Re: [PATCH] perf/report: [RFC] Handling OOM in perf report

[Jiri Olsa]

On Wed, Apr 10, 2019 at 09:17:30AM +0200, Thomas-Mich Richter wrote:

SNIP

> > 
> > 
> > ---
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > index b17f1c9bc965..eea247a26ad8 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -1933,7 +1933,7 @@ reader__process_events(struct reader *rd, struct perf_session *session,
> >  		pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
> >  		       file_offset + head, event->header.size,
> >  		       event->header.type);
> > -		err = -EINVAL;
> > +		err = skip;
> >  		goto out;
> >  	}
> >  
> > 
> 
> Above patch does not help, you simply return -ENOMEM instead of -EINVAL and processing
> stops with no indication that perf ran out of memory. Bailing out in this case is ok.
> 
> I am fine with your patch, as long as it gives a reason why processing stopped.
> In the GUI it shows on the bottom line the reason:
> 
>   0xf4198 [0x8]: failed to process type: 68 [Cannot allocate memory]

looks good, please post the full patch

thanks,
jirka

> 
> 
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index b17f1c9bc965..e89716175588 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1930,10 +1930,10 @@ reader__process_events(struct reader *rd, struct perf_session *session,
>  
>         if (size < sizeof(struct perf_event_header) ||
>             (skip = rd->process(session, event, file_pos)) < 0) {
> -               pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
> +               pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
>                        file_offset + head, event->header.size,
> -                      event->header.type);
> -               err = -EINVAL;
> +                      event->header.type, strerror(-skip));
> +               err = skip;
>                 goto out;
>         }
>  
> [root@m35lp76 perf]#
> -- 
> Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany
> --
> Vorsitzender des Aufsichtsrats: Matthias Hartmann
> Geschäftsführung: Dirk Wittkopp
> Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294
>