1 /*
   2  * Copyright (c) 2011, 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 
  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 
  31 G1GenerationCounters::G1GenerationCounters(G1MonitoringSupport* g1mm,
  32                                            const char* name,
  33                                            int ordinal, int spaces,
  34                                            size_t min_capacity,
  35                                            size_t max_capacity,
  36                                            size_t curr_capacity)
  37   : GenerationCounters(name, ordinal, spaces, min_capacity,
  38                        max_capacity, curr_capacity), _g1mm(g1mm) { }
  39 
  40 // We pad the capacity three times given that the young generation
  41 // contains three spaces (eden and two survivors).
  42 G1YoungGenerationCounters::G1YoungGenerationCounters(G1MonitoringSupport* g1mm,
  43                                                      const char* name)
  44   : G1GenerationCounters(g1mm, name, 0 /* ordinal */, 3 /* spaces */,
  45                G1MonitoringSupport::pad_capacity(0, 3) /* min_capacity */,
  46                G1MonitoringSupport::pad_capacity(g1mm->young_gen_max(), 3),
  47                G1MonitoringSupport::pad_capacity(0, 3) /* curr_capacity */) {
  48   if (UsePerfData) {
  49     update_all();
  50   }
  51 }
  52 
  53 G1OldGenerationCounters::G1OldGenerationCounters(G1MonitoringSupport* g1mm,
  54                                                  const char* name)
  55   : G1GenerationCounters(g1mm, name, 1 /* ordinal */, 1 /* spaces */,
  56                G1MonitoringSupport::pad_capacity(0) /* min_capacity */,
  57                G1MonitoringSupport::pad_capacity(g1mm->old_gen_max()),
  58                G1MonitoringSupport::pad_capacity(0) /* curr_capacity */) {
  59   if (UsePerfData) {
  60     update_all();
  61   }
  62 }
  63 
  64 void G1YoungGenerationCounters::update_all() {
  65   size_t committed =
  66             G1MonitoringSupport::pad_capacity(_g1mm->young_gen_committed(), 3);
  67   _current_size->set_value(committed);
  68 }
  69 
  70 void G1OldGenerationCounters::update_all() {
  71   size_t committed =
  72             G1MonitoringSupport::pad_capacity(_g1mm->old_gen_committed());
  73   _current_size->set_value(committed);
  74 }
  75 
  76 G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h) :
  77   _g1h(g1h),
  78   _incremental_collection_counters(NULL),
  79   _full_collection_counters(NULL),
  80   _conc_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   //   name "collector.2".  In a generational collector this would be the
 110   // STW phases in concurrent collection.
 111   _conc_collection_counters =
 112     new CollectorCounters("G1 stop-the-world phases", 2);
 113 
 114   // timer sampling for all counters supporting sampling only update the
 115   // used value.  See the take_sample() method.  G1 requires both used and
 116   // capacity updated so sampling is not currently used.  It might
 117   // be sufficient to update all counters in take_sample() even though
 118   // take_sample() only returns "used".  When sampling was used, there
 119   // were some anomolous values emitted which may have been the consequence
 120   // of not updating all values simultaneously (i.e., see the calculation done
 121   // in eden_space_used(), is it possible that the values used to
 122   // calculate either eden_used or survivor_used are being updated by
 123   // the collector when the sample is being done?).
 124   const bool sampled = false;
 125 
 126   // "Generation" and "Space" counters.
 127   //
 128   //  name "generation.1" This is logically the old generation in
 129   // generational GC terms.  The "1, 1" parameters are for
 130   // the n-th generation (=1) with 1 space.
 131   // Counters are created from minCapacity, maxCapacity, and capacity
 132   _old_collection_counters = new G1OldGenerationCounters(this, "old");
 133 
 134   //  name  "generation.1.space.0"
 135   // Counters are created from maxCapacity, capacity, initCapacity,
 136   // and used.
 137   _old_space_counters = new HSpaceCounters(_old_collection_counters->name_space(),
 138     "space", 0 /* ordinal */,
 139     pad_capacity(overall_reserved()) /* max_capacity */,
 140     pad_capacity(old_space_committed()) /* init_capacity */);
 141 
 142   //   Young collection set
 143   //  name "generation.0".  This is logically the young generation.
 144   //  The "0, 3" are parameters for the n-th generation (=0) with 3 spaces.
 145   // See  _old_collection_counters for additional counters
 146   _young_collection_counters = new G1YoungGenerationCounters(this, "young");
 147 
 148   const char* young_collection_name_space = _young_collection_counters->name_space();
 149 
 150   //  name "generation.0.space.0"
 151   // See _old_space_counters for additional counters
 152   _eden_counters = new HSpaceCounters(young_collection_name_space,
 153     "eden", 0 /* ordinal */,
 154     pad_capacity(overall_reserved()) /* max_capacity */,
 155     pad_capacity(eden_space_committed()) /* init_capacity */);
 156 
 157   //  name "generation.0.space.1"
 158   // See _old_space_counters for additional counters
 159   // Set the arguments to indicate that this survivor space is not used.
