Re: [Linux-nvdimm] another pmem variant

[Dan Williams]

On Wed, Mar 25, 2015 at 10:04 AM, Christoph Hellwig <hch@xxxxxx> 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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