Re: [PATCH] KVM: Remove redundant smp_mb() in the kvm_mmu_commit_zap_page()

From: Paolo Bonzini
Date: Thu Mar 10 2016 - 10:31:24 EST




On 10/03/2016 16:26, Paolo Bonzini wrote:
> Compared to smp_load_acquire(), smp_mb() adds an ordering between stores
> and loads.

Here, the ordering is load-store, hence...

> The load of kvm->tlbs_dirty should then be
>
> /*
> * Read tlbs_dirty before setting KVM_REQ_TLB_FLUSH in
> * kvm_make_all_cpus_request. This
> */
> long dirty_count = smp_load_acquire(kvm->tlbs_dirty);
>
> Tianyu, I think Xiao provided the information that I was missing. Would
> you like to prepare the patch?

Thanks,

Paolo