From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 02/10] KVM: arm/arm64: vgic: Avoid flushing vgic state when there's no pending IRQ
Date: Mon, 27 Mar 2017 11:52:23 +0100 [thread overview]
Message-ID: <bd56c2b3-bd4e-dd42-61bf-2ec1f81dba38@arm.com> (raw)
In-Reply-To: <20170321211059.8719-3-cdall@linaro.org>
On 21/03/17 21:10, Christoffer Dall wrote:
> From: Shih-Wei Li <shihwei@cs.columbia.edu>
>
> We do not need to flush vgic states in each world switch unless
> there is pending IRQ queued to the vgic's ap list. We can thus reduce
> the overhead by not grabbing the spinlock and not making the extra
> function call to vgic_flush_lr_state.
>
> Note: list_empty is a single atomic read (uses READ_ONCE) and can
> therefore check if a list is empty or not without the need to take the
> spinlock protecting the list.
>
> Signed-off-by: Shih-Wei Li <shihwei@cs.columbia.edu>
> Signed-off-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2017-03-27 10:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 21:10 [PATCH v2 00/10] KVM: arm/arm64: vgic: Improvements and optimizations Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 01/10] KVM: arm/arm64: vgic: Defer touching GICH_VMCR to vcpu_load/put Christoffer Dall
2017-03-27 10:49 ` Marc Zyngier
2017-03-21 21:10 ` [PATCH v2 02/10] KVM: arm/arm64: vgic: Avoid flushing vgic state when there's no pending IRQ Christoffer Dall
2017-03-27 10:52 ` Marc Zyngier [this message]
2017-03-21 21:10 ` [PATCH v2 03/10] KVM: arm/arm64: vgic: Get rid of live_lrs Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 04/10] KVM: arm/arm64: vgic: Only set underflow when actually out of LRs Christoffer Dall
2017-03-27 10:59 ` Marc Zyngier
2017-03-21 21:10 ` [PATCH v2 05/10] KVM: arm/arm64: vgic: Get rid of unnecessary process_maintenance operation Christoffer Dall
2017-03-27 11:03 ` Marc Zyngier
2017-03-21 21:10 ` [PATCH v2 06/10] KVM: arm/arm64: vgic: Get rid of unnecessary save_maint_int_state Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 07/10] KVM: arm/arm64: vgic: Get rid of MISR and EISR fields Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 08/10] KVM: arm/arm64: vgic: Implement early VGIC init functionality Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 09/10] KVM: arm/arm64: vgic: Don't check vgic_initialized in sync/flush Christoffer Dall
2017-03-21 21:10 ` [PATCH v2 10/10] KVM: arm/arm64: vgic: Improve sync_hwstate performance Christoffer Dall
2017-03-27 11:04 ` Marc Zyngier
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