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

- From: Wen Congyang \<hidden\>
- Date: 2012-07-30 03:43:23 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/07/3900328
- Thread: https://ratatoskr.run/linux-mm/2012/07/3899655/t.md

```text
At 07/27/2012 06:45 PM, Yasuaki Ishimatsu Wrote:
> Hi Wen,
> 
> 2012/07/27 19:36, Wen Congyang wrote:
>> From: Yasuaki Ishimatsu <redacted>
>>
>> The patch adds node_set_offline() and unregister_one_node() to
>> remove_memory()
>> for removing sysfs file of 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: Wen Congyang <redacted>
>> Signed-off-by: Yasuaki Ishimatsu <redacted>
>> ---
>>   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.

Hmm, if the node contains cpu, and the cpu is onlined, can we offline
this node?

Thanks
Wen Congyang

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