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Subject: Re: [PATCH 1/6] arm64/mm: Enable sysfs based memory hot add interface
To:     Anshuman Khandual <anshuman.khandual@arm.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, akpm@linux-foundation.org, will.deacon@arm.com,
        catalin.marinas@arm.com
Cc:     mhocko@suse.com, mgorman@techsingularity.net, james.morse@arm.com,
        mark.rutland@arm.com, robin.murphy@arm.com, cpandya@codeaurora.org,
        arunks@codeaurora.org, dan.j.williams@intel.com, osalvador@suse.de,
        logang@deltatee.com, pasha.tatashin@oracle.com, cai@lca.pw
References: <1554265806-11501-1-git-send-email-anshuman.khandual@arm.com>
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From:   David Hildenbrand <david@redhat.com>
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Organization: Red Hat GmbH
Message-ID: <4b9dd2b0-3b11-608c-1a40-9a3d203dd904@redhat.com>
Date:   Wed, 3 Apr 2019 10:20:32 +0200
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Sender: linux-kernel-owner@vger.kernel.org
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On 03.04.19 06:30, Anshuman Khandual wrote:
> Sysfs memory probe interface (/sys/devices/system/memory/probe) can accept
> starting physical address of an entire memory block to be hot added into
> the kernel. This is in addition to the existing ACPI based interface. This
> just enables it with the required config CONFIG_ARCH_MEMORY_PROBE.
> 

We recently discussed that the similar interface for removal should
rather be moved to a debug/test module

I wonder if we should try to do the same for the sysfs probing
interface. Rather try to get rid of it than open the doors for more users.

> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  arch/arm64/Kconfig | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 7e34b9e..a2418fb 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -266,6 +266,15 @@ config HAVE_GENERIC_GUP
>  config ARCH_ENABLE_MEMORY_HOTPLUG
>  	def_bool y
>  
> +config ARCH_MEMORY_PROBE
> +	bool "Enable /sys/devices/system/memory/probe interface"
> +	depends on MEMORY_HOTPLUG
> +	help
> +	  This option enables a sysfs /sys/devices/system/memory/probe
> +	  interface for testing. See Documentation/memory-hotplug.txt
> +	  for more information. If you are unsure how to answer this
> +	  question, answer N.
> +
>  config SMP
>  	def_bool y
>  
> 


-- 

Thanks,

David / dhildenb