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Message-ID: <6599ad830703061800n38244a8fp68b29fa0290d18d7@mail.gmail.com>
Date: Tue, 6 Mar 2007 18:00:04 -0800
From: "Paul Menage" <menage@google.com>
To: "Pavel Emelianov" <xemul@sw.ru>
Subject: Re: [RFC][PATCH 6/7] Account for the number of tasks within container
Cc: "Andrew Morton" <akpm@osdl.org>, "Srivatsa Vaddagiri" <vatsa@in.ibm.com>,
       "Balbir Singh" <balbir@in.ibm.com>, devel@openvz.org,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
       containers@lists.osdl.org, "Kirill Korotaev" <dev@sw.ru>
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Hi Pavel,

On 3/6/07, Pavel Emelianov <xemul@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