/*

 * Copyright (c) 1999, 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/shared/collectedHeap.hpp"

#include "gc/shared/threadLocalAllocBuffer.inline.hpp"

#include "logging/log.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/threadSMR.hpp"

#include "utilities/copy.hpp"

size_t       ThreadLocalAllocBuffer::_max_size = 0;

int          ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch = 0;

unsigned int ThreadLocalAllocBuffer::_target_refills = 0;

size_t ThreadLocalAllocBuffer::remaining() {

  if (end() == NULL) {

    return 0;

  }

  return pointer_delta(hard_end(), top());

}

void ThreadLocalAllocBuffer::accumulate_and_reset_statistics(ThreadLocalAllocStats* stats) {

  Thread* thr     = thread();

  size_t capacity = Universe::heap()->tlab_capacity(thr);

  size_t used     = Universe::heap()->tlab_used(thr);

  _gc_waste += (unsigned)remaining();

  size_t total_allocated = thr->allocated_bytes();

  size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc;

  _allocated_before_last_gc = total_allocated;

  print_stats("gc");

  if (_number_of_refills > 0) {

    // Update allocation history if a reasonable amount of eden was allocated.

    bool update_allocation_history = used > 0.5 * capacity;

    if (update_allocation_history) {

      // Average the fraction of eden allocated in a tlab by this

      // thread for use in the next resize operation.

      // _gc_waste is not subtracted because it's included in

      // "used".

      // The result can be larger than 1.0 due to direct to old allocations.

      // These allocations should ideally not be counted but since it is not possible

      // to filter them out here we just cap the fraction to be at most 1.0.

      double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);

      _allocation_fraction.sample(alloc_frac);

    }

    stats->update_fast_allocations(_number_of_refills,

                                   _allocated_size,

                                   _gc_waste,

                                   _fast_refill_waste,

                                   _slow_refill_waste);

  } else {

    assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&

           _slow_refill_waste == 0 && _gc_waste          == 0,

           "tlab stats == 0");

  }

  stats->update_slow_allocations(_slow_allocations);

  reset_statistics();

}

void ThreadLocalAllocBuffer::insert_filler() {

  assert(end() != NULL, "Must not be retired");

  if (top() < hard_end()) {

    Universe::heap()->fill_with_dummy_object(top(), hard_end(), true);

  }

}

void ThreadLocalAllocBuffer::make_parsable() {

  if (end() != NULL) {

    invariants();

    if (ZeroTLAB) {

      retire();

    } else {

      insert_filler();

    }

  }

}

void ThreadLocalAllocBuffer::retire(ThreadLocalAllocStats* stats) {

  if (stats != NULL) {

    accumulate_and_reset_statistics(stats);

  }

  if (end() != NULL) {

    invariants();

    thread()->incr_allocated_bytes(used_bytes());

    insert_filler();

    initialize(NULL, NULL, NULL);

  }

}

void ThreadLocalAllocBuffer::retire_before_allocation() {

  _slow_refill_waste += (unsigned int)remaining();

  retire();

}

void ThreadLocalAllocBuffer::resize() {

  // Compute the next tlab size using expected allocation amount

  assert(ResizeTLAB, "Should not call this otherwise");

  size_t alloc = (size_t)(_allocation_fraction.average() *

                          (Universe::heap()->tlab_capacity(thread()) / HeapWordSize));

  size_t new_size = alloc / _target_refills;

  size_t aligned_new_size = align_object_size(new_size);

  log_trace(gc, tlab)("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]"

                      " refills %d  alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT,

                      p2i(thread()), thread()->osthread()->thread_id(),

                      _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size);

  set_desired_size(aligned_new_size);

  set_refill_waste_limit(initial_refill_waste_limit());

}

void ThreadLocalAllocBuffer::reset_statistics() {

  _number_of_refills = 0;

  _fast_refill_waste = 0;

  _slow_refill_waste = 0;

  _gc_waste          = 0;

  _slow_allocations  = 0;

  _allocated_size    = 0;

}

void ThreadLocalAllocBuffer::fill(HeapWord* start,

                                  HeapWord* top,

                                  size_t    new_size) {

  _number_of_refills++;

  _allocated_size += new_size;

  print_stats("fill");

  assert(top <= start + new_size - alignment_reserve(), "size too small");

  initialize(start, top, start + new_size - alignment_reserve());

  // Reset amount of internal fragmentation

  set_refill_waste_limit(initial_refill_waste_limit());

