Re: [PATCH 1/3] mm/mm_init.c: get the highest zone directly

[Mike Rapoport <rppt@kernel.org>]

On Fri, May 31, 2024 at 12:26:11AM +0000, Wei Yang wrote:
> We have recorded nr_zones in pgdat, just get it directly.
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  mm/mm_init.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index aa83105b3a1b..2bcf87eab0c6 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -2136,7 +2136,7 @@ static int __init deferred_init_memmap(void *data)
>  	unsigned long first_init_pfn, flags;
>  	unsigned long start = jiffies;
>  	struct zone *zone;
> -	int zid, max_threads;
> +	int max_threads;
>  	u64 i;
>  
>  	/* Bind memory initialisation thread to a local node if possible */
> @@ -2163,12 +2163,8 @@ static int __init deferred_init_memmap(void *data)
>  	 */
>  	pgdat_resize_unlock(pgdat, &flags);
>  
> -	/* Only the highest zone is deferred so find it */
> -	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
> -		zone = pgdat->node_zones + zid;
> -		if (first_init_pfn < zone_end_pfn(zone))
> -			break;
> -	}
> +	/* Only the highest zone is deferred */
> +	zone = pgdat->node_zones + pgdat->nr_zones - 1;
>  
>  	/* If the zone is empty somebody else may have cleared out the zone */
>  	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
> @@ -2196,7 +2192,7 @@ static int __init deferred_init_memmap(void *data)
>  	}
>  zone_empty:
>  	/* Sanity check that the next zone really is unpopulated */
> -	WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
> +	WARN_ON(pgdat->nr_zones < MAX_NR_ZONES && populated_zone(++zone));
>  
>  	pr_info("node %d deferred pages initialised in %ums\n",
>  		pgdat->node_id, jiffies_to_msecs(jiffies - start));
> -- 
> 2.34.1
> 

-- 
Sincerely yours,
Mike.