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Date: Mon, 15 Apr 2024 18:26:55 +0300
From: Mike Rapoport <rppt@kernel.org>
To: skseofh@gmail.com
Cc: robh@kernel.org, saravanak@google.com, akpm@linux-foundation.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Daero Lee <daero_le.lee@samsung.com>
Subject: Re: [PATCH] memblock: add no-map alloc functions
Message-ID: <Zh1HP8IWWjexAUKN@kernel.org>
References: <20240415142448.333271-1-skseofh@gmail.com>
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In-Reply-To: <20240415142448.333271-1-skseofh@gmail.com>

On Mon, Apr 15, 2024 at 11:24:48PM +0900, skseofh@gmail.com wrote:
> From: Daero Lee <daero_le.lee@samsung.com>
> 
> Like reserved-memory with the no-map property, there are memory regions
> need to be allocated in memblock.memory marked with the
> MEMBLOCK_NOMAP flag, but sholud not be allocated in memblock.reserved.

Can you please explain your use case?
Why do you need this functionality?
 
> So, functions were added that find the required memory area in
> memblock.memory, but do not allocate it to memblock.reserved.
> 
> The early_init_dt_alloc_reserved_memory_arch function was modified
> using the no-map alloc function.
> 
> Signed-off-by: Daero Lee <daero_le.lee@samsung.com>
> ---
>  drivers/of/of_reserved_mem.c |  9 +++--
>  mm/memblock.c                | 78 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 84 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 8236ecae2953..504f2f60689c 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -40,15 +40,18 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
>  
>  	end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
>  	align = !align ? SMP_CACHE_BYTES : align;
> -	base = memblock_phys_alloc_range(size, align, start, end);
> +	if (nomap) {
> +		base = memblock_phys_alloc_range_nomap(size, align, start, end);
> +	} else {
> +		base = memblock_phys_alloc_range(size, align, start, end);
> +	}
> +	

This changes behaviour of internal function, what effect will it have on
the users?

>  	if (!base)
>  		return -ENOMEM;
>  
>  	*res_base = base;
>  	if (nomap) {
>  		err = memblock_mark_nomap(base, size);
> -		if (err)
> -			memblock_phys_free(base, size);
>  	}
>  
>  	kmemleak_ignore_phys(base);

-- 
Sincerely yours,
Mike.