linux-kernel - Re: [PATCH] arm64: mm: free the initrd reserved memblock in a aligned manner

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Message-ID: <079e43f4-fa25-98fc-835d-c3f9b96cb14f@arm.com>
Date:   Fri, 5 Jul 2019 16:11:03 +0100
From:   James Morse <james.morse@....com>
To:     Yi Wang <wang.yi59@....com.cn>
Cc:     catalin.marinas@....com, will.deacon@....com,
        akpm@...ux-foundation.org, rppt@...ux.vnet.ibm.com,
        f.fainelli@...il.com, logang@...tatee.com, robin.murphy@....com,
        ghackmann@...roid.com, hannes@...xchg.org, david@...hat.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        xue.zhihong@....com.cn, jiang.xuexin@....com.cn,
        Junhua Huang <huang.junhua@....com.cn>
Subject: Re: [PATCH] arm64: mm: free the initrd reserved memblock in a aligned
 manner

Hi,

On 04/07/2019 00:59, Yi Wang wrote:
> From: Junhua Huang <huang.junhua@....com.cn>
> 
> We should free the reserved memblock in an aligned manner 
> because the initrd reserves the memblock in an aligned manner 
> in arm64_memblock_init(). 
> Otherwise there are some fragments in memblock_reserved regions. e.g.:
> /sys/kernel/debug/memblock # cat reserved 
>    0: 0x0000000080080000..0x00000000817fafff
>    1: 0x0000000083400000..0x0000000083ffffff
>    2: 0x0000000090000000..0x000000009000407f
>    3: 0x00000000b0000000..0x00000000b000003f
>    4: 0x00000000b26184ea..0x00000000b2618fff
> The fragments like the ranges from b0000000 to b000003f and 
> from b26184ea to b2618fff should be freed.
> 
> And we can do free_reserved_area() after memblock_free(),
> as free_reserved_area() calls __free_pages(), once we've done 
> that it could be allocated somewhere else, 
> but memblock and iomem still say this is reserved memory.
> 
> Signed-off-by: Junhua Huang <huang.junhua@....com.cn>

You need to add your own Signed-off-by after Junhua Huang's. This tells the maintainer
that you're providing the patch with the 'Developer's Certificate of Origin'. Details in
/Documentation/process/submitting-patches.rst.


> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index d2adffb81b5d..03774b8bd364 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -580,8 +580,13 @@ void free_initmem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>  void __init free_initrd_mem(unsigned long start, unsigned long end)
>  {
> +	unsigned long aligned_start, aligned_end;
> +
> +	aligned_start = __virt_to_phys(start) & PAGE_MASK;
> +	aligned_end = PAGE_ALIGN(__virt_to_phys(end));

> +	memblock_free(aligned_end, aligned_end - aligned_start);

We're not free-ing the same memory as we reserved here!
(start/end typo)

>  	free_reserved_area((void *)start, (void *)end, 0, "initrd");
> -	memblock_free(__virt_to_phys(start), end - start);
> +

(stray newline)

>  }
>  #endif


Thanks,

James