Re: [PATCH 1/5] mm/vmalloc.c: change purge_ndoes as local static variable

[Uladzislau Rezki]

On Tue, Apr 15, 2025 at 10:39:48AM +0800, Baoquan He wrote:
> Static variable 'purge_ndoes' is defined in global scope, while it's
> only used in function __purge_vmap_area_lazy(). It mainly serves to
> avoid memory allocation repeatedly, especially when NR_CPUS is big.
> 
> While a local static variable can also satisfy the demand, and can
> improve code readibility. Hence move its definition into
> __purge_vmap_area_lazy().
> 
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
>  mm/vmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 6ee7fc2ec986..aca1905d3397 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2128,7 +2128,6 @@ static DEFINE_MUTEX(vmap_purge_lock);
>  
>  /* for per-CPU blocks */
>  static void purge_fragmented_blocks_allcpus(void);
> -static cpumask_t purge_nodes;
>  
>  static void
>  reclaim_list_global(struct list_head *head)
> @@ -2261,6 +2260,7 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end,
>  {
>  	unsigned long nr_purged_areas = 0;
>  	unsigned int nr_purge_helpers;
> +	static cpumask_t purge_nodes;
>  	unsigned int nr_purge_nodes;
>  	struct vmap_node *vn;
>  	int i;
> -- 
> 2.41.0
> 
Well. I do not have a strong opinion here. But right, it is only
used inside the function.

Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>

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Uladzislau Rezki