Re: [PATCH 2/4] slab: Convert __kmalloc_large_node() and free_large_kmalloc() to use folios

[Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>]

On Sat, Dec 23, 2023 at 5:28 AM Matthew Wilcox (Oracle)
<willy@xxxxxxxxxxxxx> wrote:
>
> Add folio_alloc_node() to replace alloc_pages_node() and then use
> folio APIs throughout instead of converting back to pages.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
[...]
> diff --git a/mm/slub.c b/mm/slub.c
> index 35aa706dc318..261f01915d9b 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3919,18 +3919,17 @@ EXPORT_SYMBOL(kmem_cache_alloc_node);
>   */
>  static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
>  {
> -       struct page *page;
> +       struct folio *folio;
>         void *ptr = NULL;
>         unsigned int order = get_order(size);
>
>         if (unlikely(flags & GFP_SLAB_BUG_MASK))
>                 flags = kmalloc_fix_flags(flags);
>
> -       flags |= __GFP_COMP;
> -       page = alloc_pages_node(node, flags, order);
> -       if (page) {
> -               ptr = page_address(page);
> -               mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
> +       folio = folio_alloc_node(flags, order, node);

folio_alloc_node()
->__folio_alloc_node()
->__folio_alloc()
->page_rmappable_folio()
->folio_prep_large_rmappable()

I think it's not intentional to call this?

> +       if (folio) {
> +               ptr = folio_address(folio);
> +               lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
>                                       PAGE_SIZE << order);
>         }

Thanks,
Hyeonggon