Message-ID: <4FEDF963.9040700@redhat.com>
Date: Fri, 29 Jun 2012 14:52:19 -0400
From: Rik van Riel <riel@redhat.com>
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To: Andrea Arcangeli <aarcange@redhat.com>
CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Hillf Danton <dhillf@gmail.com>, Dan Smith <danms@us.ibm.com>,
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        Paul Turner <pjt@google.com>,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Mike Galbraith <efault@gmx.de>,
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Subject: Re: [PATCH 19/40] autonuma: alloc/free/init sched_autonuma
References: <1340888180-15355-1-git-send-email-aarcange@redhat.com> <1340888180-15355-20-git-send-email-aarcange@redhat.com>
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On 06/28/2012 08:55 AM, Andrea Arcangeli wrote:
> This is where the dynamically allocated sched_autonuma structure is
> being handled.
>
> The reason for keeping this outside of the task_struct besides not
> using too much kernel stack, is to only allocate it on NUMA
> hardware. So the not NUMA hardware only pays the memory of a pointer
> in the kernel stack (which remains NULL at all times in that case).

What is not documented is the reason for keeping it at all.

What is in the data structure?

What is the data structure used for?

How do we use it?

> +	if (unlikely(alloc_task_autonuma(tsk, orig, node)))
> +		/* free_thread_info() undoes arch_dup_task_struct() too */
> +		goto out_thread_info;

Oh, you mean task_autonuma, and not sched_autonuma?

Please fix the commit message and the subject.

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