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

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

[Hao Ge]

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.

Signed-off-by: Hao Ge <hao.ge@linux.dev>
---
 drivers/base/node.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index d7647d077b66..53f4e51d6d82 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -513,6 +513,7 @@ static ssize_t node_read_meminfo(struct device *dev,
 			     "Node %d Slab:           %8lu kB\n"
 			     "Node %d SReclaimable:   %8lu kB\n"
 			     "Node %d SUnreclaim:     %8lu kB\n"
+			     "Node %d Balloon:        %8lu kB\n"
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			     "Node %d AnonHugePages:  %8lu kB\n"
 			     "Node %d ShmemHugePages: %8lu kB\n"
@@ -543,7 +544,8 @@ static ssize_t node_read_meminfo(struct device *dev,
 				    node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
 			     nid, K(sreclaimable + sunreclaimable),
 			     nid, K(sreclaimable),
-			     nid, K(sunreclaimable)
+			     nid, K(sunreclaimable),
+			     nid, K(node_page_state(pgdat, NR_BALLOON_PAGES))
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			     ,
 			     nid, K(node_page_state(pgdat, NR_ANON_THPS)),
-- 
2.25.1

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

[David Hildenbrand (Arm)]

On 5/8/26 03:53, Hao Ge 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.

Using ballooning with vNUMA is rather rare. But sure, why not.

> 
> Signed-off-by: Hao Ge <hao.ge@linux.dev>
> ---
>  drivers/base/node.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index d7647d077b66..53f4e51d6d82 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -513,6 +513,7 @@ static ssize_t node_read_meminfo(struct device *dev,
>  			     "Node %d Slab:           %8lu kB\n"
>  			     "Node %d SReclaimable:   %8lu kB\n"
>  			     "Node %d SUnreclaim:     %8lu kB\n"
> +			     "Node %d Balloon:        %8lu kB\n"
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  			     "Node %d AnonHugePages:  %8lu kB\n"
>  			     "Node %d ShmemHugePages: %8lu kB\n"
> @@ -543,7 +544,8 @@ static ssize_t node_read_meminfo(struct device *dev,
>  				    node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
>  			     nid, K(sreclaimable + sunreclaimable),
>  			     nid, K(sreclaimable),
> -			     nid, K(sunreclaimable)
> +			     nid, K(sunreclaimable),
> +			     nid, K(node_page_state(pgdat, NR_BALLOON_PAGES))
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  			     ,
>  			     nid, K(node_page_state(pgdat, NR_ANON_THPS)),


Shouldn't it be placed under "Unaccepted:", just like for /proc/meminfo?

-- 
Cheers,

David

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

[Hao Ge]

Hi David


On 2026/5/8 16:23, David Hildenbrand (Arm) wrote:
> On 5/8/26 03:53, Hao Ge 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.
> Using ballooning with vNUMA is rather rare. But sure, why not.

Yeah, it's indeed not common.

We came across this while analyzing a customer's 16C 32G VM with 2 vNUMA 
nodes and balloon enabled.


>> Signed-off-by: Hao Ge <hao.ge@linux.dev>
>> ---
>>   drivers/base/node.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/node.c b/drivers/base/node.c
>> index d7647d077b66..53f4e51d6d82 100644
>> --- a/drivers/base/node.c
>> +++ b/drivers/base/node.c
>> @@ -513,6 +513,7 @@ static ssize_t node_read_meminfo(struct device *dev,
>>   			     "Node %d Slab:           %8lu kB\n"
>>   			     "Node %d SReclaimable:   %8lu kB\n"
>>   			     "Node %d SUnreclaim:     %8lu kB\n"
>> +			     "Node %d Balloon:        %8lu kB\n"
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>   			     "Node %d AnonHugePages:  %8lu kB\n"
>>   			     "Node %d ShmemHugePages: %8lu kB\n"
>> @@ -543,7 +544,8 @@ static ssize_t node_read_meminfo(struct device *dev,
>>   				    node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
>>   			     nid, K(sreclaimable + sunreclaimable),
>>   			     nid, K(sreclaimable),
>> -			     nid, K(sunreclaimable)
>> +			     nid, K(sunreclaimable),
>> +			     nid, K(node_page_state(pgdat, NR_BALLOON_PAGES))
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>   			     ,
>>   			     nid, K(node_page_state(pgdat, NR_ANON_THPS)),
>
> Shouldn't it be placed under "Unaccepted:", just like for /proc/meminfo?
>
Good catch, thanks. I overlooked this detail -- will fix in v2.

Thanks

Best Regards

Hao