}

void ThreadLocalAllocBuffer::initialize(HeapWord* start,

                                        HeapWord* top,

                                        HeapWord* end) {

  set_start(start);

  set_top(top);

  set_pf_top(top);

  set_end(end);

  set_allocation_end(end);

  invariants();

}

void ThreadLocalAllocBuffer::initialize() {

  initialize(NULL,                    // start

             NULL,                    // top

             NULL);                   // end

  set_desired_size(initial_desired_size());

  size_t capacity = Universe::heap()->tlab_capacity(thread()) / HeapWordSize;

  double alloc_frac = desired_size() * target_refills() / (double) capacity;

  _allocation_fraction.sample(alloc_frac);

  set_refill_waste_limit(initial_refill_waste_limit());

  reset_statistics();

}

void ThreadLocalAllocBuffer::startup_initialization() {

  ThreadLocalAllocStats::initialize();

  // Assuming each thread's active tlab is, on average,

  // 1/2 full at a GC

  _target_refills = 100 / (2 * TLABWasteTargetPercent);

  // We need to set initial target refills to 2 to avoid a GC which causes VM

  // abort during VM initialization.

  _target_refills = MAX2(_target_refills, 2U);

#ifdef COMPILER2

  // If the C2 compiler is present, extra space is needed at the end of

  // TLABs, otherwise prefetching instructions generated by the C2

  // compiler will fault (due to accessing memory outside of heap).

  // The amount of space is the max of the number of lines to

  // prefetch for array and for instance allocations. (Extra space must be

  // reserved to accommodate both types of allocations.)

  //

  // Only SPARC-specific BIS instructions are known to fault. (Those

  // instructions are generated if AllocatePrefetchStyle==3 and

  // AllocatePrefetchInstr==1). To be on the safe side, however,

  // extra space is reserved for all combinations of

  // AllocatePrefetchStyle and AllocatePrefetchInstr.

  //

  // If the C2 compiler is not present, no space is reserved.

  // +1 for rounding up to next cache line, +1 to be safe

  if (is_server_compilation_mode_vm()) {

    int lines =  MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2;

    _reserve_for_allocation_prefetch = (AllocatePrefetchDistance + AllocatePrefetchStepSize * lines) /

                                       (int)HeapWordSize;

  }

#endif

  // During jvm startup, the main thread is initialized

  // before the heap is initialized.  So reinitialize it now.

  guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");

  Thread::current()->tlab().initialize();

  log_develop_trace(gc, tlab)("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT,

                               min_size(), Thread::current()->tlab().initial_desired_size(), max_size());

}

size_t ThreadLocalAllocBuffer::initial_desired_size() {

  size_t init_sz = 0;

  if (TLABSize > 0) {

    init_sz = TLABSize / HeapWordSize;

  } else {

    // Initial size is a function of the average number of allocating threads.

    unsigned int nof_threads = ThreadLocalAllocStats::allocating_threads_avg();

    init_sz  = (Universe::heap()->tlab_capacity(thread()) / HeapWordSize) /

                      (nof_threads * target_refills());

    init_sz = align_object_size(init_sz);

  }

  init_sz = MIN2(MAX2(init_sz, min_size()), max_size());

  return init_sz;

}

void ThreadLocalAllocBuffer::print_stats(const char* tag) {

  Log(gc, tlab) log;

  if (!log.is_trace()) {

    return;

  }

  Thread* thrd = thread();

  size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;

  double waste_percent = percent_of(waste, _allocated_size);

  size_t tlab_used  = Universe::heap()->tlab_used(thrd);

  log.trace("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"

            " desired_size: " SIZE_FORMAT "KB"

            " slow allocs: %d  refill waste: " SIZE_FORMAT "B"

            " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB"

            " slow: %dB fast: %dB",

            tag, p2i(thrd), thrd->osthread()->thread_id(),

            _desired_size / (K / HeapWordSize),

            _slow_allocations, _refill_waste_limit * HeapWordSize,

            _allocation_fraction.average(),

            _allocation_fraction.average() * tlab_used / K,

            _number_of_refills, waste_percent,

            _gc_waste * HeapWordSize,

            _slow_refill_waste * HeapWordSize,

            _fast_refill_waste * HeapWordSize);

}

void ThreadLocalAllocBuffer::set_sample_end(bool reset_byte_accumulation) {

  size_t heap_words_remaining = pointer_delta(_end, _top);

  size_t bytes_until_sample = thread()->heap_sampler().bytes_until_sample();

  size_t words_until_sample = bytes_until_sample / HeapWordSize;

  if (reset_byte_accumulation) {

    _bytes_since_last_sample_point = 0;

