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src/hotspot/share/gc/g1/g1ConcurrentRefine.cpp

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rev 47675 : [mq]: 8149127-rename-concurrentrefine-a
rev 47676 : imported patch 8149127-rename-concurrentrefine-b
rev 47677 : [mq]: 8149127-rename-concurrentrefine-b-stefanj-review
rev 47678 : imported patch 8140255-move-sampling-thread
rev 47679 : [mq]: 8140255-update
rev 47680 : [mq]: 8190426-lazy-init-refinement-threads


  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/g1ConcurrentRefine.hpp"
  27 #include "gc/g1/g1ConcurrentRefineThread.hpp"
  28 #include "logging/log.hpp"
  29 #include "runtime/java.hpp"
  30 #include "runtime/thread.hpp"
  31 #include "utilities/debug.hpp"
  32 #include "utilities/globalDefinitions.hpp"
  33 #include "utilities/pair.hpp"
  34 #include <math.h>
  35 









































































  36 // Arbitrary but large limits, to simplify some of the zone calculations.
  37 // The general idea is to allow expressions like
  38 //   MIN2(x OP y, max_XXX_zone)
  39 // without needing to check for overflow in "x OP y", because the
  40 // ranges for x and y have been restricted.
  41 STATIC_ASSERT(sizeof(LP64_ONLY(jint) NOT_LP64(jshort)) <= (sizeof(size_t)/2));
  42 const size_t max_yellow_zone = LP64_ONLY(max_jint) NOT_LP64(max_jshort);
  43 const size_t max_green_zone = max_yellow_zone / 2;
  44 const size_t max_red_zone = INT_MAX; // For dcqs.set_max_completed_queue.
  45 STATIC_ASSERT(max_yellow_zone <= max_red_zone);
  46 
  47 // Range check assertions for green zone values.
  48 #define assert_zone_constraints_g(green)                        \
  49   do {                                                          \
  50     size_t azc_g_green = (green);                               \
  51     assert(azc_g_green <= max_green_zone,                       \
  52            "green exceeds max: " SIZE_FORMAT, azc_g_green);     \
  53   } while (0)
  54 
  55 // Range check assertions for green and yellow zone values.


  79            azc_gyr_yellow, azc_gyr_red);                                \
  80   } while (0)
  81 
  82 // Logging tag sequence for refinement control updates.
  83 #define CTRL_TAGS gc, ergo, refine
  84 
  85 // For logging zone values, ensuring consistency of level and tags.
  86 #define LOG_ZONES(...) log_debug( CTRL_TAGS )(__VA_ARGS__)
  87 
  88 // Package for pair of refinement thread activation and deactivation
  89 // thresholds.  The activation and deactivation levels are resp. the first
  90 // and second values of the pair.
  91 typedef Pair<size_t, size_t> Thresholds;
  92 inline size_t activation_level(const Thresholds& t) { return t.first; }
  93 inline size_t deactivation_level(const Thresholds& t) { return t.second; }
  94 
  95 static Thresholds calc_thresholds(size_t green_zone,
  96                                   size_t yellow_zone,
  97                                   uint worker_i) {
  98   double yellow_size = yellow_zone - green_zone;
  99   double step = yellow_size / G1ConcurrentRefine::thread_num();
 100   if (worker_i == 0) {
 101     // Potentially activate worker 0 more aggressively, to keep
 102     // available buffers near green_zone value.  When yellow_size is
 103     // large we don't want to allow a full step to accumulate before
 104     // doing any processing, as that might lead to significantly more
 105     // than green_zone buffers to be processed by update_rs.
 106     step = MIN2(step, ParallelGCThreads / 2.0);
 107   }
 108   size_t activate_offset = static_cast<size_t>(ceil(step * (worker_i + 1)));
 109   size_t deactivate_offset = static_cast<size_t>(floor(step * worker_i));
 110   return Thresholds(green_zone + activate_offset,
 111                     green_zone + deactivate_offset);
 112 }
 113 
 114 G1ConcurrentRefine::G1ConcurrentRefine(size_t green_zone,
 115                                        size_t yellow_zone,
 116                                        size_t red_zone,
 117                                        size_t min_yellow_zone_size) :
 118   _threads(NULL),
 119   _n_worker_threads(thread_num()),
 120   _green_zone(green_zone),
 121   _yellow_zone(yellow_zone),
 122   _red_zone(red_zone),
 123   _min_yellow_zone_size(min_yellow_zone_size)
 124 {
 125   assert_zone_constraints_gyr(green_zone, yellow_zone, red_zone);

