linux-kernel - [PATCH] perf, tool: Treat all memory maps without dso file as loaded

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Date:	Wed, 24 Aug 2011 15:18:34 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	Arnaldo Carvalho de Melo <acme@...hat.com>
Cc:	a.p.zijlstra@...llo.nl, mingo@...e.hu, paulus@...ba.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] perf, tool: Treat all memory maps without dso file as loaded

On Mon, Aug 22, 2011 at 04:58:49PM +0200, Jiri Olsa wrote:
> On Mon, Aug 22, 2011 at 11:11:30AM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Mon, Aug 22, 2011 at 09:53:22AM +0200, Jiri Olsa escreveu:
> > > hi,
> > > any feedback on this?
> > 
> > Fell thru the cracks, sorry.
> >  
> > > On Wed, Aug 10, 2011 at 02:44:11PM +0200, Jiri Olsa wrote:
> > > > I get unnecessary warnings from map__load about "[stack]" maps,
> > > > saying dso cannot be loaded.
> > 
> > > > Attached patch avoids this warning for maps that are not backed-up
> > > > by dso.
> > 
> > > > I was wondering if we want to treat stack/heaps/vdso maps the same
> > > > way or if there's something special about vdso in this regard.
> > > > Because there could be another fix with setting all stack/heaps/vdso
> > > > maps as loaded, which is probably little more nicer.
> > 
> > Humm, in the vdso case we have a fallback in thread__find_addr_map, i.e.
> > its symbol rbtree is empty, we notice that and lookup the symbol in the
> > kernel symbol tables (vmlinux and modules).
> > 
> > I.e. stack/heap symbols would not apply, this fallback wouldn't happen,
> > the symbol would be unresolved, the patch then would be just to
> > map__new, as:
> > 
> > diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> > index a16ecab..0c1c11b 100644
> > --- a/tools/perf/util/map.c
> > +++ b/tools/perf/util/map.c
> > @@ -63,7 +63,9 @@ set_identity:
> >  		} else if (strcmp(filename, "[vdso]") == 0) {
> >  			dso__set_loaded(dso, self->type);
> >  			goto set_identity;
> > -		}
> > +		} else if (strcmp(filename, "[heap]") == 0 ||
> > +			   strcmp(filename, "[stack]") == 0)
> > +			dso__set_loaded(dso, self->type);
> >  	}
> >  	return self;
> >  out_delete:
> > 
> > Right?
> 
> yes, I was not completely sure I was not breaking anything else,
> so I posted the first patch.. the original patch I had is attached.
> 
> I haven't tested this one much though.. let me know and
> I can resend this one with changelog/testing..

and here it is ;)

thanks,
jirka

---
The stack/vdso/heap memory maps dont have any dso file.
Setting the perf dso objects as 'loaded' for these maps,
we avoid unnecessary warnings like:

  "Failed to open [stack], continuing without symbols"

All map__find_* functions still return NULL when searching
for symbols in these maps.

Signed-off-by: Jiri Olsa <jolsa@...hat.com>
---
 tools/perf/util/map.c |   24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index a16ecab..7e218e3 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -18,6 +18,13 @@ static inline int is_anon_memory(const char *filename)
 	return strcmp(filename, "//anon") == 0;
 }
 
+static inline int is_no_dso_memory(const char *filename)
+{
+	return !strcmp(filename, "[stack]") ||
+	       !strcmp(filename, "[vdso]")  ||
+	       !strcmp(filename, "[heap]");
+}
+
 void map__init(struct map *self, enum map_type type,
 	       u64 start, u64 end, u64 pgoff, struct dso *dso)
 {
@@ -42,9 +49,10 @@ struct map *map__new(struct list_head *dsos__list, u64 start, u64 len,
 	if (self != NULL) {
 		char newfilename[PATH_MAX];
 		struct dso *dso;
-		int anon;
+		int anon, no_dso;
 
 		anon = is_anon_memory(filename);
+		no_dso = is_no_dso_memory(filename);
 
 		if (anon) {
 			snprintf(newfilename, sizeof(newfilename), "/tmp/perf-%d.map", pid);
@@ -57,12 +65,16 @@ struct map *map__new(struct list_head *dsos__list, u64 start, u64 len,
 
 		map__init(self, type, start, start + len, pgoff, dso);
 
-		if (anon) {
-set_identity:
+		if (anon || no_dso) {
 			self->map_ip = self->unmap_ip = identity__map_ip;
-		} else if (strcmp(filename, "[vdso]") == 0) {
-			dso__set_loaded(dso, self->type);
-			goto set_identity;
+
+			/*
+			 * Set memory without DSO as loaded. All map__find_*
+			 * functions still return NULL, and we avoid the
+			 * unnecessary map__load warning.
+			 */
+			if (no_dso)
+				dso__set_loaded(dso, self->type);
 		}
 	}
 	return self;
-- 
1.7.4

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