Re: [PATCHv2] trace "exit to userspace" event

[Avi Kivity <avi@redhat.com>]

  On 10/24/2010 07:24 PM, Gleb Natapov wrote:
> On Sun, Oct 24, 2010 at 07:01:30PM +0200, Avi Kivity wrote:
> >   On 10/24/2010 04:49 PM, Gleb Natapov wrote:
> >  >Add tracepoint for userspace exit.
> >  >
> >  >
> >  >+
> >  >+TRACE_EVENT(kvm_userspace_exit,
> >  >+	    TP_PROTO(__u32 reason, int errno),
> >  >+	    TP_ARGS(reason, errno),
> >  >+
> >  >+	TP_STRUCT__entry(
> >  >+		__field(	__u32,		reason		)
> >  >+		__field(	int,		errno		)
> >  >+	),
> >  >+
> >  >+	TP_fast_assign(
> >  >+		__entry->reason		= reason;
> >  >+		__entry->errno		= errno;
> >
> >  Shouldn't this be -errno?
> >
> I check for __entry->errno<  0 below to see if exit was due to an error.
>

Then check for > 0.  If a variable is named errno, it should work as an 
input to strerror() (or a __print_symbolic for errno).

-- 
error compiling committee.c: too many arguments to function