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Date: Thu, 27 Apr 2017 13:35:34 +0200
From: Andrew Jones <drjones@redhat.com>
To: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Christoffer Dall <cdall@linaro.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Cornelia Huck <cornelia.huck@de.ibm.com>,
        James Hogan <james.hogan@imgtec.com>,
        Paul Mackerras <paulus@ozlabs.org>
Subject: Re: [PATCH v2 4/9] KVM: mark requests that do not need a wakeup
Message-ID: <20170427113534.4gofjdl7xb5xqcj4@kamzik.brq.redhat.com>
References: <20170426203227.12321-1-rkrcmar@redhat.com>
 <20170426203227.12321-5-rkrcmar@redhat.com>
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On Wed, Apr 26, 2017 at 10:32:22PM +0200, Radim Krčmář wrote:
> Some operations must ensure that the guest is not running with stale
> data, but if the guest is halted, then the update can wait until another
> event happens.  kvm_make_all_requests() currently doesn't wake up, so we
> can mark all requests used with it.
> 
> First 8 bits were arbitrarily reserved for request numbers.
> 
> Most uses of requests have the request type as a constant, so a compiler
> will optimize the '&'.
> 
> An alternative would be to have an inline function that would return
> whether the request needs a wake-up or not, but I like this one better
> even though it might produce worse assembly.
> 
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  v2: use GENMASK [Marc]
> ---
>  arch/arm/include/asm/kvm_host.h   |  2 +-
>  arch/arm64/include/asm/kvm_host.h |  2 +-
>  arch/x86/include/asm/kvm_host.h   |  6 +++---
>  include/linux/kvm_host.h          | 12 +++++++-----
>  4 files changed, 12 insertions(+), 10 deletions(-)

Reviewed-by: Andrew Jones <drjones@redhat.com>