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.hpp"
29 #include "runtime/os.hpp"
30 #include "runtime/vmThread.hpp"
31 #include "runtime/vm_operations.hpp"
32 #include "services/memBaseline.hpp"
33 #include "services/memReporter.hpp"
34 #include "services/mallocTracker.inline.hpp"
35 #include "services/memTracker.hpp"
36 #include "utilities/defaultStream.hpp"
37 #include "utilities/vmError.hpp"
38
39 #ifdef SOLARIS
40 volatile bool NMT_stack_walkable = false;
41 #else
42 volatile bool NMT_stack_walkable = true;
43 #endif
44
45 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
46 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
47
48 MemBaseline MemTracker::_baseline;
49 Mutex* MemTracker::_query_lock = NULL;
50 bool MemTracker::_is_nmt_env_valid = true;
51
52
53 NMT_TrackingLevel MemTracker::init_tracking_level() {
54 NMT_TrackingLevel level = NMT_off;
55 char buf[64];
56 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
57 const char *nmt_option = ::getenv(buf);
58 if (nmt_option != NULL) {
59 if (strcmp(nmt_option, "summary") == 0) {
60 level = NMT_summary;
61 } else if (strcmp(nmt_option, "detail") == 0) {
62 level = NMT_detail;
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 // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
73 // but it is benign, the results are the same.
74 ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
75
76 if (!MallocTracker::initialize(level) ||
77 !VirtualMemoryTracker::initialize(level)) {
78 level = NMT_off;
79 }
80 return level;
81 }
82
83 void MemTracker::init() {
84 NMT_TrackingLevel level = tracking_level();
85 if (level >= NMT_summary) {
86 if (!VirtualMemoryTracker::late_initialize(level)) {
87 shutdown();
88 return;
89 }
90 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
91 // Already OOM. It is unlikely, but still have to handle it.
92 if (_query_lock == NULL) {
93 shutdown();
94 }
95 }
96 }
97
98 bool MemTracker::check_launcher_nmt_support(const char* value) {
99 if (strcmp(value, "=detail") == 0) {
100 if (MemTracker::tracking_level() != NMT_detail) {
101 return false;
102 }
103 } else if (strcmp(value, "=summary") == 0) {
104 if (MemTracker::tracking_level() != NMT_summary) {
105 return false;
106 }
107 } else if (strcmp(value, "=off") == 0) {
108 if (MemTracker::tracking_level() != NMT_off) {
109 return false;
110 }
111 } else {
112 _is_nmt_env_valid = false;
113 }
114
115 return true;
116 }
117
118 bool MemTracker::verify_nmt_option() {
119 return _is_nmt_env_valid;
120 }
121
122 void* MemTracker::malloc_base(void* memblock) {
123 return MallocTracker::get_base(memblock);
124 }
125
126 void Tracker::record(address addr, size_t size) {
127 if (MemTracker::tracking_level() < NMT_summary) return;
128 switch(_type) {
129 case uncommit:
130 VirtualMemoryTracker::remove_uncommitted_region(addr, size);
131 break;
132 case release:
133 VirtualMemoryTracker::remove_released_region(addr, size);
134 break;
135 default:
136 ShouldNotReachHere();
137 }
138 }
139
140
141 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
142 void MemTracker::shutdown() {
143 // We can only shutdown NMT to minimal tracking level if it is ever on.
144 if (tracking_level () > NMT_minimal) {
145 transition_to(NMT_minimal);
146 }
147 }
148
149 bool MemTracker::transition_to(NMT_TrackingLevel level) {
150 NMT_TrackingLevel current_level = tracking_level();
151
152 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
153
154 if (current_level == level) {
155 return true;
156 } else if (current_level > level) {
157 // Downgrade tracking level, we want to lower the tracking 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 } else {
164 // Upgrading tracking level is not supported and has never been supported.
165 // Allocating and deallocating malloc tracking structures is not thread safe and
166 // leads to inconsistencies unless a lot coarser locks are added.
167 }
168 return true;
169 }
170
171 void MemTracker::report(bool summary_only, outputStream* output) {
172 assert(output != NULL, "No output stream");
173 MemBaseline baseline;
174 if (baseline.baseline(summary_only)) {
175 if (summary_only) {
176 MemSummaryReporter rpt(baseline, output);
177 rpt.report();
178 } else {
179 MemDetailReporter rpt(baseline, output);
180 rpt.report();
181 output->print("Metaspace:");
182 // Metadata reporting requires a safepoint, so avoid it if VM is not in good state.
183 assert(!VMError::fatal_error_in_progress(), "Do not report metadata in error report");
184 VM_PrintMetadata vmop(output, K,
185 MetaspaceUtils::rf_show_loaders |
186 MetaspaceUtils::rf_break_down_by_spacetype);
187 VMThread::execute(&vmop);
188 }
189 }
190 }
191
192 // This is a walker to gather malloc site hashtable statistics,
193 // the result is used for tuning.
194 class StatisticsWalker : public MallocSiteWalker {
195 private:
196 enum Threshold {
197 // aggregates statistics over this threshold into one
198 // line item.
