[Devel] Re: [RFC][PATCH 6/7] Account for the number of tasks within container

[Paul Menage]

Hi Pavel,

On 3/6/07, Pavel Emelianov <xemul at sw.ru> wrote:
> diff -upr linux-2.6.20.orig/include/linux/sched.h linux-2.6.20-0/include/linux/sched.h
> --- linux-2.6.20.orig/include/linux/sched.h     2007-03-06 13:33:28.000000000 +0300
> +++ linux-2.6.20-0/include/linux/sched.h        2007-03-06 13:33:28.000000000 +0300
> @@ -1052,6 +1055,9 @@ struct task_struct {
>  #ifdef CONFIG_FAULT_INJECTION
>         int make_it_fail;
>  #endif
> +#ifdef CONFIG_PROCESS_CONTAINER
> +       struct numproc_container *numproc_cnt;
> +#endif
>  };

Why do you need a pointer added to task_struct? One of the main points
of the generic containers is to avoid every different subsystem and
resource controller having to add new pointers there.

> +
> +       rcu_read_lock();
> +       np = numproc_from_cont(task_container(current, &numproc_subsys));
> +       css_get_current(&np->css);

There's no need to hold a reference here - by definition, the task's
container can't go away while the task is in it.

Also, shouldn't you have an attach() method to move the count from one
container to another when a task moves?

Paul