JemallocNodumpAllocator.h

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/*
 * Copyright 2016-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html

#pragma once

#include <folly/CPortability.h>
#include <folly/portability/Config.h>

#if defined(FOLLY_USE_JEMALLOC) && !FOLLY_SANITIZE

#include <folly/portability/SysMman.h>
#include <jemalloc/jemalloc.h>

#if (JEMALLOC_VERSION_MAJOR > 3) && defined(MADV_DONTDUMP)
#define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED 1
#if (JEMALLOC_VERSION_MAJOR == 4)
#define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_CHUNK
#define JEMALLOC_CHUNK_OR_EXTENT chunk
#else
#define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_EXTENT
#define JEMALLOC_CHUNK_OR_EXTENT extent
#endif
#endif

#endif // FOLLY_USE_JEMALLOC

#include <cstddef>

namespace folly {

class JemallocNodumpAllocator {
 public:
  enum class State {
    ENABLED,
    DISABLED,
  };

  // To be used as IOBuf::FreeFunction, userData should be set to
  // reinterpret_cast<void*>(getFlags()).
  static void deallocate(void* p, void* userData);

  explicit JemallocNodumpAllocator(State state = State::ENABLED);

  void* allocate(size_t size);
  void* reallocate(void* p, size_t size);
  void deallocate(void* p, size_t = 0);

  unsigned getArenaIndex() const {
    return arena_index_;
  }
  int getFlags() const {
    return flags_;
  }

 private:
#ifdef FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED
#ifdef FOLLY_JEMALLOC_NODUMP_ALLOCATOR_CHUNK
  static chunk_alloc_t* original_alloc_;
  static void* alloc(
      void* chunk,
#else
  static extent_hooks_t extent_hooks_;
  static extent_alloc_t* original_alloc_;
  static void* alloc(
      extent_hooks_t* extent,
      void* new_addr,
#endif
      size_t size,
      size_t alignment,
      bool* zero,
      bool* commit,
      unsigned arena_ind);
#endif // FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED

  bool extend_and_setup_arena();

  unsigned arena_index_{0};
  int flags_{0};
};

JemallocNodumpAllocator& globalJemallocNodumpAllocator();

} // namespace folly