199 report_threshold = 20
200 };
201
202 private:
203 // Number of allocation sites that have all memory freed
204 int _empty_entries;
205 // Total number of allocation sites, include empty sites
206 int _total_entries;
207 // Number of captured call stack distribution
208 int _stack_depth_distribution[NMT_TrackingStackDepth];
209 // Hash distribution
210 int _hash_distribution[report_threshold];
211 // Number of hash buckets that have entries over the threshold
212 int _bucket_over_threshold;
213
214 // The hash bucket that walker is currently walking
215 int _current_hash_bucket;
216 // The length of current hash bucket
217 int _current_bucket_length;
218 // Number of hash buckets that are not empty
219 int _used_buckets;
220 // Longest hash bucket length
221 int _longest_bucket_length;
222
223 public:
224 StatisticsWalker() : _empty_entries(0), _total_entries(0) {
225 int index = 0;
226 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
227 _stack_depth_distribution[index] = 0;
228 }
229 for (index = 0; index < report_threshold; index ++) {
230 _hash_distribution[index] = 0;
231 }
232 _bucket_over_threshold = 0;
233 _longest_bucket_length = 0;
234 _current_hash_bucket = -1;
235 _current_bucket_length = 0;
236 _used_buckets = 0;
237 }
238
239 virtual bool do_malloc_site(const MallocSite* e) {
240 if (e->size() == 0) _empty_entries ++;
241 _total_entries ++;
242
243 // stack depth distrubution
244 int frames = e->call_stack()->frames();
245 _stack_depth_distribution[frames - 1] ++;
246
247 // hash distribution
248 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
249 if (_current_hash_bucket == -1) {
250 _current_hash_bucket = hash_bucket;
251 _current_bucket_length = 1;
252 } else if (_current_hash_bucket == hash_bucket) {
253 _current_bucket_length ++;
254 } else {
255 record_bucket_length(_current_bucket_length);
256 _current_hash_bucket = hash_bucket;
257 _current_bucket_length = 1;
258 }
259 return true;
260 }
261
262 // walk completed
263 void completed() {
264 record_bucket_length(_current_bucket_length);
265 }
266
267 void report_statistics(outputStream* out) {
268 int index;
269 out->print_cr("Malloc allocation site table:");
270 out->print_cr("\tTotal entries: %d", _total_entries);
271 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
272 out->print_cr(" ");
273 out->print_cr("Hash distribution:");
274 if (_used_buckets < MallocSiteTable::hash_buckets()) {
275 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
276 }
277 for (index = 0; index < report_threshold; index ++) {
278 if (_hash_distribution[index] != 0) {
279 if (index == 0) {
280 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
281 } else if (index < 9) { // single digit
282 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
283 } else {
284 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
285 }
286 }
287 }
288 if (_bucket_over_threshold > 0) {
289 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
290 }
291 out->print_cr("most entries: %d", _longest_bucket_length);
292 out->print_cr(" ");
293 out->print_cr("Call stack depth distribution:");
294 for (index = 0; index < NMT_TrackingStackDepth; index ++) {
295 if (_stack_depth_distribution[index] > 0) {
296 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
297 }
298 }
299 }
300
301 private:
302 void record_bucket_length(int length) {
303 _used_buckets ++;
304 if (length <= report_threshold) {
305 _hash_distribution[length - 1] ++;
306 } else {
307 _bucket_over_threshold ++;
308 }
309 _longest_bucket_length = MAX2(_longest_bucket_length, length);
310 }
311 };
312
313
314 void MemTracker::record_thread_stack(void* addr, size_t size) {
315 if (tracking_level() < NMT_summary) return;
316 if (addr != NULL) {
317 // uses thread stack malloc slot for book keeping number of threads
318 MallocMemorySummary::record_malloc(0, mtThreadStack);
319 // NMT assumes thread stacks to be page aligned; but that does not have to be the case.
320 // So, for the purpose of keeping track of thread stacks, just use the inner page aligned
321 // part of the thread stack.
322 const os::range_t inner = os::inner_page_aligned_boundaries((address)addr, size);
323 record_virtual_memory_reserve(inner.addr, inner.size, CALLER_PC, mtThreadStack);
324 }
325 }
326
327 void MemTracker::release_thread_stack(void* addr, size_t size) {
328 if (tracking_level() < NMT_summary) return;
329 if (addr != NULL) {
330 // uses thread stack malloc slot for book keeping number of threads
331 MallocMemorySummary::record_free(0, mtThreadStack);
332 ThreadCritical tc;
333 if (tracking_level() < NMT_summary) return;
334 // NMT assumes thread stacks to be page aligned; but that does not have to be the case.
335 // So, for the purpose of keeping track of thread stacks, just use the inner page aligned
336 // part of the thread stack.
337 const os::range_t inner = os::inner_page_aligned_boundaries((address)addr, size);
338 VirtualMemoryTracker::remove_released_region(inner.addr, inner.size);
339 }
340 }
341
342 void MemTracker::tuning_statistics(outputStream* out) {
343 // NMT statistics
344 StatisticsWalker walker;
345 MallocSiteTable::walk_malloc_site(&walker);
346 walker.completed();
347
348 out->print_cr("Native Memory Tracking Statistics:");
349 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
350 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
351 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
352 out->print_cr(" ");
353 walker.report_statistics(out);
354 }