  }

  if (heap_words_remaining > words_until_sample) {

    HeapWord* new_end = _top + words_until_sample;

    set_end(new_end);

    _bytes_since_last_sample_point += bytes_until_sample;

  } else {

    _bytes_since_last_sample_point += heap_words_remaining * HeapWordSize;

  }

}

Thread* ThreadLocalAllocBuffer::thread() {

  return (Thread*)(((char*)this) + in_bytes(start_offset()) - in_bytes(Thread::tlab_start_offset()));

}

void ThreadLocalAllocBuffer::set_back_allocation_end() {

  _end = _allocation_end;

}

HeapWord* ThreadLocalAllocBuffer::hard_end() {

  return _allocation_end + alignment_reserve();

}

PerfVariable* ThreadLocalAllocStats::_perf_allocating_threads;

PerfVariable* ThreadLocalAllocStats::_perf_total_refills;

PerfVariable* ThreadLocalAllocStats::_perf_max_refills;

PerfVariable* ThreadLocalAllocStats::_perf_total_allocations;

PerfVariable* ThreadLocalAllocStats::_perf_total_gc_waste;

PerfVariable* ThreadLocalAllocStats::_perf_max_gc_waste;

PerfVariable* ThreadLocalAllocStats::_perf_total_slow_refill_waste;

PerfVariable* ThreadLocalAllocStats::_perf_max_slow_refill_waste;

PerfVariable* ThreadLocalAllocStats::_perf_total_fast_refill_waste;

PerfVariable* ThreadLocalAllocStats::_perf_max_fast_refill_waste;

PerfVariable* ThreadLocalAllocStats::_perf_total_slow_allocations;

PerfVariable* ThreadLocalAllocStats::_perf_max_slow_allocations;

AdaptiveWeightedAverage ThreadLocalAllocStats::_allocating_threads_avg(0);

static PerfVariable* create_perf_variable(const char* name, PerfData::Units unit, TRAPS) {

  ResourceMark rm;

  return PerfDataManager::create_variable(SUN_GC, PerfDataManager::counter_name("tlab", name), unit, THREAD);

}

void ThreadLocalAllocStats::initialize() {

  _allocating_threads_avg = AdaptiveWeightedAverage(TLABAllocationWeight);

  _allocating_threads_avg.sample(1); // One allocating thread at startup

  if (UsePerfData) {

    EXCEPTION_MARK;

    _perf_allocating_threads      = create_perf_variable("allocThreads", PerfData::U_None,  CHECK);

    _perf_total_refills           = create_perf_variable("fills",        PerfData::U_None,  CHECK);

    _perf_max_refills             = create_perf_variable("maxFills",     PerfData::U_None,  CHECK);

    _perf_total_allocations       = create_perf_variable("alloc",        PerfData::U_Bytes, CHECK);

    _perf_total_gc_waste          = create_perf_variable("gcWaste",      PerfData::U_Bytes, CHECK);

    _perf_max_gc_waste            = create_perf_variable("maxGcWaste",   PerfData::U_Bytes, CHECK);

    _perf_total_slow_refill_waste = create_perf_variable("slowWaste",    PerfData::U_Bytes, CHECK);

    _perf_max_slow_refill_waste   = create_perf_variable("maxSlowWaste", PerfData::U_Bytes, CHECK);

    _perf_total_fast_refill_waste = create_perf_variable("fastWaste",    PerfData::U_Bytes, CHECK);

    _perf_max_fast_refill_waste   = create_perf_variable("maxFastWaste", PerfData::U_Bytes, CHECK);

    _perf_total_slow_allocations  = create_perf_variable("slowAlloc",    PerfData::U_None,  CHECK);

    _perf_max_slow_allocations    = create_perf_variable("maxSlowAlloc", PerfData::U_None,  CHECK);

  }

}

ThreadLocalAllocStats::ThreadLocalAllocStats() :

    _allocating_threads(0),

    _total_refills(0),

    _max_refills(0),

    _total_allocations(0),

    _total_gc_waste(0),

    _max_gc_waste(0),

    _total_fast_refill_waste(0),

    _max_fast_refill_waste(0),

    _total_slow_refill_waste(0),

    _max_slow_refill_waste(0),

    _total_slow_allocations(0),

    _max_slow_allocations(0) {}

unsigned int ThreadLocalAllocStats::allocating_threads_avg() {

  return MAX2((unsigned int)(_allocating_threads_avg.average() + 0.5), 1U);

