[RFC PATCH v5 19/19] memory-hotplug: remove sysfs file of node

[Yasuaki Ishimatsu]

Hi Wen,

2012/07/27 19:36, Wen Congyang wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
>
> The patch adds node_set_offline() and unregister_one_node() to remove_memory()
> for removing sysfs file of node.
>
> CC: David Rientjes <rientjes at google.com>
> CC: Jiang Liu <liuj97 at gmail.com>
> CC: Len Brown <len.brown at intel.com>
> CC: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> CC: Paul Mackerras <paulus at samba.org>
> CC: Christoph Lameter <cl at linux.com>
> Cc: Minchan Kim <minchan.kim at gmail.com>
> CC: Andrew Morton <akpm at linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com>
> CC: Wen Congyang <wency at cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
> ---
>   mm/memory_hotplug.c |    5 +++++
>   1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 5ac035f..5681968 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1267,6 +1267,11 @@ int __ref remove_memory(int nid, u64 start, u64 size)
>   	/* remove memmap entry */
>   	firmware_map_remove(start, start + size, "System RAM");
>
> +	if (!node_present_pages(nid)) {

Applying [PATCH v5 17/19], pgdat->node_spanned_pages can become 0 when
all memory of the pgdat is removed. When pgdat->node_spanned_pages is 0,
it means the pgdat has no memory. So I think node_spanned_pages() is
better.

Thanks,
Yasuaki Ishimatsu

> +		node_set_offline(nid);
> +		unregister_one_node(nid);
> +	}
> +
>   	arch_remove_memory(start, size);
>   out:
>   	unlock_memory_hotplug();
>