memory/mozjemalloc/jemalloc.h
author Gabriele Svelto <gsvelto@mozilla.com>
Thu, 08 Nov 2012 20:06:50 +0100
changeset 113166 8bdc6ccc3705491adeaeb7d7d3cec439925dd058
parent 111987 6ed470203a3b6e7bcaf0dbc8ddab35840f8681d5
permissions -rw-r--r--
Bug 805855 - Add an extra function to jemalloc to free dirty unused pages. r=glandium

/* -*- Mode: C; tab-width: 8; c-basic-offset: 8 -*- */
/* vim:set softtabstop=8 shiftwidth=8: */
/*-
 * Copyright (C) 2006-2008 Jason Evans <jasone@FreeBSD.org>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice(s), this list of conditions and the following disclaimer as
 *    the first lines of this file unmodified other than the possible
 *    addition of one or more copyright notices.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice(s), this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _JEMALLOC_H_
#define _JEMALLOC_H_

#if defined(MOZ_MEMORY_DARWIN)
#include <malloc/malloc.h>
#endif
#include "jemalloc_types.h"

#if defined(MOZ_NATIVE_JEMALLOC)
#define wrap(a) a
#else
#define wrap(a) je_ ## a
#endif

#ifdef __cplusplus
extern "C" {
#endif

#if defined(MOZ_NATIVE_JEMALLOC) \
  || defined(MOZ_MEMORY_LINUX) || defined(MOZ_MEMORY_BSD)
__attribute__((weak))
#endif
void	jemalloc_stats(jemalloc_stats_t *stats);

/* Computes the usable size in advance. */
#if !defined(MOZ_MEMORY_DARWIN)
#if defined(MOZ_MEMORY_LINUX) || defined(MOZ_MEMORY_BSD)
__attribute__((weak))
#endif
#if defined(MOZ_JEMALLOC)
MOZ_IMPORT_API int wrap(nallocm)(size_t *rsize, size_t size, int flags);
#else
size_t je_malloc_good_size(size_t size);
#endif
#endif

static inline size_t je_malloc_usable_size_in_advance(size_t size) {
#if defined(MOZ_MEMORY_DARWIN)
  return malloc_good_size(size);
#elif defined(MOZ_JEMALLOC)
  if (wrap(nallocm)) {
    size_t ret;
    if (size == 0)
      size = 1;
    if (!wrap(nallocm)(&ret, size, 0))
      return ret;
  }
  return size;
#else
  if (je_malloc_good_size)
    return je_malloc_good_size(size);
  else
    return size;
#endif
}

/*
 * On some operating systems (Mac), we use madvise(MADV_FREE) to hand pages
 * back to the operating system.  On Mac, the operating system doesn't take
 * this memory back immediately; instead, the OS takes it back only when the
 * machine is running out of physical memory.
 *
 * This is great from the standpoint of efficiency, but it makes measuring our
 * actual RSS difficult, because pages which we've MADV_FREE'd shouldn't count
 * against our RSS.
 *
 * This function explicitly purges any MADV_FREE'd pages from physical memory,
 * causing our reported RSS match the amount of memory we're actually using.
 *
 * Note that this call is expensive in two ways.  First, it may be slow to
 * execute, because it may make a number of slow syscalls to free memory.  This
 * function holds the big jemalloc locks, so basically all threads are blocked
 * while this function runs.
 *
 * This function is also expensive in that the next time we go to access a page
 * which we've just explicitly decommitted, the operating system has to attach
 * to it a physical page!  If we hadn't run this function, the OS would have
 * less work to do.
 *
 * If MALLOC_DOUBLE_PURGE is not defined, this function does nothing.
 */
#if defined(MOZ_MEMORY_LINUX) || defined(MOZ_JEMALLOC)
static inline void jemalloc_purge_freed_pages() { }
#else
void    jemalloc_purge_freed_pages();
#endif

/*
 * Free all unused dirty pages in all arenas. Calling this function will slow
 * down subsequent allocations so it is recommended to use it only when
 * memory needs to be reclaimed at all costs (see bug 805855). This function
 * provides functionality similar to mallctl("arenas.purge") in jemalloc 3.
 */

#if !defined(MOZ_NATIVE_JEMALLOC)
#if defined(MOZ_MEMORY_LINUX) || defined(MOZ_MEMORY_BSD)
__attribute__((weak))
#endif /* defined(MOZ_MEMORY_LINUX) || defined(MOZ_MEMORY_BSD) */
void    jemalloc_free_dirty_pages();
#endif /* !defined(MOZ_NATIVE_JEMALLOC) */

#ifdef __cplusplus
} /* extern "C" */
#endif

#undef wrap

#endif /* _JEMALLOC_H_ */