[PATCH 3/3] mm/page_owner: add NUMA node filter

Zhen Ni
2026-04-17T19:16:11Z

Add NUMA node filtering functionality to page_owner to allow
filtering pages by specific NUMA node.

The filter allows users to focus on pages from a specific NUMA node,
which is useful for NUMA-aware memory allocation analysis and debugging.
Setting nid to -1 disables filtering (default behavior).

Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
---
mm/page_owner.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 214b58eef3d8..ebc29f3f516d 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -726,6 +726,13 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
if (unlikely(!page_ext))
continue;

+ if (READ_ONCE(owner_filter.nid) >= 0) {
+ int nid = page_to_nid(page);
+
+ if (nid != READ_ONCE(owner_filter.nid))
+ goto ext_put_continue;
+ }
+
/*
* Some pages could be missed by concurrent allocation or free,
* because we don't hold the zone lock.
@@ -987,6 +994,24 @@ static int page_owner_threshold_set(void *data, u64 val)
DEFINE_SIMPLE_ATTRIBUTE(page_owner_threshold_fops, &page_owner_threshold_get,
&page_owner_threshold_set, "%llu");

+static int page_owner_nid_filter_get(void *data, u64 *val)
+{
+ *val = READ_ONCE(owner_filter.nid);
+ return 0;
+}
+
+static int page_owner_nid_filter_set(void *data, u64 val)
+{
+ if (val >= MAX_NUMNODES && val != (u64)-1)
+ return -EINVAL;
+ WRITE_ONCE(owner_filter.nid, val);
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(page_owner_nid_filter_fops,
+ &page_owner_nid_filter_get,
+ &page_owner_nid_filter_set, "%lld");
+
static int page_owner_compact_get(void *data, u64 *val)
{
*val = READ_ONCE(owner_filter.compact);
@@ -1018,6 +1043,8 @@ static int __init pageowner_init(void)
debugfs_create_file("page_owner", 0400, NULL, NULL, &page_owner_fops);

filter_dir = debugfs_create_dir("page_owner_filter", NULL);
+ debugfs_create_file("nid", 0600, filter_dir, NULL,
+ &page_owner_nid_filter_fops);
debugfs_create_file("compact", 0600, filter_dir, NULL,
&page_owner_compact_fops);

--
2.20.1