Re: [PATCH 2/3] mm/vmalloc: extract vmap_insert_free_area helper

[Uladzislau Rezki <urezki@gmail.com>]

On Mon, Sep 14, 2026 at 11:34:01AM +0800, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
> 
> The allocation and insertion of a free vmap_area is duplicated
> between the loop body and the tail of vmap_init_free_space.  Factor
> it into a small helper so the main function only deals with computing
> the free gaps between busy regions.
> 
> Signed-off-by: Ye Liu <liuye@kylinos.cn>
> ---
>  mm/vmalloc.c | 41 ++++++++++++++++++-----------------------
>  1 file changed, 18 insertions(+), 23 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 117483dd048c..797933ba9451 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -5433,11 +5433,23 @@ module_init(proc_vmalloc_init);
>  
>  #endif
>  
> +static void __init vmap_insert_free_area(unsigned long start, unsigned long end)
> +{
> +	struct vmap_area *free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
> +
> +	if (!WARN_ON_ONCE(!free)) {
> +		free->va_start = start;
> +		free->va_end = end;
> +		insert_vmap_area_augment(free, NULL,
> +					 &free_vmap_area_root,
> +					 &free_vmap_area_list);
> +	}
> +}
> +
>  static void __init vmap_init_free_space(void)
>  {
>  	unsigned long vmap_start = 1;
>  	const unsigned long vmap_end = ULONG_MAX;
> -	struct vmap_area *free;
>  	struct vm_struct *busy;
>  
>  	/*
> @@ -5447,32 +5459,15 @@ static void __init vmap_init_free_space(void)
>  	 *  |<--------------------------------->|
>  	 */
>  	for (busy = vmlist; busy; busy = busy->next) {
> -		if ((unsigned long) busy->addr - vmap_start > 0) {
>
This line gets removed and then re-added below because of removing space
after (unsigned long). Maybe it is better to keep that space.

> -			free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
> -			if (!WARN_ON_ONCE(!free)) {
> -				free->va_start = vmap_start;
> -				free->va_end = (unsigned long) busy->addr;
> -
> -				insert_vmap_area_augment(free, NULL,
> -					&free_vmap_area_root,
> -						&free_vmap_area_list);
> -			}
> -		}
> +		if ((unsigned long)busy->addr - vmap_start > 0)
> +			vmap_insert_free_area(vmap_start,
> +					      (unsigned long)busy->addr);
>  
>  		vmap_start = (unsigned long) busy->addr + busy->size;
>  	}
>  
> -	if (vmap_end - vmap_start > 0) {
> -		free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
> -		if (!WARN_ON_ONCE(!free)) {
> -			free->va_start = vmap_start;
> -			free->va_end = vmap_end;
> -
> -			insert_vmap_area_augment(free, NULL,
> -				&free_vmap_area_root,
> -					&free_vmap_area_list);
> -		}
> -	}
> +	if (vmap_end - vmap_start > 0)
> +		vmap_insert_free_area(vmap_start, vmap_end);
>  }
>  
>  static void vmap_init_nodes(void)
> 
> -- 
> 2.25.1
> 
LGTM:

Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki