/*

 * Copyright (c) 2017, 2018, 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 "jfr/recorder/storage/jfrVirtualMemory.hpp"

#include "memory/virtualspace.hpp"

#include "runtime/globals.hpp"

#include "runtime/os.hpp"

#include "services/memTracker.hpp"

#include "utilities/globalDefinitions.hpp"

/*

 * A memory segment represents a virtual memory reservation.

 * It provides ways to commit and decommit physical storage

 * onto its virtual memory reservation.

 */

class JfrVirtualMemorySegment : public JfrCHeapObj {

  friend class JfrVirtualMemoryManager;

 private:

  JfrVirtualMemorySegment* _next;

  char* _top;

  ReservedSpace _rs;

  VirtualSpace  _virtual_memory;

  // Convenience functions to access the underlying virtual space metadata

  const u1* committed_low()  const { return (const u1*)_virtual_memory.low(); }

  const u1* committed_high() const { return (const u1*)_virtual_memory.high(); }

  const u1* reserved_low() const { return (const u1*)_virtual_memory.low_boundary(); }

  const u1* reserved_high() const { return (const u1*)_virtual_memory.high_boundary(); }

  size_t reserved_words() const  { return _virtual_memory.reserved_size() / BytesPerWord; }

  size_t committed_words() const { return _virtual_memory.actual_committed_size() / BytesPerWord; }

  bool is_pre_committed() const { return _virtual_memory.special(); }

  VirtualSpace& virtual_space() { return _virtual_memory; }

  JfrVirtualMemorySegment();

  ~JfrVirtualMemorySegment();

  JfrVirtualMemorySegment* next() const { return _next; }

  void set_next(JfrVirtualMemorySegment* v) { _next = v; }

  // Returns true if requested size is available in the committed area

  bool is_available(size_t block_size_request_words) {

    return block_size_request_words <= pointer_delta(committed_high(), _top, sizeof(char*));

  }

  // allocation pointer committed memory

  char* top() const { return _top; }

  void inc_top(size_t size_in_words) {

    assert(is_available(size_in_words), "invariant");

    _top += size_in_words * BytesPerWord;

    assert(_top <= _virtual_memory.high(), "invariant");

  }

  // initialization is the virtual memory reservation

  bool initialize(size_t reservation_size_request_bytes);

  void* take_from_committed(size_t block_size_request_words);

  // Returns committed memory

  void* commit(size_t block_size_request_words) {

    return take_from_committed(block_size_request_words);

  }

  // Commit more memory in a reservation

  bool expand_by(size_t block_size_request_words);

  // Decommits all committed memory in this reservation segment.

  void decommit();

};

JfrVirtualMemorySegment::JfrVirtualMemorySegment() :

  _next(NULL),

  _top(NULL),

  _rs(),

  _virtual_memory() {}

JfrVirtualMemorySegment::~JfrVirtualMemorySegment() {

  decommit();

  _rs.release();

}

bool JfrVirtualMemorySegment::initialize(size_t reservation_size_request_bytes) {

  assert(is_aligned(reservation_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  _rs = ReservedSpace(reservation_size_request_bytes,

                      os::vm_allocation_granularity(),

                      UseLargePages && os::can_commit_large_page_memory(),

                      false);

  if (!_rs.is_reserved()) {

    return false;

  }

  assert(_rs.base() != NULL, "invariant");

  assert(_rs.size() != 0, "invariant");

  assert(is_aligned(_rs.base(), os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(_rs.size(), os::vm_allocation_granularity()), "invariant");

  os::trace_page_sizes("Jfr", reservation_size_request_bytes,

                              reservation_size_request_bytes,

                              os::vm_page_size(),

                              _rs.base(),

                              _rs.size());

  MemTracker::record_virtual_memory_type((address)_rs.base(), mtTracing);

  assert(is_aligned(_rs.base(), os::vm_page_size()), "invariant");

  assert(is_aligned(_rs.size(), os::vm_page_size()), "invariant");

  // ReservedSpaces marked as special will have the entire memory

  // pre-committed. Setting a committed size will make sure that

  // committed_size and actual_committed_size agrees.

  const size_t pre_committed_size = _rs.special() ? _rs.size() : 0;

  const bool result = virtual_space().initialize_with_granularity(_rs, pre_committed_size, os::vm_page_size());

  if (result) {

    assert(virtual_space().committed_size() == virtual_space().actual_committed_size(),

      "Checking that the pre-committed memory was registered by the VirtualSpace");

    _top = virtual_space().low();

  }

  return result;

}

bool JfrVirtualMemorySegment::expand_by(size_t block_size_request_words) {

  size_t block_size_request_bytes = block_size_request_words * BytesPerWord;

  const size_t uncommitted = virtual_space().reserved_size() - virtual_space().actual_committed_size();

  if (uncommitted < block_size_request_bytes) {

    // commit whatever is left in the reservation

    block_size_request_bytes = uncommitted;

  }

  assert(is_aligned(block_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  // commit block in reserved memory

  bool result = virtual_space().expand_by(block_size_request_bytes, false);

  assert(result, "Failed to commit memory");

  return result;

}

void JfrVirtualMemorySegment::decommit() {

  assert(_virtual_memory.committed_size() == _virtual_memory.actual_committed_size(),

    "The committed memory doesn't match the expanded memory.");

  const size_t committed_size = virtual_space().actual_committed_size();

  if (committed_size > 0) {

    virtual_space().shrink_by(committed_size);

  }

  assert(_virtual_memory.actual_committed_size() == 0, "invariant");

}

// Attempt to get a committed block

void* JfrVirtualMemorySegment::take_from_committed(size_t block_size_request_words) {

  // The virtual spaces are always expanded by the

  // commit granularity to enforce the following condition.

  // Without this the is_available check will not work correctly.

  assert(_virtual_memory.committed_size() == _virtual_memory.actual_committed_size(),

    "The committed memory doesn't match the expanded memory.");

  if (!is_available(block_size_request_words)) {

    return NULL;

  }

  void* const block = top();

  assert(block != NULL, "invariant");

  inc_top(block_size_request_words);

  return block;

}

class JfrVirtualMemoryManager : public JfrCHeapObj {

 typedef JfrVirtualMemorySegment Segment;

 private:

  Segment* _segments;

  Segment* _current_segment;

  size_t _reservation_size_request_words;

  size_t _reservation_size_request_limit_words; // total reservation limit

  // Sum of reserved and committed memory in the segments

  size_t _current_reserved_words;

  size_t _current_committed_words;

  void link(Segment* segment);

  Segment* current();

  void inc_reserved_words(size_t words);

  void inc_committed_words(size_t words);

  bool new_segment(size_t reservation_size_request_words);

  bool expand_segment_by(Segment* segment, size_t block_size_request_words);

  bool expand_by(size_t block_size_request_words, size_t reservation_size_request_words);

  bool can_reserve() const;

 public:

  JfrVirtualMemoryManager();

  ~JfrVirtualMemoryManager();

  bool initialize(size_t reservation_size_request_words, size_t segment_count = 1);

  void* commit(size_t requested_block_size_words);

  bool is_full() const {

    return reserved_high() == committed_high();

  }

  const u1* committed_low() const { return _current_segment->committed_low(); }

  const u1* committed_high() const { return _current_segment->committed_high(); }

  const u1* reserved_low() const { return _current_segment->reserved_low(); }

  const u1* reserved_high() const { return _current_segment->reserved_high(); }

};

JfrVirtualMemoryManager::JfrVirtualMemoryManager() :

  _segments(NULL),

  _current_segment(NULL),

  _reservation_size_request_words(0),

  _reservation_size_request_limit_words(0),

  _current_reserved_words(0),

  _current_committed_words(0) {}

JfrVirtualMemoryManager::~JfrVirtualMemoryManager() {

  JfrVirtualMemorySegment* segment = _segments;

  while (segment != NULL) {

    JfrVirtualMemorySegment* next_segment = segment->next();

    delete segment;

    segment = next_segment;

