sys_process_madvise
asmlinkage long sys_process_madvise(int pidfd, const struct iovec __user *vec,
__SYSCALL(__NR_process_madvise, sys_process_madvise)
__SYSCALL(__NR_process_madvise, sys_process_madvise)
count = sys_process_madvise(PIDFD_SELF, vec, 6, MADV_GUARD_INSTALL, 0);
count = sys_process_madvise(PIDFD_SELF, vec, 6, MADV_GUARD_REMOVE, 0);
ret = sys_process_madvise(self->remote_pidfd, &vec, 1, MADV_COLLAPSE,
ret = sys_process_madvise(self->remote_pidfd, &vec, 1, MADV_DONTNEED,
ret = sys_process_madvise(-1, &vec, 1, MADV_DONTNEED, 0);
ret = sys_process_madvise(STDIN_FILENO, &vec, 1, MADV_DONTNEED, 0);
ret = sys_process_madvise(pidfd, &vec, 1025, MADV_DONTNEED, 0);
ret = sys_process_madvise(pidfd, &vec, 1, MADV_DONTNEED, invalid_flag);
ret = sys_process_madvise(pidfd, vec, madvise_pages, MADV_DONTNEED, 0);