1 /*
2 * Copyright (c) 2012, 2017, 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 "jvm.h"
26
27 #include "runtime/mutex.hpp"
28 #include "services/memBaseline.hpp"
29 #include "services/memReporter.hpp"
30 #include "services/mallocTracker.inline.hpp"
31 #include "services/memTracker.hpp"
32 #include "utilities/defaultStream.hpp"
33
34 #ifdef SOLARIS
35 volatile bool NMT_stack_walkable = false;
36 #else
37 volatile bool NMT_stack_walkable = true;
38 #endif
39
40 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
41 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
42
43 MemBaseline MemTracker::_baseline;
44 Mutex* MemTracker::_query_lock = NULL;
45 bool MemTracker::_is_nmt_env_valid = true;
46
47
48 NMT_TrackingLevel MemTracker::init_tracking_level() {
49 NMT_TrackingLevel level = NMT_off;
50 char buf[64];
51 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
52 const char *nmt_option = ::getenv(buf);
53 if (nmt_option != NULL) {
54 if (strcmp(nmt_option, "summary") == 0) {
55 level = NMT_summary;
56 } else if (strcmp(nmt_option, "detail") == 0) {
57 level = NMT_detail;
58 } else if (strcmp(nmt_option, "off") != 0) {
59 // The option value is invalid
60 _is_nmt_env_valid = false;
61 }
62
63 // Remove the environment variable to avoid leaking to child processes
64 os::unsetenv(buf);
65 }
66
67 // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
68 // but it is benign, the results are the same.
69 ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
70
71 if (!MallocTracker::initialize(level) ||
72 !VirtualMemoryTracker::initialize(level)) {
73 level = NMT_off;
74 }
75 return level;
76 }
77
78 void MemTracker::init() {
79 NMT_TrackingLevel level = tracking_level();
80 if (level >= NMT_summary) {
81 if (!VirtualMemoryTracker::late_initialize(level)) {
82 shutdown();
83 return;
84 }
85 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
86 // Already OOM. It is unlikely, but still have to handle it.
87 if (_query_lock == NULL) {
88 shutdown();
89 }
90 }
91 }
92
93 bool MemTracker::check_launcher_nmt_support(const char* value) {
94 if (strcmp(value, "=detail") == 0) {
95 if (MemTracker::tracking_level() != NMT_detail) {
96 return false;
97 }
98 } else if (strcmp(value, "=summary") == 0) {
99 if (MemTracker::tracking_level() != NMT_summary) {
100 return false;
101 }
102 } else if (strcmp(value, "=off") == 0) {
103 if (MemTracker::tracking_level() != NMT_off) {
104 return false;
105 }
106 } else {
107 _is_nmt_env_valid = false;
108 }
109
110 return true;
111 }
112
113 bool MemTracker::verify_nmt_option() {
114 return _is_nmt_env_valid;
115 }
116
117 void* MemTracker::malloc_base(void* memblock) {
118 return MallocTracker::get_base(memblock);
119 }
120
121 void Tracker::record(address addr, size_t size) {
122 if (MemTracker::tracking_level() < NMT_summary) return;
123 switch(_type) {
124 case uncommit:
125 VirtualMemoryTracker::remove_uncommitted_region(addr, size);
126 break;
127 case release:
128 VirtualMemoryTracker::remove_released_region(addr, size);
129 break;
130 default:
131 ShouldNotReachHere();
132 }
133 }
134
135
136 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
137 void MemTracker::shutdown() {
138 // We can only shutdown NMT to minimal tracking level if it is ever on.
139 if (tracking_level () > NMT_minimal) {
140 transition_to(NMT_minimal);
141 }
142 }
143
144 bool MemTracker::transition_to(NMT_TrackingLevel level) {
145 NMT_TrackingLevel current_level = tracking_level();
146
147 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
148
149 if (current_level == level) {
150 return true;
151 } else if (current_level > level) {
152 // Downgrade tracking level, we want to lower the tracking level first
153 _tracking_level = level;
154 // Make _tracking_level visible immediately.
155 OrderAccess::fence();
156 VirtualMemoryTracker::transition(current_level, level);
157 MallocTracker::transition(current_level, level);
158 } else {
159 // Upgrading tracking level is not supported and has never been supported.
160 // Allocating and deallocating malloc tracking structures is not thread safe and
161 // leads to inconsistencies unless a lot coarser locks are added.
