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From: Thomas Gleixner <tglx@kernel.org>
To: Jisheng Zhang <jszhang@kernel.org>, Catalin Marinas
 <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Arnd Bergmann
 <arnd@arndb.de>, Paul Walmsley <pjw@kernel.org>, Palmer Dabbelt
 <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, Alexandre Ghiti
 <alex@ghiti.fr>, Guo Ren <guoren@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
 linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org,
 linux-csky@vger.kernel.org
Subject: Re: [PATCH 2/3] genirq: use runtime constant to optimize
 handle_arch_irq access
In-Reply-To: <20260220090922.1506-3-jszhang@kernel.org>
References: <20260220090922.1506-1-jszhang@kernel.org>
 <20260220090922.1506-3-jszhang@kernel.org>
Date: Sun, 22 Feb 2026 23:06:11 +0100
Message-ID: <877bs4wi0c.ffs@tglx>
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On Fri, Feb 20 2026 at 17:09, Jisheng Zhang wrote:
> Currently, on GENERIC_IRQ_MULTI_HANDLER platforms, the handle_arch_irq
> is a pointer which is set during booting, and every irq processing needs
> to access it, so it sits in hot code path. We can use the
> runtime constant mechanism which was introduced by Linus to speed up
> its accessing.

The proper solution is to use a static call and update it in
set_handle_irq().  That removes the complete indirect call issue from
the hot path.

Thanks,

        tglx