1 /*
2 * Copyright (c) 2012, 2018, 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 "runtime/orderAccess.inline.hpp"
29 #include "runtime/vmThread.hpp"
30 #include "runtime/vm_operations.hpp"
31 #include "services/memBaseline.hpp"
32 #include "services/memReporter.hpp"
33 #include "services/mallocTracker.inline.hpp"
34 #include "services/memTracker.hpp"
35 #include "utilities/defaultStream.hpp"
36 #include "utilities/vmError.hpp"
37
38 #ifdef SOLARIS
39 volatile bool NMT_stack_walkable = false;
40 #else
41 volatile bool NMT_stack_walkable = true;
42 #endif
43
44 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
45 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
46
47 MemBaseline MemTracker::_baseline;
48 Mutex* MemTracker::_query_lock = NULL;
49 bool MemTracker::_is_nmt_env_valid = true;
50
51
52 NMT_TrackingLevel MemTracker::init_tracking_level() {
53 NMT_TrackingLevel level = NMT_off;
54 char buf[64];
55 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
56 const char *nmt_option = ::getenv(buf);
57 if (nmt_option != NULL) {
58 if (strcmp(nmt_option, "summary") == 0) {
59 level = NMT_summary;
60 } else if (strcmp(nmt_option, "detail") == 0) {
61 level = NMT_detail;
62 } else if (strcmp(nmt_option, "off") != 0) {
63 // The option value is invalid
64 _is_nmt_env_valid = false;
65 }
66
67 // Remove the environment variable to avoid leaking to child processes
68 os::unsetenv(buf);
69 }
70
71 // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
72 // but it is benign, the results are the same.
73 ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
74
75 if (!MallocTracker::initialize(level) ||
76 !VirtualMemoryTracker::initialize(level)) {
77 level = NMT_off;
78 }
79 return level;
80 }
81
82 void MemTracker::init() {
83 NMT_TrackingLevel level = tracking_level();
84 if (level >= NMT_summary) {
85 if (!VirtualMemoryTracker::late_initialize(level)) {
86 shutdown();
87 return;
88 }
89 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
90 // Already OOM. It is unlikely, but still have to handle it.
91 if (_query_lock == NULL) {
92 shutdown();
93 }
94 }
95 }
96
97 bool MemTracker::check_launcher_nmt_support(const char* value) {
98 if (strcmp(value, "=detail") == 0) {
99 if (MemTracker::tracking_level() != NMT_detail) {
100 return false;
101 }
102 } else if (strcmp(value, "=summary") == 0) {
103 if (MemTracker::tracking_level() != NMT_summary) {
104 return false;
105 }
106 } else if (strcmp(value, "=off") == 0) {
107 if (MemTracker::tracking_level() != NMT_off) {
108 return false;
109 }
110 } else {
111 _is_nmt_env_valid = false;
112 }
113
114 return true;
115 }
116
117 bool MemTracker::verify_nmt_option() {
118 return _is_nmt_env_valid;
119 }
120
121 void* MemTracker::malloc_base(void* memblock) {
122 return MallocTracker::get_base(memblock);
123 }
124
125 void Tracker::record(address addr, size_t size) {
126 if (MemTracker::tracking_level() < NMT_summary) return;
127 switch(_type) {
128 case uncommit:
129 VirtualMemoryTracker::remove_uncommitted_region(addr, size);
130 break;
131 case release:
132 VirtualMemoryTracker::remove_released_region(addr, size);
133 break;
134 default:
135 ShouldNotReachHere();
136 }
137 }
138
139
140 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
141 void MemTracker::shutdown() {
142 // We can only shutdown NMT to minimal tracking level if it is ever on.
143 if (tracking_level () > NMT_minimal) {
144 transition_to(NMT_minimal);
145 }
146 }
147
148 bool MemTracker::transition_to(NMT_TrackingLevel level) {
149 NMT_TrackingLevel current_level = tracking_level();
150
151 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
152
153 if (current_level == level) {
154 return true;
155 } else if (current_level > level) {
156 // Downgrade tracking level, we want to lower the tracking level first
157 _tracking_level = level;
158 // Make _tracking_level visible immediately.
159 OrderAccess::fence();
160 VirtualMemoryTracker::transition(current_level, level);
161 MallocTracker::transition(current_level, level);
162 } else {
163 // Upgrading tracking level is not supported and has never been supported.
164 // Allocating and deallocating malloc tracking structures is not thread safe and
165 // leads to inconsistencies unless a lot coarser locks are added.
