>>> On 23.02.17 at 12:55, <xuqu...@huawei.com> wrote: > On February 23, 2017 7:01 PM, Jan Beulich wrote: >>>>> On 23.02.17 at 11:53, <xuqu...@huawei.com> wrote: >>> IOW, >>> which vcpu does the 'current' refer to? >>> which cpu does the ' smp_processor_id()' refer to? >> >>current: currently running vCPU > > in a SMP machine, are there more than one currently running vCPU?
Of course. "current" obviously is the one running on the CPU we're on. > I think so, the condition "if ( running && (in_irq() || (v != current)) )", > in > __vmx_deliver_posted_interrupt() looks strange -- when vCPU is running, why > to > check ' v != current '.. > > >>smp_processor_id(): processor ID of the CPU we're running on >> > I think if vcpu is running, ' cpu != smp_processor_id() ' should be true. > > > I think we could simplify __vmx_deliver_posted_interrupt(): > > 1. set VCPU_KICK_SOFTIRQ bit of v->processor. > 2. IF vcpu is running: > - send_IPI > ELSE > - vcpu_kick If this can be done in a race free manner (after all, the running state of a vCPU running on another pCPU may change at any time) ... Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
