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Date:   Fri, 30 Oct 2020 10:25:08 +0000
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Cc:     linux-arm-kernel@lists.infradead.org, patches@amperecomputing.com,
        linux-kernel@vger.kernel.org, Anshuman.Khandual@arm.com,
        Valentin.Schneider@arm.com, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2] arm64: NUMA: Kconfig: Increase NODES_SHIFT to 4
Message-ID: <20201030102507.GB23196@gaia>
References: <20201029203752.1114948-1-vanshikonda@os.amperecomputing.com>
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On Thu, Oct 29, 2020 at 01:37:52PM -0700, Vanshidhar Konda wrote:
> The current arm64 default config limits max NUMA nodes available on
> system to 4 (NODES_SHIFT = 2). Today's arm64 systems can reach or
> exceed 16 NUMA nodes. To accomodate current hardware and to fit
> NODES_SHIFT within page flags on arm64, increase NODES_SHIFT to 4.
> 
> Discussion on v1 of the patch:
> https://lkml.org/lkml/2020/10/20/767

Better use a stable link to refer to the past discussion:

Link: https://lore.kernel.org/r/20201020173409.1266576-1-vanshikonda@os.amperecomputing.com

> Signed-off-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
> ---
>  arch/arm64/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f858c352f72a..cffcc677011f 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -982,7 +982,7 @@ config NUMA
>  config NODES_SHIFT
>  	int "Maximum NUMA Nodes (as a power of 2)"
>  	range 1 10
> -	default "2"
> +	default "4"
>  	depends on NEED_MULTIPLE_NODES
>  	help
>  	  Specify the maximum number of NUMA Nodes available on the target

Acked-by: Catalin Marinas <catalin.marinas@arm.com>