}

void ThreadLocalAllocStats::update_fast_allocations(unsigned int refills,

                                       size_t allocations,

                                       size_t gc_waste,

                                       size_t fast_refill_waste,

                                       size_t slow_refill_waste) {

  _allocating_threads      += 1;

  _total_refills           += refills;

  _max_refills              = MAX2(_max_refills, refills);

  _total_allocations       += allocations;

  _total_gc_waste          += gc_waste;

  _max_gc_waste             = MAX2(_max_gc_waste, gc_waste);

  _total_fast_refill_waste += fast_refill_waste;

  _max_fast_refill_waste    = MAX2(_max_fast_refill_waste, fast_refill_waste);

  _total_slow_refill_waste += slow_refill_waste;

  _max_slow_refill_waste    = MAX2(_max_slow_refill_waste, slow_refill_waste);

}

void ThreadLocalAllocStats::update_slow_allocations(unsigned int allocations) {

  _total_slow_allocations += allocations;

  _max_slow_allocations    = MAX2(_max_slow_allocations, allocations);

}

void ThreadLocalAllocStats::update(const ThreadLocalAllocStats& other) {

  _allocating_threads      += other._allocating_threads;

  _total_refills           += other._total_refills;

  _max_refills              = MAX2(_max_refills, other._max_refills);

  _total_allocations       += other._total_allocations;

  _total_gc_waste          += other._total_gc_waste;

  _max_gc_waste             = MAX2(_max_gc_waste, other._max_gc_waste);

  _total_fast_refill_waste += other._total_fast_refill_waste;

  _max_fast_refill_waste    = MAX2(_max_fast_refill_waste, other._max_fast_refill_waste);

  _total_slow_refill_waste += other._total_slow_refill_waste;

  _max_slow_refill_waste    = MAX2(_max_slow_refill_waste, other._max_slow_refill_waste);

  _total_slow_allocations  += other._total_slow_allocations;

  _max_slow_allocations     = MAX2(_max_slow_allocations, other._max_slow_allocations);

}

void ThreadLocalAllocStats::reset() {

  _allocating_threads      = 0;

  _total_refills           = 0;

  _max_refills             = 0;

  _total_allocations       = 0;

  _total_gc_waste          = 0;

  _max_gc_waste            = 0;

  _total_fast_refill_waste = 0;

  _max_fast_refill_waste   = 0;

  _total_slow_refill_waste = 0;

  _max_slow_refill_waste   = 0;

  _total_slow_allocations  = 0;

  _max_slow_allocations    = 0;

}

void ThreadLocalAllocStats::publish() {

  if (_total_allocations == 0) {

    return;

  }

  _allocating_threads_avg.sample(_allocating_threads);

  const size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;

  const double waste_percent = percent_of(waste, _total_allocations);

  log_debug(gc, tlab)("TLAB totals: thrds: %d  refills: %d max: %d"

                      " slow allocs: %d max %d waste: %4.1f%%"

                      " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"

                      " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"

                      " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B",

                      _allocating_threads, _total_refills, _max_refills,

                      _total_slow_allocations, _max_slow_allocations, waste_percent,

                      _total_gc_waste * HeapWordSize, _max_gc_waste * HeapWordSize,

                      _total_slow_refill_waste * HeapWordSize, _max_slow_refill_waste * HeapWordSize,

                      _total_fast_refill_waste * HeapWordSize, _max_fast_refill_waste * HeapWordSize);

  if (UsePerfData) {

    _perf_allocating_threads      ->set_value(_allocating_threads);

    _perf_total_refills           ->set_value(_total_refills);

    _perf_max_refills             ->set_value(_max_refills);

    _perf_total_allocations       ->set_value(_total_allocations);

    _perf_total_gc_waste          ->set_value(_total_gc_waste);

    _perf_max_gc_waste            ->set_value(_max_gc_waste);

    _perf_total_slow_refill_waste ->set_value(_total_slow_refill_waste);

    _perf_max_slow_refill_waste   ->set_value(_max_slow_refill_waste);

    _perf_total_fast_refill_waste ->set_value(_total_fast_refill_waste);

    _perf_max_fast_refill_waste   ->set_value(_max_fast_refill_waste);

    _perf_total_slow_allocations  ->set_value(_total_slow_allocations);

    _perf_max_slow_allocations    ->set_value(_max_slow_allocations);

  }

}

size_t ThreadLocalAllocBuffer::end_reserve() {

  size_t reserve_size = Universe::heap()->tlab_alloc_reserve();

  return MAX2(reserve_size, (size_t)_reserve_for_allocation_prefetch);

}