1 /*
   2  * Copyright (c) 2011, 2016, 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 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/g1CollectedHeap.inline.hpp"
  27 #include "gc/g1/g1MonitoringSupport.hpp"
  28 #include "gc/g1/g1Policy.hpp"
  29 #include "gc/shared/hSpaceCounters.hpp"
  30 #include "memory/metaspaceCounters.hpp"
  31 
  32 G1GenerationCounters::G1GenerationCounters(G1MonitoringSupport* g1mm,
  33                                            const char* name,
  34                                            int ordinal, int spaces,
  35                                            size_t min_capacity,
  36                                            size_t max_capacity,
  37                                            size_t curr_capacity)
  38   : GenerationCounters(name, ordinal, spaces, min_capacity,
  39                        max_capacity, curr_capacity), _g1mm(g1mm) { }
  40 
  41 // We pad the capacity three times given that the young generation
  42 // contains three spaces (eden and two survivors).
  43 G1YoungGenerationCounters::G1YoungGenerationCounters(G1MonitoringSupport* g1mm,
  44                                                      const char* name)
  45   : G1GenerationCounters(g1mm, name, 0 /* ordinal */, 3 /* spaces */,
  46                G1MonitoringSupport::pad_capacity(0, 3) /* min_capacity */,
  47                G1MonitoringSupport::pad_capacity(g1mm->young_gen_max(), 3),
  48                G1MonitoringSupport::pad_capacity(0, 3) /* curr_capacity */) {
  49   if (UsePerfData) {
  50     update_all();
  51   }
  52 }
  53 
  54 G1OldGenerationCounters::G1OldGenerationCounters(G1MonitoringSupport* g1mm,
  55                                                  const char* name)
  56   : G1GenerationCounters(g1mm, name, 1 /* ordinal */, 1 /* spaces */,
  57                G1MonitoringSupport::pad_capacity(0) /* min_capacity */,
  58                G1MonitoringSupport::pad_capacity(g1mm->old_gen_max()),
  59                G1MonitoringSupport::pad_capacity(0) /* curr_capacity */) {
  60   if (UsePerfData) {
  61     update_all();
  62   }
  63 }
  64 
  65 void G1YoungGenerationCounters::update_all() {
  66   size_t committed =
  67             G1MonitoringSupport::pad_capacity(_g1mm->young_gen_committed(), 3);
  68   _current_size->set_value(committed);
  69 }
  70 
  71 void G1OldGenerationCounters::update_all() {
  72   size_t committed =
  73             G1MonitoringSupport::pad_capacity(_g1mm->old_gen_committed());
  74   _current_size->set_value(committed);
  75 }
  76 
  77 G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h) :
  78   _g1h(g1h),
  79   _incremental_collection_counters(NULL),
  80   _full_collection_counters(NULL),
  81   _old_collection_counters(NULL),
  82   _old_space_counters(NULL),
  83   _young_collection_counters(NULL),
  84   _eden_counters(NULL),
  85   _from_counters(NULL),
  86   _to_counters(NULL),
  87 
  88   _overall_reserved(0),
  89   _overall_committed(0),    _overall_used(0),
  90   _young_region_num(0),
  91   _young_gen_committed(0),
  92   _eden_committed(0),       _eden_used(0),
  93   _survivor_committed(0),   _survivor_used(0),
  94   _old_committed(0),        _old_used(0) {
  95 
  96   _overall_reserved = g1h->max_capacity();
  97   recalculate_sizes();
  98 
  99   // Counters for GC collections
 100   //
 101   //  name "collector.0".  In a generational collector this would be the
 102   // young generation collection.
 103   _incremental_collection_counters =
 104     new CollectorCounters("G1 incremental collections", 0);
 105   //   name "collector.1".  In a generational collector this would be the
 106   // old generation collection.
