# Re: \[Patch v4 06/12\] memory-hotplug: unregister memory section on SPARSEMEM\_VMEMMAP

- From: Tang Chen \<hidden\>
- Date: 2012-12-04 09:35:10 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/12/3967349
- Thread: https://ratatoskr.run/linux-mm/2012/11/3963802/t.md

```text
On 11/27/2012 06:00 PM, Wen Congyang wrote:
> From: Yasuaki Ishimatsu<redacted>
>
> Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even if
> we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
>
> So the patch add unregister_memory_section() into __remove_section().
>
> CC: David Rientjes<rientjes@google.com>
> CC: Jiang Liu<redacted>
> CC: Len Brown<redacted>
> CC: Christoph Lameter<redacted>
> Cc: Minchan Kim<redacted>
> CC: Andrew Morton<akpm@linux-foundation.org>
> CC: KOSAKI Motohiro<redacted>
> Signed-off-by: Yasuaki Ishimatsu<redacted>
> Signed-off-by: Wen Congyang<redacted>

__remove_section() of CONFIG_SPARSEMEM_VMEMMAP will be integrated
into one in [PATCH 08/12], so I think we can merge this patch into
[PATCH 08/12].

Reviewed-by: Tang Chen <redacted>

> ---
>   mm/memory_hotplug.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e741732..171610d 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -279,11 +279,14 @@ static int __meminit __add_section(int nid, struct zone *zone,
>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
>   static int __remove_section(struct zone *zone, struct mem_section *ms)
>   {
> -	/*
> -	 * XXX: Freeing memmap with vmemmap is not implement yet.
> -	 *      This should be removed later.
> -	 */
> -	return -EBUSY;
> +	int ret = -EINVAL;
> +
> +	if (!valid_section(ms))
> +		return ret;
> +
> +	ret = unregister_memory_section(ms);
> +
> +	return ret;
>   }
>   #else
>   static int __remove_section(struct zone *zone, struct mem_section *ms)
```