Re: [PATCH v2] mm/balloon: expose per-node balloon pages in node meminfo

[Hao Ge <hao.ge@linux.dev>]

Hi Andrew


On 2026/5/9 02:31, Andrew Morton wrote:
> On Fri,  8 May 2026 17:47:36 +0800 Hao Ge <hao.ge@linux.dev> wrote:
>
>> Commit 835de37603ef ("meminfo: add a per node counter for balloon
>> drivers") added NR_BALLOON_PAGES and exposed it in /proc/meminfo.
>> However, the per-node view at /sys/devices/system/node/nodeX/meminfo
>> was not updated, even though the counter is already tracked per-node.
>>
>> Add it to node_read_meminfo() so users can see balloon usage per
>> NUMA node without having to parse the raw vmstat file.
>>
>> ...
>>
>> --- a/drivers/base/node.c
>> +++ b/drivers/base/node.c
>> @@ -523,6 +523,7 @@ static ssize_t node_read_meminfo(struct device *dev,
>>   #ifdef CONFIG_UNACCEPTED_MEMORY
>>   			     "Node %d Unaccepted:     %8lu kB\n"
>>   #endif
>> +			     "Node %d Balloon:        %8lu kB\n"
>>   			     ,
>>   			     nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
>>   			     nid, K(node_page_state(pgdat, NR_WRITEBACK)),
>> @@ -556,6 +557,8 @@ static ssize_t node_read_meminfo(struct device *dev,
>>   			     ,
>>   			     nid, K(sum_zone_node_page_state(nid, NR_UNACCEPTED))
>>   #endif
>> +			     ,
>> +			     nid, K(node_page_state(pgdat, NR_BALLOON_PAGES))
>>   			    );
>>   	len += hugetlb_report_node_meminfo(buf, len, nid);
>>   	return len;
> This was prepared against a kernel whcih didn't have 2232ba9c7931 ("mm:
> add gpu active/reclaim per-node stat counters (v2)").  Which was added
> in February, btw.

Sorry about that — I failed to git pull the latest code before preparing 
the v2 patch,

so I didn't realize commit 2232ba9c7931 ("mm: add gpu active/reclaim 
per-node stat counters (v2)")

had already been merged in February.

I apologize for the trouble this caused you.

> Please check my fixings:
>
> --- a/drivers/base/node.c~mm-balloon-expose-per-node-balloon-pages-in-node-meminfo
> +++ a/drivers/base/node.c
> @@ -525,6 +525,7 @@ static ssize_t node_read_meminfo(struct
>   #endif
>   			     "Node %d GPUActive:      %8lu kB\n"
>   			     "Node %d GPUReclaim:     %8lu kB\n"
> +			     "Node %d Balloon:        %8lu kB\n"
>   			     ,
>   			     nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
>   			     nid, K(node_page_state(pgdat, NR_WRITEBACK)),
> @@ -560,7 +561,8 @@ static ssize_t node_read_meminfo(struct
>   #endif
>   			     ,
>   			     nid, K(node_page_state(pgdat, NR_GPU_ACTIVE)),
> -			     nid, K(node_page_state(pgdat, NR_GPU_RECLAIM))
> +			     nid, K(node_page_state(pgdat, NR_GPU_RECLAIM)),
> +			     nid, K(node_page_state(pgdat, NR_BALLOON_PAGES))
>   			    );
>   	len += hugetlb_report_node_meminfo(buf, len, nid);
>   	return len;
> _

As David suggested, the node meminfo fields should match the 
/proc/meminfo ordering.

So in the v3 I rebased on the latest tree and put Balloon between 
Unaccepted and GPUActive.

Here is the v3 patch: 
https://lore.kernel.org/all/20260509005631.17183-1-hao.ge@linux.dev/

  Sorry again for the inconvenience, Could you please replace the v2 
patch in mm-new with this v3?

Thanks

Best Regards

Hao