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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Fri, 6 Oct 2023 16:51:07 +0200
Message-ID: <CAMuHMdV4qx3iQzqksfnvckk_PK9Zas0U=p-xv3pVwJ6hWLpejA@mail.gmail.com>
Subject: Re: Arches that don't support PREEMPT
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ankur Arora <ankur.a.arora@oracle.com>,
        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,
        linux-m68k@lists.linux-m68k.org,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        linux-um@lists.infradead.org, Brian Cain <bcain@quicinc.com>,
        linux-hexagon@vger.kernel.org,
        Richard Henderson <richard.henderson@linaro.org>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>, linux-alpha@vger.kernel.org
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Hi Willy,

On Tue, Sep 19, 2023 at 3:01 PM Matthew Wilcox <willy@infradead.org> 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 ...
>
> I suspect none of these architecture maintainers have any idea there's a
> problem.  Look at commit 87a4c375995e and the discussion in
> https://lore.kernel.org/lkml/20180724175646.3621-1-hch@lst.de/
>
> Let's cc those maintainers so they can remove this and fix whatever
> breaks.

Looks like your scare tactics are working ;-)
[PATCH/RFC] m68k: Add full preempt support
https://lore.kernel.org/all/7858a184cda66e0991fd295c711dfed7e4d1248c.1696603287.git.geert@linux-m68k.org

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds