/*

 * Copyright (c) 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 "logging/log.hpp"

#include "logging/logStream.hpp"

#include "memory/metaspace/metachunk.hpp"

#include "memory/metaspace.hpp"

#include "memory/metaspace/chunkManager.hpp"

#include "memory/metaspace/metaDebug.hpp"

#include "memory/metaspace/metaspaceCommon.hpp"

#include "memory/metaspace/occupancyMap.hpp"

#include "memory/metaspace/virtualSpaceNode.hpp"

#include "memory/virtualspace.hpp"

#include "runtime/os.hpp"

#include "services/memTracker.hpp"

#include "utilities/copy.hpp"

#include "utilities/debug.hpp"

#include "utilities/globalDefinitions.hpp"

namespace metaspace {

// Decide if large pages should be committed when the memory is reserved.

static bool should_commit_large_pages_when_reserving(size_t bytes) {

  if (UseLargePages && UseLargePagesInMetaspace && !os::can_commit_large_page_memory()) {

    size_t words = bytes / BytesPerWord;

    bool is_class = false; // We never reserve large pages for the class space.

    if (MetaspaceGC::can_expand(words, is_class) &&

        MetaspaceGC::allowed_expansion() >= words) {

      return true;

    }

  }

  return false;

}

// byte_size is the size of the associated virtualspace.

VirtualSpaceNode::VirtualSpaceNode(bool is_class, size_t bytes) :

    _next(NULL), _is_class(is_class), _rs(), _top(NULL), _container_count(0), _occupancy_map(NULL) {

  assert_is_aligned(bytes, Metaspace::reserve_alignment());

  bool large_pages = should_commit_large_pages_when_reserving(bytes);

  _rs = ReservedSpace(bytes, Metaspace::reserve_alignment(), large_pages);

  if (_rs.is_reserved()) {

    assert(_rs.base() != NULL, "Catch if we get a NULL address");

    assert(_rs.size() != 0, "Catch if we get a 0 size");

    assert_is_aligned(_rs.base(), Metaspace::reserve_alignment());

    assert_is_aligned(_rs.size(), Metaspace::reserve_alignment());

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

  }

}

void VirtualSpaceNode::purge(ChunkManager* chunk_manager) {

  // When a node is purged, lets give it a thorough examination.

  DEBUG_ONLY(verify(true);)

  Metachunk* chunk = first_chunk();

  Metachunk* invalid_chunk = (Metachunk*) top();

  while (chunk < invalid_chunk ) {

    assert(chunk->is_tagged_free(), "Should be tagged free");

    MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();

    chunk_manager->remove_chunk(chunk);

    chunk->remove_sentinel();

    assert(chunk->next() == NULL &&

        chunk->prev() == NULL,

        "Was not removed from its list");

    chunk = (Metachunk*) next;

  }

}

void VirtualSpaceNode::print_map(outputStream* st, bool is_class) const {

  if (bottom() == top()) {

    return;

  }

  const size_t spec_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;

  const size_t small_chunk_size = is_class ? ClassSmallChunk : SmallChunk;

  const size_t med_chunk_size = is_class ? ClassMediumChunk : MediumChunk;

  int line_len = 100;

  const size_t section_len = align_up(spec_chunk_size * line_len, med_chunk_size);

  line_len = (int)(section_len / spec_chunk_size);

  static const int NUM_LINES = 4;

  char* lines[NUM_LINES];

  for (int i = 0; i < NUM_LINES; i ++) {

    lines[i] = (char*)os::malloc(line_len, mtInternal);

  }

  int pos = 0;

  const MetaWord* p = bottom();

  const Metachunk* chunk = (const Metachunk*)p;

  const MetaWord* chunk_end = p + chunk->word_size();

  while (p < top()) {

    if (pos == line_len) {

      pos = 0;

      for (int i = 0; i < NUM_LINES; i ++) {

        st->fill_to(22);

        st->print_raw(lines[i], line_len);

        st->cr();

