On 04/13/2011 05:09 PM, Jan Kiszka wrote:
Hi Xiao,
while tracing a guest with all events enabled, I notices some issues
with kvm mmu instrumentations. A critical one:
TRACE_EVENT(
kvm_mmu_audit,
TP_PROTO(struct kvm_vcpu *vcpu, int audit_point),
TP_ARGS(vcpu, audit_point),
TP_STRUCT__entry(
__field(struct kvm_vcpu *, vcpu)
__field(int, audit_point)
),
TP_fast_assign(
__entry->vcpu = vcpu;
__entry->audit_point = audit_point;
),
TP_printk("vcpu:%d %s", __entry->vcpu->cpu,
audit_point_name[__entry->audit_point])
);
Saving the vcpu reference to the trace buffer can break on dump if the
vcpu was destroyed in the meantime. I was about to fix that by saving
vcpu->cpu instead, but then I wondered what kind of information you
actually need here. The triggering host cpu is automatically recorded by
ftrace anyway. Can you comment on this / clean it up? Also, it would be
nice to use __print_symbolic for translating audit_point to a string as
that would also work for trace-cmd/kernelshark.
IIRC the audit trace is only used to get a low cost invocation for the
audit machinery; it's not actually useful as a user tracepoint.
We should probably switch to static_branch() instead
(https://lwn.net/Articles/429447/).
--
error compiling committee.c: too many arguments to function
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