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 MemBaseline MemTracker::_baseline;
  43 Mutex*      MemTracker::_query_lock = NULL;
  44 bool MemTracker::_is_nmt_env_valid = true;
  45 
  46 
  47 NMT_TrackingLevel MemTracker::init_tracking_level() {
  48   NMT_TrackingLevel level = NMT_off;
  49   char buf[64];
  50   jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
  51   const char *nmt_option = ::getenv(buf);
  52   if (nmt_option != NULL) {
  53     if (strcmp(nmt_option, "summary") == 0) {
  54       level = NMT_summary;
  55     } else if (strcmp(nmt_option, "detail") == 0) {
  56 #if PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
  57       level = NMT_detail;
  58 #else
  59       level = NMT_summary;
  60 #endif // PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
  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 !PLATFORM_NATIVE_STACK_WALKING_SUPPORTED
  99       jio_fprintf(defaultStream::error_stream(),
 100         "NMT detail is not supported on this platform.  Using NMT summary instead.\n");
 101     if (MemTracker::tracking_level() != NMT_summary) {
 102     return false;
 103   }
 104 #else
 105     if (MemTracker::tracking_level() != NMT_detail) {
 106       return false;
 107     }
 108 #endif
 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   } else {
 170     // Upgrading tracking level is not supported and has never been supported.
 171     // Allocating and deallocating malloc tracking structures is not thread safe and
 172     // leads to inconsistencies unless a lot coarser locks are added.
 173   }
 174   return true;
 175 }
 176 
 177 void MemTracker::report(bool summary_only, outputStream* output) {
 178  assert(output != NULL, "No output stream");
 179   MemBaseline baseline;
 180   if (baseline.baseline(summary_only)) {
 181     if (summary_only) {
 182       MemSummaryReporter rpt(baseline, output);
 183       rpt.report();
 184     } else {
 185       MemDetailReporter rpt(baseline, output);
 186       rpt.report();
 187     }
 188   }
 189 }
 190 
 191 // This is a walker to gather malloc site hashtable statistics,
 192 // the result is used for tuning.
 193 class StatisticsWalker : public MallocSiteWalker {
 194  private:
 195   enum Threshold {
 196     // aggregates statistics over this threshold into one
 197     // line item.
 198     report_threshold = 20
 199   };
 200 
 201  private:
 202   // Number of allocation sites that have all memory freed
 203   int   _empty_entries;
 204   // Total number of allocation sites, include empty sites
 205   int   _total_entries;
 206   // Number of captured call stack distribution
 207   int   _stack_depth_distribution[NMT_TrackingStackDepth];
 208   // Hash distribution
 209   int   _hash_distribution[report_threshold];
 210   // Number of hash buckets that have entries over the threshold
 211   int   _bucket_over_threshold;
 212 
 213   // The hash bucket that walker is currently walking
 214   int   _current_hash_bucket;
 215   // The length of current hash bucket
 216   int   _current_bucket_length;
 217   // Number of hash buckets that are not empty
 218   int   _used_buckets;
 219   // Longest hash bucket length
 220   int   _longest_bucket_length;
 221 
 222  public:
 223   StatisticsWalker() : _empty_entries(0), _total_entries(0) {
 224     int index = 0;
 225     for (index = 0; index < NMT_TrackingStackDepth; index ++) {
 226       _stack_depth_distribution[index] = 0;
 227     }
 228     for (index = 0; index < report_threshold; index ++) {
 229       _hash_distribution[index] = 0;
 230     }
 231     _bucket_over_threshold = 0;
 232     _longest_bucket_length = 0;
 233     _current_hash_bucket = -1;
 234     _current_bucket_length = 0;
 235     _used_buckets = 0;
 236   }
 237 
 238   virtual bool do_malloc_site(const MallocSite* e) {
 239     if (e->size() == 0) _empty_entries ++;
 240     _total_entries ++;
 241 
 242     // stack depth distrubution
 243     int frames = e->call_stack()->frames();
 244     _stack_depth_distribution[frames - 1] ++;
 245 
 246     // hash distribution
 247     int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
 248     if (_current_hash_bucket == -1) {
 249       _current_hash_bucket = hash_bucket;
 250       _current_bucket_length = 1;
 251     } else if (_current_hash_bucket == hash_bucket) {
 252       _current_bucket_length ++;
 253     } else {
 254       record_bucket_length(_current_bucket_length);
 255       _current_hash_bucket = hash_bucket;
 256       _current_bucket_length = 1;
 257     }
 258     return true;
 259   }
 260 
 261   // walk completed
 262   void completed() {
 263     record_bucket_length(_current_bucket_length);
 264   }
 265 
 266   void report_statistics(outputStream* out) {
 267     int index;
 268     out->print_cr("Malloc allocation site table:");
 269     out->print_cr("\tTotal entries: %d", _total_entries);
 270     out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
 271     out->print_cr(" ");
 272     out->print_cr("Hash distribution:");
 273     if (_used_buckets < MallocSiteTable::hash_buckets()) {
 274       out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
 275     }
 276     for (index = 0; index < report_threshold; index ++) {
 277       if (_hash_distribution[index] != 0) {
 278         if (index == 0) {
 279           out->print_cr("  %d    entry: %d", 1, _hash_distribution[0]);
 280         } else if (index < 9) { // single digit
 281           out->print_cr("  %d  entries: %d", (index + 1), _hash_distribution[index]);
 282         } else {
 283           out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
 284         }
 285       }
 286     }
 287     if (_bucket_over_threshold > 0) {
 288       out->print_cr(" >%d entries: %d", report_threshold,  _bucket_over_threshold);
 289     }
 290     out->print_cr("most entries: %d", _longest_bucket_length);
 291     out->print_cr(" ");
 292     out->print_cr("Call stack depth distribution:");
 293     for (index = 0; index < NMT_TrackingStackDepth; index ++) {
 294       if (_stack_depth_distribution[index] > 0) {
 295         out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
 296       }
 297     }
 298   }
 299 
 300  private:
 301   void record_bucket_length(int length) {
 302     _used_buckets ++;
 303     if (length <= report_threshold) {
 304       _hash_distribution[length - 1] ++;
 305     } else {
 306       _bucket_over_threshold ++;
 307     }
 308     _longest_bucket_length = MAX2(_longest_bucket_length, length);
 309   }
 310 };
 311 
 312 
 313 void MemTracker::tuning_statistics(outputStream* out) {
 314   // NMT statistics
 315   StatisticsWalker walker;
 316   MallocSiteTable::walk_malloc_site(&walker);
 317   walker.completed();
 318 
 319   out->print_cr("Native Memory Tracking Statistics:");
 320   out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
 321   out->print_cr("             Tracking stack depth: %d", NMT_TrackingStackDepth);
 322   NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
 323   out->print_cr(" ");
 324   walker.report_statistics(out);
 325 }