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Subject: Re: [PATCH v4 0/3] KVM: Yield to IPI target if necessary
To:     Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
References: <1560255830-8656-1-git-send-email-wanpengli@tencent.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <0b42a3b4-91eb-4cc8-201a-8da0a944403a@redhat.com>
Date:   Tue, 2 Jul 2019 18:49:00 +0200
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On 11/06/19 14:23, Wanpeng Li wrote:
> The idea is from Xen, when sending a call-function IPI-many to vCPUs, 
> yield if any of the IPI target vCPUs was preempted. 17% performance 
> increasement of ebizzy benchmark can be observed in an over-subscribe 
> environment. (w/ kvm-pv-tlb disabled, testing TLB flush call-function 
> IPI-many since call-function is not easy to be trigged by userspace 
> workload).
> 
> v3 -> v4: 
>  * check map->phys_map[dest_id]
>  * more cleaner kvm_sched_yield()
> 
> v2 -> v3:
>  * add bounds-check on dest_id
> 
> v1 -> v2:
>  * check map is not NULL
>  * check map->phys_map[dest_id] is not NULL
>  * make kvm_sched_yield static
>  * change dest_id to unsinged long
> 
> Wanpeng Li (3):
>   KVM: X86: Yield to IPI target if necessary
>   KVM: X86: Implement PV sched yield hypercall
>   KVM: X86: Expose PV_SCHED_YIELD CPUID feature bit to guest
> 
>  Documentation/virtual/kvm/cpuid.txt      |  4 ++++
>  Documentation/virtual/kvm/hypercalls.txt | 11 +++++++++++
>  arch/x86/include/uapi/asm/kvm_para.h     |  1 +
>  arch/x86/kernel/kvm.c                    | 21 +++++++++++++++++++++
>  arch/x86/kvm/cpuid.c                     |  3 ++-
>  arch/x86/kvm/x86.c                       | 21 +++++++++++++++++++++
>  include/uapi/linux/kvm_para.h            |  1 +
>  7 files changed, 61 insertions(+), 1 deletion(-)
> 

Queued, thanks.

Paolo