Re: [PATCH v2 1/3] mm/page_owner: add filter infrastructure

[Zi Yan]

On 19 Apr 2026, at 11:55, Zhen Ni wrote:

> Add data structure for page_owner filtering functionality and create
> debugfs directory for filter controls.
>
> This adds:
> - enum page_owner_print_mode with values for full_stack and stack_handle
> - struct page_owner_filter with print_mode and nid_mask fields
> - Static owner_filter instance initialized with default values
> - page_owner_filter debugfs directory
>
> The filter infrastructure will be used to add print_mode and NUMA node
> filtering capabilities in subsequent commits.
>
> Link: https://lore.kernel.org/linux-mm/20260417154638.22370-2-zhen.ni@xxxxxxxxxxxx/
> Suggested-by: Zi Yan <ziy@xxxxxxxxxx>
> Signed-off-by: Zhen Ni <zhen.ni@xxxxxxxxxxxx>
> ---
>
> Changes in v2:
> - Use enum page_owner_print_mode instead of bool 'compact' for better clarity
> - Use nodemask_t instead of int 'nid' to support multi-node filtering
> ---
>  mm/page_owner.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)

The patch can be folded into Patch 2. Otherwise, these new types are not
used and page_owner_filter folder is just empty.


>
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 8178e0be557f..5884d883837e 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -54,6 +54,21 @@ struct stack_print_ctx {
>  	u8 flags;
>  };
>
> +enum page_owner_print_mode {
> +	PAGE_OWNER_PRINT_FULL_STACK,
> +	PAGE_OWNER_PRINT_STACK_HANDLE,
> +};
> +
> +struct page_owner_filter {
> +	enum page_owner_print_mode print_mode;
> +	nodemask_t nid_mask;
> +};
> +
> +static struct page_owner_filter owner_filter = {
> +	.print_mode = PAGE_OWNER_PRINT_FULL_STACK,
> +	.nid_mask = NODE_MASK_NONE,
> +};
> +
>  static bool page_owner_enabled __initdata;
>  DEFINE_STATIC_KEY_FALSE(page_owner_inited);
>
> @@ -973,7 +988,7 @@ DEFINE_SIMPLE_ATTRIBUTE(page_owner_threshold_fops, &page_owner_threshold_get,
>
>  static int __init pageowner_init(void)
>  {
> -	struct dentry *dir;
> +	struct dentry *dir, *filter_dir;
>
>  	if (!static_branch_unlikely(&page_owner_inited)) {
>  		pr_info("page_owner is disabled\n");
> @@ -981,6 +996,9 @@ 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);
> +
>  	dir = debugfs_create_dir("page_owner_stacks", NULL);
>  	debugfs_create_file("show_stacks", 0400, dir,
>  			    (void *)(STACK_PRINT_FLAG_STACK |
> -- 
> 2.20.1


Best Regards,
Yan, Zi