1 /*
2 * Copyright (c) 2012, 2014, 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 char nmt_option[64];
51 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
52 if (os::getenv(buf, nmt_option, sizeof(nmt_option))) {
53 if (strcmp(nmt_option, "summary") == 0) {
54 level = NMT_summary;
55 } else if (strcmp(nmt_option, "detail") == 0) {
56 #if PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
57 level = NMT_detail;
58 #else
59 level = NMT_summary;
60 #endif // PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
61 } else if (strcmp(nmt_option, "off") != 0) {
62 // The option value is invalid
63 _is_nmt_env_valid = false;
64 }
65
66 // Remove the environment variable to avoid leaking to child processes
67 os::unsetenv(buf);
68 }
69
70 // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
71 // but it is benign, the results are the same.
72 ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
73
74 if (!MallocTracker::initialize(level) ||
75 !VirtualMemoryTracker::initialize(level)) {
76 level = NMT_off;
77 }
78 return level;
79 }
80
81 void MemTracker::init() {
82 NMT_TrackingLevel level = tracking_level();
83 if (level >= NMT_summary) {
84 if (!VirtualMemoryTracker::late_initialize(level)) {
85 shutdown();
86 return;
87 }
88 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
89 // Already OOM. It is unlikely, but still have to handle it.
90 if (_query_lock == NULL) {
91 shutdown();
92 }
93 }
94 }
95
96 bool MemTracker::check_launcher_nmt_support(const char* value) {
97 if (strcmp(value, "=detail") == 0) {
98 #if !PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
99 jio_fprintf(defaultStream::error_stream(),
100 "NMT detail is not supported on this platform. Using NMT summary instead.\n");
101 if (MemTracker::tracking_level() != NMT_summary) {
102 return false;
103 }
104 #else
105 if (MemTracker::tracking_level() != NMT_detail) {
106 return false;
107 }
108 #endif
109 } else if (strcmp(value, "=summary") == 0) {
110 if (MemTracker::tracking_level() != NMT_summary) {
111 return false;
112 }
113 } else if (strcmp(value, "=off") == 0) {
114 if (MemTracker::tracking_level() != NMT_off) {
115 return false;
116 }
117 } else {
118 _is_nmt_env_valid = false;
119 }
120
121 return true;
122 }
123
124 bool MemTracker::verify_nmt_option() {
125 return _is_nmt_env_valid;
126 }
127
128 void* MemTracker::malloc_base(void* memblock) {
129 return MallocTracker::get_base(memblock);
130 }
131
132 void Tracker::record(address addr, size_t size) {
133 if (MemTracker::tracking_level() < NMT_summary) return;
134 switch(_type) {
135 case uncommit:
136 VirtualMemoryTracker::remove_uncommitted_region(addr, size);
137 break;
138 case release:
139 VirtualMemoryTracker::remove_released_region(addr, size);
140 break;
141 default:
142 ShouldNotReachHere();
143 }
144 }
145
146
147 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
148 void MemTracker::shutdown() {
149 // We can only shutdown NMT to minimal tracking level if it is ever on.
150 if (tracking_level () > NMT_minimal) {
151 transition_to(NMT_minimal);
152 }
153 }
154
155 bool MemTracker::transition_to(NMT_TrackingLevel level) {
156 NMT_TrackingLevel current_level = tracking_level();
157
158 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
159
160 if (current_level == level) {
161 return true;
162 } else if (current_level > level) {
163 // Downgrade tracking level, we want to lower the tracking level first
164 _tracking_level = level;
165 // Make _tracking_level visible immediately.
166 OrderAccess::fence();
167 VirtualMemoryTracker::transition(current_level, level);
168 MallocTracker::transition(current_level, level);
169 } else {
170 // Upgrading tracking level is not supported and has never been supported.
171 // Allocating and deallocating malloc tracking structures is not thread safe and
172 // leads to inconsistencies unless a lot coarser locks are added.
173 }
174 return true;
175 }
176
177 void MemTracker::report(bool summary_only, outputStream* output) {
178 assert(output != NULL, "No output stream");
179 MemBaseline baseline;
180 if (baseline.baseline(summary_only)) {
181 if (summary_only) {
182 MemSummaryReporter rpt(baseline, output);
183 rpt.report();
184 } else {
185 MemDetailReporter rpt(baseline, output);
186 rpt.report();
187 }
188 }
189 }
190
191 // This is a walker to gather malloc site hashtable statistics,
192 // the result is used for tuning.