 126 }
 127 
 128 static size_t calc_min_yellow_zone_size() {
 129   size_t step = G1ConcRefinementThresholdStep;
 130   uint n_workers = G1ConcurrentRefine::thread_num();
 131   if ((max_yellow_zone / step) < n_workers) {
 132     return max_yellow_zone;
 133   } else {
 134     return step * n_workers;
 135   }
 136 }
 137 
 138 static size_t calc_init_green_zone() {
 139   size_t green = G1ConcRefinementGreenZone;
 140   if (FLAG_IS_DEFAULT(G1ConcRefinementGreenZone)) {
 141     green = ParallelGCThreads;
 142   }
 143   return MIN2(green, max_green_zone);
 144 }
 145 
 146 static size_t calc_init_yellow_zone(size_t green, size_t min_size) {
 147   size_t config = G1ConcRefinementYellowZone;
 148   size_t size = 0;
 149   if (FLAG_IS_DEFAULT(G1ConcRefinementYellowZone)) {
 150     size = green * 2;


 174   size_t red_zone = calc_init_red_zone(green_zone, yellow_zone);
 175 
 176   LOG_ZONES("Initial Refinement Zones: "
 177             "green: " SIZE_FORMAT ", "
 178             "yellow: " SIZE_FORMAT ", "
 179             "red: " SIZE_FORMAT ", "
 180             "min yellow size: " SIZE_FORMAT,
 181             green_zone, yellow_zone, red_zone, min_yellow_zone_size);
 182 
 183   G1ConcurrentRefine* cr = new G1ConcurrentRefine(green_zone,
 184                                                   yellow_zone,
 185                                                   red_zone,
 186                                                   min_yellow_zone_size);
 187 
 188   if (cr == NULL) {
 189     *ecode = JNI_ENOMEM;
 190     vm_shutdown_during_initialization("Could not create G1ConcurrentRefine");
 191     return NULL;
 192   }
 193 
 194   cr->_threads = NEW_C_HEAP_ARRAY_RETURN_NULL(G1ConcurrentRefineThread*, cr->_n_worker_threads, mtGC);
 195   if (cr->_threads == NULL) {
 196     *ecode = JNI_ENOMEM;
 197     vm_shutdown_during_initialization("Could not allocate an array for G1ConcurrentRefineThread");
 198     return NULL;
 199   }
 200 
 201   uint worker_id_offset = DirtyCardQueueSet::num_par_ids();
 202 
 203   G1ConcurrentRefineThread *next = NULL;
 204   for (uint i = cr->_n_worker_threads - 1; i != UINT_MAX; i--) {
 205     Thresholds thresholds = calc_thresholds(green_zone, yellow_zone, i);
 206     G1ConcurrentRefineThread* t =
 207       new G1ConcurrentRefineThread(cr,
 208                                    next,
 209                                    worker_id_offset,
 210                                    i,
 211                                    activation_level(thresholds),
 212                                    deactivation_level(thresholds));
 213     assert(t != NULL, "Conc refine should have been created");
 214     if (t->osthread() == NULL) {
 215       *ecode = JNI_ENOMEM;
 216       vm_shutdown_during_initialization("Could not create G1ConcurrentRefineThread");
 217       return NULL;
 218     }
 219 
 220     assert(t->cr() == cr, "Conc refine thread should refer to this");
 221     cr->_threads[i] = t;
 222     next = t;
 223   }
 224 
 225   *ecode = JNI_OK;
 226   return cr;
 227 }
 228 
 229 void G1ConcurrentRefine::stop() {
 230   for (uint i = 0; i < _n_worker_threads; i++) {
 231     _threads[i]->stop();
 232   }
 233 }
 234 
 235 void G1ConcurrentRefine::update_thread_thresholds() {
 236   for (uint i = 0; i < _n_worker_threads; i++) {
 237     Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, i);
 238     _threads[i]->update_thresholds(activation_level(thresholds),
 239                                    deactivation_level(thresholds));
 240   }
 241 }
 242 
 243 G1ConcurrentRefine::~G1ConcurrentRefine() {
 244   for (uint i = 0; i < _n_worker_threads; i++) {
 245     delete _threads[i];
 246   }
 247   FREE_C_HEAP_ARRAY(G1ConcurrentRefineThread*, _threads);
 248 }
 249 
 250 void G1ConcurrentRefine::threads_do(ThreadClosure *tc) {
 251   for (uint i = 0; i < _n_worker_threads; i++) {
 252     tc->do_thread(_threads[i]);
 253   }
 254 }
 255 
 256 uint G1ConcurrentRefine::thread_num() {
 257   return G1ConcRefinementThreads;
 258 }
 259 
 260 void G1ConcurrentRefine::print_threads_on(outputStream* st) const {
 261   for (uint i = 0; i < _n_worker_threads; ++i) {
 262     _threads[i]->print_on(st);
 263     st->cr();
 264   }
 265 }
 266 
 267 static size_t calc_new_green_zone(size_t green,
 268                                   double update_rs_time,
 269                                   size_t update_rs_processed_buffers,
 270                                   double goal_ms) {
 271   // Adjust green zone based on whether we're meeting the time goal.
 272   // Limit to max_green_zone.
 273   const double inc_k = 1.1, dec_k = 0.9;
 274   if (update_rs_time > goal_ms) {
 275     if (green > 0) {
 276       green = static_cast<size_t>(green * dec_k);
 277     }
 278   } else if (update_rs_time < goal_ms &&
 279              update_rs_processed_buffers > green) {
 280     green = static_cast<size_t>(MAX2(green * inc_k, green + 1.0));
 281     green = MIN2(green, max_green_zone);
 282   }
 283   return green;
 284 }


