Re: [PATCH 01/12] perf tools: Separate generic code in dso__data_file_size

Jiri Olsa
2019-05-23T07:49:14Z

On Thu, May 23, 2019 at 12:10:02PM +0900, Namhyung Kim wrote:
> Hi Jirka,
>
> On Mon, May 13, 2019 at 10:00:15PM +0200, Jiri Olsa wrote:
> > On Mon, May 13, 2019 at 04:47:54PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Wed, May 08, 2019 at 03:19:59PM +0200, Jiri Olsa escreveu:
> > > > Moving file specific code in dso__data_file_size function
> > > > into separate file_size function. I'll add bpf specific
> > > > code in following patches.
> > >
> > > I'm applying this patch, as it just moves things around, no logic
> > > change, but can you please clarify a question I have after looking at
> > > this patch?
> > >
> > > > Link: http://lkml.kernel.org/n/tip-rkcsft4a0f8sw33p67llxf0d@git.kernel.org
> > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > > ---
> > > > tools/perf/util/dso.c | 19 ++++++++++++-------
> > > > 1 file changed, 12 insertions(+), 7 deletions(-)
> > > >
> > > > diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> > > > index e059976d9d93..cb6199c1390a 100644
> > > > --- a/tools/perf/util/dso.c
> > > > +++ b/tools/perf/util/dso.c
> > > > @@ -898,18 +898,12 @@ static ssize_t cached_read(struct dso *dso, struct machine *machine,
> > > > return r;
> > > > }
> > > >
> > > > -int dso__data_file_size(struct dso *dso, struct machine *machine)
> > > > +static int file_size(struct dso *dso, struct machine *machine)
> > > > {
> > > > int ret = 0;
> > > > struct stat st;
> > > > char sbuf[STRERR_BUFSIZE];
> > > >
> > > > - if (dso->data.file_size)
> > > > - return 0;
> > > > -
> > > > - if (dso->data.status == DSO_DATA_STATUS_ERROR)
> > > > - return -1;
> > > > -
> > > > pthread_mutex_lock(&dso__data_open_lock);
> > > >
> > > > /*
> > > > @@ -938,6 +932,17 @@ int dso__data_file_size(struct dso *dso, struct machine *machine)
> > > > return ret;
> > > > }
> > > >
> > > > +int dso__data_file_size(struct dso *dso, struct machine *machine)
> > > > +{
> > > > + if (dso->data.file_size)
> > > > + return 0;
> > > > +
> > > > + if (dso->data.status == DSO_DATA_STATUS_ERROR)
> > > > + return -1;
> > > > +
> > > > + return file_size(dso, machine);
> > > > +}
> > >
> > >
> > > So the name of the function suggests we want to know the
> > > "data_file_size" of a dso, then the logic in it returns _zero_ if a
> > > member named "dso->data.file_size" is _not_ zero, can you please
> > > clarify?
> > >
> > > I was expecting something like:
> > >
> > > if (dso->data.file_size)
> > > return dso->data.file_size;
> > >
> > > I.e. if we had already read it, return the cached value, otherwise go
> > > and call some other function to get that info somehow.
> >
> > we keep the data size in dso->data.file_size,
> > the function just updates it
> >
> > the return code is the error code.. not sure,
> > why its like that, but it is ;-)
> >
> > maybe we wanted separate size and error code,
> > because the size needs to be u64 and we use
> > int everywhere.. less casting
>
> Maybe we can rename it to dso__update_file_size().

sounds good, I'll queue it

thanks,
jirka