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Date:   Tue, 19 Apr 2022 16:44:06 +0530
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Subject: Re: [PATCH v2 7/9] mm: Calc the right pfn if page size is not 4K
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To:     Wupeng Ma <mawupeng1@huawei.com>, akpm@linux-foundation.org,
        catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net
Cc:     ardb@kernel.org, tglx@linutronix.de, mingo@redhat.com,
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References: <20220414101314.1250667-1-mawupeng1@huawei.com>
 <20220414101314.1250667-8-mawupeng1@huawei.com>
From:   Anshuman Khandual <anshuman.khandual@arm.com>
In-Reply-To: <20220414101314.1250667-8-mawupeng1@huawei.com>
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On 4/14/22 15:43, Wupeng Ma wrote:
> From: Ma Wupeng <mawupeng1@huawei.com>
> 
> Previous 0x100000 is used to check the 4G limit in
> find_zone_movable_pfns_for_nodes(). This is right in x86 because
> the page size can only be 4K. But 16K and 64K are available in
> arm64. So replace it with PHYS_PFN(SZ_4G).
> 
> Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
> ---
>  mm/page_alloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 6e5b4488a0c5..570d0ebf98df 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7870,7 +7870,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>  
>  			usable_startpfn = memblock_region_memory_base_pfn(r);
>  
> -			if (usable_startpfn < 0x100000) {
> +			if (usable_startpfn < PHYS_PFN(SZ_4G)) {
>  				mem_below_4gb_not_mirrored = true;
>  				continue;
>  			}

Regardless PFN value should never be encoded directly.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>