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Fri, 24 Jan 2020 06:02:42 -0800 (PST) Received: from google.com ([2a00:79e0:d:110:d6cc:2030:37c1:9964]) by smtp.gmail.com with ESMTPSA id o1sm7474771wrn.84.2020.01.24.06.02.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jan 2020 06:02:41 -0800 (PST) Date: Fri, 24 Jan 2020 14:02:37 +0000 From: Quentin Perret To: Marc Zyngier Cc: Will Deacon , Mike Rapoport , Anshuman Khandual , Catalin Marinas , Russell King , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Mike Rapoport , kvmarm@lists.cs.columbia.edu, kernel-team@android.com Subject: Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables Message-ID: <20200124140237.GA180536@google.com> References: <20200113111323.10463-1-rppt@kernel.org> <20200122185017.GA17321@willie-the-truck> <20200124122053.GA150292@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Friday 24 Jan 2020 at 13:34:35 (+0000), Marc Zyngier wrote: > I don't disagree at all. To be honest, I've been on the cusp of getting > rid of it for a while, for multiple reasons: > > - It has no users (as you noticed) > - It is hardly tested (a consequence of the above) > - It isn't feature complete (no debug, no PMU) > - It doesn't follow any of the evolution of the architecture (a more > generic feature of the 32bit port, probably because people run their > 64bit-capable cores in 64bit mode) > - It is becoming a mess of empty stubs > > The maintenance aspect hasn't been a real problem so far. Even the NV > support is only about 200 lines of stubs. But what you have in mind is > going to be much more invasive, and I wouldn't want an unused feature to > get in the way. > > What I may end-up doing is to send a RFC series to remove the 32bit host > support from the tree during in the 5.6 cycle, targeting 5.7. If someone > shouts loudly during that time frame, we keep it and you'll have to work > around it. If nobody cares, then dropping it is the right thing to do. > > Would that be OK with you? Absolutely. And yes, if there are users of the 32 bits port, it'll be on us to work around in a clean way, but I think this is perfectly fair. I'll be happy to try and test your RFC series when it goes on the list if that can help. Thanks! Quentin