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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: Thomas Gleixner , Peter Zijlstra , John Paul Adrian Glaubitz Cc: Matthew Wilcox , 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> <87y1h2ur98.ffs@tglx> From: Anton Ivanov In-Reply-To: <87y1h2ur98.ffs@tglx> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Clacks-Overhead: GNU Terry Pratchett X-Rspamd-Queue-Id: BF6A0100018 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: i6o7ftwf8skk31ea4s8e4azrjq3sh6q4 X-HE-Tag: 1695136902-965267 X-HE-Meta: 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 DgCJnfo9 3pHSmUAGbxiqqTCcXVG2je3+zOXbBoO/D2Cz+7ke7eI8MzB7gFlQXIEbfnvzmdptMFAjcTVOoV9pGPKbp7NHrRT6iXsAmGTOXG/ebJPrskpj1Y1SRL72P6h2ZsVYUqFO2XttRXVy1h55u1N6xiwm5tZ49Vib+56fmcP1I4s8VSNV2CNLn18+vTPrzQw== 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 19/09/2023 16:17, Thomas Gleixner wrote: > On Tue, Sep 19 2023 at 15:21, Anton Ivanov wrote: >> On 19/09/2023 14:42, Peter Zijlstra wrote: >>> 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. > What's so difficult about it? It's been a while. I remember that I dropped it at the time, but do not remember the full details. There was some stuff related to FP state and a few other issues I ran into while rewriting the interrupt controller. Some of it may be resolved by now as we are using host cpu flags, etc. I can give it another go :) > > Thanks, > > tglx > -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/