From: Marc Zyngier <maz@kernel.org>
To: Austin Kim <austindh.kim@gmail.com>
Cc: will@kernel.org, catalin.marinas@arm.com,
linux-kernel@vger.kernel.org, austin.kim@lge.com,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] KVM: arm64: vgic: declear local variable 'flags' before for loop starts
Date: Sat, 12 Jun 2021 12:10:43 +0100 [thread overview]
Message-ID: <87eed7tk24.wl-maz@kernel.org> (raw)
In-Reply-To: <20210612110014.GA1211@raspberrypi>
On Sat, 12 Jun 2021 12:00:14 +0100,
Austin Kim <austindh.kim@gmail.com> wrote:
>
> From: Austin Kim <austin.kim@lge.com>
>
> Normally local variable 'flags' is defined out of for loop,
> when 'flags' is used as the second parameter in a call to
> spinlock_irq[save/restore] function.
>
> So it had better declear local variable 'flags' ahead of for loop.
Why better? Reducing the scope of a variable is in general good
practice. Do you see any material advantage in moving this variable
out of the loop? Does the compiler generate better code?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Austin Kim <austindh.kim@gmail.com>
Cc: james.morse@arm.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
austin.kim@lge.com
Subject: Re: [PATCH] KVM: arm64: vgic: declear local variable 'flags' before for loop starts
Date: Sat, 12 Jun 2021 12:10:43 +0100 [thread overview]
Message-ID: <87eed7tk24.wl-maz@kernel.org> (raw)
In-Reply-To: <20210612110014.GA1211@raspberrypi>
On Sat, 12 Jun 2021 12:00:14 +0100,
Austin Kim <austindh.kim@gmail.com> wrote:
>
> From: Austin Kim <austin.kim@lge.com>
>
> Normally local variable 'flags' is defined out of for loop,
> when 'flags' is used as the second parameter in a call to
> spinlock_irq[save/restore] function.
>
> So it had better declear local variable 'flags' ahead of for loop.
Why better? Reducing the scope of a variable is in general good
practice. Do you see any material advantage in moving this variable
out of the loop? Does the compiler generate better code?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Austin Kim <austindh.kim@gmail.com>
Cc: james.morse@arm.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
austin.kim@lge.com
Subject: Re: [PATCH] KVM: arm64: vgic: declear local variable 'flags' before for loop starts
Date: Sat, 12 Jun 2021 12:10:43 +0100 [thread overview]
Message-ID: <87eed7tk24.wl-maz@kernel.org> (raw)
In-Reply-To: <20210612110014.GA1211@raspberrypi>
On Sat, 12 Jun 2021 12:00:14 +0100,
Austin Kim <austindh.kim@gmail.com> wrote:
>
> From: Austin Kim <austin.kim@lge.com>
>
> Normally local variable 'flags' is defined out of for loop,
> when 'flags' is used as the second parameter in a call to
> spinlock_irq[save/restore] function.
>
> So it had better declear local variable 'flags' ahead of for loop.
Why better? Reducing the scope of a variable is in general good
practice. Do you see any material advantage in moving this variable
out of the loop? Does the compiler generate better code?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2021-06-12 11:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-12 11:00 [PATCH] KVM: arm64: vgic: declear local variable 'flags' before for loop starts Austin Kim
2021-06-12 11:00 ` Austin Kim
2021-06-12 11:00 ` Austin Kim
2021-06-12 11:10 ` Marc Zyngier [this message]
2021-06-12 11:10 ` Marc Zyngier
2021-06-12 11:10 ` Marc Zyngier
2021-06-12 13:32 ` Austin Kim
2021-06-12 13:32 ` Austin Kim
2021-06-12 13:32 ` Austin Kim
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