33 lines · cpp
1//===---------- Linux implementation of the POSIX posix_madvise function --===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "src/sys/mman/posix_madvise.h"10 11#include "src/__support/OSUtil/syscall.h" // For internal syscall function.12#include "src/__support/common.h"13#include "src/__support/macros/config.h"14 15#include <sys/syscall.h> // For syscall numbers.16 17namespace LIBC_NAMESPACE_DECL {18 19// This function is currently linux only. It has to be refactored suitably if20// posix_madvise is to be supported on non-linux operating systems also.21LLVM_LIBC_FUNCTION(int, posix_madvise, (void *addr, size_t size, int advice)) {22 // POSIX_MADV_DONTNEED does nothing because the default MADV_DONTNEED may23 // cause data loss, which the posix madvise does not allow.24 if (advice == POSIX_MADV_DONTNEED) {25 return 0;26 }27 int ret = LIBC_NAMESPACE::syscall_impl<int>(28 SYS_madvise, reinterpret_cast<long>(addr), size, advice);29 return ret < 0 ? -ret : 0;30}31 32} // namespace LIBC_NAMESPACE_DECL33