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Tue, 17 Nov 2020 09:58:54 -0500 X-MC-Unique: CKHrpfupMZW4GVIDn1JBQQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 305BD5F9E6; Tue, 17 Nov 2020 14:58:52 +0000 (UTC) Received: from [10.36.114.99] (ovpn-114-99.ams2.redhat.com [10.36.114.99]) by smtp.corp.redhat.com (Postfix) with ESMTP id 012896EF49; Tue, 17 Nov 2020 14:58:49 +0000 (UTC) Subject: Re: [RFC] depopulate_range_driver_managed() for removing page-table mappings for hot-added memory blocks To: Christoph Hellwig , Sudarshan Rajagopalan References: <20201114102853.GA8618@infradead.org> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Tue, 17 Nov 2020 15:58:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20201114102853.GA8618@infradead.org> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201117_095900_460043_80F20FEE X-CRM114-Status: GOOD ( 20.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Anshuman Khandual , Catalin Marinas , linux-kernel@vger.kernel.org, Steven Price , Suren Baghdasaryan , Will Deacon , linux-arm-kernel@lists.infradead.org, Pratik Patel Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 14.11.20 11:28, Christoph Hellwig wrote: > On Fri, Nov 13, 2020 at 06:41:22PM -0800, Sudarshan Rajagopalan wrote: >> >> Hello, >> >> When memory blocks are removed, along with removing the memmap entries, >> memory resource and memory block devices, the arch specific >> arch_remove_memory() is called which takes care of tearing down the >> page-tables. >> >> Suppose there???s a usecase where the removed memory blocks will be added >> back into the system at later point, > > Stop this crap. If you have a use case post the actual use here, > including code and specs. If you don't have that don't waste peoples > time on your pipe dream. > Adding to that, we (upstream people) are not interested in introducing and maintaining kernel interfaces/infrastructure only relevant to out-of-tree / proprietary drivers. If you're planning on upstreaming, then please share the actual problem you are trying to solve and the issues you see with the current interfaces/infrastructure, best along with an RFC that shows the bigger picture. Having that said, what you describe sounds more like a special kind of allocation, whereby the linear mapping is removed, similar to [1]. [1] https://lkml.kernel.org/r/20201111145322.15793-1-david@redhat.com -- Thanks, David / dhildenb _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel