Hi Xinhui, 2016-06-28 22:43 GMT+08:00 Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>: > This is to fix some lock holder preemption issues. Some other locks > implementation do a spin loop before acquiring the lock itself. Currently > kernel has an interface of bool vcpu_is_preempted(int cpu). It take the cpu > as parameter and return true if the cpu is preempted. Then kernel can break > the spin loops upon on the retval of vcpu_is_preempted. > > As kernel has used this interface, So lets support it. > > Only pSeries need supoort it. And the fact is powerNV are built into same > kernel image with pSeries. So we need return false if we are runnig as > powerNV. The another fact is that lppaca->yiled_count keeps zero on > powerNV. So we can just skip the machine type. Lock holder vCPU preemption can be detected by hardware pSeries or paravirt method? Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
