Re: [PATCH 2/2] mm/page_owner: simplify zone iteration logic in init_early_allocated_pages()

[Ye Liu <ye.liu@linux.dev>]

在 2025/9/30 17:21, Hu Song 写道:
> From: Song Hu <husong@kylinos.cn>
>
> The current implementation uses nested loops: first iterating over all
> online nodes, then over zones within each node. This can be simplified
> by using the for_each_populated_zone() macro which directly iterates
> through all populated zones.
>
> This change:
> 1. Removes the intermediate init_zones_in_node() function
> 2. Simplifies init_early_allocated_pages() to use direct zone iteration
> 3. Updates init_pages_in_zone() to take only zone parameter and access
>    node_id via zone->zone_pgdat
>
> The functionality remains identical, but the code is cleaner and more
> maintainable.
>
> Signed-off-by: Song Hu <husong@kylinos.cn>


Reviewed-by: Ye Liu <liuye@kylinos.cn>

> ---
>  mm/page_owner.c | 23 +++++------------------
>  1 file changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index bb88b72b6062..b170b27d87a1 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -757,7 +757,7 @@ static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
>  	return file->f_pos;
>  }
>  
> -static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
> +static void init_pages_in_zone(struct zone *zone)
>  {
>  	unsigned long pfn = zone->zone_start_pfn;
>  	unsigned long end_pfn = zone_end_pfn(zone);
> @@ -824,28 +824,15 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
>  	}
>  
>  	pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
> -		pgdat->node_id, zone->name, count);
> -}
> -
> -static void init_zones_in_node(pg_data_t *pgdat)
> -{
> -	struct zone *zone;
> -	struct zone *node_zones = pgdat->node_zones;
> -
> -	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
> -		if (!populated_zone(zone))
> -			continue;
> -
> -		init_pages_in_zone(pgdat, zone);
> -	}
> +		zone->zone_pgdat->node_id, zone->name, count);
>  }
>  
>  static void init_early_allocated_pages(void)
>  {
> -	pg_data_t *pgdat;
> +	struct zone *zone;
>  
> -	for_each_online_pgdat(pgdat)
> -		init_zones_in_node(pgdat);
> +	for_each_populated_zone(zone)
> +		init_pages_in_zone(zone);
>  }
>  
>  static const struct file_operations page_owner_fops = {

-- 
Thanks,
Ye Liu