193 class StatisticsWalker : public MallocSiteWalker {
194 private:
195 enum Threshold {
196 // aggregates statistics over this threshold into one
197 // line item.
198 report_threshold = 20
199 };
200
201 private:
202 // Number of allocation sites that have all memory freed
203 int _empty_entries;
204 // Total number of allocation sites, include empty sites
205 int _total_entries;
206 // Number of captured call stack distribution
207 int _stack_depth_distribution[NMT_TrackingStackDepth];
208 // Hash distribution
209 int _hash_distribution[report_threshold];
210 // Number of hash buckets that have entries over the threshold
211 int _bucket_over_threshold;
212
213 // The hash bucket that walker is currently walking
214 int _current_hash_bucket;
215 // The length of current hash bucket
216 int _current_bucket_length;
217 // Number of hash buckets that are not empty
218 int _used_buckets;
219 // Longest hash bucket length
220 int _longest_bucket_length;
221
222 public:
223 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
224 int index = 0;
225 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
226 _stack_depth_distribution[index] = 0;
227 }
228 for (index = 0; index < report_threshold; index ++) {
229 _hash_distribution[index] = 0;
230 }
231 _bucket_over_threshold = 0;
232 _longest_bucket_length = 0;
233 _current_hash_bucket = -1;
234 _current_bucket_length = 0;
235 _used_buckets = 0;
236 }
237
238 virtual bool do_malloc_site(const MallocSite* e) {
239 if (e->size() == 0) _empty_entries ++;
240 _total_entries ++;
241
242 // stack depth distrubution
243 int frames = e->call_stack()->frames();
244 _stack_depth_distribution[frames - 1] ++;
245
246 // hash distribution
247 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
248 if (_current_hash_bucket == -1) {
249 _current_hash_bucket = hash_bucket;
250 _current_bucket_length = 1;
251 } else if (_current_hash_bucket == hash_bucket) {
252 _current_bucket_length ++;
253 } else {
254 record_bucket_length(_current_bucket_length);
255 _current_hash_bucket = hash_bucket;
256 _current_bucket_length = 1;
257 }
258 return true;
259 }
260
261 // walk completed
262 void completed() {
263 record_bucket_length(_current_bucket_length);
264 }
265
266 void report_statistics(outputStream* out) {
267 int index;
268 out->print_cr("Malloc allocation site table:");
269 out->print_cr("\tTotal entries: %d", _total_entries);
270 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
271 out->print_cr(" ");
272 out->print_cr("Hash distribution:");
273 if (_used_buckets < MallocSiteTable::hash_buckets()) {
274 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
275 }
276 for (index = 0; index < report_threshold; index ++) {
277 if (_hash_distribution[index] != 0) {
278 if (index == 0) {
279 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
280 } else if (index < 9) { // single digit
281 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
282 } else {
283 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
284 }
285 }
286 }
287 if (_bucket_over_threshold > 0) {
288 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
289 }
290 out->print_cr("most entries: %d", _longest_bucket_length);
291 out->print_cr(" ");
292 out->print_cr("Call stack depth distribution:");
293 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
294 if (_stack_depth_distribution[index] > 0) {
295 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
296 }
297 }
298 }
299
300 private:
301 void record_bucket_length(int length) {
302 _used_buckets ++;
303 if (length <= report_threshold) {
304 _hash_distribution[length - 1] ++;
305 } else {
306 _bucket_over_threshold ++;
307 }
308 _longest_bucket_length = MAX2(_longest_bucket_length, length);
309 }
310 };
311
312
313 void MemTracker::tuning_statistics(outputStream* out) {
314 // NMT statistics
315 StatisticsWalker walker;
316 MallocSiteTable::walk_malloc_site(&walker);
317 walker.completed();
318
319 out->print_cr("Native Memory Tracking Statistics:");
320 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
321 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
322 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
323 out->print_cr(" ");
324 walker.report_statistics(out);
325 }
326