/*

 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1BarrierSet.hpp"

#include "gc/g1/g1ConcurrentRefine.hpp"

#include "gc/g1/g1ConcurrentRefineThread.hpp"

#include "gc/g1/g1DirtyCardQueue.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "runtime/java.hpp"

#include "runtime/thread.hpp"

#include "utilities/debug.hpp"

#include "utilities/globalDefinitions.hpp"

#include "utilities/pair.hpp"

#include <math.h>

G1ConcurrentRefineThread* G1ConcurrentRefineThreadControl::create_refinement_thread(uint worker_id, bool initializing) {

  G1ConcurrentRefineThread* result = NULL;

  if (initializing || !InjectGCWorkerCreationFailure) {

    result = new G1ConcurrentRefineThread(_cr, worker_id);

  }

  if (result == NULL || result->osthread() == NULL) {

    log_warning(gc)("Failed to create refinement thread %u, no more %s",

                    worker_id,

                    result == NULL ? "memory" : "OS threads");

  }

  return result;

}

G1ConcurrentRefineThreadControl::G1ConcurrentRefineThreadControl() :

  _cr(NULL),

  _threads(NULL),

  _num_max_threads(0)

{

}

G1ConcurrentRefineThreadControl::~G1ConcurrentRefineThreadControl() {

  for (uint i = 0; i < _num_max_threads; i++) {

    G1ConcurrentRefineThread* t = _threads[i];

    if (t != NULL) {

      delete t;

    }

  }

  FREE_C_HEAP_ARRAY(G1ConcurrentRefineThread*, _threads);

}

jint G1ConcurrentRefineThreadControl::initialize(G1ConcurrentRefine* cr, uint num_max_threads) {

  assert(cr != NULL, "G1ConcurrentRefine must not be NULL");

  _cr = cr;

  _num_max_threads = num_max_threads;

  _threads = NEW_C_HEAP_ARRAY_RETURN_NULL(G1ConcurrentRefineThread*, num_max_threads, mtGC);

  if (_threads == NULL) {

    vm_shutdown_during_initialization("Could not allocate thread holder array.");

    return JNI_ENOMEM;

  }

  for (uint i = 0; i < num_max_threads; i++) {

    if (UseDynamicNumberOfGCThreads && i != 0 /* Always start first thread. */) {

      _threads[i] = NULL;

    } else {

      _threads[i] = create_refinement_thread(i, true);

      if (_threads[i] == NULL) {

        vm_shutdown_during_initialization("Could not allocate refinement threads.");

        return JNI_ENOMEM;

      }

    }

  }

  return JNI_OK;

}

void G1ConcurrentRefineThreadControl::maybe_activate_next(uint cur_worker_id) {

  assert(cur_worker_id < _num_max_threads,

         "Activating another thread from %u not allowed since there can be at most %u",

         cur_worker_id, _num_max_threads);

  if (cur_worker_id == (_num_max_threads - 1)) {

    // Already the last thread, there is no more thread to activate.

    return;

  }

  uint worker_id = cur_worker_id + 1;

  G1ConcurrentRefineThread* thread_to_activate = _threads[worker_id];

  if (thread_to_activate == NULL) {

    // Still need to create the thread...

    _threads[worker_id] = create_refinement_thread(worker_id, false);

    thread_to_activate = _threads[worker_id];

  }

  if (thread_to_activate != NULL && !thread_to_activate->is_active()) {

    thread_to_activate->activate();

  }

}

void G1ConcurrentRefineThreadControl::print_on(outputStream* st) const {

  for (uint i = 0; i < _num_max_threads; ++i) {

    if (_threads[i] != NULL) {

      _threads[i]->print_on(st);

      st->cr();

    }

  }

}

void G1ConcurrentRefineThreadControl::worker_threads_do(ThreadClosure* tc) {

  for (uint i = 0; i < _num_max_threads; i++) {

    if (_threads[i] != NULL) {

      tc->do_thread(_threads[i]);

    }

  }

}

void G1ConcurrentRefineThreadControl::stop() {

  for (uint i = 0; i < _num_max_threads; i++) {

    if (_threads[i] != NULL) {

      _threads[i]->stop();

    }

  }

}

// Arbitrary but large limits, to simplify some of the zone calculations.

// The general idea is to allow expressions like

//   MIN2(x OP y, max_XXX_zone)

// without needing to check for overflow in "x OP y", because the

// ranges for x and y have been restricted.

