On 11/20/2014 08:01 AM, Steven Rostedt wrote: > On Thu, 20 Nov 2014 13:10:12 +0100 > Alexander Graf <agraf@xxxxxxx> wrote: > >> >> >> On 20.11.14 11:40, Aneesh Kumar K.V wrote: >>> "Suresh E. Warrier" <warrier@xxxxxxxxxxxxxxxxxx> writes: >>> >>>> This patch adds trace points in the guest entry and exit code and also >>>> for exceptions handled by the host in kernel mode - hypercalls and page >>>> faults. The new events are added to /sys/kernel/debug/tracing/events >>>> under a new subsystem called kvm_hv. >>> >>> ........ >>> >>>> /* Set this explicitly in case thread 0 doesn't have a vcpu */ >>>> @@ -1687,6 +1691,9 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc) >>>> >>>> vc->vcore_state = VCORE_RUNNING; >>>> preempt_disable(); >>>> + >>>> + trace_kvmppc_run_core(vc, 0); >>>> + >>>> spin_unlock(&vc->lock); >>> >>> Do we really want to call tracepoint with spin lock held ? Is that a good >>> thing to do ?. >> >> I thought it was safe to call tracepoints inside of spin lock regions? >> Steve? >> > > There's tracepoints in the guts of the scheduler where rq lock is held. > Don't worry about it. The tracing system is lockless. > Thanks for confirming. -suresh > -- Steve > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
