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References: <20240228072216.95130-1-yaoma@linux.alibaba.com> <20240228072216.95130-4-yaoma@linux.alibaba.com>
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From: Doug Anderson <dianders@chromium.org>
Date: Wed, 28 Feb 2024 14:44:50 -0800
Message-ID: <CAD=FV=W7gOpLw2VwRO7EwwNoqSJFM8iC0-R1GC4RHtz4=fwa5A@mail.gmail.com>
Subject: Re: [PATCHv11 3/4] genirq: Avoid summation loops for /proc/interrupts
To: Bitao Hu <yaoma@linux.alibaba.com>
Cc: tglx@linutronix.de, liusong@linux.alibaba.com, akpm@linux-foundation.org, 
	pmladek@suse.com, kernelfans@gmail.com, deller@gmx.de, npiggin@gmail.com, 
	tsbogend@alpha.franken.de, James.Bottomley@hansenpartnership.com, 
	jan.kiszka@siemens.com, linux-kernel@vger.kernel.org, 
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, 
	linuxppc-dev@lists.ozlabs.org
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Hi,

On Tue, Feb 27, 2024 at 11:22=E2=80=AFPM Bitao Hu <yaoma@linux.alibaba.com>=
 wrote:
>
> show_interrupts() unconditionally accumulates the per CPU interrupt
> statistics to determine whether an interrupt was ever raised.
>
> This can be avoided for all interrupts which are not strictly per CPU
> and not of type NMI because those interrupts provide already an
> accumulated counter. The required logic is already implemented in
> kstat_irqs().
>
> Split the inner access logic out of kstat_irqs() and use it for
> kstat_irqs() and show_interrupts() to avoid the accumulation loop
> when possible.
>
> Originally-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Bitao Hu <yaoma@linux.alibaba.com>
> Reviewed-by: Liu Song <liusong@linux.alibaba.com>
> ---
>  kernel/irq/internals.h |  2 ++
>  kernel/irq/irqdesc.c   | 16 +++++++++++-----
>  kernel/irq/proc.c      |  6 ++----
>  3 files changed, 15 insertions(+), 9 deletions(-)

Reviewed-by: Douglas Anderson <dianders@chromium.org>