Re: [PATCH -next v2 1/2] mm: shrinker: add new event to trace shrink count

[Bixuan Cui <cuibixuan@xxxxxxxx>]

在 2023/12/13 22:44, Steven Rostedt 写道:
> > +TRACE_EVENT(mm_shrink_count_end,
> > +	TP_PROTO(struct shrinker *shr, struct shrink_control *sc, long freeable),
> > +
> > +	TP_ARGS(shr, sc, freeable),
> > +
> > +	TP_STRUCT__entry(
> > +		__field(struct shrinker *, shr)
> > +		__field(void *, shrink)
> > +		__field(int, nid)
> int :  4 bytes
>
> > +		__field(long, freeable)
> long: 8 bytes
>
>
> You may want to swap the above, otherwise you added a hole in the trace
> event. The compiler will add 4 bytes of padding between 'nid' and
> 'freeable'. That is, if you change it to:
>
> 	TP_STRUCT__entry(
> 		__field(struct shrinker *, shr)
> 		__field(void *, shrink)
> 		__field(long, freeable)
> 		__field(int, nid)
>
> You will save 4 bytes per event in the ring buffer.

Thanks for your advice, I will fix it.

Thanks,
Bixuan Cui