove();
160 if (edge->pointee() != NULL) {
161 DFSClosure::find_leaks_from_edge(_edge_store, _mark_bits, edge);
162 }
163 }
164 }
165
process_queue()166 void BFSClosure::process_queue() {
167 assert(_current_frontier_level == 0, "invariant");
168 assert(_next_frontier_idx == 0, "invariant");
169 assert(_prev_frontier_idx == 0, "invariant");
170
171 _next_frontier_idx = _edge_queue->top();
172 while (!is_complete()) {
173 iterate(_edge_queue->remove()); // edge_queue.remove() increments bottom
174 }
175 }
176
step_frontier() const177 void BFSClosure::step_frontier() const {
178 log_completed_frontier();
179 ++_current_frontier_level;
180 _prev_frontier_idx = _next_frontier_idx;
181 _next_frontier_idx = _edge_queue->top();
182 }
183
is_complete() const184 bool BFSClosure::is_complete() const {
185 if (_edge_queue->bottom() < _next_frontier_idx) {
186 return false;
187 }
188 if (_edge_queue->bottom() > _next_frontier_idx) {
189 // fallback onto DFS as part of processing the frontier
190 assert(_dfs_fallback_idx >= _prev_frontier_idx, "invariant");
191 assert(_dfs_fallback_idx < _next_frontier_idx, "invariant");
192 log_dfs_fallback();
193 return true;
194 }
195 assert(_edge_queue->bottom() == _next_frontier_idx, "invariant");
196 if (_edge_queue->is_empty()) {
197 return true;
198 }
199 step_frontier();
200 return false;
201 }
202
iterate(const Edge * parent)203 void BFSClosure::iterate(const Edge* parent) {
204 assert(parent != NULL, "invariant");
205 const oop pointee = parent->pointee();
206 assert(pointee != NULL, "invariant");
207 _current_parent = parent;
208 pointee->oop_iterate(this);
209 }
210
do_oop(oop * ref)211 void BFSClosure::do_oop(oop* ref) {
212 assert(ref != NULL, "invariant");
213 assert(is_aligned(ref, HeapWordSize), "invariant");
214 const oop pointee = *ref;
215 if (pointee != NULL) {
216 closure_impl(ref, pointee);
217 }
218 }
219
do_oop(narrowOop * ref)220 void BFSClosure::do_oop(narrowOop* ref) {
221 assert(ref != NULL, "invariant");
222 assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
223 const oop pointee = oopDesc::load_decode_heap_oop(ref);
224 if (pointee != NULL) {
225 closure_impl(UnifiedOop::encode(ref), pointee);
226 }
227 }
228
do_root(const oop * ref)229 void BFSClosure::do_root(const oop* ref) {
230 assert(ref != NULL, "invariant");
231 if (!_edge_queue->is_full()) {
232 _edge_queue->add(NULL, ref);
233 }
234 }
235