1 /*
2 * Copyright (c) 2012, 2015, 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
26 #include "runtime/mutex.hpp"
27 #include "services/memBaseline.hpp"
28 #include "services/memReporter.hpp"
29 #include "services/mallocTracker.inline.hpp"
30 #include "services/memTracker.hpp"
31 #include "utilities/defaultStream.hpp"
32
33 #ifdef SOLARIS
34 volatile bool NMT_stack_walkable = false;
35 #else
36 volatile bool NMT_stack_walkable = true;
37 #endif
38
39 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
40 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
41
42 MemBaseline MemTracker::_baseline;
43 Mutex* MemTracker::_query_lock = NULL;
44 bool MemTracker::_is_nmt_env_valid = true;
45
46
47 NMT_TrackingLevel MemTracker::init_tracking_level() {
48 NMT_TrackingLevel level = NMT_off;
49 char buf[64];
50 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
51 const char *nmt_option = ::getenv(buf);
52 if (nmt_option != NULL) {
53 if (strcmp(nmt_option, "summary") == 0) {
54 level = NMT_summary;
55 } else if (strcmp(nmt_option, "detail") == 0) {
56 level = NMT_detail;
57 } else if (strcmp(nmt_option, "off") != 0) {
58 // The option value is invalid
59 _is_nmt_env_valid = false;
60 }
61
62 // Remove the environment variable to avoid leaking to child processes
63 os::unsetenv(buf);
64 }
65
66 // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
67 // but it is benign, the results are the same.
68 ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
69
70 if (!MallocTracker::initialize(level) ||
71 !VirtualMemoryTracker::initialize(level)) {
72 level = NMT_off;
73 }
74 return level;
75 }
76
77 void MemTracker::init() {
78 NMT_TrackingLevel level = tracking_level();
79 if (level >= NMT_summary) {
80 if (!VirtualMemoryTracker::late_initialize(level)) {
81 shutdown();
82 return;
83 }
84 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
85 // Already OOM. It is unlikely, but still have to handle it.
86 if (_query_lock == NULL) {
87 shutdown();
88 }
89 }
90 }
91
92 bool MemTracker::check_launcher_nmt_support(const char* value) {
93 if (strcmp(value, "=detail") == 0) {
94 if (MemTracker::tracking_level() != NMT_detail) {
95 return false;
96 }
97 } else if (strcmp(value, "=summary") == 0) {
98 if (MemTracker::tracking_level() != NMT_summary) {
99 return false;
100 }
101 } else if (strcmp(value, "=off") == 0) {
102 if (MemTracker::tracking_level() != NMT_off) {
103 return false;
104 }
105 } else {
106 _is_nmt_env_valid = false;
107 }
108
109 return true;
110 }
111
112 bool MemTracker::verify_nmt_option() {
113 return _is_nmt_env_valid;
114 }
115
116 void* MemTracker::malloc_base(void* memblock) {
117 return MallocTracker::get_base(memblock);
118 }
119
120 void Tracker::record(address addr, size_t size) {
121 if (MemTracker::tracking_level() < NMT_summary) return;
122 switch(_type) {
123 case uncommit:
124 VirtualMemoryTracker::remove_uncommitted_region(addr, size);
125 break;
126 case release:
127 VirtualMemoryTracker::remove_released_region(addr, size);
128 break;
129 default:
130 ShouldNotReachHere();
131 }
132 }
133
134
135 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
136 void MemTracker::shutdown() {
137 // We can only shutdown NMT to minimal tracking level if it is ever on.
138 if (tracking_level () > NMT_minimal) {
139 transition_to(NMT_minimal);
140 }
141 }
142
143 bool MemTracker::transition_to(NMT_TrackingLevel level) {
144 NMT_TrackingLevel current_level = tracking_level();
145
146 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
147
148 if (current_level == level) {
149 return true;
150 } else if (current_level > level) {
151 // Downgrade tracking level, we want to lower the tracking level first
152 _tracking_level = level;
153 // Make _tracking_level visible immediately.
154 OrderAccess::fence();
155 VirtualMemoryTracker::transition(current_level, level);
156 MallocTracker::transition(current_level, level);
157 } else {
158 // Upgrading tracking level is not supported and has never been supported.
159 // Allocating and deallocating malloc tracking structures is not thread safe and
160 // leads to inconsistencies unless a lot coarser locks are added.
