Messages in this thread | | | From | Pingfan Liu <> | Subject | [PATCHv3 0/3] arm64/irqentry: remove duplicate housekeeping of rcu | Date | Thu, 30 Sep 2021 21:17:05 +0800 |
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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.
V2 -> V3: Drop other patches and concentrate on the purpose of [3-4/5] of V2. And lift the level, where to add {irq_enter,exit}_rcu(), from the interrupt controler to exception entry
History: V1: https://lore.kernel.org/linux-arm-kernel/1607912752-12481-1-git-send-email-kernelfans@gmail.com V2: https://lore.kernel.org/linux-arm-kernel/20210924132837.45994-1-kernelfans@gmail.com
Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Julien Thierry <julien.thierry@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yuichi Ito <ito-yuichi@fujitsu.com> Cc: linux-kernel@vger.kernel.org To: linux-arm-kernel@lists.infradead.org
Mark Rutland (1): arm64: entry: refactor EL1 interrupt entry logic
Pingfan Liu (2): kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional arm64/entry-common: supplement irq accounting
arch/arm64/Kconfig | 1 + arch/arm64/kernel/entry-common.c | 48 +++++++++++++++++--------------- kernel/irq/Kconfig | 3 ++ kernel/irq/irqdesc.c | 4 +++ 4 files changed, 34 insertions(+), 22 deletions(-)
-- 2.31.1
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