Subject: Re: [PATCH repost] sched: export sched_set/getaffinity to modules

From: Oleg Nesterov <[email-masked]>
Date: Thu, 1 Jul 2010 16:46:24 +0200

On 07/01, Tejun Heo wrote:
>
> All that's necessary is shortcutting indirection through kthreadd.
> ie. An exported function which looks like the following,
>
>  struct kthread_clone_or_whatever(int (*threadfn).....)
>  {
> 	struct kthread_create_info create;
> 	int pid;
>
> 	INIT create;
>
> 	pid = kernel_thread(kthread, &create, CLONE_FS...);
> 	if (pid < 0)
> 		return ERROR;
> 	wait_for_completion(&create.done);
>
> 	if (!IS_ERR(create.result))
> 		SET NAME;
> 	return create.result;
>  }
>
> It might be a good idea to make the function take extra clone flags
> but anyways once created cloned task can be treated the same way as
> other kthreads, so nothing else needs to be changed.

This makes kthread_stop() work. Otherwise the new thread is just
the CLONE_VM child of the caller, and the caller is the user-mode
task doing ioctl() ?

Oleg.