sysdeps/unix/sysv/linux/posix_madvise.c

   1 /* Copyright (C) 2007-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <sysdep.h>
  19 #include <sys/mman.h>
  20
  21
  22 int
  23 posix_madvise (void *addr, size_t len, int advice)
  24 {
  25   /* We have one problem: the kernel's MADV_DONTNEED does not
  26      correspond to POSIX's POSIX_MADV_DONTNEED.  The former simply
  27      discards changes made to the memory without writing it back to
  28      disk, if this would be necessary.  The POSIX behavior does not
  29      allow this.  There is no functionality mapping the POSIX behavior
  30      so far so we ignore that advice for now.  */
  31   if (advice == POSIX_MADV_DONTNEED)
  32     return 0;
  33
  34   int result = INTERNAL_SYSCALL_CALL (madvise, addr, len, advice);
  35   return INTERNAL_SYSCALL_ERRNO (result);
  36 }