/*

 * Copyright (c) 2017, 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 "memory/allocation.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/metaspaceShared.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/atomic.hpp"

#include "runtime/os.hpp"

#include "runtime/task.hpp"

#include "runtime/threadCritical.hpp"

#include "services/memTracker.hpp"

#include "utilities/ostream.hpp"

//--------------------------------------------------------------------------------------

// ChunkPool implementation

// MT-safe pool of chunks to reduce malloc/free thrashing

// NB: not using Mutex because pools are used before Threads are initialized

class ChunkPool: public CHeapObj<mtInternal> {

  Chunk*       _first;        // first cached Chunk; its first word points to next chunk

  size_t       _num_chunks;   // number of unused chunks in pool

  size_t       _num_used;     // number of chunks currently checked out

  const size_t _size;         // size of each chunk (must be uniform)

  // Our four static pools

  static ChunkPool* _large_pool;

  static ChunkPool* _medium_pool;

  static ChunkPool* _small_pool;

  static ChunkPool* _tiny_pool;

  // return first element or null

  void* get_first() {

    Chunk* c = _first;

    if (_first) {

      _first = _first->next();

      _num_chunks--;

    }

    return c;

  }

 public:

  // All chunks in a ChunkPool has the same size

   ChunkPool(size_t size) : _size(size) { _first = NULL; _num_chunks = _num_used = 0; }

  // Allocate a new chunk from the pool (might expand the pool)

  NOINLINE void* allocate(size_t bytes, AllocFailType alloc_failmode) {

    assert(bytes == _size, "bad size");

    void* p = NULL;

    // No VM lock can be taken inside ThreadCritical lock, so os::malloc

    // should be done outside ThreadCritical lock due to NMT

    { ThreadCritical tc;

      _num_used++;

      p = get_first();

    }

    if (p == NULL) p = os::malloc(bytes, mtChunk, CURRENT_PC);

    if (p == NULL && alloc_failmode == AllocFailStrategy::EXIT_OOM) {

      vm_exit_out_of_memory(bytes, OOM_MALLOC_ERROR, "ChunkPool::allocate");

    }

    return p;

  }

  // Return a chunk to the pool

  void free(Chunk* chunk) {

    assert(chunk->length() + Chunk::aligned_overhead_size() == _size, "bad size");

    ThreadCritical tc;

    _num_used--;

    // Add chunk to list

    chunk->set_next(_first);

    _first = chunk;

    _num_chunks++;

  }

  // Prune the pool

  void free_all_but(size_t n) {

    Chunk* cur = NULL;

    Chunk* next;

    {

      // if we have more than n chunks, free all of them

      ThreadCritical tc;

      if (_num_chunks > n) {

        // free chunks at end of queue, for better locality

        cur = _first;

        for (size_t i = 0; i < (n - 1) && cur != NULL; i++) cur = cur->next();

        if (cur != NULL) {

          next = cur->next();

          cur->set_next(NULL);

          cur = next;

          // Free all remaining chunks while in ThreadCritical lock

          // so NMT adjustment is stable.

          while(cur != NULL) {

            next = cur->next();

            os::free(cur);

            _num_chunks--;

            cur = next;

          }

        }

      }

    }

  }

  // Accessors to preallocated pool's

  static ChunkPool* large_pool()  { assert(_large_pool  != NULL, "must be initialized"); return _large_pool;  }

  static ChunkPool* medium_pool() { assert(_medium_pool != NULL, "must be initialized"); return _medium_pool; }

  static ChunkPool* small_pool()  { assert(_small_pool  != NULL, "must be initialized"); return _small_pool;  }

  static ChunkPool* tiny_pool()   { assert(_tiny_pool   != NULL, "must be initialized"); return _tiny_pool;   }

  static void initialize() {

    _large_pool  = new ChunkPool(Chunk::size        + Chunk::aligned_overhead_size());

    _medium_pool = new ChunkPool(Chunk::medium_size + Chunk::aligned_overhead_size());

    _small_pool  = new ChunkPool(Chunk::init_size   + Chunk::aligned_overhead_size());

    _tiny_pool   = new ChunkPool(Chunk::tiny_size   + Chunk::aligned_overhead_size());

  }

  static void clean() {

    enum { BlocksToKeep = 5 };

     _tiny_pool->free_all_but(BlocksToKeep);

