On Wed, Feb 28, 2018 at 03:01:24PM -0800, William Tu wrote:
> On Wed, Feb 28, 2018 at 2:14 PM, Ben Pfaff <[email protected]> wrote:
> > On Mon, Feb 26, 2018 at 01:43:39PM -0800, William Tu wrote:
> >> On Wed, Feb 14, 2018 at 3:03 PM, Ben Pfaff <[email protected]> wrote:
> >> > On Wed, Feb 14, 2018 at 10:56:08AM -0800, William Tu wrote:
> >> >> Usually ofproto/trace is used to debug the flow translation error.
> >> >> When translation error such as recursion too deep or too many resubmit,
> >> >> the issue might happen momentary; flows causing the recursion expire
> >> >> when users try to debug it.  This patch enables the ofproto trace
> >> >> automatically when recursion is too deep or too many resubmit, by
> >> >> invoking the translation again, and log the ofproto trace as warnings.
> >> >> Since the log will be huge, rate limit to one per minute.
> >> >>
> >> >> VMWare-BZ: #2054659
> >> >> Signed-off-by: William Tu <[email protected]>
> >> >> Tested-by: Greg Rose <[email protected]>
> >> >> Reviewed-by: Greg Rose <[email protected]>
> >> >
> >> > Thanks for working on this!
> >> >
> >> > Some of the data passed to ofproto_trace() is also passed to the
> >> > xlate_actions() call, indirectly.  Did you check whether that data is
> >> > possibly modified by xlate_actions()?  If it is, then we might have to
> >> > reconsider this approach, because flow data, etc. is very large and I
> >> > don't think that we can afford to always make a copy of it in advance on
> >> > the chance that the original might be needed for tracing later.
> >>
> >> We pass the "const struct flow *" and "const struct dp_packet *" to
> >> the ofproto_trace(),
> >> so I think these two data is unmodified and xlate_in_init() actually make 
> >> a copy
> >> of the "struct flow", so xlate_actions() modifies a separate copy of the 
> >> flow.
> >
> > OK.
> >
> >> > I think that VLOG_WARN is a very high log level for this data.  I would
> >> > tend to use DBG.
> >> >
> >> I worried that most of the time DBG is not on, and asking people
> >> to turn it on and reproduce the issue is hard.  Can we keep VLOG_WARN and
> >> rate limit to very low frequent, "VLOG_RATE_LIMIT_INIT(1, 5);",?
> >
> > OK, let's try that.
> 
> Thanks Ben.
> Should I send another version of the patch?

Yes please.
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