hphp/util/maphuge.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16 #pragma once
  17
  18 #include <folly/portability/SysMman.h>
  19
  20 namespace HPHP {
  21
  22 inline constexpr bool hugePagesSupported() {
  23 #ifdef MADV_HUGEPAGE
  24   // Kernels earlier than 3.2.28 may have bugs dealing with MADV_HUGEPAGE.  The
  25   // bug should've been fixed in production kernels now, so we no longer do
  26   // run-time kernel version checks.
  27   return true;
  28 #else
  29   return false;
  30 #endif
  31 }
  32
  33 inline void hintHuge(void* mem, size_t length) {
  34 #ifdef MADV_HUGEPAGE
  35   if (hugePagesSupported()) {
  36     madvise(mem, length, MADV_HUGEPAGE);
  37   }
  38 #endif
  39 }
  40
  41 }
  42