From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH] KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions Date: Thu, 20 Nov 2014 13:10:12 +0100 Message-ID: <546DDA24.8040604@suse.de> References: <54653EBC.2020805@linux.vnet.ibm.com> <87r3wy6tp0.fsf@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Paul Mackerras , rostedt@goodmis.org To: "Aneesh Kumar K.V" , "Suresh E. Warrier" , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Return-path: In-Reply-To: <87r3wy6tp0.fsf@linux.vnet.ibm.com> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 20.11.14 11:40, Aneesh Kumar K.V wrote: > "Suresh E. Warrier" 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? Alex