/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Some Linux kernels -- specifically, newer versions of Android and

// some B2G devices -- have a feature for assigning names to ranges of

// anonymous memory (i.e., memory that doesn't have a "name" in the

// form of an underlying mapped file).  These names are reported in

// /proc/<pid>/smaps alongside system-level memory usage information

// such as Proportional Set Size (memory usage adjusted for sharing

// between processes), which allows reporting this information at a

// finer granularity than would otherwise be possible (e.g.,

// separating malloc() heap from JS heap).

//

// Existing memory can be tagged with MozTagAnonymousMemory(); it will

// tag the range of complete pages containing the given interval, so

// the results may be inexact if the range isn't page-aligned.

// MozTaggedAnonymousMmap() can be used like mmap() with an extra

// parameter, and will tag the returned memory if the mapping was

// successful (and if it was in fact anonymous).

//

// NOTE: The pointer given as the "tag" argument MUST remain valid as

// long as the mapping exists.  The referenced string is read when

// /proc/<pid>/smaps or /proc/<pid>/maps is read, not when the tag is

// established, so freeing it or changing its contents will have

// unexpected results.  Using a static string is probably best.

//

// Also note that this header can be used by both C and C++ code.

#ifndef mozilla_TaggedAnonymousMemory_h

#define mozilla_TaggedAnonymousMemory_h

#ifndef XP_WIN

#include <sys/types.h>

#include <sys/mman.h>

#include "mozilla/Types.h"

#ifdef ANDROID

#ifdef __cplusplus

extern "C" {

#endif

MFBT_API void MozTagAnonymousMemory(const void* aPtr, size_t aLength,

                                    const char* aTag);

MFBT_API void* MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt,

                                      int aFlags, int aFd, off_t aOffset,

                                      const char* aTag);

MFBT_API int MozTaggedMemoryIsSupported(void);

#ifdef __cplusplus

}  // extern "C"

#endif

#else  // ANDROID

static inline void MozTagAnonymousMemory(const void* aPtr, size_t aLength,

                                         const char* aTag) {}

static inline void* MozTaggedAnonymousMmap(void* aAddr, size_t aLength,

                                           int aProt, int aFlags, int aFd,

                                           off_t aOffset, const char* aTag) {

  return mmap(aAddr, aLength, aProt, aFlags, aFd, aOffset);

}

static inline int MozTaggedMemoryIsSupported(void) { return 0; }

#endif  // ANDROID

#endif  // !XP_WIN

#endif  // mozilla_TaggedAnonymousMemory_h