 309                                     update_rs_processed_buffers,
 310                                     goal_ms);
 311   _yellow_zone = calc_new_yellow_zone(_green_zone, _min_yellow_zone_size);
 312   _red_zone = calc_new_red_zone(_green_zone, _yellow_zone);
 313 
 314   assert_zone_constraints_gyr(_green_zone, _yellow_zone, _red_zone);
 315   LOG_ZONES("Updated Refinement Zones: "
 316             "green: " SIZE_FORMAT ", "
 317             "yellow: " SIZE_FORMAT ", "
 318             "red: " SIZE_FORMAT,
 319             _green_zone, _yellow_zone, _red_zone);
 320 }
 321 
 322 void G1ConcurrentRefine::adjust(double update_rs_time,
 323                                 size_t update_rs_processed_buffers,
 324                                 double goal_ms) {
 325   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
 326 
 327   if (G1UseAdaptiveConcRefinement) {
 328     update_zones(update_rs_time, update_rs_processed_buffers, goal_ms);
 329     update_thread_thresholds();
 330 
 331     // Change the barrier params
 332     if (_n_worker_threads == 0) {
 333       // Disable dcqs notification when there are no threads to notify.
 334       dcqs.set_process_completed_threshold(INT_MAX);
 335     } else {
 336       // Worker 0 is the primary; wakeup is via dcqs notification.
 337       STATIC_ASSERT(max_yellow_zone <= INT_MAX);
 338       size_t activate = _threads[0]->activation_threshold();
 339       dcqs.set_process_completed_threshold((int)activate);
 340     }
 341     dcqs.set_max_completed_queue((int)red_zone());
 342   }
 343 
 344   size_t curr_queue_size = dcqs.completed_buffers_num();
 345   if (curr_queue_size >= yellow_zone()) {
 346     dcqs.set_completed_queue_padding(curr_queue_size);
 347   } else {
 348     dcqs.set_completed_queue_padding(0);
 349   }
 350   dcqs.notify_if_necessary();







































 351 }


  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/g1ConcurrentRefine.hpp"
  27 #include "gc/g1/g1ConcurrentRefineThread.hpp"
  28 #include "logging/log.hpp"
  29 #include "runtime/java.hpp"
  30 #include "runtime/thread.hpp"
  31 #include "utilities/debug.hpp"
  32 #include "utilities/globalDefinitions.hpp"
  33 #include "utilities/pair.hpp"
  34 #include <math.h>
  35 
  36 G1ConcurrentRefineThreadControl::G1ConcurrentRefineThreadControl() :
  37   _cg1r(NULL),
  38   _threads(NULL),
  39   _num_max_threads(0)
  40 {
  41 }
  42 
  43 G1ConcurrentRefineThreadControl::~G1ConcurrentRefineThreadControl() {
  44   for (uint i = 0; i < _num_max_threads; i++) {
  45     G1ConcurrentRefineThread* t = _threads[i];
  46     if (t != NULL) {
  47       delete t;
  48     }
  49   }
  50   FREE_C_HEAP_ARRAY(G1ConcurrentRefineThread*, _threads);
  51 }
  52 
  53 void G1ConcurrentRefineThreadControl::initialize(G1ConcurrentRefine* cg1r, uint num_max_threads) {
  54   assert(cg1r != NULL, "Passed g1ConcurrentRefine must not be NULL");
  55   _cg1r = cg1r;
  56   _num_max_threads = num_max_threads;
  57   _threads = NEW_C_HEAP_ARRAY(G1ConcurrentRefineThread*, num_max_threads, mtGC);
  58   for (uint i = 0; i < num_max_threads; i++) {
  59     if (UseDynamicNumberOfGCThreads) {
  60       _threads[i] = NULL;
  61     } else {
  62       _threads[i] = new G1ConcurrentRefineThread(_cg1r, i);
  63     }
  64   }
  65 }
  66 
  67 void G1ConcurrentRefineThreadControl::maybe_activate_next(uint cur_worker_id) {
  68   assert(cur_worker_id < _num_max_threads, "Tried to activate from impossible thread %u", cur_worker_id);
  69   if (cur_worker_id == (_num_max_threads - 1)) {
  70     // Already the last thread, there is no more thread to activate.
  71     return;
  72   }
  73 
  74   uint worker_id = cur_worker_id + 1;
  75   G1ConcurrentRefineThread* thread_to_activate = _threads[worker_id];
  76   if (thread_to_activate == NULL) {
  77     // Still need to create the thread...
  78     _threads[worker_id] = new G1ConcurrentRefineThread(_cg1r, worker_id);
  79     thread_to_activate = _threads[worker_id];
  80   }
  81   thread_to_activate->activate();
  82 }
  83 
  84 void G1ConcurrentRefineThreadControl::print_on(outputStream* st) const {
  85   for (uint i = 0; i < _num_max_threads; ++i) {
  86     if (_threads[i] != NULL) {
  87       _threads[i]->print_on(st);
  88       st->cr();
  89     }
  90   }
  91 }
  92 
  93 void G1ConcurrentRefineThreadControl::worker_threads_do(ThreadClosure* tc) {
  94   for (uint i = 0; i < _num_max_threads; i++) {
  95     if (_threads[i] != NULL) {
  96       tc->do_thread(_threads[i]);
  97     }
  98   }
  99 }
 100 
 101 void G1ConcurrentRefineThreadControl::stop() {
 102   for (uint i = 0; i < _num_max_threads; i++) {
 103     if (_threads[i] != NULL) {
 104       _threads[i]->stop();
 105     }
 106   }
 107 }
 108 
 109 // Arbitrary but large limits, to simplify some of the zone calculations.
 110 // The general idea is to allow expressions like
 111 //   MIN2(x OP y, max_XXX_zone)
 112 // without needing to check for overflow in "x OP y", because the
 113 // ranges for x and y have been restricted.
 114 STATIC_ASSERT(sizeof(LP64_ONLY(jint) NOT_LP64(jshort)) <= (sizeof(size_t)/2));
 115 const size_t max_yellow_zone = LP64_ONLY(max_jint) NOT_LP64(max_jshort);
 116 const size_t max_green_zone = max_yellow_zone / 2;
 117 const size_t max_red_zone = INT_MAX; // For dcqs.set_max_completed_queue.
 118 STATIC_ASSERT(max_yellow_zone <= max_red_zone);
 119 
 120 // Range check assertions for green zone values.
 121 #define assert_zone_constraints_g(green)                        \
 122   do {                                                          \
 123     size_t azc_g_green = (green);                               \
 124     assert(azc_g_green <= max_green_zone,                       \
 125            "green exceeds max: " SIZE_FORMAT, azc_g_green);     \
 126   } while (0)
 127 
 128 // Range check assertions for green and yellow zone values.