STATIC_ASSERT(sizeof(LP64_ONLY(jint) NOT_LP64(jshort)) <= (sizeof(size_t)/2));

const size_t max_yellow_zone = LP64_ONLY(max_jint) NOT_LP64(max_jshort);

const size_t max_green_zone = max_yellow_zone / 2;

const size_t max_red_zone = INT_MAX; // For dcqs.set_max_cards.

STATIC_ASSERT(max_yellow_zone <= max_red_zone);

// Range check assertions for green zone values.

#define assert_zone_constraints_g(green)                        \

  do {                                                          \

    size_t azc_g_green = (green);                               \

    assert(azc_g_green <= max_green_zone,                       \

           "green exceeds max: " SIZE_FORMAT, azc_g_green);     \

  } while (0)

// Range check assertions for green and yellow zone values.

#define assert_zone_constraints_gy(green, yellow)                       \

  do {                                                                  \

    size_t azc_gy_green = (green);                                      \

    size_t azc_gy_yellow = (yellow);                                    \

    assert_zone_constraints_g(azc_gy_green);                            \

    assert(azc_gy_yellow <= max_yellow_zone,                            \

           "yellow exceeds max: " SIZE_FORMAT, azc_gy_yellow);          \

    assert(azc_gy_green <= azc_gy_yellow,                               \

           "green (" SIZE_FORMAT ") exceeds yellow (" SIZE_FORMAT ")",  \

           azc_gy_green, azc_gy_yellow);                                \

  } while (0)

// Range check assertions for green, yellow, and red zone values.

#define assert_zone_constraints_gyr(green, yellow, red)                 \

  do {                                                                  \

    size_t azc_gyr_green = (green);                                     \

    size_t azc_gyr_yellow = (yellow);                                   \

    size_t azc_gyr_red = (red);                                         \

    assert_zone_constraints_gy(azc_gyr_green, azc_gyr_yellow);          \

    assert(azc_gyr_red <= max_red_zone,                                 \

           "red exceeds max: " SIZE_FORMAT, azc_gyr_red);               \

    assert(azc_gyr_yellow <= azc_gyr_red,                               \

           "yellow (" SIZE_FORMAT ") exceeds red (" SIZE_FORMAT ")",    \

           azc_gyr_yellow, azc_gyr_red);                                \

  } while (0)

// Logging tag sequence for refinement control updates.

#define CTRL_TAGS gc, ergo, refine

// For logging zone values, ensuring consistency of level and tags.

#define LOG_ZONES(...) log_debug( CTRL_TAGS )(__VA_ARGS__)

// Package for pair of refinement thread activation and deactivation

// thresholds.  The activation and deactivation levels are resp. the first

// and second values of the pair.

typedef Pair<size_t, size_t> Thresholds;

inline size_t activation_level(const Thresholds& t) { return t.first; }

inline size_t deactivation_level(const Thresholds& t) { return t.second; }

static Thresholds calc_thresholds(size_t green_zone,

                                  size_t yellow_zone,

                                  uint worker_id) {

  double yellow_size = yellow_zone - green_zone;

  double step = yellow_size / G1ConcurrentRefine::max_num_threads();

  if (worker_id == 0) {

    // Potentially activate worker 0 more aggressively, to keep

    // available buffers near green_zone value.  When yellow_size is

    // large we don't want to allow a full step to accumulate before

    // doing any processing, as that might lead to significantly more

    // than green_zone buffers to be processed during scanning.

    step = MIN2(step, ParallelGCThreads / 2.0);

  }

  size_t activate_offset = static_cast<size_t>(ceil(step * (worker_id + 1)));

  size_t deactivate_offset = static_cast<size_t>(floor(step * worker_id));

  return Thresholds(green_zone + activate_offset,

                    green_zone + deactivate_offset);

}

G1ConcurrentRefine::G1ConcurrentRefine(size_t green_zone,

                                       size_t yellow_zone,

                                       size_t red_zone,

                                       size_t min_yellow_zone_size) :

  _thread_control(),

  _green_zone(green_zone),

  _yellow_zone(yellow_zone),

  _red_zone(red_zone),

  _min_yellow_zone_size(min_yellow_zone_size)

{

  assert_zone_constraints_gyr(green_zone, yellow_zone, red_zone);

}

jint G1ConcurrentRefine::initialize() {

  return _thread_control.initialize(this, max_num_threads());

