Re: [PATCH v2 3/3] mm/page_owner: add NUMA node filter with nodelist support

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 19 Apr 2026 23:55:40 +0800 Zhen Ni <zhen.ni@easystack.cn> wrote:

> Add NUMA node filtering functionality to page_owner to allow
> filtering pages by specific NUMA node(s) using nodelist format.
> 
> The filter allows users to focus on pages from specific NUMA nodes,
> which is useful for NUMA-aware memory allocation analysis and debugging.

AI review
(https://sashiko.dev/#/patchset/20260419155540.376847-1-zhen.ni@easystack.cn)
wonders if it's legitimate to use READ_ONCE/WRITE_ONCE against a
nodemask_t.  And indeed, my x86_64 allmodconfig hit compile time
asserts over this.

So I took them out:

--- a/mm/page_owner.c~mm-page_owner-add-numa-node-filter-with-nodelist-support-fix
+++ a/mm/page_owner.c
@@ -732,7 +732,7 @@ read_page_owner(struct file *file, char
 			continue;
 
 		/* NUMA node filter using bitmask */
-		mask = READ_ONCE(owner_filter.nid_mask);
+		mask = owner_filter.nid_mask;
 		if (!nodes_empty(mask)) {
 			int nid = page_to_nid(page);
 
@@ -1049,7 +1049,7 @@ static ssize_t nid_filter_write(struct f
 		goto out_free;
 	}
 
-	WRITE_ONCE(owner_filter.nid_mask, mask);
+	owner_filter.nid_mask = mask;
 	ret = count;
 
 out_free:
@@ -1059,7 +1059,7 @@ out_free:
 
 static int nid_filter_show(struct seq_file *m, void *v)
 {
-	nodemask_t mask = READ_ONCE(owner_filter.nid_mask);
+	nodemask_t mask = owner_filter.nid_mask;
 
 	if (nodes_empty(mask))
 		seq_puts(m, "-1\n");
_