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Received: from shell.armlinux.org.uk ([2002:4e20:1eda:1:5054:ff:fe00:4ec]:37940) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jg6SZ-0002pb-2E; Tue, 02 Jun 2020 13:56:03 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jg6SW-0004P5-PH; Tue, 02 Jun 2020 13:56:00 +0100 Date: Tue, 2 Jun 2020 13:56:00 +0100 From: Russell King - ARM Linux admin To: Geert Uytterhoeven Subject: Re: [PATCH 0/2] ARM: Allow either FLATMEM or SPARSEMEM on the multiplatform build Message-ID: <20200602125600.GW1551@shell.armlinux.org.uk> References: <20200521081825.1348844-1-rppt@linux.ibm.com> <20200521120308.GR1551@shell.armlinux.org.uk> <20200521123327.GQ1059226@linux.ibm.com> <20200521140745.GS1059226@linux.ibm.com> <20200521145020.GS1551@shell.armlinux.org.uk> <20200602122247.GV1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200602_055613_415158_BBE8795B X-CRM114-Status: GOOD ( 24.40 ) 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: Florian Fainelli , Arnd Bergmann , Stephen Boyd , Kevin Cernekee , Mike Rapoport , Doug Berger , Gregory Fong , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 02, 2020 at 02:37:45PM +0200, Geert Uytterhoeven wrote: > Hi Russell, > > On Tue, Jun 2, 2020 at 2:22 PM Russell King - ARM Linux admin > wrote: > > On Tue, Jun 02, 2020 at 02:18:48PM +0200, Geert Uytterhoeven wrote: > > > On Thu, May 21, 2020 at 4:50 PM Russell King - ARM Linux admin > > > wrote: > > > > On Thu, May 21, 2020 at 05:07:45PM +0300, Mike Rapoport wrote: > > > > > Ah, when either of these patforms will become a part of the > > > > > multiplatform build, the only option for multiplatform build will be > > > > > sparsemem. > > > > > So it would be nice if somebody could check the cost of using sparsemem > > > > > vs flatmem, espessially on low end machines. > > > > > > > > Do you think they will become part of multiplatform? > > > > > > > > If they're low-end machines, then adding: > > > > > > > > (a) the additional memory overhead of a multiplatform kernel > > > > (b) the additional runtime overhead of the complexities of multiplatform > > > > kernels > > > > > > > > is surely an odd thing to do, especially when few really care about > > > > these platforms becoming part of a multiplatform kernel, except those > > > > who like the idea of multiplat. > > > > > > The fallacy of "multi-platform", again? > > > > > > Isn't it a requirement for any new ARM v7-A platforms to be part of > > > ARCH_MULTI_V7, even if it's a low-end machine? > > > > What does ARMv7 have to do with this thread, that is discussing the > > older ARMv4 platforms? I find your comments above irrelevent to > > this discussion, and seems to be worded to provoke a reaction. > > Sorry, I used ARMv7 as an example, as it's rare for any new ARMv4 > platforms to show up. But the recently introduced sam9x60 (ARMv5) is > part of ARCH_MULTI_V5, and I expect it will be used with less than the > 256 MiB provided on the dev board. > > Nevertheless, there's a movement to convert everything to ARCH_MULTI_V* > where possible. So it matters for all variants. First, please understand that I have nothing against multiplatform. What I do have problems with is the "lets move everything to multiplatform" without fully reasoning it out, especially when it comes to older platforms that have limited attraction for the whole motivation behind multiplatform, which is the convenience of distributions. multiplatform is the current fad-de-jour, and everyone is in a "you MUST convert EVERYTHING to it, because it's the best thing since sliced bread". multiplatform comes with it a load of forced-enabled options that are force-enabled. Should RiscPC be forced to have the common clock support built into the kernel, when it doesn't' have _any_ controllable clocks, when it's likely that the machines have limited memory available? Yes, I have recently booted the RiscPC with a 5.x kernel, and no, it didn't need very much fixing, the code is quite *stable* (oh, I blaspheme, we can't have stable code in Linux, we must change it every five minutes.) I think, maybe, you should leave these decisions to people who actually have the platforms, know them inside out, and can assess whether conversion really makes sense or not, rather than blindly joining the zombie march repeating "multiplatform is great, everything must be multiplatform". What is patently obvious is that in Linux, there is no tolerance of someone who has a differing view, and they end up receiving reaction provoking comments designed to inflame the situation. Difference of opinion must be suppressed at all costs! -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel