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

Cornelia Huck
2017-04-27T12:00:28Z

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>