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 NativeCallStack emptyStack(0, false);
43
44 MemBaseline MemTracker::_baseline;
45 Mutex* MemTracker::_query_lock = NULL;
46 bool MemTracker::_is_nmt_env_valid = true;
47
48
49 NMT_TrackingLevel MemTracker::init_tracking_level() {
50 NMT_TrackingLevel level = NMT_off;
51 char buf[64];
52 char nmt_option[64];
53 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
54 if (os::getenv(buf, nmt_option, sizeof(nmt_option))) {
55 if (strcmp(nmt_option, "summary") == 0) {
56 level = NMT_summary;
57 } else if (strcmp(nmt_option, "detail") == 0) {
58 #if PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
59 level = NMT_detail;
60 #else
61 level = NMT_summary;
62 #endif // PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
63 } else if (strcmp(nmt_option, "off") != 0) {
64 // The option value is invalid
65 _is_nmt_env_valid = false;
66 }
67
68 // Remove the environment variable to avoid leaking to child processes
69 os::unsetenv(buf);
70 }
71
72 if (!MallocTracker::initialize(level) ||
73 !VirtualMemoryTracker::initialize(level)) {
74 level = NMT_off;
75 }
76 return level;
77 }
78
79 void MemTracker::init() {
80 if (tracking_level() >= NMT_summary) {
81 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
82 // Already OOM. It is unlikely, but still have to handle it.
83 if (_query_lock == NULL) {
84 shutdown();
85 }
86 }
87 }
88
89 bool MemTracker::check_launcher_nmt_support(const char* value) {
90 if (strcmp(value, "=detail") == 0) {
91 #if !PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
92 jio_fprintf(defaultStream::error_stream(),
93 "NMT detail is not supported on this platform. Using NMT summary instead.\n");
94 if (MemTracker::tracking_level() != NMT_summary) {
95 return false;
96 }
97 #else
98 if (MemTracker::tracking_level() != NMT_detail) {
99 return false;
100 }
101 #endif
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
141 // by lock
142 void MemTracker::shutdown() {
143 // We can only shutdown NMT to minimal tracking level if it is
144 // ever on.
145 if (tracking_level () > NMT_minimal) {
146 transition_to(NMT_minimal);
147 }
148 }
149
150 bool MemTracker::transition_to(NMT_TrackingLevel level) {
151 NMT_TrackingLevel current_level = tracking_level();
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
157 // level first
158 _tracking_level = level;
159 // Make _tracking_level visible immediately.
160 OrderAccess::fence();
161 VirtualMemoryTracker::transition(current_level, level);
162 MallocTracker::transition(current_level, level);
163
164 if (level == NMT_minimal) _baseline.reset();
165 } else {
166 VirtualMemoryTracker::transition(current_level, level);
167 MallocTracker::transition(current_level, level);
168
169 _tracking_level = level;
170 // Make _tracking_level visible immediately.
171 OrderAccess::fence();
172 }
173
174 return true;
175 }
176
177 void MemTracker::final_report(outputStream* output) {
178 assert(output != NULL, "No output stream");
179 if (tracking_level() >= NMT_summary) {
180 MallocMemorySnapshot* malloc_memory_snapshot =
181 MallocMemorySummary::as_snapshot();
182 malloc_memory_snapshot->make_adjustment();
183
184 VirtualMemorySnapshot* virtual_memory_snapshot =
185 VirtualMemorySummary::as_snapshot();
186
187 MemSummaryReporter rptr(malloc_memory_snapshot,
188 virtual_memory_snapshot, output);
189 rptr.report();
190 // shutdown NMT, the data no longer accurate
191 shutdown();
192 }
193 }
194
195 // This is a walker to gather malloc site hashtable statistics,
196 // the result is used for tuning.
197 class StatisticsWalker : public MallocSiteWalker {
198 private:
199 enum Threshold {
200 // aggregates statistics over this threshold into one
201 // line item.
202 report_threshold = 20
203 };
204
205 private:
206 // Number of allocation sites that have all memory freed
207 int _empty_entries;
208 // Total number of allocation sites, include empty sites
209 int _total_entries;
210 // Number of captured call stack distribution
211 int _stack_depth_distribution[NMT_TrackingStackDepth];
212 // Hash distribution
213 int _hash_distribution[report_threshold];
214 // Number of hash buckets that have entries over the threshold
215 int _bucket_over_threshold;
216
217 // The hash bucket that walker is currently walking
218 int _current_hash_bucket;
219 // The length of current hash bucket
220 int _current_bucket_length;
221 // Number of hash buckets that are not empty
222 int _used_buckets;
223 // Longest hash bucket length
224 int _longest_bucket_length;
225
226 public:
227 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
228 int index = 0;
229 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
230 _stack_depth_distribution[index] = 0;
231 }
232 for (index = 0; index < report_threshold; index ++) {
233 _hash_distribution[index] = 0;
234 }
235 _bucket_over_threshold = 0;
236 _longest_bucket_length = 0;
237 _current_hash_bucket = -1;
238 _current_bucket_length = 0;
239 _used_buckets = 0;
240 }
241
242 virtual bool do_malloc_site(const MallocSite* e) {
243 if (e->size() == 0) _empty_entries ++;
244 _total_entries ++;
245
246 // stack depth distrubution
247 int frames = e->call_stack()->frames();
248 _stack_depth_distribution[frames - 1] ++;
249
250 // hash distribution
251 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
252 if (_current_hash_bucket == -1) {
253 _current_hash_bucket = hash_bucket;
254 _current_bucket_length = 1;
255 } else if (_current_hash_bucket == hash_bucket) {
256 _current_bucket_length ++;
257 } else {
258 record_bucket_length(_current_bucket_length);
259 _current_hash_bucket = hash_bucket;
260 _current_bucket_length = 1;
261 }
262 return true;
263 }
264
265 // walk completed
266 void completed() {
267 record_bucket_length(_current_bucket_length);
268 }
269
270 void report_statistics(outputStream* out) {
271 int index;
272 out->print_cr("Malloc allocation site table:");
273 out->print_cr("\tTotal entries: %d", _total_entries);
274 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
275 out->print_cr(" ");
276 out->print_cr("Hash distribution:");
277 if (_used_buckets < MallocSiteTable::hash_buckets()) {
278 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
279 }
280 for (index = 0; index < report_threshold; index ++) {
281 if (_hash_distribution[index] != 0) {
282 if (index == 0) {
283 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
284 } else if (index < 9) { // single digit
285 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
286 } else {
287 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
288 }
289 }
290 }
291 if (_bucket_over_threshold > 0) {
292 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
293 }
294 out->print_cr("most entries: %d", _longest_bucket_length);
295 out->print_cr(" ");
296 out->print_cr("Call stack depth distribution:");
297 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
298 if (_stack_depth_distribution[index] > 0) {
299 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
300 }
301 }
302 }
303
304 private:
305 void record_bucket_length(int length) {
306 _used_buckets ++;
307 if (length <= report_threshold) {
308 _hash_distribution[length - 1] ++;
309 } else {
310 _bucket_over_threshold ++;
311 }
312 _longest_bucket_length = MAX2(_longest_bucket_length, length);
313 }
314 };
315
316
317 void MemTracker::tuning_statistics(outputStream* out) {
318 // NMT statistics
319 StatisticsWalker walker;
320 MallocSiteTable::walk_malloc_site(&walker);
321 walker.completed();
322
323 out->print_cr("Native Memory Tracking Statistics:");
324 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
325 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
326 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
327 out->print_cr(" ");
328 walker.report_statistics(out);
329 }
330