linux-kernel - Re: [PATCH] ARM: smp: Fix missing backtrace IPI statics

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Message-ID: <Zqu5ck+Ik8KlzE0O@shell.armlinux.org.uk>
Date: Thu, 1 Aug 2024 17:36:02 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Jinjie Ruan <ruanjinjie@...wei.com>
Cc: dianders@...omium.org, mhocko@...e.com, akpm@...ux-foundation.org,
	maz@...nel.org, vschneid@...hat.com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: smp: Fix missing backtrace IPI statics

On Thu, Aug 01, 2024 at 05:40:22PM +0800, Jinjie Ruan wrote:
> It is similar to ARM64 commit 916b93f4e865 ("arm64: smp: Fix missing IPI
> statistics"), commit 56afcd3dbd19 ("ARM: Allow IPIs to be handled as normal
> interrupts") set CPU_BACKTRACE IPI "IRQ_HIDDEN" flag but not show it in
> show_ipi_list(), which cause the interrupt kstat_irqs accounting
> is missing in display.

I don't see why this needs to be included. If this IPI fires, it means
that the kernel has suffered a lockup and is probably not very useful.
So the chances of being able to read out from /proc/interrupts a non-
zero "CPU backtrace interrupts" figure is highly unlikely.

So, I don't see much point to this change.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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