     _small_pool->free_all_but(BlocksToKeep);

     _medium_pool->free_all_but(BlocksToKeep);

     _large_pool->free_all_but(BlocksToKeep);

  }

};

ChunkPool* ChunkPool::_large_pool  = NULL;

ChunkPool* ChunkPool::_medium_pool = NULL;

ChunkPool* ChunkPool::_small_pool  = NULL;

ChunkPool* ChunkPool::_tiny_pool   = NULL;

void chunkpool_init() {

  ChunkPool::initialize();

}

void

Chunk::clean_chunk_pool() {

  ChunkPool::clean();

}

//--------------------------------------------------------------------------------------

// ChunkPoolCleaner implementation

//

class ChunkPoolCleaner : public PeriodicTask {

  enum { CleaningInterval = 5000 };      // cleaning interval in ms

 public:

   ChunkPoolCleaner() : PeriodicTask(CleaningInterval) {}

   void task() {

     ChunkPool::clean();

   }

};

//--------------------------------------------------------------------------------------

// Chunk implementation

void* Chunk::operator new (size_t requested_size, AllocFailType alloc_failmode, size_t length) throw() {

  // requested_size is equal to sizeof(Chunk) but in order for the arena

  // allocations to come out aligned as expected the size must be aligned

  // to expected arena alignment.

  // expect requested_size but if sizeof(Chunk) doesn't match isn't proper size we must align it.

  assert(ARENA_ALIGN(requested_size) == aligned_overhead_size(), "Bad alignment");

  size_t bytes = ARENA_ALIGN(requested_size) + length;

  switch (length) {

   case Chunk::size:        return ChunkPool::large_pool()->allocate(bytes, alloc_failmode);

   case Chunk::medium_size: return ChunkPool::medium_pool()->allocate(bytes, alloc_failmode);

   case Chunk::init_size:   return ChunkPool::small_pool()->allocate(bytes, alloc_failmode);

   case Chunk::tiny_size:   return ChunkPool::tiny_pool()->allocate(bytes, alloc_failmode);

   default: {

     void* p = os::malloc(bytes, mtChunk, CALLER_PC);

     if (p == NULL && alloc_failmode == AllocFailStrategy::EXIT_OOM) {

       vm_exit_out_of_memory(bytes, OOM_MALLOC_ERROR, "Chunk::new");

     }

     return p;

   }

  }

}

void Chunk::operator delete(void* p) {

  Chunk* c = (Chunk*)p;

  switch (c->length()) {

   case Chunk::size:        ChunkPool::large_pool()->free(c); break;

   case Chunk::medium_size: ChunkPool::medium_pool()->free(c); break;

   case Chunk::init_size:   ChunkPool::small_pool()->free(c); break;

   case Chunk::tiny_size:   ChunkPool::tiny_pool()->free(c); break;

   default:

     ThreadCritical tc;  // Free chunks under TC lock so that NMT adjustment is stable.

     os::free(c);

  }

}

Chunk::Chunk(size_t length) : _len(length) {

  _next = NULL;         // Chain on the linked list

}

void Chunk::chop() {

  Chunk *k = this;

  while( k ) {

    Chunk *tmp = k->next();

    // clear out this chunk (to detect allocation bugs)

    if (ZapResourceArea) memset(k->bottom(), badResourceValue, k->length());

    delete k;                   // Free chunk (was malloc'd)

    k = tmp;

  }

}

void Chunk::next_chop() {

  _next->chop();

  _next = NULL;

}

void Chunk::start_chunk_pool_cleaner_task() {

#ifdef ASSERT

  static bool task_created = false;

  assert(!task_created, "should not start chuck pool cleaner twice");

  task_created = true;

#endif

  ChunkPoolCleaner* cleaner = new ChunkPoolCleaner();

  cleaner->enroll();

}

//------------------------------Arena------------------------------------------

Arena::Arena(MEMFLAGS flag, size_t init_size) : _flags(flag), _size_in_bytes(0)  {

  size_t round_size = (sizeof (char *)) - 1;

  init_size = (init_size+round_size) & ~round_size;

  _first = _chunk = new (AllocFailStrategy::EXIT_OOM, init_size) Chunk(init_size);

  _hwm = _chunk->bottom();      // Save the cached hwm, max

  _max = _chunk->top();

  MemTracker::record_new_arena(flag);

  set_size_in_bytes(init_size);

