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Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: Arches that don't support PREEMPT Content-Language: en-US To: Peter Zijlstra , John Paul Adrian Glaubitz Cc: Matthew Wilcox , Thomas Gleixner , Linus Torvalds , Ankur Arora , linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, mgorman@suse.de, rostedt@goodmis.org, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, Geert Uytterhoeven , linux-m68k@lists.linux-m68k.org, Richard Weinberger , Johannes Berg , linux-um@lists.infradead.org, Brian Cain , linux-hexagon@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Matt Turner , linux-alpha@vger.kernel.org References: <87zg1u1h5t.fsf@oracle.com> <20230911150410.GC9098@noisy.programming.kicks-ass.net> <87h6o01w1a.fsf@oracle.com> <20230912082606.GB35261@noisy.programming.kicks-ass.net> <87cyyfxd4k.ffs@tglx> <87led2wdj0.ffs@tglx> <0e69f7df80dc5878071deb0d80938138d19de1d1.camel@physik.fu-berlin.de> <20230919134218.GA39281@noisy.programming.kicks-ass.net> From: Anton Ivanov In-Reply-To: <20230919134218.GA39281@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Clacks-Overhead: GNU Terry Pratchett X-Rspamd-Queue-Id: 904141C0017 X-Rspam-User: X-Stat-Signature: rjqm1cdbcfymz41j5des1a56e4exi7ka X-Rspamd-Server: rspam03 X-HE-Tag: 1695133322-116140 X-HE-Meta: U2FsdGVkX19kMAYb4Hxj6nERSD6ItT3gWkeSoTbCm2kOoxDQYkhNyXHbiFYEsEqEODYjAguO8uMkZtB+jigHNLxPklRR65v8bZ6tUNCbuzjrqOOjI1eNQ2WJnjE9LHEnw0XWYdsKDIGkdE+uA0JvFfHF/dUHgzY4+TSIiEP+JhrawvyDYXkoZkUiI6PErWYGV1w2E43JlB3nYt+dFznV2rAZ/vnJSOHCFFsKxUzaebv2NIOSwRas9NKynsJvO2A9Hq+udhQIHEGC4BLtSVKSepm3V8vSMXQVq1uTd25h99WfHrvcXNnG7CBBus2hfkAaKnirSfuVIrlHTmJ23MuQ2oRNnhzBO1xX6veiYgca1PUkOlYYT+54vZU4zGvxRN6zvLVD76/0lQpixbw/ZZTByn8U9hev4nRViwsbptOsh1xLPGpwMhHKv+Mr7jdPZqRHQbnuHfFK/Qx+j4Yoq30M6I9xOkdUflOD60q+9AjKLVnSuVJZtO9ZriyY/9n5EI0gvYVReO04OmD1e9SsbxwsWevgoVKbg25gz5ZEGW3wEvd6aCBWUCs9wPkbbQ686azHCkJD9CmE/ZutgtoTvrLf9BFr2c7vSrlfHvcuiky9GI/hIPTdf+dC7Zv7OgQtEc3YC8J0OmU89HVKt3qsrwVdJcj9dWagQ5sypyaEKIi1SQeiQkWj3y/E2A37/IJrQ6lWrDLON2E3Y48EOabfv8Kzsk55kwnb1X2jJhQNsZ4MucQ6nNQIzgbNLIucGhtK0WE1bsbxmYIEUd+FqUh6bDogqsG72AEGOcTfJ65Pye+K65gCf0Fd/M3YdQcweC4Q23TeEXtCoSGVljgbnw6KQYZEeC7Mqsja7CYCG1HXZmdkyPP2TbFia7Wn629s620e5Rkz08lXRVtZUL4nVDB0FuRM+Lv2GxJX0ZOLyj4JYgMqWVyd8GsZwkQNnNqrs+enXqBVgg8xoFK9K8Dc4spdhLT ieKznGBP tn7JXMGPPcvoN//4lj8h+lFvwUXMjWc7RV2eetkWJt9FqzGMKQ7BEkXaHnCAkyRAwlNWeAr7ua9knvnSX0ZKiOLfUYi7Oc3+Hd/pQ/RuTnXneqaNi4Got/qxAKjBw3SZyjwrZYN2A/UTgqcyveZlL0szcAEObT425aczBq5W7Q7vVC4ncoRDCvlChNAc6Ze+Bd+6taUJKI9f9wYPgxv15LHkFLIK8w5iyDhfNX/uDr2ts4XP0tIMcSeJ5qw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000003, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 19/09/2023 14:42, Peter Zijlstra wrote: > On Tue, Sep 19, 2023 at 03:37:24PM +0200, John Paul Adrian Glaubitz wrote: >> On Tue, 2023-09-19 at 14:00 +0100, Matthew Wilcox wrote: >>> On Tue, Sep 19, 2023 at 02:30:59PM +0200, Thomas Gleixner wrote: >>>> Though it just occured to me that there are dragons lurking: >>>> >>>> arch/alpha/Kconfig: select ARCH_NO_PREEMPT >>>> arch/hexagon/Kconfig: select ARCH_NO_PREEMPT >>>> arch/m68k/Kconfig: select ARCH_NO_PREEMPT if !COLDFIRE >>>> arch/um/Kconfig: select ARCH_NO_PREEMPT >>> >>> Sounds like three-and-a-half architectures which could be queued up for >>> removal right behind ia64 ... >> >> The agreement to kill off ia64 wasn't an invitation to kill off other stuff >> that people are still working on! Can we please not do this? > > If you're working on one of them, then surely it's a simple matter of > working on adding CONFIG_PREEMPT support :-) In the case of UML adding preempt will be quite difficult. I looked at this a few years back. At the same time it is used for kernel test and other stuff. It is not exactly abandonware on a CPU found in archaeological artifacts of past civilizations like ia64. > > _______________________________________________ > linux-um mailing list > linux-um@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-um > -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/