  }

}

// for now only allow a singleton segment per virtual memory client

bool JfrVirtualMemoryManager::initialize(size_t reservation_size_request_words, size_t segment_count /* 1 */) {

  assert(is_aligned(reservation_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  _reservation_size_request_words = reservation_size_request_words;

  assert(segment_count > 0, "invariant");

  _reservation_size_request_limit_words = reservation_size_request_words * segment_count;

  assert(is_aligned(_reservation_size_request_limit_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  return new_segment(_reservation_size_request_words);

}

bool JfrVirtualMemoryManager::can_reserve() const  {

  return _reservation_size_request_limit_words == 0 ? true : _current_reserved_words < _reservation_size_request_limit_words;

}

// Allocate another segment and add it to the list.

bool JfrVirtualMemoryManager::new_segment(size_t reservation_size_request_words) {

  assert(reservation_size_request_words > 0, "invariant");

  assert(is_aligned(reservation_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  Segment* segment = new Segment();

  if (NULL == segment) {

    return false;

  }

  if (!segment->initialize(reservation_size_request_words * BytesPerWord)) {

    delete segment;

    return false;

  }

  assert(segment->reserved_words() == reservation_size_request_words,

    "Actual reserved memory size differs from requested reservation memory size");

  link(segment);

  return true;

}

bool JfrVirtualMemoryManager::expand_segment_by(JfrVirtualMemorySegment* segment, size_t block_size_request_words) {

  assert(segment != NULL, "invariant");

  const size_t before = segment->committed_words();

  const bool result = segment->expand_by(block_size_request_words);

  const size_t after = segment->committed_words();

  // after and before can be the same if the memory was pre-committed.

  assert(after >= before, "Inconsistency");

  inc_committed_words(after - before);

  return result;

}

void JfrVirtualMemoryManager::inc_reserved_words(size_t words) {

  _current_reserved_words += words;

}

JfrVirtualMemorySegment* JfrVirtualMemoryManager::current() {

  return _current_segment;

}

void JfrVirtualMemoryManager::inc_committed_words(size_t words) {

  _current_committed_words += words;

}

bool JfrVirtualMemoryManager::expand_by(size_t block_size_request_words, size_t reservation_size_request_words) {

  assert(is_aligned(block_size_request_words * BytesPerWord, os::vm_page_size()), "invariant");

  assert(is_aligned(block_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(reservation_size_request_words * BytesPerWord, os::vm_page_size()), "invariant");

  assert(is_aligned(reservation_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  assert(block_size_request_words <= reservation_size_request_words, "invariant");

  // Attempt to commit more memory from the the current virtual space reservation.

  if (expand_segment_by(current(), block_size_request_words)) {

    return true;

  }

  // reached limit of what is allowed to be reserved?

  if (!can_reserve()) {

    return false;

  }

  // Get another segment.

  if (!new_segment(reservation_size_request_words)) {

    return false;

  }

  if (current()->is_pre_committed()) {

    // The memory was pre-committed, so we are done here.

    assert(block_size_request_words <= current()->committed_words(),

           "The new VirtualSpace was pre-committed, so it"

           "should be large enough to fit the alloc request.");

    return true;

  }

  return expand_segment_by(current(), block_size_request_words);

}

void JfrVirtualMemoryManager::link(JfrVirtualMemorySegment* segment) {

  assert(segment != NULL, "invariant");

  if (_segments == NULL) {

    _segments = segment;

  } else {

    assert(_current_segment != NULL, "invariant");

    assert(_segments == _current_segment, "invariant");

    _current_segment->set_next(segment);

  }

  _current_segment = segment;

  inc_reserved_words(segment->reserved_words());

  inc_committed_words(segment->committed_words());

