From: Will Deacon <will.deacon@arm.com>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: linux-kernel@vger.kernel.org,
Julien Thierry <julien.thierry@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Julien Grall <julien.grall@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 1/3] arm64: entry: Remove unneeded need_resched() loop
Date: Fri, 1 Feb 2019 10:21:54 +0000 [thread overview]
Message-ID: <20190201102154.GB26637@fuggles.cambridge.arm.com> (raw)
In-Reply-To: <20190131182339.9835-2-valentin.schneider@arm.com>
On Thu, Jan 31, 2019 at 06:23:37PM +0000, Valentin Schneider wrote:
> Since the enabling and disabling of IRQs within preempt_schedule_irq()
> is contained in a need_resched() loop, we don't need the outer arch
> code loop.
>
> Reported-by: Julien Thierry <julien.thierry@arm.com>
> Reported-by: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Julien Grall <julien.grall@arm.com>
> Cc: Julien Thierry <julien.thierry@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: linux-arm-kernel@lists.infradead.org
> ---
> arch/arm64/kernel/entry.S | 11 +----------
> 1 file changed, 1 insertion(+), 10 deletions(-)
>
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 0ec0c46b2c0c..4d0c81f29a60 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -611,7 +611,7 @@ el1_irq:
> #ifdef CONFIG_PREEMPT
> ldr x24, [tsk, #TSK_TI_PREEMPT] // get preempt count
> cbnz x24, 1f // preempt count != 0
> - bl el1_preempt
> + bl preempt_schedule_irq // irq en/disable is done inside
> 1:
> #endif
> #ifdef CONFIG_TRACE_IRQFLAGS
> @@ -620,15 +620,6 @@ el1_irq:
> kernel_exit 1
> ENDPROC(el1_irq)
>
> -#ifdef CONFIG_PREEMPT
> -el1_preempt:
> - mov x24, lr
> -1: bl preempt_schedule_irq // irq en/disable is done inside
> - ldr x0, [tsk, #TSK_TI_FLAGS] // get new tasks TI_FLAGS
> - tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling?
> - ret x24
> -#endif
> -
Acked-by: Will Deacon <will.deacon@arm.com>
Catalin can pick this up for 5.1.
Will
next prev parent reply other threads:[~2019-02-01 10:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-31 18:23 [RFC PATCH 0/3] arm/arm64: entry: Remove need_resched() loop Valentin Schneider
2019-01-31 18:23 ` [RFC PATCH 1/3] arm64: entry: Remove unneeded " Valentin Schneider
2019-02-01 8:46 ` Julien Thierry
2019-02-01 10:21 ` Will Deacon [this message]
2019-02-04 16:55 ` Catalin Marinas
2019-01-31 18:23 ` [RFC PATCH 2/3] ARM: " Valentin Schneider
2019-02-01 8:49 ` Julien Thierry
2019-01-31 18:23 ` [RFC PATCH 3/3] sched/Documentation: Point out use of preempt_schedule_irq() Valentin Schneider
2019-02-01 8:45 ` Julien Thierry
2019-02-01 10:27 ` Valentin Schneider
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