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SubjectRe: [Linux-nvdimm] another pmem variant
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On Wed, Mar 25, 2015 at 10:04 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Wed, Mar 25, 2015 at 10:00:26AM -0700, Dan Williams wrote:
>> The kernel command line would simply be the standard/existing memmap=
>> to reserve a memory range. Then, when the platform device loads, it
>> does a request_firmware() to inject a binary table that further carves
>> memory into ranges to which the pmem driver attaches. No need for the
>> legacy system BIOS to be upgraded to the "new way".
>
> Ewww...
>
>> It does do the right thing in kernel space. The userspace utility
>> creates the binary table (once) that can be compiled into the platform
>> device driver or auto-loaded by an initrd. The problem with a new
>> memmap= is that it is too coarse. For example you can't do things
>> like specify a pmem range per-NUMA node.
>
> Sure you can as long as you know the layout. memmap= can be specified
> multiple times. Again, I see absolutely zero benefit of doing crap
> like request_firmware() to convert interface, and I'm also tired of
> having this talk about code that will eventually be released and should
> be superior (and from all that I can guess so far will actually be far
> worse).

You and me both...


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