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Date:   Mon, 04 Oct 2021 17:30:26 +0100
From:   Marc Zyngier <>
To:     Pingfan Liu <>
        Mark Rutland <>,
        "Paul E. McKenney" <>,
        Catalin Marinas <>,
        Will Deacon <>, Joey Gouly <>,
        Sami Tolvanen <>,
        Julien Thierry <>,
        Thomas Gleixner <>,
        Yuichi Ito <>,
Subject: Re: [PATCHv4 1/3] kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional

On Fri, 01 Oct 2021 15:44:04 +0100,
Pingfan Liu <> wrote:
> When an IRQ is taken, some accounting needs to be performed to enter and
> exit IRQ context around the IRQ handler. Historically arch code would
> leave this to the irqchip or core IRQ code, but these days we want this
> to happen in exception entry code, and architectures such as arm64 do
> this.
> Currently handle_domain_irq() performs this entry/exit accounting, and
> if used on an architecture where the entry code also does this, the
> entry/exit accounting will be performed twice per IRQ. This is
> problematic as core RCU code such as rcu_is_cpu_rrupt_from_idle()
> depends on this happening once per IRQ, and will not detect quescent
> periods correctly, leading to stall warnings.
> As irqchip drivers which use handle_domain_irq() need to work on
> architectures with or without their own entry/exit accounting, this
> patch makes handle_domain_irq() conditionally perform the entry
> accounting depending on a new HAVE_ARCH_IRQENTRY Kconfig symbol that
> architectures can select if they perform this entry accounting
> themselves.
> For architectures which do not select the symbol. there should be no
> functional change as a result of this patch.
> Signed-off-by: Pingfan Liu <>
> Reviewed-by: Mark Rutland <>
> Cc: "Paul E. McKenney" <>
> Cc: Catalin Marinas <>
> Cc: Will Deacon <>
> Cc: Marc Zyngier <>
> Cc: Joey Gouly <>
> Cc: Sami Tolvanen <>
> Cc: Julien Thierry <>
> Cc: Thomas Gleixner <>
> Cc: Yuichi Ito <>
> Cc:
> To:

Reviewed-by: Marc Zyngier <>


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