# Re: \[Patch v4 12/12\] memory-hotplug: free node\_data when a node is offlined

- From: Tang Chen \<hidden\>
- Date: 2012-12-04 10:11:19 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/12/3967363
- Thread: https://ratatoskr.run/linux-mm/2012/11/3963802/t.md

```text
On 11/27/2012 06:00 PM, Wen Congyang wrote:
> We call hotadd_new_pgdat() to allocate memory to store node_data. So we
> should free it when removing a node.
>
> CC: David Rientjes<rientjes@google.com>
> CC: Jiang Liu<redacted>
> CC: Len Brown<redacted>
> CC: Benjamin Herrenschmidt<benh@kernel.crashing.org>
> CC: Paul Mackerras<redacted>
> CC: Christoph Lameter<redacted>
> Cc: Minchan Kim<redacted>
> CC: Andrew Morton<akpm@linux-foundation.org>
> CC: KOSAKI Motohiro<redacted>
> CC: Yasuaki Ishimatsu<redacted>
> Signed-off-by: Wen Congyang<redacted>

Reviewed-by: Tang Chen <redacted>

> ---
>   mm/memory_hotplug.c | 20 +++++++++++++++++++-
>   1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 449663e..d1451ab 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1309,9 +1309,12 @@ static int check_cpu_on_node(void *data)
>   /* offline the node if all memory sections of this node are removed */
>   static void try_offline_node(int nid)
>   {
> +	pg_data_t *pgdat = NODE_DATA(nid);
>   	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> -	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
> +	unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
>   	unsigned long pfn;
> +	struct page *pgdat_page = virt_to_page(pgdat);
> +	int i;
>
>   	for (pfn = start_pfn; pfn<  end_pfn; pfn += PAGES_PER_SECTION) {
>   		unsigned long section_nr = pfn_to_section_nr(pfn);
> @@ -1338,6 +1341,21 @@ static void try_offline_node(int nid)
>   	 */
>   	node_set_offline(nid);
>   	unregister_one_node(nid);
> +
> +	if (!PageSlab(pgdat_page)&&  !PageCompound(pgdat_page))
> +		/* node data is allocated from boot memory */
> +		return;
> +
> +	/* free waittable in each zone */
> +	for (i = 0; i<  MAX_NR_ZONES; i++) {
> +		struct zone *zone = pgdat->node_zones + i;
> +
> +		if (zone->wait_table)
> +			vfree(zone->wait_table);
> +	}
> +
> +	arch_refresh_nodedata(nid, NULL);
> +	arch_free_nodedata(pgdat);
>   }
>
>   int __ref remove_memory(int nid, u64 start, u64 size)
```