On Tue, Nov 22, 2016 at 09:55:21AM -0500, Steven Rostedt wrote: > On Tue, 22 Nov 2016 11:01:27 +0100 > Uwe Kleine-König <u...@kleine-koenig.org> wrote: > > > diff --git a/include/trace/events/mdio.h b/include/trace/events/mdio.h > > new file mode 100644 > > index 000000000000..468e2d095d19 > > --- /dev/null > > +++ b/include/trace/events/mdio.h > > @@ -0,0 +1,42 @@ > > +#undef TRACE_SYSTEM > > +#define TRACE_SYSTEM mdio > > + > > +#if !defined(_TRACE_MDIO_H) || defined(TRACE_HEADER_MULTI_READ) > > +#define _TRACE_MDIO_H > > + > > +#include <linux/tracepoint.h> > > + > > +TRACE_EVENT_CONDITION(mdio_access, > > + > > + TP_PROTO(struct mii_bus *bus, int read, > > + unsigned addr, unsigned regnum, u16 val, int err), > > + > > + TP_ARGS(bus, read, addr, regnum, val, err), > > + > > + TP_CONDITION(err >= 0), > > + > > + TP_STRUCT__entry( > > + __array(char, busid, MII_BUS_ID_SIZE) > > + __field(int, read) > > read is just a 0 or 1. What about making it a char? That way we can > pack this better. If I'm not mistaken, MII_BUS_ID_SIZE is (20 - 3) or > 17. If read is just one byte, then it can fit in one of those three > bytes, and you save 4 extra bytes (assuming addr will be 4 byte > aligned).
addr could also be cast into a u8. There are a maximum of 32 addresses on an MDIO bus. Because of clause 45 MDIO, regnum needs to remain a u32. Andrew