Re: [PATCH] mm/slub: replace alloc_pages with folio_alloc

[Matthew Wilcox]

On Sun, May 29, 2022 at 12:11:58AM +0800, bh1scw@xxxxxxxxx wrote:
> From: Fanjun Kong <bh1scw@xxxxxxxxx>
> 
> This patch will use folio allocation functions for allocating pages.

That's not actually a good idea.  folio_alloc() will do the
prep_transhuge_page() step which isn't needed for slab.

> Signed-off-by: Fanjun Kong <bh1scw@xxxxxxxxx>
> ---
>  mm/slub.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index e5535020e0fd..00c4049a17d6 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1794,9 +1794,9 @@ static inline struct slab *alloc_slab_page(gfp_t flags, int node,
>  	unsigned int order = oo_order(oo);
>  
>  	if (node == NUMA_NO_NODE)
> -		folio = (struct folio *)alloc_pages(flags, order);
> +		folio = (struct folio *)folio_alloc(flags, order);
>  	else
> -		folio = (struct folio *)__alloc_pages_node(node, flags, order);
> +		folio = (struct folio *)__folio_alloc_node(node, flags, order);
>  
>  	if (!folio)
>  		return NULL;
> -- 
> 2.36.0
> 
>