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Subject: Re: [PATCH] nommu: remove __GFP_HIGHMEM in vmalloc/vzalloc
To:     Chen Li <chenli@uniontech.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <875z00rnp8.wl-chenli@uniontech.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Message-ID: <a15f99c4-14a9-8f81-6fd9-45caa46ebc72@redhat.com>
Date:   Wed, 5 May 2021 13:14:22 +0200
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On 03.05.21 14:44, Chen Li wrote:
> 
>  From mm/nommu.c:
> void *__vmalloc(unsigned long size, gfp_t gfp_mask)
> {
> 	/*
> 	 *  You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
> 	 * returns only a logical address.
> 	 */
> 	return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
> }
> 
> nommu's __vmalloc just uses kmalloc internally and elimitates __GFP_HIGHMEM,
> so it makes no sense to add __GFP_HIGHMEM for nommu's vmalloc/vzalloc.
> 
> Signed-off-by: Chen Li <chenli@uniontech.com>
> ---
>   mm/nommu.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 5c9ab799c0e6..339a2f2eb1aa 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -233,7 +233,7 @@ long vwrite(char *buf, char *addr, unsigned long count)
>    */
>   void *vmalloc(unsigned long size)
>   {
> -       return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM);
> +       return __vmalloc(size, GFP_KERNEL);
>   }
>   EXPORT_SYMBOL(vmalloc);
>   
> @@ -251,7 +251,7 @@ EXPORT_SYMBOL(vmalloc);
>    */
>   void *vzalloc(unsigned long size)
>   {
> -	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
> +	return __vmalloc(size, GFP_KERNEL | __GFP_ZERO);
>   }
>   EXPORT_SYMBOL(vzalloc);
>   
> 

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

-- 
Thanks,

David / dhildenb