1 /* 2 * Copyright (c) 2012, 2017, 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/vmThread.hpp" 29 #include "runtime/vm_operations.hpp" 30 #include "services/memBaseline.hpp" 31 #include "services/memReporter.hpp" 32 #include "services/mallocTracker.inline.hpp" 33 #include "services/memTracker.hpp" 34 #include "utilities/defaultStream.hpp" 35 #include "utilities/vmError.hpp" 36 37 #ifdef SOLARIS 38 volatile bool NMT_stack_walkable = false; 39 #else 40 volatile bool NMT_stack_walkable = true; 41 #endif 42 43 volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown; 44 NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown; 45 46 MemBaseline MemTracker::_baseline; 47 Mutex* MemTracker::_query_lock = NULL; 48 bool MemTracker::_is_nmt_env_valid = true; 49 50 51 NMT_TrackingLevel MemTracker::init_tracking_level() { 52 NMT_TrackingLevel level = NMT_off; 53 char buf[64]; 54 jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id()); 55 const char *nmt_option = ::getenv(buf); 56 if (nmt_option != NULL) { 57 if (strcmp(nmt_option, "summary") == 0) { 58 level = NMT_summary; 59 } else if (strcmp(nmt_option, "detail") == 0) { 60 level = NMT_detail; 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 (MemTracker::tracking_level() != NMT_detail) { 99 return false; 100 } 101 } else if (strcmp(value, "=summary") == 0) { 102 if (MemTracker::tracking_level() != NMT_summary) { 103 return false; 104 } 105 } else if (strcmp(value, "=off") == 0) { 106 if (MemTracker::tracking_level() != NMT_off) { 107 return false; 108 } 109 } else { 110 _is_nmt_env_valid = false; 111 } 112 113 return true; 114 } 115 116 bool MemTracker::verify_nmt_option() { 117 return _is_nmt_env_valid; 118 } 119 120 void* MemTracker::malloc_base(void* memblock) { 121 return MallocTracker::get_base(memblock); 122 } 123 124 void Tracker::record(address addr, size_t size) { 125 if (MemTracker::tracking_level() < NMT_summary) return; 126 switch(_type) { 127 case uncommit: 128 VirtualMemoryTracker::remove_uncommitted_region(addr, size); 129 break; 130 case release: 131 VirtualMemoryTracker::remove_released_region(addr, size); 132 break; 133 default: 134 ShouldNotReachHere(); 135 } 136 } 137 138 139 // Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock 140 void MemTracker::shutdown() { 141 // We can only shutdown NMT to minimal tracking level if it is ever on. 142 if (tracking_level () > NMT_minimal) { 143 transition_to(NMT_minimal); 144 } 145 } 146 147 bool MemTracker::transition_to(NMT_TrackingLevel level) { 148 NMT_TrackingLevel current_level = tracking_level(); 149 150 assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off"); 151 152 if (current_level == level) { 153 return true; 154 } else if (current_level > level) { 155 // Downgrade tracking level, we want to lower the tracking level first 156 _tracking_level = level; 157 // Make _tracking_level visible immediately. 158 OrderAccess::fence(); 159 VirtualMemoryTracker::transition(current_level, level); 160 MallocTracker::transition(current_level, level); 161 } else { 162 // Upgrading tracking level is not supported and has never been supported. 163 // Allocating and deallocating malloc tracking structures is not thread safe and 164 // leads to inconsistencies unless a lot coarser locks are added. 165 } 166 return true; 167 } 168 169 void MemTracker::report(bool summary_only, outputStream* output) { 170 assert(output != NULL, "No output stream"); 171 MemBaseline baseline; 172 if (baseline.baseline(summary_only)) { 173 if (summary_only) { 174 MemSummaryReporter rpt(baseline, output); 175 rpt.report(); 176 } else { 177 MemDetailReporter rpt(baseline, output); 178 rpt.report(); 179 180 // Metadata reporting requires a safepoint, so avoid it if VM is not in good state. 181 assert(!VMError::fatal_error_in_progress(), "Do not report metadata in error report"); 182 VM_PrintMetadata vmop(output, K); 183 VMThread::execute(&vmop); 184 } 185 } 186 } 187 188 // This is a walker to gather malloc site hashtable statistics, 189 // the result is used for tuning. 