linux-kernel - Re: [PATCH] perf map: Do not display load warning for maps without dso

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Date:	Mon, 22 Aug 2011 16:58:49 +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: Re: [PATCH] perf map: Do not display load warning for maps without
 dso

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..

thanks,
jirka

---
 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..a5e9007 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;
-- 
1.7.1


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