}

static size_t buffers_to_cards(size_t value) {

  return value * G1UpdateBufferSize;

}

static size_t calc_min_yellow_zone_size() {

  size_t step = buffers_to_cards(G1ConcRefinementThresholdStep);

  uint n_workers = G1ConcurrentRefine::max_num_threads();

  if ((max_yellow_zone / step) < n_workers) {

    return max_yellow_zone;

  } else {

    return step * n_workers;

  }

}

static size_t calc_init_green_zone() {

  size_t green = G1ConcRefinementGreenZone;

  if (FLAG_IS_DEFAULT(G1ConcRefinementGreenZone)) {

    green = ParallelGCThreads;

  }

  green = buffers_to_cards(green);

  return MIN2(green, max_green_zone);

}

static size_t calc_init_yellow_zone(size_t green, size_t min_size) {

  size_t config = buffers_to_cards(G1ConcRefinementYellowZone);

  size_t size = 0;

  if (FLAG_IS_DEFAULT(G1ConcRefinementYellowZone)) {

    size = green * 2;

  } else if (green < config) {

    size = config - green;

  }

  size = MAX2(size, min_size);

  size = MIN2(size, max_yellow_zone);

  return MIN2(green + size, max_yellow_zone);

}

static size_t calc_init_red_zone(size_t green, size_t yellow) {

  size_t size = yellow - green;

  if (!FLAG_IS_DEFAULT(G1ConcRefinementRedZone)) {

    size_t config = buffers_to_cards(G1ConcRefinementRedZone);

    if (yellow < config) {

      size = MAX2(size, config - yellow);

    }

  }

  return MIN2(yellow + size, max_red_zone);

}

G1ConcurrentRefine* G1ConcurrentRefine::create(jint* ecode) {

  size_t min_yellow_zone_size = calc_min_yellow_zone_size();

  size_t green_zone = calc_init_green_zone();

  size_t yellow_zone = calc_init_yellow_zone(green_zone, min_yellow_zone_size);

  size_t red_zone = calc_init_red_zone(green_zone, yellow_zone);

  LOG_ZONES("Initial Refinement Zones: "

            "green: " SIZE_FORMAT ", "

            "yellow: " SIZE_FORMAT ", "

            "red: " SIZE_FORMAT ", "

            "min yellow size: " SIZE_FORMAT,

            green_zone, yellow_zone, red_zone, min_yellow_zone_size);

  G1ConcurrentRefine* cr = new G1ConcurrentRefine(green_zone,

                                                  yellow_zone,

                                                  red_zone,

                                                  min_yellow_zone_size);

  if (cr == NULL) {

    *ecode = JNI_ENOMEM;

    vm_shutdown_during_initialization("Could not create G1ConcurrentRefine");

    return NULL;

  }

  *ecode = cr->initialize();

  return cr;

}

void G1ConcurrentRefine::stop() {

  _thread_control.stop();

}

G1ConcurrentRefine::~G1ConcurrentRefine() {

}

void G1ConcurrentRefine::threads_do(ThreadClosure *tc) {

  _thread_control.worker_threads_do(tc);

}

uint G1ConcurrentRefine::max_num_threads() {

  return G1ConcRefinementThreads;

}

void G1ConcurrentRefine::print_threads_on(outputStream* st) const {

  _thread_control.print_on(st);

}

static size_t calc_new_green_zone(size_t green,

                                  double logged_cards_scan_time,

                                  size_t processed_logged_cards,

                                  double goal_ms) {

  // Adjust green zone based on whether we're meeting the time goal.

  // Limit to max_green_zone.

  const double inc_k = 1.1, dec_k = 0.9;

  if (logged_cards_scan_time > goal_ms) {

    if (green > 0) {

      green = static_cast<size_t>(green * dec_k);

    }

  } else if (logged_cards_scan_time < goal_ms &&

             processed_logged_cards > green) {

    green = static_cast<size_t>(MAX2(green * inc_k, green + 1.0));

    green = MIN2(green, max_green_zone);

  }

  return green;

}

static size_t calc_new_yellow_zone(size_t green, size_t min_yellow_size) {

  size_t size = green * 2;

  size = MAX2(size, min_yellow_size);

  return MIN2(green + size, max_yellow_zone);

}

static size_t calc_new_red_zone(size_t green, size_t yellow) {

  return MIN2(yellow + (yellow - green), max_red_zone);