}

void* JfrVirtualMemoryManager::commit(size_t block_size_request_words) {

  assert(is_aligned(block_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  void* block = current()->commit(block_size_request_words);

  if (block != NULL) {

    return block;

  }

  assert(block == NULL, "invariant");

  if (is_full()) {

    return NULL;

  }

  assert(block_size_request_words <= _reservation_size_request_words, "invariant");

  if (expand_by(block_size_request_words, _reservation_size_request_words)) {

    block = current()->commit(block_size_request_words);

    assert(block != NULL, "The allocation was expected to succeed after the expansion");

  }

  return block;

}

JfrVirtualMemory::JfrVirtualMemory() :

  _vmm(NULL),

  _reserved_low(),

  _reserved_high(),

  _top(NULL),

  _commit_point(NULL),

  _physical_commit_size_request_words(0),

  _aligned_datum_size_bytes(0) {}

JfrVirtualMemory::~JfrVirtualMemory() {

  assert(_vmm != NULL, "invariant");

  delete _vmm;

}

size_t JfrVirtualMemory::aligned_datum_size_bytes() const {

  return _aligned_datum_size_bytes;

}

static void adjust_allocation_ratio(size_t* const reservation_size_bytes, size_t* const commit_size_bytes) {

  assert(reservation_size_bytes != NULL, "invariant");

  assert(*reservation_size_bytes > 0, "invariant");

  assert(commit_size_bytes != NULL, "invariant");

  assert(*commit_size_bytes > 0, "invariant");

  assert(*reservation_size_bytes >= *commit_size_bytes, "invariant");

  assert(is_aligned(*reservation_size_bytes, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(*commit_size_bytes, os::vm_allocation_granularity()), "invariant");

  size_t reservation_size_units = *reservation_size_bytes / os::vm_allocation_granularity();

  size_t commit_size_units = *commit_size_bytes / os::vm_allocation_granularity();

  assert(reservation_size_units > 0, "invariant");

  assert(commit_size_units > 0, "invariant");

  size_t original_ratio_units = reservation_size_units / commit_size_units;

  size_t rem = reservation_size_units % commit_size_units;

  assert(original_ratio_units > 0, "invariant");

  if (rem > 0) {

    reservation_size_units -= rem % original_ratio_units;

    commit_size_units += rem / original_ratio_units;

  }

  assert(commit_size_units > 0, "invariant");

  assert(reservation_size_units % original_ratio_units == 0, "invariant");

  assert(original_ratio_units * commit_size_units == reservation_size_units , "invariant");

  assert(original_ratio_units == reservation_size_units / commit_size_units, "invariant");

  *reservation_size_bytes = reservation_size_units * os::vm_allocation_granularity();

  *commit_size_bytes = commit_size_units * os::vm_allocation_granularity();

  assert((*reservation_size_bytes % *commit_size_bytes) == 0, "invariant");

}

void* JfrVirtualMemory::initialize(size_t reservation_size_request_bytes,

                                   size_t block_size_request_bytes,

                                   size_t datum_size_bytes /* 1 */) {

  assert(_vmm == NULL, "invariant");

  _vmm = new JfrVirtualMemoryManager();

  if (_vmm == NULL) {

    return NULL;

  }

  assert(reservation_size_request_bytes > 0, "invariant");

  _aligned_datum_size_bytes = align_up(datum_size_bytes, BytesPerWord);

  assert(is_aligned(_aligned_datum_size_bytes, BytesPerWord), "invariant");

  reservation_size_request_bytes = ReservedSpace::allocation_align_size_up(reservation_size_request_bytes);

  assert(is_aligned(reservation_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(reservation_size_request_bytes, _aligned_datum_size_bytes), "invariant");

  block_size_request_bytes = MAX2(block_size_request_bytes, (size_t)os::vm_allocation_granularity());

  block_size_request_bytes = ReservedSpace::allocation_align_size_up(block_size_request_bytes);

  assert(is_aligned(block_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(block_size_request_bytes, _aligned_datum_size_bytes), "invariant");

