1 /*
2 * Copyright (c) 2012, 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 "jvm.h"
26
27 #include "runtime/orderAccess.hpp"
28 #include "runtime/vmThread.hpp"
29 #include "runtime/vmOperations.hpp"
30 #include "services/memBaseline.hpp"
31 #include "services/memReporter.hpp"
32 #include "services/mallocTracker.inline.hpp"
33 #include "services/memTracker.hpp"
34 #include "services/threadStackTracker.hpp"
35 #include "utilities/debug.hpp"
36 #include "utilities/defaultStream.hpp"
37 #include "utilities/vmError.hpp"
38
39 #ifdef _WINDOWS
40 #include <windows.h>
41 #endif
42
43 #ifdef SOLARIS
44 volatile bool NMT_stack_walkable = false;
45 #else
46 volatile bool NMT_stack_walkable = true;
47 #endif
48
49 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
50 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
51
52 MemBaseline MemTracker::_baseline;
53 bool MemTracker::_is_nmt_env_valid = true;
54
55 static const size_t buffer_size = 64;
56
57 NMT_TrackingLevel MemTracker::init_tracking_level() {
58 // Memory type is encoded into tracking header as a byte field,
59 // make sure that we don't overflow it.
60 STATIC_ASSERT(mt_number_of_types <= max_jubyte);
61
62 char nmt_env_variable[buffer_size];
63 jio_snprintf(nmt_env_variable, sizeof(nmt_env_variable), "NMT_LEVEL_%d", os::current_process_id());
64 const char* nmt_env_value;
65 #ifdef _WINDOWS
66 // Read the NMT environment variable from the PEB instead of the CRT
67 char value[buffer_size];
68 nmt_env_value = GetEnvironmentVariable(nmt_env_variable, value, (DWORD)sizeof(value)) != 0 ? value : NULL;
69 #else
70 nmt_env_value = ::getenv(nmt_env_variable);
71 #endif
72 NMT_TrackingLevel level = NMT_off;
73 if (nmt_env_value != NULL) {
74 if (strcmp(nmt_env_value, "summary") == 0) {
75 level = NMT_summary;
76 } else if (strcmp(nmt_env_value, "detail") == 0) {
77 level = NMT_detail;
78 } else if (strcmp(nmt_env_value, "off") != 0) {
79 // The value of the environment variable is invalid
80 _is_nmt_env_valid = false;
81 }
82 // Remove the environment variable to avoid leaking to child processes
83 os::unsetenv(nmt_env_variable);
84 }
85
86 if (!MallocTracker::initialize(level) ||
87 !VirtualMemoryTracker::initialize(level)) {
88 level = NMT_off;
89 }
90 return level;
91 }
92
93 void MemTracker::init() {
94 NMT_TrackingLevel level = tracking_level();
95 if (level >= NMT_summary) {
96 if (!VirtualMemoryTracker::late_initialize(level) ||
97 !ThreadStackTracker::late_initialize(level)) {
98 shutdown();
99 return;
100 }
101 }
102 }
103
104 bool MemTracker::check_launcher_nmt_support(const char* value) {
105 if (strcmp(value, "=detail") == 0) {
106 if (MemTracker::tracking_level() != NMT_detail) {
107 return false;
108 }
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 ThreadStackTracker::transition(current_level, level);
170 } else {
171 // Upgrading tracking level is not supported and has never been supported.
172 // Allocating and deallocating malloc tracking structures is not thread safe and
173 // leads to inconsistencies unless a lot coarser locks are added.
174 }
175 return true;
176 }
177
178
179 static volatile bool g_final_report_did_run = false;
180 void MemTracker::final_report(outputStream* output) {
181 // This function is called during both error reporting and normal VM exit.
182 // However, it should only ever run once. E.g. if the VM crashes after
183 // printing the final report during normal VM exit, it should not print
184 // the final report again. In addition, it should be guarded from
185 // recursive calls in case NMT reporting itself crashes.
186 if (Atomic::cmpxchg(true, &g_final_report_did_run, false) == false) {
187 NMT_TrackingLevel level = tracking_level();
188 if (level >= NMT_summary) {
189 report(level == NMT_summary, output);
190 }
191 }
192 }
193
194 void MemTracker::report(bool summary_only, outputStream* output) {
195 assert(output != NULL, "No output stream");
196 MemBaseline baseline;
197 if (baseline.baseline(summary_only)) {
198 if (summary_only) {
199 MemSummaryReporter rpt(baseline, output);
200 rpt.report();
201 } else {
202 MemDetailReporter rpt(baseline, output);
203 rpt.report();
204 output->print("Metaspace:");
205 // The basic metaspace report avoids any locking and should be safe to
206 // be called at any time.