162 }
163 return true;
164 }
165
166 void MemTracker::report(bool summary_only, outputStream* output) {
167 assert(output != NULL, "No output stream");
168 MemBaseline baseline;
169 if (baseline.baseline(summary_only)) {
170 if (summary_only) {
171 MemSummaryReporter rpt(baseline, output);
172 rpt.report();
173 } else {
174 MemDetailReporter rpt(baseline, output);
175 rpt.report();
176 }
177 }
178 }
179
180 // This is a walker to gather malloc site hashtable statistics,
181 // the result is used for tuning.
182 class StatisticsWalker : public MallocSiteWalker {
183 private:
184 enum Threshold {
185 // aggregates statistics over this threshold into one
186 // line item.
187 report_threshold = 20
188 };
189
190 private:
191 // Number of allocation sites that have all memory freed
192 int _empty_entries;
193 // Total number of allocation sites, include empty sites
194 int _total_entries;
195 // Number of captured call stack distribution
196 int _stack_depth_distribution[NMT_TrackingStackDepth];
197 // Hash distribution
198 int _hash_distribution[report_threshold];
199 // Number of hash buckets that have entries over the threshold
200 int _bucket_over_threshold;
201
202 // The hash bucket that walker is currently walking
203 int _current_hash_bucket;
204 // The length of current hash bucket
205 int _current_bucket_length;
206 // Number of hash buckets that are not empty
207 int _used_buckets;
208 // Longest hash bucket length
209 int _longest_bucket_length;
210
211 public:
212 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
213 int index = 0;
214 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
215 _stack_depth_distribution[index] = 0;
216 }
217 for (index = 0; index < report_threshold; index ++) {
218 _hash_distribution[index] = 0;
219 }
220 _bucket_over_threshold = 0;
221 _longest_bucket_length = 0;
222 _current_hash_bucket = -1;
223 _current_bucket_length = 0;
224 _used_buckets = 0;
225 }
226
227 virtual bool do_malloc_site(const MallocSite* e) {
228 if (e->size() == 0) _empty_entries ++;
229 _total_entries ++;
230
231 // stack depth distrubution
232 int frames = e->call_stack()->frames();
233 _stack_depth_distribution[frames - 1] ++;
234
235 // hash distribution
236 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
237 if (_current_hash_bucket == -1) {
238 _current_hash_bucket = hash_bucket;
239 _current_bucket_length = 1;
240 } else if (_current_hash_bucket == hash_bucket) {
241 _current_bucket_length ++;
242 } else {
243 record_bucket_length(_current_bucket_length);
244 _current_hash_bucket = hash_bucket;
245 _current_bucket_length = 1;
246 }
247 return true;
248 }
249
250 // walk completed
251 void completed() {
252 record_bucket_length(_current_bucket_length);
253 }
254
255 void report_statistics(outputStream* out) {
256 int index;
257 out->print_cr("Malloc allocation site table:");
258 out->print_cr("\tTotal entries: %d", _total_entries);
259 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
260 out->print_cr(" ");
261 out->print_cr("Hash distribution:");
262 if (_used_buckets < MallocSiteTable::hash_buckets()) {
263 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
264 }
265 for (index = 0; index < report_threshold; index ++) {
266 if (_hash_distribution[index] != 0) {
267 if (index == 0) {
268 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
269 } else if (index < 9) { // single digit
270 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
271 } else {
272 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
273 }
274 }
275 }
276 if (_bucket_over_threshold > 0) {
277 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
278 }
279 out->print_cr("most entries: %d", _longest_bucket_length);
280 out->print_cr(" ");
281 out->print_cr("Call stack depth distribution:");
282 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
283 if (_stack_depth_distribution[index] > 0) {
284 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
285 }
286 }
287 }
288
289 private:
290 void record_bucket_length(int length) {
291 _used_buckets ++;
292 if (length <= report_threshold) {
293 _hash_distribution[length - 1] ++;
294 } else {
295 _bucket_over_threshold ++;
296 }
297 _longest_bucket_length = MAX2(_longest_bucket_length, length);
298 }
299 };
300
301
302 void MemTracker::tuning_statistics(outputStream* out) {
303 // NMT statistics
304 StatisticsWalker walker;
305 MallocSiteTable::walk_malloc_site(&walker);
306 walker.completed();
307
308 out->print_cr("Native Memory Tracking Statistics:");
309 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
310 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
311 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
312 out->print_cr(" ");
313 walker.report_statistics(out);
314 }