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To:     Linus Torvalds <torvalds@linux-foundation.org>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Ankur Arora <ankur.a.arora@oracle.com>,
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        Geert Uytterhoeven <geert@linux-m68k.org>,
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        Richard Henderson <richard.henderson@linaro.org>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>, linux-alpha@vger.kernel.org
Subject: Re: Arches that don't support PREEMPT
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Date:   Wed, 20 Sep 2023 10:26:25 +0200
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On Tue, Sep 19 2023 at 10:25, Linus Torvalds wrote:
> PeterZ mentioned the generic entry code, which does this for the entry
> path. But it actually goes much deeper: just do a
>
>     git grep preempt_disable arch/x86/kernel
>
> and then do the same for some other architectures.
>
> Looking at alpha, for example, there *are* hits for it, so at least
> some of the code there clearly *tries* to do it. But does it cover all
> the required parts? If it's never been tested, I'd be surprised if
> it's all just ready to go.

Interestingly enough m68k has zero instances, but it supports PREEMPT on
the COLDFIRE subarchitecture...