}

Arena::Arena(MEMFLAGS flag) : _flags(flag), _size_in_bytes(0) {

  _first = _chunk = new (AllocFailStrategy::EXIT_OOM, Chunk::init_size) Chunk(Chunk::init_size);

  _hwm = _chunk->bottom();      // Save the cached hwm, max

  _max = _chunk->top();

  MemTracker::record_new_arena(flag);

  set_size_in_bytes(Chunk::init_size);

}

Arena *Arena::move_contents(Arena *copy) {

  copy->destruct_contents();

  copy->_chunk = _chunk;

  copy->_hwm   = _hwm;

  copy->_max   = _max;

  copy->_first = _first;

  // workaround rare racing condition, which could double count

  // the arena size by native memory tracking

  size_t size = size_in_bytes();

  set_size_in_bytes(0);

  copy->set_size_in_bytes(size);

  // Destroy original arena

  reset();

  return copy;            // Return Arena with contents

}

Arena::~Arena() {

  destruct_contents();

  MemTracker::record_arena_free(_flags);

}

void* Arena::operator new(size_t size) throw() {

  assert(false, "Use dynamic memory type binding");

  return NULL;

}

void* Arena::operator new (size_t size, const std::nothrow_t&  nothrow_constant) throw() {

  assert(false, "Use dynamic memory type binding");

  return NULL;

}

  // dynamic memory type binding

void* Arena::operator new(size_t size, MEMFLAGS flags) throw() {

  return (void *) AllocateHeap(size, flags, CALLER_PC);

}

void* Arena::operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw() {

  return (void*)AllocateHeap(size, flags, CALLER_PC, AllocFailStrategy::RETURN_NULL);

}

void Arena::operator delete(void* p) {

  FreeHeap(p);

}

// Destroy this arenas contents and reset to empty

void Arena::destruct_contents() {

  if (UseMallocOnly && _first != NULL) {

    char* end = _first->next() ? _first->top() : _hwm;

    free_malloced_objects(_first, _first->bottom(), end, _hwm);

  }

  // reset size before chop to avoid a rare racing condition

  // that can have total arena memory exceed total chunk memory

  set_size_in_bytes(0);

  _first->chop();

  reset();

}

// This is high traffic method, but many calls actually don't

// change the size

void Arena::set_size_in_bytes(size_t size) {

  if (_size_in_bytes != size) {

    _size_in_bytes = size;

    MemTracker::record_arena_size_change(delta, _flags);

  }

}

// Total of all Chunks in arena

size_t Arena::used() const {

  size_t sum = _chunk->length() - (_max-_hwm); // Size leftover in this Chunk

  Chunk *k = _first;

  while( k != _chunk) {         // Whilst have Chunks in a row

    sum += k->length();         // Total size of this Chunk

    k = k->next();              // Bump along to next Chunk

  }

  return sum;                   // Return total consumed space.

}

void Arena::signal_out_of_memory(size_t sz, const char* whence) const {

  vm_exit_out_of_memory(sz, OOM_MALLOC_ERROR, "%s", whence);

}

// Grow a new Chunk

void* Arena::grow(size_t x, AllocFailType alloc_failmode) {

  // Get minimal required size.  Either real big, or even bigger for giant objs

  size_t len = MAX2(x, (size_t) Chunk::size);

  Chunk *k = _chunk;            // Get filled-up chunk address

  _chunk = new (alloc_failmode, len) Chunk(len);

  if (_chunk == NULL) {

    _chunk = k;                 // restore the previous value of _chunk

    return NULL;

  }

  if (k) k->set_next(_chunk);   // Append new chunk to end of linked list

  else _first = _chunk;

  _hwm  = _chunk->bottom();     // Save the cached hwm, max

  _max =  _chunk->top();

  set_size_in_bytes(size_in_bytes() + len);

  void* result = _hwm;

  _hwm += x;

  return result;

}

// Reallocate storage in Arena.

void *Arena::Arealloc(void* old_ptr, size_t old_size, size_t new_size, AllocFailType alloc_failmode) {

  if (new_size == 0) return NULL;

#ifdef ASSERT

  if (UseMallocOnly) {

    // always allocate a new object  (otherwise we'll free this one twice)

    char* copy = (char*)Amalloc(new_size, alloc_failmode);

    if (copy == NULL) {

      return NULL;