207 MetaspaceUtils::print_basic_report(output, K);
208 }
209 }
210 }
211
212 // This is a walker to gather malloc site hashtable statistics,
213 // the result is used for tuning.
214 class StatisticsWalker : public MallocSiteWalker {
215 private:
216 enum Threshold {
217 // aggregates statistics over this threshold into one
218 // line item.
219 report_threshold = 20
220 };
221
222 private:
223 // Number of allocation sites that have all memory freed
224 int _empty_entries;
225 // Total number of allocation sites, include empty sites
226 int _total_entries;
227 // Number of captured call stack distribution
228 int _stack_depth_distribution[NMT_TrackingStackDepth];
229 // Hash distribution
230 int _hash_distribution[report_threshold];
231 // Number of hash buckets that have entries over the threshold
232 int _bucket_over_threshold;
233
234 // The hash bucket that walker is currently walking
235 int _current_hash_bucket;
236 // The length of current hash bucket
237 int _current_bucket_length;
238 // Number of hash buckets that are not empty
239 int _used_buckets;
240 // Longest hash bucket length
241 int _longest_bucket_length;
242
243 public:
244 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
245 int index = 0;
246 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
247 _stack_depth_distribution[index] = 0;
248 }
249 for (index = 0; index < report_threshold; index ++) {
250 _hash_distribution[index] = 0;
251 }
252 _bucket_over_threshold = 0;
253 _longest_bucket_length = 0;
254 _current_hash_bucket = -1;
255 _current_bucket_length = 0;
256 _used_buckets = 0;
257 }
258
259 virtual bool do_malloc_site(const MallocSite* e) {
260 if (e->size() == 0) _empty_entries ++;
261 _total_entries ++;
262
263 // stack depth distrubution
264 int frames = e->call_stack()->frames();
265 _stack_depth_distribution[frames - 1] ++;
266
267 // hash distribution
268 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
269 if (_current_hash_bucket == -1) {
270 _current_hash_bucket = hash_bucket;
271 _current_bucket_length = 1;
272 } else if (_current_hash_bucket == hash_bucket) {
273 _current_bucket_length ++;
274 } else {
275 record_bucket_length(_current_bucket_length);
276 _current_hash_bucket = hash_bucket;
277 _current_bucket_length = 1;
278 }
279 return true;
280 }
281
282 // walk completed
283 void completed() {
284 record_bucket_length(_current_bucket_length);
285 }
286
287 void report_statistics(outputStream* out) {
288 int index;
289 out->print_cr("Malloc allocation site table:");
290 out->print_cr("\tTotal entries: %d", _total_entries);
291 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
292 out->print_cr(" ");
293 out->print_cr("Hash distribution:");
294 if (_used_buckets < MallocSiteTable::hash_buckets()) {
295 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
296 }
297 for (index = 0; index < report_threshold; index ++) {
298 if (_hash_distribution[index] != 0) {
299 if (index == 0) {
300 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
301 } else if (index < 9) { // single digit
302 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
303 } else {
304 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
305 }
306 }
307 }
308 if (_bucket_over_threshold > 0) {
309 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
310 }
311 out->print_cr("most entries: %d", _longest_bucket_length);
312 out->print_cr(" ");
313 out->print_cr("Call stack depth distribution:");
314 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
315 if (_stack_depth_distribution[index] > 0) {
316 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
317 }
318 }
319 }
320
321 private:
322 void record_bucket_length(int length) {
323 _used_buckets ++;
324 if (length <= report_threshold) {
325 _hash_distribution[length - 1] ++;
326 } else {
327 _bucket_over_threshold ++;
328 }
329 _longest_bucket_length = MAX2(_longest_bucket_length, length);
330 }
331 };
332
333
334 void MemTracker::tuning_statistics(outputStream* out) {
335 // NMT statistics
336 StatisticsWalker walker;
337 MallocSiteTable::walk_malloc_site(&walker);
338 walker.completed();
339
340 out->print_cr("Native Memory Tracking Statistics:");
341 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
342 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
343 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
344 out->print_cr(" ");
345 walker.report_statistics(out);
346 }