Subject: Re: [PATCH 4/7] Allow sysfs memory directories to be split
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nathan Fontenot <nfont@austin.ibm.com>, linux-kernel@vger.kernel.org,
        linuxppc-dev@ozlabs.org
In-Reply-To: <20100714093550.40036034.kamezawa.hiroyu@jp.fujitsu.com>
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	 <20100713152854.ec1f4d6a.kamezawa.hiroyu@jp.fujitsu.com>
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Date: Tue, 13 Jul 2010 20:26:56 -0700
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On Wed, 2010-07-14 at 09:35 +0900, KAMEZAWA Hiroyuki wrote:
>   2. I'd like to write a configfs module for handling memory hotplug even when
>      sysfs directroy is not created.
>      Because configfs support rmdir/mkdir, the user (ppc's daemon?) has to do
>      
>      When offlining section X.
>      # insmod configfs_memory.ko
>      # mount -t configfs none /configfs
>      # mkdir /configfs/memoryX
>      # echo offline > /configfs/memoryX/state
>      # rmdir /configfs/memoryX
> 
>   And making this operation as the default bahavior for all arch's memory hotplug may
>   be better...
> 
> Dave, how do you think ? Because ppc guys uses "probe" interface already,
> this can be handled... no ?

I think creating a interface to duplicate the existing sysfs one is a
bad idea.  I also think removing the existing sysfs one isn't feasible
since there are users, and it's truly part of the ABI.  So, I'm not
really a fan on the configfs interface. :(

I really do think the sysfs interface is fixable.  We should at least
give it a good shot before largely duplicating its functionality.

-- Dave

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