[RFC PATCH 2/12] memory-hogplug : check memory offline in offline_pages

[David Rientjes]

On Wed, 27 Jun 2012, Yasuaki Ishimatsu wrote:

> Index: linux-3.5-rc4/mm/memory_hotplug.c
> ===================================================================
> --- linux-3.5-rc4.orig/mm/memory_hotplug.c	2012-06-26 13:28:16.743211538 +0900
> +++ linux-3.5-rc4/mm/memory_hotplug.c	2012-06-26 13:48:38.264940468 +0900
> @@ -887,6 +887,11 @@ static int __ref offline_pages(unsigned
> 
>  	lock_memory_hotplug();
> 
> +	if (memory_is_offline(start_pfn, end_pfn)) {
> +		ret = 0;
> +		goto out;
> +	}
> +
>  	zone = page_zone(pfn_to_page(start_pfn));
>  	node = zone_to_nid(zone);
>  	nr_pages = end_pfn - start_pfn;

Are there additional prerequisites for this patch?  Otherwise it changes 
the return value of offline_memory() which will now call 
acpi_memory_powerdown_device() in the acpi memhotplug case when disabling.  
Is that a problem?