      }

    }

    if (pos == 0) {

      st->print(PTR_FORMAT ":", p2i(p));

    }

    if (p == chunk_end) {

      chunk = (Metachunk*)p;

      chunk_end = p + chunk->word_size();

    }

    // line 1: chunk starting points (a dot if that area is a chunk start).

    lines[0][pos] = p == (const MetaWord*)chunk ? '.' : ' ';

    // Line 2: chunk type (x=spec, s=small, m=medium, h=humongous), uppercase if

    // chunk is in use.

    const bool chunk_is_free = ((Metachunk*)chunk)->is_tagged_free();

    if (chunk->word_size() == spec_chunk_size) {

      lines[1][pos] = chunk_is_free ? 'x' : 'X';

    } else if (chunk->word_size() == small_chunk_size) {

      lines[1][pos] = chunk_is_free ? 's' : 'S';

    } else if (chunk->word_size() == med_chunk_size) {

      lines[1][pos] = chunk_is_free ? 'm' : 'M';

    } else if (chunk->word_size() > med_chunk_size) {

      lines[1][pos] = chunk_is_free ? 'h' : 'H';

    } else {

      ShouldNotReachHere();

    }

    // Line 3: chunk origin

    const ChunkOrigin origin = chunk->get_origin();

    lines[2][pos] = origin == origin_normal ? ' ' : '0' + (int) origin;

    // Line 4: Virgin chunk? Virgin chunks are chunks created as a byproduct of padding or splitting,

    //         but were never used.

    lines[3][pos] = chunk->get_use_count() > 0 ? ' ' : 'v';

    p += spec_chunk_size;

    pos ++;

  }

  if (pos > 0) {

    for (int i = 0; i < NUM_LINES; i ++) {

      st->fill_to(22);

      st->print_raw(lines[i], line_len);

      st->cr();

    }

  }

  for (int i = 0; i < NUM_LINES; i ++) {

    os::free(lines[i]);

  }

}

#ifdef ASSERT

// Verify counters, all chunks in this list node and the occupancy map.

void VirtualSpaceNode::verify(bool slow) {

  log_trace(gc, metaspace, freelist)("verifying %s virtual space node (%s).",

    (is_class() ? "class space" : "metaspace"), (slow ? "slow" : "quick"));

  // Fast mode: just verify chunk counters and basic geometry

  // Slow mode: verify chunks and occupancy map

  uintx num_in_use_chunks = 0;

  Metachunk* chunk = first_chunk();

  Metachunk* invalid_chunk = (Metachunk*) top();

  // Iterate the chunks in this node and verify each chunk.

  while (chunk < invalid_chunk ) {

    if (slow) {

      do_verify_chunk(chunk);

    }

    if (!chunk->is_tagged_free()) {

      num_in_use_chunks ++;

    }

    const size_t s = chunk->word_size();

    // Prevent endless loop on invalid chunk size.

    assert(is_valid_chunksize(is_class(), s), "Invalid chunk size: " SIZE_FORMAT ".", s);

    MetaWord* next = ((MetaWord*)chunk) + s;

    chunk = (Metachunk*) next;

  }

  assert(_container_count == num_in_use_chunks, "Container count mismatch (real: " UINTX_FORMAT

      ", counter: " UINTX_FORMAT ".", num_in_use_chunks, _container_count);

  // Also verify the occupancy map.

  if (slow) {

    occupancy_map()->verify(bottom(), top());

  }

}

// Verify that all free chunks in this node are ideally merged

// (there not should be multiple small chunks where a large chunk could exist.)

void VirtualSpaceNode::verify_free_chunks_are_ideally_merged() {

  Metachunk* chunk = first_chunk();

  Metachunk* invalid_chunk = (Metachunk*) top();

  // Shorthands.

  const size_t size_med = (is_class() ? ClassMediumChunk : MediumChunk) * BytesPerWord;

  const size_t size_small = (is_class() ? ClassSmallChunk : SmallChunk) * BytesPerWord;

  int num_free_chunks_since_last_med_boundary = -1;

  int num_free_chunks_since_last_small_boundary = -1;

  bool error = false;

  char err[256];

  while (!error && chunk < invalid_chunk ) {

    // Test for missed chunk merge opportunities: count number of free chunks since last chunk boundary.

    // Reset the counter when encountering a non-free chunk.

    if (chunk->get_chunk_type() != HumongousIndex) {

      if (chunk->is_tagged_free()) {

        // Count successive free, non-humongous chunks.

        if (is_aligned(chunk, size_small)) {

          if (num_free_chunks_since_last_small_boundary > 0) {

            error = true;

            jio_snprintf(err, sizeof(err), "Missed chunk merge opportunity to merge a small chunk preceding " PTR_FORMAT ".", p2i(chunk));

          } else {

            num_free_chunks_since_last_small_boundary = 0;

          }

        } else if (num_free_chunks_since_last_small_boundary != -1) {

          num_free_chunks_since_last_small_boundary ++;

        }

        if (is_aligned(chunk, size_med)) {

          if (num_free_chunks_since_last_med_boundary > 0) {

            error = true;

            jio_snprintf(err, sizeof(err), "Missed chunk merge opportunity to merge a medium chunk preceding " PTR_FORMAT ".", p2i(chunk));

          } else {

            num_free_chunks_since_last_med_boundary = 0;

          }

        } else if (num_free_chunks_since_last_med_boundary != -1) {

          num_free_chunks_since_last_med_boundary ++;

        }

      } else {

        // Encountering a non-free chunk, reset counters.

        num_free_chunks_since_last_med_boundary = -1;

        num_free_chunks_since_last_small_boundary = -1;

      }

    } else {

      // One cannot merge areas with a humongous chunk in the middle. Reset counters.

      num_free_chunks_since_last_med_boundary = -1;

      num_free_chunks_since_last_small_boundary = -1;

    }

    if (error) {

      print_map(tty, is_class());

      fatal("%s", err);

    }

    MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();

    chunk = (Metachunk*) next;

  }

}

#endif // ASSERT

void VirtualSpaceNode::inc_container_count() {

  assert_lock_strong(MetaspaceExpand_lock);

  _container_count++;

}

void VirtualSpaceNode::dec_container_count() {

  assert_lock_strong(MetaspaceExpand_lock);

  _container_count--;

}

VirtualSpaceNode::~VirtualSpaceNode() {

  _rs.release();

  if (_occupancy_map != NULL) {

    delete _occupancy_map;

  }

#ifdef ASSERT

  size_t word_size = sizeof(*this) / BytesPerWord;

  Copy::fill_to_words((HeapWord*) this, word_size, 0xf1f1f1f1);

#endif

}

size_t VirtualSpaceNode::used_words_in_vs() const {

  return pointer_delta(top(), bottom(), sizeof(MetaWord));

}

// Space committed in the VirtualSpace

size_t VirtualSpaceNode::capacity_words_in_vs() const {

  return pointer_delta(end(), bottom(), sizeof(MetaWord));

}

size_t VirtualSpaceNode::free_words_in_vs() const {

  return pointer_delta(end(), top(), sizeof(MetaWord));

}

// Given an address larger than top(), allocate padding chunks until top is at the given address.

void VirtualSpaceNode::allocate_padding_chunks_until_top_is_at(MetaWord* target_top) {

  assert(target_top > top(), "Sanity");

  // Padding chunks are added to the freelist.

  ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(is_class());

  // shorthands

  const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();

  const size_t small_word_size = chunk_manager->small_chunk_word_size();

  const size_t med_word_size = chunk_manager->medium_chunk_word_size();

  while (top() < target_top) {

    // We could make this coding more generic, but right now we only deal with two possible chunk sizes

    // for padding chunks, so it is not worth it.

    size_t padding_chunk_word_size = small_word_size;

    if (is_aligned(top(), small_word_size * sizeof(MetaWord)) == false) {

      assert_is_aligned(top(), spec_word_size * sizeof(MetaWord)); // Should always hold true.

      padding_chunk_word_size = spec_word_size;

    }

    MetaWord* here = top();

    assert_is_aligned(here, padding_chunk_word_size * sizeof(MetaWord));

    inc_top(padding_chunk_word_size);

    // Create new padding chunk.

    ChunkIndex padding_chunk_type = get_chunk_type_by_size(padding_chunk_word_size, is_class());

    assert(padding_chunk_type == SpecializedIndex || padding_chunk_type == SmallIndex, "sanity");

    Metachunk* const padding_chunk =

        ::new (here) Metachunk(padding_chunk_type, is_class(), padding_chunk_word_size, this);

    assert(padding_chunk == (Metachunk*)here, "Sanity");

    DEBUG_ONLY(padding_chunk->set_origin(origin_pad);)

    log_trace(gc, metaspace, freelist)("Created padding chunk in %s at "

        PTR_FORMAT ", size " SIZE_FORMAT_HEX ".",

        (is_class() ? "class space " : "metaspace"),

        p2i(padding_chunk), padding_chunk->word_size() * sizeof(MetaWord));

    // Mark chunk start in occupancy map.

    occupancy_map()->set_chunk_starts_at_address((MetaWord*)padding_chunk, true);

    // Chunks are born as in-use (see MetaChunk ctor). So, before returning

    // the padding chunk to its chunk manager, mark it as in use (ChunkManager

    // will assert that).

    do_update_in_use_info_for_chunk(padding_chunk, true);

    // Return Chunk to freelist.

    inc_container_count();

    chunk_manager->return_single_chunk(padding_chunk);

    // Please note: at this point, ChunkManager::return_single_chunk()

    // may already have merged the padding chunk with neighboring chunks, so

    // it may have vanished at this point. Do not reference the padding

    // chunk beyond this point.

  }

  assert(top() == target_top, "Sanity");

} // allocate_padding_chunks_until_top_is_at()

// Allocates the chunk from the virtual space only.

// This interface is also used internally for debugging.  Not all

// chunks removed here are necessarily used for allocation.

Metachunk* VirtualSpaceNode::take_from_committed(size_t chunk_word_size) {

  // Non-humongous chunks are to be allocated aligned to their chunk

  // size. So, start addresses of medium chunks are aligned to medium

  // chunk size, those of small chunks to small chunk size and so

  // forth. This facilitates merging of free chunks and reduces

  // fragmentation. Chunk sizes are spec < small < medium, with each

  // larger chunk size being a multiple of the next smaller chunk

  // size.

  // Because of this alignment, me may need to create a number of padding

  // chunks. These chunks are created and added to the freelist.

  // The chunk manager to which we will give our padding chunks.

  ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(is_class());

  // shorthands

  const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();

  const size_t small_word_size = chunk_manager->small_chunk_word_size();

  const size_t med_word_size = chunk_manager->medium_chunk_word_size();

  assert(chunk_word_size == spec_word_size || chunk_word_size == small_word_size ||

      chunk_word_size >= med_word_size, "Invalid chunk size requested.");

  // Chunk alignment (in bytes) == chunk size unless humongous.

  // Humongous chunks are aligned to the smallest chunk size (spec).

  const size_t required_chunk_alignment = (chunk_word_size > med_word_size ?

      spec_word_size : chunk_word_size) * sizeof(MetaWord);

  // Do we have enough space to create the requested chunk plus

  // any padding chunks needed?

  MetaWord* const next_aligned =

      static_cast<MetaWord*>(align_up(top(), required_chunk_alignment));

  if (!is_available((next_aligned - top()) + chunk_word_size)) {

    return NULL;

  }

  // Before allocating the requested chunk, allocate padding chunks if necessary.

