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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Sat, May 16, 2015 at 09:10:59PM +0900, Masami Hiramatsu escreveu:
> On 2015/05/16 5:07, Arnaldo Carvalho de Melo wrote:
> > Em Sat, May 16, 2015 at 12:15:45AM +0900, Masami Hiramatsu escreveu:
> >> On 2015/05/15 21:14, Wang Nan wrote:
> >>> Commit 4c859351226c920b227fec040a3b447f0d482af3 ("perf probe: Support
> >>> glob wildcards for function name") introduces a problem:
> >>>
> >>>   # /root/perf probe kmem_cache_free
> >>>  Failed to find symbol kmem_cache_free in kernel
> >>>    Error: Failed to add events.
> >>>
> >>> The reason is the replacement of map__for_each_symbol_by_name() (by
> >>> map__for_each_symbol()). Although their names are similay,
> >>> map__for_each_symbol doesn't call map__load() and dso__sort_by_name()
> >>> before searching. The missing of map__load() causes this problem
> >>> because it search symbol before load dso map.
> >>
> >> Oops, yes. But I think we'd better fix map__for_each_symbol() to call
> >> map__load() if the map is not loaded, doesn't it?
> > 
> > Well, that is something for a follow up patch, I'm applying his patch as
> > it fixes a problem and is trivially correct.
> 
> OK, then I'm OK for this patch.

Ok, tranforming the above statement into an Acked-by, ok?
 
> 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@huawei.com>
> >>> ---
> >>>  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@hitachi.com