161 }
162 return true;
163 }
164
165 void MemTracker::report(bool summary_only, outputStream* output) {
166 assert(output != NULL, "No output stream");
167 MemBaseline baseline;
168 if (baseline.baseline(summary_only)) {
169 if (summary_only) {
170 MemSummaryReporter rpt(baseline, output);
171 rpt.report();
172 } else {
173 MemDetailReporter rpt(baseline, output);
174 rpt.report();
175 }
176 }
177 }
178
179 // This is a walker to gather malloc site hashtable statistics,
180 // the result is used for tuning.
181 class StatisticsWalker : public MallocSiteWalker {
182 private:
183 enum Threshold {
184 // aggregates statistics over this threshold into one
185 // line item.
186 report_threshold = 20
187 };
188
189 private:
190 // Number of allocation sites that have all memory freed
191 int _empty_entries;
192 // Total number of allocation sites, include empty sites
193 int _total_entries;
194 // Number of captured call stack distribution
195 int _stack_depth_distribution[NMT_TrackingStackDepth];
196 // Hash distribution
197 int _hash_distribution[report_threshold];
198 // Number of hash buckets that have entries over the threshold
199 int _bucket_over_threshold;
200
201 // The hash bucket that walker is currently walking
202 int _current_hash_bucket;
203 // The length of current hash bucket
204 int _current_bucket_length;
205 // Number of hash buckets that are not empty
206 int _used_buckets;
207 // Longest hash bucket length
208 int _longest_bucket_length;
209
210 public:
211 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
212 int index = 0;
213 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
214 _stack_depth_distribution[index] = 0;
215 }
216 for (index = 0; index < report_threshold; index ++) {
217 _hash_distribution[index] = 0;
218 }
219 _bucket_over_threshold = 0;
220 _longest_bucket_length = 0;
221 _current_hash_bucket = -1;
222 _current_bucket_length = 0;
223 _used_buckets = 0;
224 }
225
226 virtual bool do_malloc_site(const MallocSite* e) {
227 if (e->size() == 0) _empty_entries ++;
228 _total_entries ++;
229
230 // stack depth distrubution
231 int frames = e->call_stack()->frames();
232 _stack_depth_distribution[frames - 1] ++;
233
234 // hash distribution
235 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
236 if (_current_hash_bucket == -1) {
237 _current_hash_bucket = hash_bucket;
238 _current_bucket_length = 1;
239 } else if (_current_hash_bucket == hash_bucket) {
240 _current_bucket_length ++;
241 } else {
242 record_bucket_length(_current_bucket_length);
243 _current_hash_bucket = hash_bucket;
244 _current_bucket_length = 1;
245 }
246 return true;
247 }
248
249 // walk completed
250 void completed() {
251 record_bucket_length(_current_bucket_length);
252 }
253
254 void report_statistics(outputStream* out) {
255 int index;
256 out->print_cr("Malloc allocation site table:");
257 out->print_cr("\tTotal entries: %d", _total_entries);
258 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
259 out->print_cr(" ");
260 out->print_cr("Hash distribution:");
261 if (_used_buckets < MallocSiteTable::hash_buckets()) {
262 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
263 }
264 for (index = 0; index < report_threshold; index ++) {
265 if (_hash_distribution[index] != 0) {
266 if (index == 0) {
267 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
268 } else if (index < 9) { // single digit
269 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
270 } else {
271 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
272 }
273 }
274 }
275 if (_bucket_over_threshold > 0) {
276 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
277 }
278 out->print_cr("most entries: %d", _longest_bucket_length);
279 out->print_cr(" ");
280 out->print_cr("Call stack depth distribution:");
281 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
282 if (_stack_depth_distribution[index] > 0) {
283 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
284 }
285 }
286 }
287
288 private:
289 void record_bucket_length(int length) {
290 _used_buckets ++;
291 if (length <= report_threshold) {
292 _hash_distribution[length - 1] ++;
293 } else {
294 _bucket_over_threshold ++;
295 }
296 _longest_bucket_length = MAX2(_longest_bucket_length, length);
297 }
298 };
299
300
301 void MemTracker::tuning_statistics(outputStream* out) {
302 // NMT statistics
303 StatisticsWalker walker;
304 MallocSiteTable::walk_malloc_site(&walker);
305 walker.completed();
306
307 out->print_cr("Native Memory Tracking Statistics:");
308 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
309 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
310 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
311 out->print_cr(" ");
312 walker.report_statistics(out);
313 }