On 08/03/12 12:45, Davidlohr Bueso wrote:
> From: Davidlohr Bueso <dave@xxxxxxx>
>
> Since most guests will have paging enabled for memory management, add likely() optimization
> around CR0.PG checks.
> {
> - return kvm_read_cr0_bits(vcpu, X86_CR0_PG);
> + return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
IMHO likely/unlikely should be considered more as fast-path/slow-path and not as often/less often.
Is that the case here? This patch might cause a mis-prediction for non-paging guests all
the time.
Non-paging might be really irrelevant, so I am just making a point, since
likely/unlikely is mis-used too often especially for "most users do it that way".
Christian
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