glibc/sysdeps/unix/sysv/linux/posix_madvise.c

38 lines
1.4 KiB
C

/* Copyright (C) 2007-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <sys/mman.h>
int
posix_madvise (void *addr, size_t len, int advice)
{
/* We have one problem: the kernel's MADV_DONTNEED does not
correspond to POSIX's POSIX_MADV_DONTNEED. The former simply
discards changes made to the memory without writing it back to
disk, if this would be necessary. The POSIX behavior does not
allow this. There is no functionality mapping the POSIX behavior
so far so we ignore that advice for now. */
if (advice == POSIX_MADV_DONTNEED)
return 0;
INTERNAL_SYSCALL_DECL (err);
int result = INTERNAL_SYSCALL (madvise, err, 3, addr, len, advice);
return INTERNAL_SYSCALL_ERRNO (result, err);
}