linux-kernel - Re: [PATCH v3] mm/sparse.c: Use kvmalloc_node/kvfree to alloc/free memmap for the classic sparse

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Message-ID: <5c6351e9-1539-40c9-0057-cc58116ecc3a@redhat.com>
Date:   Fri, 13 Mar 2020 16:04:46 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Baoquan He <bhe@...hat.com>, linux-kernel@...r.kernel.org,
        willy@...radead.org
Cc:     linux-mm@...ck.org, mhocko@...e.com, akpm@...ux-foundation.org,
        richard.weiyang@...il.com
Subject: Re: [PATCH v3] mm/sparse.c: Use kvmalloc_node/kvfree to alloc/free
 memmap for the classic sparse

On 12.03.20 15:17, Baoquan He wrote:
> This change makes populate_section_memmap()/depopulate_section_memmap
> much simpler.
> 
> Suggested-by: Michal Hocko <mhocko@...nel.org>
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
> v2->v3:
>   Remove __GFP_NOWARN and use array_size when calling kvmalloc_node()
>   per Matthew's comments.
> 
>  mm/sparse.c | 27 +++------------------------
>  1 file changed, 3 insertions(+), 24 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index bf6c00a28045..bb99633575b5 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -734,35 +734,14 @@ static void free_map_bootmem(struct page *memmap)
>  struct page * __meminit populate_section_memmap(unsigned long pfn,
>  		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
> -	struct page *page, *ret;
> -	unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
> -
> -	page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
> -	if (page)
> -		goto got_map_page;
> -
> -	ret = vmalloc(memmap_size);
> -	if (ret)
> -		goto got_map_ptr;
> -
> -	return NULL;
> -got_map_page:
> -	ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
> -got_map_ptr:
> -
> -	return ret;
> +	return kvmalloc_node(array_size(sizeof(struct page),
> +			PAGES_PER_SECTION), GFP_KERNEL, nid);


Indentation of the parameters looks wrong/weird. Maybe just calculate
memmap_size outside of the call, makes it easier to read IMHO.

Apart from that, looks good to me.

Reviewed-by: David Hildenbrand <david@...hat.com>

-- 
Thanks,

David / dhildenb