190 class StatisticsWalker : public MallocSiteWalker { 191 private: 192 enum Threshold { 193 // aggregates statistics over this threshold into one 194 // line item. 195 report_threshold = 20 196 }; 197 198 private: 199 // Number of allocation sites that have all memory freed 200 int _empty_entries; 201 // Total number of allocation sites, include empty sites 202 int _total_entries; 203 // Number of captured call stack distribution 204 int _stack_depth_distribution[NMT_TrackingStackDepth]; 205 // Hash distribution 206 int _hash_distribution[report_threshold]; 207 // Number of hash buckets that have entries over the threshold 208 int _bucket_over_threshold; 209 210 // The hash bucket that walker is currently walking 211 int _current_hash_bucket; 212 // The length of current hash bucket 213 int _current_bucket_length; 214 // Number of hash buckets that are not empty 215 int _used_buckets; 216 // Longest hash bucket length 217 int _longest_bucket_length; 218 219 public: 220 StatisticsWalker() : _empty_entries(0), _total_entries(0) { 221 int index = 0; 222 for (index = 0; index < NMT_TrackingStackDepth; index ++) { 223 _stack_depth_distribution[index] = 0; 224 } 225 for (index = 0; index < report_threshold; index ++) { 226 _hash_distribution[index] = 0; 227 } 228 _bucket_over_threshold = 0; 229 _longest_bucket_length = 0; 230 _current_hash_bucket = -1; 231 _current_bucket_length = 0; 232 _used_buckets = 0; 233 } 234 235 virtual bool do_malloc_site(const MallocSite* e) { 236 if (e->size() == 0) _empty_entries ++; 237 _total_entries ++; 238 239 // stack depth distrubution 240 int frames = e->call_stack()->frames(); 241 _stack_depth_distribution[frames - 1] ++; 242 243 // hash distribution 244 int hash_bucket = e->hash() % MallocSiteTable::hash_buckets(); 245 if (_current_hash_bucket == -1) { 246 _current_hash_bucket = hash_bucket; 247 _current_bucket_length = 1; 248 } else if (_current_hash_bucket == hash_bucket) { 249 _current_bucket_length ++; 250 } else { 251 record_bucket_length(_current_bucket_length); 252 _current_hash_bucket = hash_bucket; 253 _current_bucket_length = 1; 254 } 255 return true; 256 } 257 258 // walk completed 259 void completed() { 260 record_bucket_length(_current_bucket_length); 261 } 262 263 void report_statistics(outputStream* out) { 264 int index; 265 out->print_cr("Malloc allocation site table:"); 266 out->print_cr("\tTotal entries: %d", _total_entries); 267 out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries); 268 out->print_cr(" "); 269 out->print_cr("Hash distribution:"); 270 if (_used_buckets < MallocSiteTable::hash_buckets()) { 271 out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets)); 272 } 273 for (index = 0; index < report_threshold; index ++) { 274 if (_hash_distribution[index] != 0) { 275 if (index == 0) { 276 out->print_cr(" %d entry: %d", 1, _hash_distribution[0]); 277 } else if (index < 9) { // single digit 278 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]); 279 } else { 280 out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]); 281 } 282 } 283 } 284 if (_bucket_over_threshold > 0) { 285 out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold); 286 } 287 out->print_cr("most entries: %d", _longest_bucket_length); 288 out->print_cr(" "); 289 out->print_cr("Call stack depth distribution:"); 290 for (index = 0; index < NMT_TrackingStackDepth; index ++) { 291 if (_stack_depth_distribution[index] > 0) { 292 out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]); 293 } 294 } 295 } 296 297 private: 298 void record_bucket_length(int length) { 299 _used_buckets ++; 300 if (length <= report_threshold) { 301 _hash_distribution[length - 1] ++; 302 } else { 303 _bucket_over_threshold ++; 304 } 305 _longest_bucket_length = MAX2(_longest_bucket_length, length); 306 } 307 }; 308 309 310 void MemTracker::tuning_statistics(outputStream* out) { 311 // NMT statistics 312 StatisticsWalker walker; 313 MallocSiteTable::walk_malloc_site(&walker); 314 walker.completed(); 315 316 out->print_cr("Native Memory Tracking Statistics:"); 317 out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets()); 318 out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth); 319 NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());) 320 out->print_cr(" "); 321 walker.report_statistics(out); 322 }