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[95.233.134.55]) by smtp.gmail.com with ESMTPSA id x5-20020adff645000000b0031276f8be22sm3092993wrp.97.2023.06.20.18.10.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jun 2023 18:10:21 -0700 (PDT) From: "Fabio M. De Francesco" To: Linus Walleij , Andrew Morton , Jonathan Corbet Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, Matthew Wilcox , Randy Dunlap , Mike Rapoport , Jonathan Cameron , Bagas Sanjaya Subject: Re: [PATCH v5] Documentation/mm: Initial page table documentation Date: Wed, 21 Jun 2023 03:10:19 +0200 Message-ID: <13291493.dW097sEU6C@suse> In-Reply-To: References: <20230614072548.996940-1-linus.walleij@linaro.org> <3045029.CbtlEUcBR6@suse> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On luned=C3=AC 19 giugno 2023 10:16:56 CEST Linus Walleij wrote: > On Sun, Jun 18, 2023 at 3:16=E2=80=AFPM Fabio M. De Francesco >=20 > wrote: > > I am writing to express my dissent regarding the proposal to add basic > > information about the role of hierarchical (multi-level) page tables in > > mapping virtual memory to physical page frames. [...] =20 > Assuming that newcomers to the Linux kernel have formal academic > background or specifically operating system education is a bit thick > IMO, suffice to read pages 108-111 of Glyn Moody's book > "Rebel Code" about the background of the network maintainer. > There are a whole bunch of random people attracted to Linux > development. Linus, I must admit that I have had a change of heart regarding the necessity of t= his=20 documentation. This change came about after reading Jon's reply, as well as your own. However, it wasn't just because of the two of you. It was mainly due to my= =20 conversations with some colleagues I work with, who hold M.Sc. degrees in=20 Computer Science.=20 Despite not having a formal background in CS or CE myself, I have taken the= =20 time to self-teach the subject matter, which I expected them to be well-ver= sed=20 in. To my surprise, they only have a vague understanding of page tables and the= =20 fact that processes use addresses that may not correspond to physical=20 locations. That's about it! Hence, I now fully support your initiative and want to express my gratitude= =20 for undertaking this task. The only thing I would prefer not to see is the historical reference to the= =20 first implementation of hierarchical page tables. After all, many concepts= =20 implemented in Linux are derived or adapted from existing knowledge or=20 implementations in other kernels. However, I can also understand why you=20 prefer to have it as an introduction to the subject. Once again thanks, =46abio