    }

    size_t n = MIN2(old_size, new_size);

    if (n > 0) memcpy(copy, old_ptr, n);

    Afree(old_ptr,old_size);    // Mostly done to keep stats accurate

    return copy;

  }

#endif

  char *c_old = (char*)old_ptr; // Handy name

  // Stupid fast special case

  if( new_size <= old_size ) {  // Shrink in-place

    if( c_old+old_size == _hwm) // Attempt to free the excess bytes

      _hwm = c_old+new_size;    // Adjust hwm

    return c_old;

  }

  // make sure that new_size is legal

  size_t corrected_new_size = ARENA_ALIGN(new_size);

  // See if we can resize in-place

  if( (c_old+old_size == _hwm) &&       // Adjusting recent thing

      (c_old+corrected_new_size <= _max) ) {      // Still fits where it sits

    _hwm = c_old+corrected_new_size;      // Adjust hwm

    return c_old;               // Return old pointer

  }

  // Oops, got to relocate guts

  void *new_ptr = Amalloc(new_size, alloc_failmode);

  if (new_ptr == NULL) {

    return NULL;

  }

  memcpy( new_ptr, c_old, old_size );

  Afree(c_old,old_size);        // Mostly done to keep stats accurate

  return new_ptr;

}

// Determine if pointer belongs to this Arena or not.

bool Arena::contains( const void *ptr ) const {

#ifdef ASSERT

  if (UseMallocOnly) {

    // really slow, but not easy to make fast

    if (_chunk == NULL) return false;

    char** bottom = (char**)_chunk->bottom();

    for (char** p = (char**)_hwm - 1; p >= bottom; p--) {

      if (*p == ptr) return true;

    }

    for (Chunk *c = _first; c != NULL; c = c->next()) {

      if (c == _chunk) continue;  // current chunk has been processed

      char** bottom = (char**)c->bottom();

      for (char** p = (char**)c->top() - 1; p >= bottom; p--) {

        if (*p == ptr) return true;

      }

    }

    return false;

  }

#endif

  if( (void*)_chunk->bottom() <= ptr && ptr < (void*)_hwm )

    return true;                // Check for in this chunk

  for (Chunk *c = _first; c; c = c->next()) {

    if (c == _chunk) continue;  // current chunk has been processed

    if ((void*)c->bottom() <= ptr && ptr < (void*)c->top()) {

      return true;              // Check for every chunk in Arena

    }

  }

  return false;                 // Not in any Chunk, so not in Arena

}

#ifdef ASSERT

void* Arena::malloc(size_t size) {

  assert(UseMallocOnly, "shouldn't call");

  // use malloc, but save pointer in res. area for later freeing

  char** save = (char**)internal_malloc_4(sizeof(char*));

  return (*save = (char*)os::malloc(size, mtChunk));

}

// for debugging with UseMallocOnly

void* Arena::internal_malloc_4(size_t x) {

  assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );

  check_for_overflow(x, "Arena::internal_malloc_4");

  if (_hwm + x > _max) {

    return grow(x);

  } else {

    char *old = _hwm;

    _hwm += x;

    return old;

  }

}

#endif

//--------------------------------------------------------------------------------------

// Non-product code

#ifndef PRODUCT

// debugging code

inline void Arena::free_all(char** start, char** end) {

  for (char** p = start; p < end; p++) if (*p) os::free(*p);

}

void Arena::free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2) {

  assert(UseMallocOnly, "should not call");

  // free all objects malloced since resource mark was created; resource area

  // contains their addresses

  if (chunk->next()) {

    // this chunk is full, and some others too

    for (Chunk* c = chunk->next(); c != NULL; c = c->next()) {

      char* top = c->top();

      if (c->next() == NULL) {

        top = hwm2;     // last junk is only used up to hwm2

        assert(c->contains(hwm2), "bad hwm2");

      }

      free_all((char**)c->bottom(), (char**)top);

    }

    assert(chunk->contains(hwm), "bad hwm");

    assert(chunk->contains(max), "bad max");

    free_all((char**)hwm, (char**)max);

  } else {

    // this chunk was partially used

    assert(chunk->contains(hwm), "bad hwm");

    assert(chunk->contains(hwm2), "bad hwm2");

    free_all((char**)hwm, (char**)hwm2);

  }

}

#endif // Non-product