Re: [PATCHv2] trace-cmd: add kvm_mmu_prepare_zap_page even and fix kvm_mmu_get_page event output in kvm plugin

[Gleb Natapov <gleb@redhat.com>]

On Mon, Jan 28, 2013 at 10:23:50AM -0500, Steven Rostedt wrote:
> On Mon, 2013-01-28 at 13:12 +0200, Gleb Natapov wrote:
> > Ping.
> > 
> > On Thu, Dec 27, 2012 at 01:34:15PM +0200, Gleb Natapov wrote:
> > > kvm_mmu_zap_page event was renamed to kvm_mmu_prepare_zap_page. Add new
> > > even, but leave the old one to parse older traces.  Print out "created"
> > > field for kvm_mmu_get_page event.
> > > 
> > > Signed-off-by: Gleb Natapov <gleb@redhat.com>
> > > diff --git a/plugin_kvm.c b/plugin_kvm.c
> > > index 55812ef..9b376d8 100644
> > > --- a/plugin_kvm.c
> > > +++ b/plugin_kvm.c
> > > @@ -382,7 +382,7 @@ static int kvm_mmu_print_role(struct trace_seq *s, struct pevent_record *record,
> > >  	} else
> > >  		trace_seq_printf(s, "WORD: %08x", role.word);
> > >  
> > > -	pevent_print_num_field(s, " root %u",  event,
> > > +	pevent_print_num_field(s, " root %u ",  event,
> > >  			       "root_count", record, 1);
> > >  
> > >  	if (pevent_get_field_val(s, event, "unsync", record, &val, 1) < 0)
> > > @@ -397,6 +397,11 @@ static int kvm_mmu_get_page_handler(struct trace_seq *s, struct pevent_record *r
> > >  {
> > >  	unsigned long long val;
> > >  
> > > +	if (pevent_get_field_val(s, event, "created", record, &val, 1) < 0)
> 
> Is "created" a new field? Or is it something that has always been there
> but never displayed?
> 
Always been there, but for some reason, was not displayed.

> If it is new, then instead of returning '-1' if it's not found, could
> you just ignore it. I don't want old kernels to start breaking on new
> trace-cmd plugins.
> 
> Thanks,
> 
> -- Steve
> 
> > > +		return -1;
> > > +
> > > +	trace_seq_printf(s, "%s ", val ? "new" : "existing");
> > > +
> > >  	if (pevent_get_field_val(s, event, "gfn", record, &val, 1) < 0)
> > >  		return -1;
> > >  
> > > @@ -433,5 +438,9 @@ int PEVENT_PLUGIN_LOADER(struct pevent *pevent)
> > >  	pevent_register_event_handler(pevent, -1, "kvmmmu", "kvm_mmu_zap_page",
> > >  				      kvm_mmu_print_role, NULL);
> > >  
> > > +	pevent_register_event_handler(pevent, -1, "kvmmmu",
> > > +			"kvm_mmu_prepare_zap_page", kvm_mmu_print_role,
> > > +			NULL);
> > > +
> > >  	return 0;
> > >  }
> > > --
> > > 			Gleb.
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> > --
> > 			Gleb.
> 

--
			Gleb.