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From: Qi Zheng <zhengqi.arch@bytedance.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: 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>
Subject: Re: [RFC PATCH 1/2] arm64: run softirqs on the per-CPU IRQ stack
Date: Thu, 7 Jul 2022 23:05:21 +0800	[thread overview]
Message-ID: <ae96bd02-bd6b-b948-405f-973beb7f9a0d@bytedance.com> (raw)
In-Reply-To: <CAK8P3a2D1KXY_a952Aw_7hH+yzYpqQaBA5LkmkfF6EwiLUgNSA@mail.gmail.com>



On 2022/7/7 21:53, Arnd Bergmann wrote:
> 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.

I just glanced at arch/um/, and it's really different from the rest:

  * Unlike i386, UML doesn't receive IRQs on the normal kernel stack
  * and switch over to the IRQ stack after some preparation.

> 
>         Arnd

-- 
Thanks,
Qi

WARNING: multiple messages have this Message-ID (diff)
From: Qi Zheng <zhengqi.arch@bytedance.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: 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>
Subject: Re: [RFC PATCH 1/2] arm64: run softirqs on the per-CPU IRQ stack
Date: Thu, 7 Jul 2022 23:05:21 +0800	[thread overview]
Message-ID: <ae96bd02-bd6b-b948-405f-973beb7f9a0d@bytedance.com> (raw)
In-Reply-To: <CAK8P3a2D1KXY_a952Aw_7hH+yzYpqQaBA5LkmkfF6EwiLUgNSA@mail.gmail.com>



On 2022/7/7 21:53, Arnd Bergmann wrote:
> 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.

I just glanced at arch/um/, and it's really different from the rest:

  * Unlike i386, UML doesn't receive IRQs on the normal kernel stack
  * and switch over to the IRQ stack after some preparation.

> 
>         Arnd

-- 
Thanks,
Qi

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-07-07 15:05 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-07 11:05 [RFC PATCH 0/2] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng
2022-07-07 11:05 ` Qi Zheng
2022-07-07 11:05 ` [RFC PATCH 1/2] " Qi Zheng
2022-07-07 11:05   ` Qi Zheng
2022-07-07 12:58   ` Arnd Bergmann
2022-07-07 12:58     ` Arnd Bergmann
2022-07-07 13:43     ` Qi Zheng
2022-07-07 13:43       ` Qi Zheng
2022-07-07 13:53       ` Arnd Bergmann
2022-07-07 13:53         ` Arnd Bergmann
2022-07-07 15:05         ` Qi Zheng [this message]
2022-07-07 15:05           ` Qi Zheng
2022-07-08  2:56   ` kernel test robot
2022-07-07 11:05 ` [RFC PATCH 2/2] arm64: support HAVE_IRQ_EXIT_ON_IRQ_STACK Qi Zheng
2022-07-07 11:05   ` Qi Zheng
2022-07-07 12:49   ` Arnd Bergmann
2022-07-07 12:49     ` Arnd Bergmann
2022-07-07 13:38     ` Qi Zheng
2022-07-07 13:38       ` Qi Zheng
2022-07-07 14:41       ` Arnd Bergmann
2022-07-07 14:41         ` Arnd Bergmann
2022-07-07 15:00         ` Qi Zheng
2022-07-07 15:00           ` Qi Zheng
2022-07-07 20:55           ` Arnd Bergmann
2022-07-07 20:55             ` Arnd Bergmann
2022-07-08  3:13             ` Qi Zheng
2022-07-08  3:13               ` Qi Zheng
2022-07-08  8:52               ` Arnd Bergmann
2022-07-08  8:52                 ` Arnd Bergmann
2022-07-08  9:13                 ` Qi Zheng
2022-07-08  9:13                   ` Qi Zheng

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