Re: [PATCH v2 3/3] device-dax: Add system ram (add_memory()) with MHP_NO_FIRMWARE_MEMMAP

[Dave Hansen]

On 4/30/20 3:29 AM, David Hildenbrand wrote:
> Currently, when adding memory, we create entries in /sys/firmware/memmap/
> as "System RAM". This does not reflect the reality and will lead to
> kexec-tools to add that memory to the fixed-up initial memmap for a
> kexec kernel (loaded via kexec_load()). The memory will be considered
> initial System RAM by the kexec kernel.
> 
> We should let the kexec kernel decide how to use that memory - just as
> we do during an ordinary reboot.
...
> -	rc = add_memory(numa_node, new_res->start, resource_size(new_res), 0);
> +	rc = add_memory(numa_node, new_res->start, resource_size(new_res),
> +			MHP_NO_FIRMWARE_MEMMAP);

Looks fine.  But, if you send another revision, could you add a comment
about the actual goal of MHP_NO_FIRMWARE_MEMMAP?  Maybe:

	/*
	 * MHP_NO_FIRMWARE_MEMMAP ensures that future
	 * kexec'd kernels will not treat this as RAM.
	 */

Not a biggie, though.

Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>