Re: [Qemu-devel] [ndctl PATCH 0/8] dimm label space initialization support

[Eric Blake]

On 10/19/2016 11:47 AM, Dan Williams wrote:
> The 4.9 kernel added support for sub-dividing PMEM.  With this kernel
> patch [1] on top of that baseline, the PMEM-sub-division support can be
> enabled for QEMU-KVM and any other platforms that advertise both un-aliased
> PMEM regions and support for the label DSM commands [2].
> 
> Given this increasing need to perform a label management operation
> across a set of DIMMs this update also adds glob(3) support.  For
> example you can now write commands like:
> 
>     ndctl zero-labels nmem[2-4]

This is slightly scary, as it depends on the user not having any file
named nmem2, nmem3, or nmem4 in the current working directory.  Your
example should probably encourage proper shell quoting, as in:

ndctl zero-labels 'nmem[2-4]'

> 
> ...as a shorthand for:
> 
>     ndctl zero-labels nmem2 nmem3 nmem4

By the way, depending on the user's shell, they can already have
shorthand as in:

ndctl zero-labels nmem{2,3,4}

where the shell does the expansion instead of you having to do a glob
after the fact.  Which makes me wonder if this syntactic sugar is worth
maintaining.


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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