Re: [PATCH 4/4] memory-hotplug: auto offline page_cgroup when onliningmemory block failed

[Ni zhan Chen]

On 09/27/2012 01:45 PM, wency@xxxxxxxxxxxxxx wrote:
> From: Wen Congyang <wency@xxxxxxxxxxxxxx>
>
> When a memory block is onlined, we will try allocate memory on that node
> to store page_cgroup. If onlining the memory block failed, we don't
> offline the page cgroup, and we have no chance to offline this page cgroup
> unless the memory block is onlined successfully again. It will cause
> that we can't hot-remove the memory device on that node, because some
> memory is used to store page cgroup. If onlining the memory block
> is failed, there is no need to stort page cgroup for this memory. So
> auto offline page_cgroup when onlining memory block failed.

looks reasonable to me. thanks.

> CC: David Rientjes <rientjes@xxxxxxxxxx>
> CC: Jiang Liu <liuj97@xxxxxxxxx>
> CC: Len Brown <len.brown@xxxxxxxxx>
> CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> CC: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> ---
>   mm/page_cgroup.c |    3 +++
>   1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> index 5ddad0c..44db00e 100644
> --- a/mm/page_cgroup.c
> +++ b/mm/page_cgroup.c
> @@ -251,6 +251,9 @@ static int __meminit page_cgroup_callback(struct notifier_block *self,
>   				mn->nr_pages, mn->status_change_nid);
>   		break;
>   	case MEM_CANCEL_ONLINE:
> +		offline_page_cgroup(mn->start_pfn,
> +				mn->nr_pages, mn->status_change_nid);
> +		break;
>   	case MEM_GOING_OFFLINE:
>   		break;
>   	case MEM_ONLINE:

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