 107   _full_collection_counters =
 108     new CollectorCounters("G1 stop-the-world full collections", 1);
 109 
 110   // timer sampling for all counters supporting sampling only update the
 111   // used value.  See the take_sample() method.  G1 requires both used and
 112   // capacity updated so sampling is not currently used.  It might
 113   // be sufficient to update all counters in take_sample() even though
 114   // take_sample() only returns "used".  When sampling was used, there
 115   // were some anomolous values emitted which may have been the consequence
 116   // of not updating all values simultaneously (i.e., see the calculation done
 117   // in eden_space_used(), is it possible that the values used to
 118   // calculate either eden_used or survivor_used are being updated by
 119   // the collector when the sample is being done?).
 120   const bool sampled = false;
 121 
 122   // "Generation" and "Space" counters.
 123   //
 124   //  name "generation.1" This is logically the old generation in
 125   // generational GC terms.  The "1, 1" parameters are for
 126   // the n-th generation (=1) with 1 space.
 127   // Counters are created from minCapacity, maxCapacity, and capacity
 128   _old_collection_counters = new G1OldGenerationCounters(this, "old");
 129 
 130   //  name  "generation.1.space.0"
 131   // Counters are created from maxCapacity, capacity, initCapacity,
 132   // and used.
 133   _old_space_counters = new HSpaceCounters(_old_collection_counters->name_space(),
 134     "space", 0 /* ordinal */,
 135     pad_capacity(overall_reserved()) /* max_capacity */,
 136     pad_capacity(old_space_committed()) /* init_capacity */);
 137 
 138   //   Young collection set
 139   //  name "generation.0".  This is logically the young generation.
 140   //  The "0, 3" are parameters for the n-th generation (=0) with 3 spaces.
 141   // See  _old_collection_counters for additional counters
 142   _young_collection_counters = new G1YoungGenerationCounters(this, "young");
 143 
 144   const char* young_collection_name_space = _young_collection_counters->name_space();
 145 
 146   //  name "generation.0.space.0"
 147   // See _old_space_counters for additional counters
 148   _eden_counters = new HSpaceCounters(young_collection_name_space,
 149     "eden", 0 /* ordinal */,
 150     pad_capacity(overall_reserved()) /* max_capacity */,
 151     pad_capacity(eden_space_committed()) /* init_capacity */);
 152 
 153   //  name "generation.0.space.1"
 154   // See _old_space_counters for additional counters
 155   // Set the arguments to indicate that this survivor space is not used.
 156   _from_counters = new HSpaceCounters(young_collection_name_space,
 157     "s0", 1 /* ordinal */,
 158     pad_capacity(0) /* max_capacity */,
 159     pad_capacity(0) /* init_capacity */);
 160 
 161   //  name "generation.0.space.2"
 162   // See _old_space_counters for additional counters
 163   _to_counters = new HSpaceCounters(young_collection_name_space,
 164     "s1", 2 /* ordinal */,
 165     pad_capacity(overall_reserved()) /* max_capacity */,
 166     pad_capacity(survivor_space_committed()) /* init_capacity */);
 167 
 168   if (UsePerfData) {
 169     // Given that this survivor space is not used, we update it here
 170     // once to reflect that its used space is 0 so that we don't have to
 171     // worry about updating it again later.
 172     _from_counters->update_used(0);
 173   }
 174 }
 175 
 176 void G1MonitoringSupport::recalculate_sizes() {
 177   G1CollectedHeap* g1 = g1h();
 178 
 179   // Recalculate all the sizes from scratch. We assume that this is
 180   // called at a point where no concurrent updates to the various
 181   // values we read here are possible (i.e., at a STW phase at the end
 182   // of a GC).
 183 
 184   uint young_list_length = g1->young_regions_count();
 185   uint survivor_list_length = g1->survivor_regions_count();
 186   assert(young_list_length >= survivor_list_length, "invariant");
 187   uint eden_list_length = young_list_length - survivor_list_length;
 188   // Max length includes any potential extensions to the young gen
 189   // we'll do when the GC locker is active.
