Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 1/2] mm/memory_hotplug: allow marking of memory sections
 as hotpluggable
To:     Mike Rapoport <rppt@kernel.org>,
        Sudarshan Rajagopalan <sudaraja@codeaurora.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Steven Price <steven.price@arm.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Suren Baghdasaryan <surenb@google.com>
References: <cover.1602899443.git.sudaraja@codeaurora.org>
 <2cba881c51e42cfe5ba213e09273642136e8ef93.1602899443.git.sudaraja@codeaurora.org>
 <20201017082600.GB16395@kernel.org>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <51333360-bcf6-0d21-923c-ce8aca4c8719@redhat.com>
Date:   Sat, 17 Oct 2020 11:36:39 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.3.1
MIME-Version: 1.0
In-Reply-To: <20201017082600.GB16395@kernel.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 17.10.20 10:26, Mike Rapoport wrote:
> On Fri, Oct 16, 2020 at 07:02:23PM -0700, Sudarshan Rajagopalan wrote:
>> Certain architectures such as arm64 doesn't allow boot memory to be
>> offlined and removed. Distinguish certain memory sections as
>> "hotpluggable" which can be marked by module drivers stating to memory
>> hotplug layer that these sections can be offlined and then removed.
> 
> I don't quite follow why marking sections as hotpluggable or not should
> be done by a device driver. Can you describe in more details your
> use-case and why there is a need to add a flag to the memory map?
> 

This seems to be related to

https://lkml.kernel.org/r/de8388df2fbc5a6a33aab95831ba7db4@codeaurora.org

After reading how the driver is trying to abuse memory hot(un)plug
infrastructure, my tentative

Nacked-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb