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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 7 Jul 2022 15:53:20 +0200
Message-ID: <CAK8P3a2D1KXY_a952Aw_7hH+yzYpqQaBA5LkmkfF6EwiLUgNSA@mail.gmail.com>
Subject: Re: [RFC PATCH 1/2] arm64: run softirqs on the per-CPU IRQ stack
To:     Qi Zheng <zhengqi.arch@bytedance.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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On Thu, Jul 7, 2022 at 3:43 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote:
> On 2022/7/7 20:58, Arnd Bergmann wrote:
> > On Thu, Jul 7, 2022 at 1:05 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote:
> > Are there any architectures left that use IRQ stacks but don't
> > set HAVE_SOFTIRQ_ON_OWN_STACK? If not, we could
> > also consider removing the Kconfig symbol and just requiring
> > it to be done this way (for non-PREEMPT_RT).
>
> I haven't taken a close look at other architectures than x86 and arm,
> but I think it's a good idea.

I had another look in the meantime, and I think it's only mips and loongarch
now that don't use HAVE_SOFTIRQ_ON_OWN_STACK. Not sure about
arch/um/, which is a bit different from the rest.

       Arnd