Re: [PATCH v2 2/2] kfence: Alloc kfence_pool after system startup

[Marco Elver <elver@xxxxxxxxxx>]

On Sat, 5 Mar 2022 at 15:49, Tianchen Ding <dtcccc@xxxxxxxxxxxxxxxxx> wrote:
[...]
> +static int kfence_init_late(void)
> +{
> +       const unsigned long nr_pages = KFENCE_POOL_SIZE / PAGE_SIZE;
> +       struct page *pages;
> +
> +       pages = alloc_contig_pages(nr_pages, GFP_KERNEL, first_online_node, NULL);

> mm/kfence/core.c:836:17: error: implicit declaration of function ‘alloc_contig_pages’ [-Werror=implicit-function-declaration]

This doesn't build without CMA. See ifdef CONFIG_CONTIG_ALLOC in
gfp.h, which declares alloc_contig_pages.

Will alloc_pages() work as you expect? If so, perhaps only use
alloc_contig_pages() #ifdef CONFIG_CONTIG_ALLOC.

Thanks,
-- Marco