 190   uint young_list_max_length = g1->g1_policy()->young_list_max_length();
 191   assert(young_list_max_length >= survivor_list_length, "invariant");
 192   uint eden_list_max_length = young_list_max_length - survivor_list_length;
 193 
 194   _overall_used = g1->used_unlocked();
 195   _eden_used = (size_t) eden_list_length * HeapRegion::GrainBytes;
 196   _survivor_used = (size_t) survivor_list_length * HeapRegion::GrainBytes;
 197   _young_region_num = young_list_length;
 198   _old_used = subtract_up_to_zero(_overall_used, _eden_used + _survivor_used);
 199 
 200   // First calculate the committed sizes that can be calculated independently.
 201   _survivor_committed = _survivor_used;
 202   _old_committed = HeapRegion::align_up_to_region_byte_size(_old_used);
 203 
 204   // Next, start with the overall committed size.
 205   _overall_committed = g1->capacity();
 206   size_t committed = _overall_committed;
 207 
 208   // Remove the committed size we have calculated so far (for the
 209   // survivor and old space).
 210   assert(committed >= (_survivor_committed + _old_committed), "sanity");
 211   committed -= _survivor_committed + _old_committed;
 212 
 213   // Next, calculate and remove the committed size for the eden.
 214   _eden_committed = (size_t) eden_list_max_length * HeapRegion::GrainBytes;
 215   // Somewhat defensive: be robust in case there are inaccuracies in
 216   // the calculations
 217   _eden_committed = MIN2(_eden_committed, committed);
 218   committed -= _eden_committed;
 219 
 220   // Finally, give the rest to the old space...
 221   _old_committed += committed;
 222   // ..and calculate the young gen committed.
 223   _young_gen_committed = _eden_committed + _survivor_committed;
 224 
 225   assert(_overall_committed ==
 226          (_eden_committed + _survivor_committed + _old_committed),
 227          "the committed sizes should add up");
 228   // Somewhat defensive: cap the eden used size to make sure it
 229   // never exceeds the committed size.
 230   _eden_used = MIN2(_eden_used, _eden_committed);
 231   // _survivor_committed and _old_committed are calculated in terms of
 232   // the corresponding _*_used value, so the next two conditions
 233   // should hold.
 234   assert(_survivor_used <= _survivor_committed, "post-condition");
 235   assert(_old_used <= _old_committed, "post-condition");
 236 }
 237 
 238 void G1MonitoringSupport::recalculate_eden_size() {
 239   G1CollectedHeap* g1 = g1h();
 240 
 241   // When a new eden region is allocated, only the eden_used size is
 242   // affected (since we have recalculated everything else at the last GC).
 243 
 244   uint young_region_num = g1h()->young_regions_count();
 245   if (young_region_num > _young_region_num) {
 246     uint diff = young_region_num - _young_region_num;
 247     _eden_used += (size_t) diff * HeapRegion::GrainBytes;
 248     // Somewhat defensive: cap the eden used size to make sure it
 249     // never exceeds the committed size.
 250     _eden_used = MIN2(_eden_used, _eden_committed);
 251     _young_region_num = young_region_num;
 252   }
 253 }
 254 
 255 void G1MonitoringSupport::update_sizes() {
 256   recalculate_sizes();
 257   if (UsePerfData) {
 258     eden_counters()->update_capacity(pad_capacity(eden_space_committed()));
 259     eden_counters()->update_used(eden_space_used());
 260     // only the to survivor space (s1) is active, so we don't need to
 261     // update the counters for the from survivor space (s0)
 262     to_counters()->update_capacity(pad_capacity(survivor_space_committed()));
 263     to_counters()->update_used(survivor_space_used());
 264     old_space_counters()->update_capacity(pad_capacity(old_space_committed()));
 265     old_space_counters()->update_used(old_space_used());
 266     old_collection_counters()->update_all();
 267     young_collection_counters()->update_all();
 268     MetaspaceCounters::update_performance_counters();
 269     CompressedClassSpaceCounters::update_performance_counters();
 270   }
 271 }
 272 
 273 void G1MonitoringSupport::update_eden_size() {
 274   recalculate_eden_size();
 275   if (UsePerfData) {
 276     eden_counters()->update_used(eden_space_used());
 277   }
 278 }