The Tor Browser: memory/build/mozmemory.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     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/. */

     5 #ifndef mozmemory_h

     6 #define mozmemory_h

     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  */

    17 #ifndef MOZ_MEMORY

    18 #  error Should not include mozmemory.h when MOZ_MEMORY is not set

    19 #endif

    21 #include "mozmemory_wrap.h"

    22 #include "mozilla/Attributes.h"

    23 #include "mozilla/Types.h"

    24 #include "jemalloc_types.h"

    26 MOZ_BEGIN_EXTERN_C

    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);

    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. */

    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 }

    49 #  define malloc_good_size _malloc_good_size

    50 #endif

    52 MOZ_JEMALLOC_API void jemalloc_stats(jemalloc_stats_t *stats);

    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();

    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();

    89 MOZ_END_EXTERN_C

    91 #endif /* mozmemory_h */

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