memory/build/mozmemory.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozmemory_h
   6 #define mozmemory_h
   7
   8 /*
   9  * This header is meant to be used when the following functions are
  10  * necessary:
  11  *   - malloc_good_size (used to be called je_malloc_usable_in_advance)
  12  *   - jemalloc_stats
  13  *   - jemalloc_purge_freed_pages
  14  *   - jemalloc_free_dirty_pages
  15  */
  16
  17 #ifndef MOZ_MEMORY
  18 #  error Should not include mozmemory.h when MOZ_MEMORY is not set
  19 #endif
  20
  21 #include "mozmemory_wrap.h"
  22 #include "mozilla/Attributes.h"
  23 #include "mozilla/Types.h"
  24 #include "jemalloc_types.h"
  25
  26 MOZ_BEGIN_EXTERN_C
  27
  28 /*
  29  * On OSX, malloc/malloc.h contains the declaration for malloc_good_size,
  30  * which will call back in jemalloc, through the zone allocator so just use it.
  31  */
  32 #ifdef XP_DARWIN
  33 #  include <malloc/malloc.h>
  34 #else
  35 MOZ_MEMORY_API size_t malloc_good_size_impl(size_t size);
  36
  37 /* Note: the MOZ_GLUE_IN_PROGRAM ifdef below is there to avoid -Werror turning
  38  * the protective if into errors. MOZ_GLUE_IN_PROGRAM is what triggers MFBT_API
  39  * to use weak imports. */
  40
  41 static inline size_t _malloc_good_size(size_t size) {
  42 #  if defined(MOZ_GLUE_IN_PROGRAM) && !defined(IMPL_MFBT)
  43   if (!malloc_good_size)
  44     return size;
  45 #  endif
  46   return malloc_good_size_impl(size);
  47 }
  48
  49 #  define malloc_good_size _malloc_good_size
  50 #endif
  51
  52 MOZ_JEMALLOC_API void jemalloc_stats(jemalloc_stats_t *stats);
  53
  54 /*
  55  * On some operating systems (Mac), we use madvise(MADV_FREE) to hand pages
  56  * back to the operating system.  On Mac, the operating system doesn't take
  57  * this memory back immediately; instead, the OS takes it back only when the
  58  * machine is running out of physical memory.
  59  *
  60  * This is great from the standpoint of efficiency, but it makes measuring our
  61  * actual RSS difficult, because pages which we've MADV_FREE'd shouldn't count
  62  * against our RSS.
  63  *
  64  * This function explicitly purges any MADV_FREE'd pages from physical memory,
  65  * causing our reported RSS match the amount of memory we're actually using.
  66  *
  67  * Note that this call is expensive in two ways.  First, it may be slow to
  68  * execute, because it may make a number of slow syscalls to free memory.  This
  69  * function holds the big jemalloc locks, so basically all threads are blocked
  70  * while this function runs.
  71  *
  72  * This function is also expensive in that the next time we go to access a page
  73  * which we've just explicitly decommitted, the operating system has to attach
  74  * to it a physical page!  If we hadn't run this function, the OS would have
  75  * less work to do.
  76  *
  77  * If MALLOC_DOUBLE_PURGE is not defined, this function does nothing.
  78  */
  79 MOZ_JEMALLOC_API void jemalloc_purge_freed_pages();
  80
  81 /*
  82  * Free all unused dirty pages in all arenas. Calling this function will slow
  83  * down subsequent allocations so it is recommended to use it only when
  84  * memory needs to be reclaimed at all costs (see bug 805855). This function
  85  * provides functionality similar to mallctl("arenas.purge") in jemalloc 3.
  86  */
  87 MOZ_JEMALLOC_API void jemalloc_free_dirty_pages();
  88
  89 MOZ_END_EXTERN_C
  90
  91 #endif /* mozmemory_h */