  // adjustment to valid ratio in units of vm_allocation_granularity

  adjust_allocation_ratio(&reservation_size_request_bytes, &block_size_request_bytes);

  assert(is_aligned(reservation_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(reservation_size_request_bytes, _aligned_datum_size_bytes), "invariant");

  assert(is_aligned(block_size_request_bytes, os::vm_allocation_granularity()), "invariant");

  assert(is_aligned(block_size_request_bytes, _aligned_datum_size_bytes), "invariant");

  assert((reservation_size_request_bytes % block_size_request_bytes) == 0, "invariant");

  const size_t reservation_size_request_words = reservation_size_request_bytes / BytesPerWord;

  _physical_commit_size_request_words = block_size_request_bytes / BytesPerWord;

  // virtual memory reservation

  if (!_vmm->initialize(reservation_size_request_words)) {

    // is implicitly "full" if reservation fails

    assert(is_full(), "invariant");

    return NULL;

  }

  _reserved_low = (const u1*)_vmm->reserved_low();

  _reserved_high = (const u1*)_vmm->reserved_high();

  // reservation complete

  _top = (u1*)_vmm->committed_high();

  _commit_point = _top;

  assert(_reserved_low == _top, "invariant"); // initial empty state

  assert((size_t)(_reserved_high - _reserved_low) == reservation_size_request_bytes, "invariant");

  // initial commit

  commit_memory_block();

  return _top;

}

void* JfrVirtualMemory::commit(size_t block_size_request_words) {

  assert(_vmm != NULL, "invariant");

  assert(is_aligned(block_size_request_words * BytesPerWord, os::vm_allocation_granularity()), "invariant");

  return _vmm->commit(block_size_request_words);

}

bool JfrVirtualMemory::is_full() const {

  return _top == _reserved_high;

}

bool JfrVirtualMemory::is_empty() const {

  return _top == _reserved_low;

}

bool JfrVirtualMemory::commit_memory_block() {

  assert(_vmm != NULL, "invariant");

  assert(!is_full(), "invariant");

  assert(_top == _commit_point, "invariant");

  void* const block = _vmm->commit(_physical_commit_size_request_words);

  if (block != NULL) {

    _commit_point = _vmm->committed_high();

    return true;

  }

  // all reserved virtual memory is committed

  assert(block == NULL, "invariant");

  assert(_vmm->reserved_high() == _vmm->committed_high(), "invariant");

  return false;

}

void* JfrVirtualMemory::new_datum() {

  assert(_vmm != NULL, "invariant");

  assert(!is_full(), "invariant");

  if (_top == _commit_point) {

    if (!commit_memory_block()) {

      assert(is_full(), "invariant");

      return NULL;

    }

  }

  assert(_top + _aligned_datum_size_bytes <= _commit_point, "invariant");

  u1* allocation = _top;

  _top += _aligned_datum_size_bytes;

  assert(is_aligned(allocation, _aligned_datum_size_bytes), "invariant");

  return allocation;

}

void* JfrVirtualMemory::index_ptr(size_t index) {

  assert((index * _aligned_datum_size_bytes) + _reserved_low < _commit_point, "invariant");

  return (void*)((index * _aligned_datum_size_bytes) + _reserved_low);

}

void* JfrVirtualMemory::get(size_t index) {

  return index_ptr(index);

}

size_t JfrVirtualMemory::count() const {

  return (_top - _reserved_low) / _aligned_datum_size_bytes;

}

size_t JfrVirtualMemory::live_set() const {

  return _top - _reserved_low;

}

size_t JfrVirtualMemory::reserved_size() const {

  return _reserved_high - _reserved_low;

}

bool JfrVirtualMemory::compact(size_t index) {

  assert(index > 0, "invariant");

  assert(index <= reserved_size(), "invariant");

  const u1* low = static_cast<u1*>(index_ptr(index));

  const size_t block_size = _top - low;

  memcpy(const_cast<u1*>(_reserved_low), low, block_size);