166 }
167 return true;
168 }
169
170 void MemTracker::report(bool summary_only, outputStream* output) {
171 assert(output != NULL, "No output stream");
172 MemBaseline baseline;
173 if (baseline.baseline(summary_only)) {
174 if (summary_only) {
175 MemSummaryReporter rpt(baseline, output);
176 rpt.report();
177 } else {
178 MemDetailReporter rpt(baseline, output);
179 rpt.report();
180
181 // Metadata reporting requires a safepoint, so avoid it if VM is not in good state.
182 assert(!VMError::fatal_error_in_progress(), "Do not report metadata in error report");
183 VM_PrintMetadata vmop(output, K);
184 VMThread::execute(&vmop);
185 }
186 }
187 }
188
189 // This is a walker to gather malloc site hashtable statistics,
190 // the result is used for tuning.
191 class StatisticsWalker : public MallocSiteWalker {
192 private:
193 enum Threshold {
194 // aggregates statistics over this threshold into one
195 // line item.
196 report_threshold = 20
197 };
198
199 private:
200 // Number of allocation sites that have all memory freed
201 int _empty_entries;
202 // Total number of allocation sites, include empty sites
203 int _total_entries;
204 // Number of captured call stack distribution
205 int _stack_depth_distribution[NMT_TrackingStackDepth];
206 // Hash distribution
207 int _hash_distribution[report_threshold];
208 // Number of hash buckets that have entries over the threshold
209 int _bucket_over_threshold;
210
211 // The hash bucket that walker is currently walking
212 int _current_hash_bucket;
213 // The length of current hash bucket
214 int _current_bucket_length;
215 // Number of hash buckets that are not empty
216 int _used_buckets;
217 // Longest hash bucket length
218 int _longest_bucket_length;
219
220 public:
221 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
222 int index = 0;
223 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
224 _stack_depth_distribution[index] = 0;
225 }
226 for (index = 0; index < report_threshold; index ++) {
227 _hash_distribution[index] = 0;
228 }
229 _bucket_over_threshold = 0;
230 _longest_bucket_length = 0;
231 _current_hash_bucket = -1;
232 _current_bucket_length = 0;
233 _used_buckets = 0;
234 }
235
236 virtual bool do_malloc_site(const MallocSite* e) {
237 if (e->size() == 0) _empty_entries ++;
238 _total_entries ++;
239
240 // stack depth distrubution
241 int frames = e->call_stack()->frames();
242 _stack_depth_distribution[frames - 1] ++;
243
244 // hash distribution
245 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
246 if (_current_hash_bucket == -1) {
247 _current_hash_bucket = hash_bucket;
248 _current_bucket_length = 1;
249 } else if (_current_hash_bucket == hash_bucket) {
250 _current_bucket_length ++;
251 } else {
252 record_bucket_length(_current_bucket_length);
253 _current_hash_bucket = hash_bucket;
254 _current_bucket_length = 1;
255 }
256 return true;
257 }
258
259 // walk completed
260 void completed() {
261 record_bucket_length(_current_bucket_length);
262 }
263
264 void report_statistics(outputStream* out) {
265 int index;
266 out->print_cr("Malloc allocation site table:");
267 out->print_cr("\tTotal entries: %d", _total_entries);
268 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
269 out->print_cr(" ");
270 out->print_cr("Hash distribution:");
271 if (_used_buckets < MallocSiteTable::hash_buckets()) {
272 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
273 }
274 for (index = 0; index < report_threshold; index ++) {
275 if (_hash_distribution[index] != 0) {
276 if (index == 0) {
277 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
278 } else if (index < 9) { // single digit
279 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
280 } else {
281 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
282 }
283 }
284 }
285 if (_bucket_over_threshold > 0) {
286 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
287 }
288 out->print_cr("most entries: %d", _longest_bucket_length);
289 out->print_cr(" ");
290 out->print_cr("Call stack depth distribution:");
291 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
292 if (_stack_depth_distribution[index] > 0) {
293 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
294 }
295 }
296 }
297
298 private:
299 void record_bucket_length(int length) {
300 _used_buckets ++;
301 if (length <= report_threshold) {
302 _hash_distribution[length - 1] ++;
303 } else {
304 _bucket_over_threshold ++;
305 }
306 _longest_bucket_length = MAX2(_longest_bucket_length, length);
307 }
308 };
309
310
311 void MemTracker::tuning_statistics(outputStream* out) {
312 // NMT statistics
313 StatisticsWalker walker;
314 MallocSiteTable::walk_malloc_site(&walker);
315 walker.completed();
316
317 out->print_cr("Native Memory Tracking Statistics:");
318 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
319 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
320 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
321 out->print_cr(" ");
322 walker.report_statistics(out);
323 }