 160   _from_counters = new HSpaceCounters(young_collection_name_space,
 161     "s0", 1 /* ordinal */,
 162     pad_capacity(0) /* max_capacity */,
 163     pad_capacity(0) /* init_capacity */);
 164 
 165   //  name "generation.0.space.2"
 166   // See _old_space_counters for additional counters
 167   _to_counters = new HSpaceCounters(young_collection_name_space,
 168     "s1", 2 /* ordinal */,
 169     pad_capacity(overall_reserved()) /* max_capacity */,
 170     pad_capacity(survivor_space_committed()) /* init_capacity */);
 171 
 172   if (UsePerfData) {
 173     // Given that this survivor space is not used, we update it here
 174     // once to reflect that its used space is 0 so that we don't have to
 175     // worry about updating it again later.
 176     _from_counters->update_used(0);
 177   }
 178 }
 179 
 180 void G1MonitoringSupport::recalculate_sizes() {
 181   G1CollectedHeap* g1 = g1h();
 182 
 183   // Recalculate all the sizes from scratch. We assume that this is
 184   // called at a point where no concurrent updates to the various
 185   // values we read here are possible (i.e., at a STW phase at the end
 186   // of a GC).
 187 
 188   uint young_list_length = g1->young_regions_count();
 189   uint survivor_list_length = g1->survivor_regions_count();
 190   assert(young_list_length >= survivor_list_length, "invariant");
 191   uint eden_list_length = young_list_length - survivor_list_length;
 192   // Max length includes any potential extensions to the young gen
 193   // we'll do when the GC locker is active.
 194   uint young_list_max_length = g1->g1_policy()->young_list_max_length();
 195   assert(young_list_max_length >= survivor_list_length, "invariant");
 196   uint eden_list_max_length = young_list_max_length - survivor_list_length;
 197 
 198   _overall_used = g1->used_unlocked();
 199   _eden_used = (size_t) eden_list_length * HeapRegion::GrainBytes;
 200   _survivor_used = (size_t) survivor_list_length * HeapRegion::GrainBytes;
 201   _young_region_num = young_list_length;
 202   _old_used = subtract_up_to_zero(_overall_used, _eden_used + _survivor_used);
 203 
 204   // First calculate the committed sizes that can be calculated independently.
 205   _survivor_committed = _survivor_used;
 206   _old_committed = HeapRegion::align_up_to_region_byte_size(_old_used);
 207 
 208   // Next, start with the overall committed size.
 209   _overall_committed = g1->capacity();
 210   size_t committed = _overall_committed;
 211 
 212   // Remove the committed size we have calculated so far (for the
 213   // survivor and old space).
 214   assert(committed >= (_survivor_committed + _old_committed), "sanity");
 215   committed -= _survivor_committed + _old_committed;
 216 
 217   // Next, calculate and remove the committed size for the eden.
 218   _eden_committed = (size_t) eden_list_max_length * HeapRegion::GrainBytes;
 219   // Somewhat defensive: be robust in case there are inaccuracies in
 220   // the calculations
 221   _eden_committed = MIN2(_eden_committed, committed);
 222   committed -= _eden_committed;
 223 
 224   // Finally, give the rest to the old space...
 225   _old_committed += committed;
 226   // ..and calculate the young gen committed.
 227   _young_gen_committed = _eden_committed + _survivor_committed;
 228 
 229   assert(_overall_committed ==
 230          (_eden_committed + _survivor_committed + _old_committed),
 231          "the committed sizes should add up");
 232   // Somewhat defensive: cap the eden used size to make sure it
 233   // never exceeds the committed size.
 234   _eden_used = MIN2(_eden_used, _eden_committed);
 235   // _survivor_committed and _old_committed are calculated in terms of
 236   // the corresponding _*_used value, so the next two conditions
 237   // should hold.
 238   assert(_survivor_used <= _survivor_committed, "post-condition");
 239   assert(_old_used <= _old_committed, "post-condition");
 240 }
 241 
 242 void G1MonitoringSupport::recalculate_eden_size() {
 243   G1CollectedHeap* g1 = g1h();
 244 
 245   // When a new eden region is allocated, only the eden_used size is
 246   // affected (since we have recalculated everything else at the last GC).
 247 
 248   uint young_region_num = g1h()->young_regions_count();
 249   if (young_region_num > _young_region_num) {
 250     uint diff = young_region_num - _young_region_num;
 251     _eden_used += (size_t) diff * HeapRegion::GrainBytes;
 252     // Somewhat defensive: cap the eden used size to make sure it
 253     // never exceeds the committed size.
 254     _eden_used = MIN2(_eden_used, _eden_committed);
 255     _young_region_num = young_region_num;
 256   }
 257 }
 258 
 259 void G1MonitoringSupport::update_sizes() {
 260   recalculate_sizes();
 261   if (UsePerfData) {
 262     eden_counters()->update_capacity(pad_capacity(eden_space_committed()));
 263     eden_counters()->update_used(eden_space_used());
 264     // only the to survivor space (s1) is active, so we don't need to
 265     // update the counters for the from survivor space (s0)
 266     to_counters()->update_capacity(pad_capacity(survivor_space_committed()));
 267     to_counters()->update_used(survivor_space_used());
 268     old_space_counters()->update_capacity(pad_capacity(old_space_committed()));
 269     old_space_counters()->update_used(old_space_used());
 270     old_collection_counters()->update_all();
 271     young_collection_counters()->update_all();
 272     MetaspaceCounters::update_performance_counters();
 273     CompressedClassSpaceCounters::update_performance_counters();
 274   }
 275 }
 276 
 277 void G1MonitoringSupport::update_eden_size() {
 278   recalculate_eden_size();
 279   if (UsePerfData) {
 280     eden_counters()->update_used(eden_space_used());
 281   }
 282 }