}

void G1ConcurrentRefine::update_zones(double logged_cards_scan_time,

                                      size_t processed_logged_cards,

                                      double goal_ms) {

  log_trace( CTRL_TAGS )("Updating Refinement Zones: "

                         "logged cards scan time: %.3fms, "

                         "processed cards: " SIZE_FORMAT ", "

                         "goal time: %.3fms",

                         logged_cards_scan_time,

                         processed_logged_cards,

                         goal_ms);

  _green_zone = calc_new_green_zone(_green_zone,

                                    logged_cards_scan_time,

                                    processed_logged_cards,

                                    goal_ms);

  _yellow_zone = calc_new_yellow_zone(_green_zone, _min_yellow_zone_size);

  _red_zone = calc_new_red_zone(_green_zone, _yellow_zone);

  assert_zone_constraints_gyr(_green_zone, _yellow_zone, _red_zone);

  LOG_ZONES("Updated Refinement Zones: "

            "green: " SIZE_FORMAT ", "

            "yellow: " SIZE_FORMAT ", "

            "red: " SIZE_FORMAT,

            _green_zone, _yellow_zone, _red_zone);

}

void G1ConcurrentRefine::adjust(double logged_cards_scan_time,

                                size_t processed_logged_cards,

                                double goal_ms) {

  G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();

  if (G1UseAdaptiveConcRefinement) {

    update_zones(logged_cards_scan_time, processed_logged_cards, goal_ms);

    // Change the barrier params

    if (max_num_threads() == 0) {

      // Disable dcqs notification when there are no threads to notify.

      dcqs.set_process_cards_threshold(G1DirtyCardQueueSet::ProcessCardsThresholdNever);

    } else {

      // Worker 0 is the primary; wakeup is via dcqs notification.

      STATIC_ASSERT(max_yellow_zone <= INT_MAX);

      size_t activate = activation_threshold(0);

      dcqs.set_process_cards_threshold(activate);

    }

    dcqs.set_max_cards(red_zone());

  }

  size_t curr_queue_size = dcqs.num_cards();

  if ((dcqs.max_cards() > 0) &&

      (curr_queue_size >= yellow_zone())) {

    dcqs.set_max_cards_padding(curr_queue_size);

  } else {

    dcqs.set_max_cards_padding(0);

  }

  dcqs.notify_if_necessary();

}

G1ConcurrentRefine::RefinementStats G1ConcurrentRefine::total_refinement_stats() const {

  struct CollectData : public ThreadClosure {

    Tickspan _total_time;

    size_t _total_cards;

    CollectData() : _total_time(), _total_cards(0) {}

    virtual void do_thread(Thread* t) {

      G1ConcurrentRefineThread* crt = static_cast<G1ConcurrentRefineThread*>(t);

      _total_time += crt->total_refinement_time();

      _total_cards += crt->total_refined_cards();

    }

  } collector;

  // Cast away const so we can call non-modifying closure on threads.

  const_cast<G1ConcurrentRefine*>(this)->threads_do(&collector);

  return RefinementStats(collector._total_time, collector._total_cards);

}

size_t G1ConcurrentRefine::activation_threshold(uint worker_id) const {

  Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);

  return activation_level(thresholds);

}

size_t G1ConcurrentRefine::deactivation_threshold(uint worker_id) const {

  Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);

  return deactivation_level(thresholds);

}

uint G1ConcurrentRefine::worker_id_offset() {

  return G1DirtyCardQueueSet::num_par_ids();

}

void G1ConcurrentRefine::maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers) {

  if (num_cur_buffers > activation_threshold(worker_id + 1)) {

    _thread_control.maybe_activate_next(worker_id);

  }

}

bool G1ConcurrentRefine::do_refinement_step(uint worker_id,

                                            size_t* total_refined_cards) {

  G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();

  size_t curr_cards = dcqs.num_cards();

  // If the number of the cards falls down into the yellow zone,

  // that means that the transition period after the evacuation pause has ended.

  // Since the value written to the DCQS is the same for all threads, there is no

  // need to synchronize.

  if (dcqs.max_cards_padding() > 0 && curr_cards <= yellow_zone()) {

    dcqs.set_max_cards_padding(0);

  }

  maybe_activate_more_threads(worker_id, curr_cards);

  // Process the next buffer, if there are enough left.

  return dcqs.refine_completed_buffer_concurrently(worker_id + worker_id_offset(),

                                                   deactivation_threshold(worker_id),

                                                   total_refined_cards);

}