Re: [PATCH tip/perf/core] perf probe: Load map before glob matching

From: Arnaldo Carvalho de Melo
Date: Tue May 19 2015 - 09:46:38 EST


Em Tue, May 19, 2015 at 08:41:30AM +0900, Masami Hiramatsu escreveu:
> On 2015/05/18 22:17, Arnaldo Carvalho de Melo wrote:
> > Em Sat, May 16, 2015 at 09:10:59PM +0900, Masami Hiramatsu escreveu:
> >> On 2015/05/16 5:07, Arnaldo Carvalho de Melo wrote:
> >> OK, then I'm OK for this patch.
> >
> > Ok, tranforming the above statement into an Acked-by, ok?
>
> Yes, here is my ack :)
>
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
>
>
> And also, I've found that including map__load() in map__for_each_symbol()
> is not good idea. Also I think map__for_each_symbol_by_name() should
> not call map__load(), since the "filter" argument will be ignored if
> the map is already loaded. This means that the iterated elements can
> be changed.
> So, obviously the map should be loaded before calling map__for_each_XXX.

Right, agreed with your comments, and that filter thing needs moving to
some other suitable place, like setting a filter at symbol system start,
etc.

- Arnaldo

> Thank you,
>
> >
> >> Thank you,
> >>
> >>>
> >>> - Arnaldo
> >>>
> >>>> Thank you,
> >>>>
> >>>>>
> >>>>> This patch ensures map__load() is called before using
> >>>>> map__for_each_symbol().
> >>>>>
> >>>>> After this patch:
> >>>>>
> >>>>> # /root/perf probe kmem_cache_free
> >>>>> Added new event:
> >>>>> probe:kmem_cache_free (on kmem_cache_free%return)
> >>>>>
> >>>>> You can now use it in all perf tools, such as:
> >>>>>
> >>>>> perf record -e probe:kmem_cache_free -aR sleep 1
> >>>>>
> >>>>> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> >>>>> ---
> >>>>> tools/perf/util/probe-event.c | 3 +++
> >>>>> 1 file changed, 3 insertions(+)
> >>>>>
> >>>>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> >>>>> index 2399dc4..1faa1e6 100644
> >>>>> --- a/tools/perf/util/probe-event.c
> >>>>> +++ b/tools/perf/util/probe-event.c
> >>>>> @@ -2499,6 +2499,9 @@ static int find_probe_functions(struct map *map, char *name)
> >>>>> struct symbol *sym;
> >>>>> struct rb_node *tmp;
> >>>>>
> >>>>> + if (map__load(map, NULL) < 0)
> >>>>> + return 0;
> >>>>> +
> >>>>> map__for_each_symbol(map, sym, tmp) {
> >>>>> if (strglobmatch(sym->name, name))
> >>>>> found++;
> >>>>>
> >>>>
> >> --
> >> Masami HIRAMATSU
> >> Linux Technology Research Center, System Productivity Research Dept.
> >> Center for Technology Innovation - Systems Engineering
> >> Hitachi, Ltd., Research & Development Group
> >> E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
> >
>
>
> --
> Masami HIRAMATSU
> Linux Technology Research Center, System Productivity Research Dept.
> Center for Technology Innovation - Systems Engineering
> Hitachi, Ltd., Research & Development Group
> E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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