 152            azc_gyr_yellow, azc_gyr_red);                                \
 153   } while (0)
 154 
 155 // Logging tag sequence for refinement control updates.
 156 #define CTRL_TAGS gc, ergo, refine
 157 
 158 // For logging zone values, ensuring consistency of level and tags.
 159 #define LOG_ZONES(...) log_debug( CTRL_TAGS )(__VA_ARGS__)
 160 
 161 // Package for pair of refinement thread activation and deactivation
 162 // thresholds.  The activation and deactivation levels are resp. the first
 163 // and second values of the pair.
 164 typedef Pair<size_t, size_t> Thresholds;
 165 inline size_t activation_level(const Thresholds& t) { return t.first; }
 166 inline size_t deactivation_level(const Thresholds& t) { return t.second; }
 167 
 168 static Thresholds calc_thresholds(size_t green_zone,
 169                                   size_t yellow_zone,
 170                                   uint worker_i) {
 171   double yellow_size = yellow_zone - green_zone;
 172   double step = yellow_size / G1ConcurrentRefine::max_num_threads();
 173   if (worker_i == 0) {
 174     // Potentially activate worker 0 more aggressively, to keep
 175     // available buffers near green_zone value.  When yellow_size is
 176     // large we don't want to allow a full step to accumulate before
 177     // doing any processing, as that might lead to significantly more
 178     // than green_zone buffers to be processed by update_rs.
 179     step = MIN2(step, ParallelGCThreads / 2.0);
 180   }
 181   size_t activate_offset = static_cast<size_t>(ceil(step * (worker_i + 1)));
 182   size_t deactivate_offset = static_cast<size_t>(floor(step * worker_i));
 183   return Thresholds(green_zone + activate_offset,
 184                     green_zone + deactivate_offset);
 185 }
 186 
 187 G1ConcurrentRefine::G1ConcurrentRefine(size_t green_zone,
 188                                        size_t yellow_zone,
 189                                        size_t red_zone,
 190                                        size_t min_yellow_zone_size) :
 191   _thread_control(),

 192   _green_zone(green_zone),
 193   _yellow_zone(yellow_zone),
 194   _red_zone(red_zone),
 195   _min_yellow_zone_size(min_yellow_zone_size)
 196 {
 197   assert_zone_constraints_gyr(green_zone, yellow_zone, red_zone);
 198   _thread_control.initialize(this, max_num_threads());
 199 }
 200 
 201 static size_t calc_min_yellow_zone_size() {
 202   size_t step = G1ConcRefinementThresholdStep;
 203   uint n_workers = G1ConcurrentRefine::max_num_threads();
 204   if ((max_yellow_zone / step) < n_workers) {
 205     return max_yellow_zone;
 206   } else {
 207     return step * n_workers;
 208   }
 209 }
 210 
 211 static size_t calc_init_green_zone() {
 212   size_t green = G1ConcRefinementGreenZone;
 213   if (FLAG_IS_DEFAULT(G1ConcRefinementGreenZone)) {
 214     green = ParallelGCThreads;
 215   }
 216   return MIN2(green, max_green_zone);
 217 }
 218 
 219 static size_t calc_init_yellow_zone(size_t green, size_t min_size) {
 220   size_t config = G1ConcRefinementYellowZone;
 221   size_t size = 0;
 222   if (FLAG_IS_DEFAULT(G1ConcRefinementYellowZone)) {
 223     size = green * 2;


 247   size_t red_zone = calc_init_red_zone(green_zone, yellow_zone);
 248 
 249   LOG_ZONES("Initial Refinement Zones: "
 250             "green: " SIZE_FORMAT ", "
 251             "yellow: " SIZE_FORMAT ", "
 252             "red: " SIZE_FORMAT ", "
 253             "min yellow size: " SIZE_FORMAT,
 254             green_zone, yellow_zone, red_zone, min_yellow_zone_size);
 255 
 256   G1ConcurrentRefine* cr = new G1ConcurrentRefine(green_zone,
 257                                                   yellow_zone,
 258                                                   red_zone,
 259                                                   min_yellow_zone_size);
 260 
 261   if (cr == NULL) {
 262     *ecode = JNI_ENOMEM;
 263     vm_shutdown_during_initialization("Could not create G1ConcurrentRefine");
 264     return NULL;
 265   }
 266 































 267   *ecode = JNI_OK;
 268   return cr;
 269 }
 270 
 271 void G1ConcurrentRefine::stop() {
 272   _thread_control.stop();










 273 }
 274 
 275 G1ConcurrentRefine::~G1ConcurrentRefine() {




 276 }
 277 
 278 void G1ConcurrentRefine::threads_do(ThreadClosure *tc) {
 279   _thread_control.worker_threads_do(tc);


 280 }
 281 
 282 uint G1ConcurrentRefine::max_num_threads() {
 283   return G1ConcRefinementThreads;
 284 }
 285 
 286 void G1ConcurrentRefine::print_threads_on(outputStream* st) const {
 287   _thread_control.print_on(st);



