Groups > linux.kernel > #1632060

Re: [PATCH v2 4/9] KVM: mark requests that do not need a wakeup

From	Cornelia Huck <cornelia.huck@de.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 4/9] KVM: mark requests that do not need a wakeup
Date	2017-04-27 14:10 +0200
Message-ID	<tAQpc-ol-29@gated-at.bofh.it> (permalink)
References	<tABTb-7dC-3@gated-at.bofh.it> <tABTc-7dC-19@gated-at.bofh.it>
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On Wed, 26 Apr 2017 22:32:22 +0200
Radim Krčmář <rkrcmar@redhat.com> 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: Cornelia Huck <cornelia.huck@de.ibm.com>

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[PATCH v2 4/9] KVM: mark requests that do not need a wakeup Radim Krčmář <rkrcmar@redhat.com> - 2017-04-26 22:40 +0200
  Re: [PATCH v2 4/9] KVM: mark requests that do not need a wakeup Andrew Jones <drjones@redhat.com> - 2017-04-27 13:40 +0200
  Re: [PATCH v2 4/9] KVM: mark requests that do not need a wakeup Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-04-27 14:10 +0200

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