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Date: Fri, 23 Sep 2011 15:27:41 -0400
From: Rik van Riel <riel@redhat.com>
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To: Michel Lespinasse <walken@google.com>
CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Dave Hansen <dave@linux.vnet.ibm.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Johannes Weiner <jweiner@redhat.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Hugh Dickins <hughd@google.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Michael Wolf <mjwolf@us.ibm.com>
Subject: Re: [PATCH 2/8] kstaled: documentation and config option.
References: <1316230753-8693-1-git-send-email-walken@google.com> <1316230753-8693-3-git-send-email-walken@google.com>
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On 09/16/2011 11:39 PM, Michel Lespinasse wrote:
> Extend memory cgroup documentation do describe the optional idle page
> tracking features, and add the corresponding configuration option.
>
>
> Signed-off-by: Michel Lespinasse<walken@google.com>

> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -370,3 +370,13 @@ config CLEANCACHE
>   	  in a negligible performance hit.
>
>   	  If unsure, say Y to enable cleancache
> +
> +config KSTALED
> +       depends on CGROUP_MEM_RES_CTLR

Looking at patch #3, I wonder if this needs to be dependent
on 64 bit, or at least make sure this is not selected when
a user builds a 32 bit kernel with NUMA.

The reason is that on a 32 bit system we could run out of
page flags + zone bits + node bits.

> +       bool "Per-cgroup idle page tracking"
> +       help
> +         This feature allows the kernel to report the amount of user pages
> +	 in a cgroup that have not been touched in a given time.
> +	 This information may be used to size the cgroups and/or for
> +	 job placement within a compute cluster.
> +	 See Documentation/cgroups/memory.txt for a more complete description.



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