Re: [Linux-nvdimm] [PATCH v2] pmem: Initial version of persistent memory driver

From: Dan Williams
Date: Thu Sep 11 2014 - 12:31:24 EST


On Thu, Sep 11, 2014 at 3:45 AM, Boaz Harrosh <boaz@xxxxxxxxxxxxx> wrote:
> On 09/11/2014 02:01 AM, Dan Williams wrote:
> <>
>>
>> Imagine you want to deploy a policy like "use half of the memory
>> provided by the dimm in slot3, i.e. the only one with a battery".
>> That sort of thing gets unwieldy in a command line string compared to
>> a description table format that we can update at will.
>>
>
> Actually it is easy to do, why? I do this here in the lab all the time.
> with a "command line" with this code you see here.
>
> [DDR3 NvDIMM which means I need memmap=16G\$32G on Kernel command line.
> Then: modprobe pmem map=8G@32G,4G@44G,...
> and so on Just as a simple example where 2/4-3/4 addresses are not used.
> You can have holes in the middle or what ever you want. This here is just
> a table in comma-separated format. If we need like flags in future we can
> extend the format to nn@ss:flags, but I do no have any 3rd column yet]

The point I am getting at is not requiring a priori knowledge of the
physical memory map of a system. Rather, place holder variables to
enable simple dynamic discovery.

> And again I have in the pipe a dynamic interface added on top of
> the module param one. So it will all be there soon. Without reverting
> the old one.

Why start on step 2 when we haven't got agreement on step 1?
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