  // We only need to do this for small or medium chunks: specialized chunks are the

  // smallest size, hence always aligned. Homungous chunks are allocated unaligned

  // (implicitly, also aligned to smallest chunk size).

  if ((chunk_word_size == med_word_size || chunk_word_size == small_word_size) && next_aligned > top())  {

    log_trace(gc, metaspace, freelist)("Creating padding chunks in %s between %p and %p...",

        (is_class() ? "class space " : "metaspace"),

        top(), next_aligned);

    allocate_padding_chunks_until_top_is_at(next_aligned);

    // Now, top should be aligned correctly.

    assert_is_aligned(top(), required_chunk_alignment);

  }

  // Now, top should be aligned correctly.

  assert_is_aligned(top(), required_chunk_alignment);

  // Bottom of the new chunk

  MetaWord* chunk_limit = top();

  assert(chunk_limit != NULL, "Not safe to call this method");

  // 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_space.committed_size() == _virtual_space.actual_committed_size(),

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

  if (!is_available(chunk_word_size)) {

    LogTarget(Trace, gc, metaspace, freelist) lt;

    if (lt.is_enabled()) {

      LogStream ls(lt);

      ls.print("VirtualSpaceNode::take_from_committed() not available " SIZE_FORMAT " words ", chunk_word_size);

      // Dump some information about the virtual space that is nearly full

      print_on(&ls);

    }

    return NULL;

  }

  // Take the space  (bump top on the current virtual space).

  inc_top(chunk_word_size);

  // Initialize the chunk

  ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class());

  Metachunk* result = ::new (chunk_limit) Metachunk(chunk_type, is_class(), chunk_word_size, this);

  assert(result == (Metachunk*)chunk_limit, "Sanity");

  occupancy_map()->set_chunk_starts_at_address((MetaWord*)result, true);

  do_update_in_use_info_for_chunk(result, true);

  inc_container_count();

#ifdef ASSERT

  EVERY_NTH(VerifyMetaspaceInterval)

    chunk_manager->locked_verify(true);

    verify(true);

  END_EVERY_NTH

  do_verify_chunk(result);

#endif

  result->inc_use_count();

  return result;

}

// Expand the virtual space (commit more of the reserved space)

bool VirtualSpaceNode::expand_by(size_t min_words, size_t preferred_words) {

  size_t min_bytes = min_words * BytesPerWord;

  size_t preferred_bytes = preferred_words * BytesPerWord;

  size_t uncommitted = virtual_space()->reserved_size() - virtual_space()->actual_committed_size();

  if (uncommitted < min_bytes) {

    return false;

  }

  size_t commit = MIN2(preferred_bytes, uncommitted);

  bool result = virtual_space()->expand_by(commit, false);

  if (result) {

    log_trace(gc, metaspace, freelist)("Expanded %s virtual space list node by " SIZE_FORMAT " words.",

        (is_class() ? "class" : "non-class"), commit);

    DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_committed_space_expanded));

  } else {

    log_trace(gc, metaspace, freelist)("Failed to expand %s virtual space list node by " SIZE_FORMAT " words.",

        (is_class() ? "class" : "non-class"), commit);

  }

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

  return result;

}

Metachunk* VirtualSpaceNode::get_chunk_vs(size_t chunk_word_size) {

  assert_lock_strong(MetaspaceExpand_lock);

  Metachunk* result = take_from_committed(chunk_word_size);

  return result;

}

bool VirtualSpaceNode::initialize() {

  if (!_rs.is_reserved()) {

    return false;

  }

  // These are necessary restriction to make sure that the virtual space always

  // grows in steps of Metaspace::commit_alignment(). If both base and size are

  // aligned only the middle alignment of the VirtualSpace is used.

  assert_is_aligned(_rs.base(), Metaspace::commit_alignment());

  assert_is_aligned(_rs.size(), Metaspace::commit_alignment());

  // 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.

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

  bool result = virtual_space()->initialize_with_granularity(_rs, pre_committed_size,

      Metaspace::commit_alignment());

  if (result) {

    assert(virtual_space()->committed_size() == virtual_space()->actual_committed_size(),

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

    set_top((MetaWord*)virtual_space()->low());

  }