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Subject: Re: [RFC, 3/7] NUMA hotplug emulator
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Greg KH <gregkh@suse.de>
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Date: Thu, 13 May 2010 10:54:52 -0700
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On Thu, 2010-05-13 at 09:55 -0700, Greg KH wrote:
> > Add a sysfs entry "probe" under /sys/devices/system/node/:
> > 
> >  - to show all fake offlined nodes:
> >     $ cat /sys/devices/system/node/probe
> > 
> >  - to hotadd a fake offlined node, e.g. nodeid is N:
> >     $ echo N > /sys/devices/system/node/probe
> 
> As you are trying to add a new sysfs file, please create the matching
> Documentation/ABI/ file as well.
> 
> Also note that sysfs files are "one value per file", which I don't think
> this file follows, right?

I think in this case, it was meant to be a list of acceptable parameters
rather than a set of values, kinda like /sys/power/state.  Instead, I
guess we could have:

	/sys/devices/system/node/probeable/3
	/sys/devices/system/node/probeable/43
	/sys/devices/system/node/probeable/65
	/sys/devices/system/node/probeable/5145

and the knowledge that you need to pick one of those to echo
into /sys/devices/system/node/probe.  But, it's a lot more self
explanatory if you 'cat /sys/devices/system/node/probe', and then pick
one of those to echo back into the file.

Seems like a decent place to violate the "rule". :)

-- Dave