 288 }
 289 
 290 static size_t calc_new_green_zone(size_t green,
 291                                   double update_rs_time,
 292                                   size_t update_rs_processed_buffers,
 293                                   double goal_ms) {
 294   // Adjust green zone based on whether we're meeting the time goal.
 295   // Limit to max_green_zone.
 296   const double inc_k = 1.1, dec_k = 0.9;
 297   if (update_rs_time > goal_ms) {
 298     if (green > 0) {
 299       green = static_cast<size_t>(green * dec_k);
 300     }
 301   } else if (update_rs_time < goal_ms &&
 302              update_rs_processed_buffers > green) {
 303     green = static_cast<size_t>(MAX2(green * inc_k, green + 1.0));
 304     green = MIN2(green, max_green_zone);
 305   }
 306   return green;
 307 }


 332                                     update_rs_processed_buffers,
 333                                     goal_ms);
 334   _yellow_zone = calc_new_yellow_zone(_green_zone, _min_yellow_zone_size);
 335   _red_zone = calc_new_red_zone(_green_zone, _yellow_zone);
 336 
 337   assert_zone_constraints_gyr(_green_zone, _yellow_zone, _red_zone);
 338   LOG_ZONES("Updated Refinement Zones: "
 339             "green: " SIZE_FORMAT ", "
 340             "yellow: " SIZE_FORMAT ", "
 341             "red: " SIZE_FORMAT,
 342             _green_zone, _yellow_zone, _red_zone);
 343 }
 344 
 345 void G1ConcurrentRefine::adjust(double update_rs_time,
 346                                 size_t update_rs_processed_buffers,
 347                                 double goal_ms) {
 348   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
 349 
 350   if (G1UseAdaptiveConcRefinement) {
 351     update_zones(update_rs_time, update_rs_processed_buffers, goal_ms);

 352 
 353     // Change the barrier params
 354     if (max_num_threads() == 0) {
 355       // Disable dcqs notification when there are no threads to notify.
 356       dcqs.set_process_completed_threshold(INT_MAX);
 357     } else {
 358       // Worker 0 is the primary; wakeup is via dcqs notification.
 359       STATIC_ASSERT(max_yellow_zone <= INT_MAX);
 360       size_t activate = activation_threshold(0);
 361       dcqs.set_process_completed_threshold((int)activate);
 362     }
 363     dcqs.set_max_completed_queue((int)red_zone());
 364   }
 365 
 366   size_t curr_queue_size = dcqs.completed_buffers_num();
 367   if (curr_queue_size >= yellow_zone()) {
 368     dcqs.set_completed_queue_padding(curr_queue_size);
 369   } else {
 370     dcqs.set_completed_queue_padding(0);
 371   }
 372   dcqs.notify_if_necessary();
 373 }
 374 
 375 size_t G1ConcurrentRefine::activation_threshold(uint worker_id) const {
 376   Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
 377   return activation_level(thresholds);
 378 }
 379 
 380 size_t G1ConcurrentRefine::deactivation_threshold(uint worker_id) const {
 381   Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
 382   return deactivation_level(thresholds);
 383 }
 384 
 385 uint G1ConcurrentRefine::worker_id_offset() {
 386   return DirtyCardQueueSet::num_par_ids();
 387 }
 388 
 389 void G1ConcurrentRefine::maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers) {
 390   if (activation_threshold(worker_id + 1) > num_cur_buffers) {
 391     _thread_control.maybe_activate_next(worker_id);
 392   }
 393 }
 394 
 395 bool G1ConcurrentRefine::do_refinement_step(uint worker_id) {
 396   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
 397 
 398   size_t curr_buffer_num = dcqs.completed_buffers_num();
 399   // If the number of the buffers falls down into the yellow zone,
 400   // that means that the transition period after the evacuation pause has ended.
 401   // Since the value written to the DCQS is the same for all threads, there is no
 402   // need to synchronize.
 403   if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= yellow_zone()) {
 404     dcqs.set_completed_queue_padding(0);
 405   }
 406 
 407   maybe_activate_more_threads(worker_id, curr_buffer_num);
 408 
 409   // Process the next buffer, if there are enough left.
 410   return dcqs.refine_completed_buffer_concurrently(worker_id + worker_id_offset(),
 411                                                    deactivation_threshold(worker_id));
 412 }
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