Re: [PATCH] perf report: Add 'tgid' sort key

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Feb 25, 2025 at 08:48:56PM +0100, Arnaldo Carvalho de Melo wrote:
> On Tue, Feb 25, 2025 at 08:25:35PM +0100, Arnaldo Carvalho de Melo wrote:
> > On Tue, Feb 25, 2025 at 08:11:17PM +0100, Arnaldo Carvalho de Melo wrote:
> > > On Tue, Feb 25, 2025 at 08:07:18PM +0100, Arnaldo Carvalho de Melo wrote:
> > > > On Mon, Feb 24, 2025 at 11:51:35PM -0800, Namhyung Kim wrote:
> > > > > On Mon, Feb 24, 2025 at 08:40:37PM -0800, Ian Rogers wrote:
> > > > > > On Mon, Feb 24, 2025 at 6:51 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > > > > > On Mon, Feb 24, 2025 at 10:18:37AM -0800, Ian Rogers wrote:
> > > > > [SNIP]
> > > > > > > > I thought the real-time processing had to use
> > > > > > > > maps__fixup_overlap_and_insert (rather than maps__insert) as mmap
> > > > > > > > events only give us VMA data and two mmaps may have been merged.
> > > > > > > > Shouldn't doing this change be the simplest fix?
> > > 
> > > > > > > Make sense.  How about this?
> > > 
> > > > > > Lgtm, I have no way to test the issue. Why does maps__fixup_end need
> > > > > > to get pushed later?
> > > 
> > > > > I just noticed it would add extra kernel maps after modules.  I think it
> > > > > should fixup end address of the kernel maps after adding all maps first.
> > > 
> > > > > Arnaldo, can you please test this?
> > >  
> > > > Trying it now.
> > > 
> > > Now we have something different:
> > > 
> > > root@number:~# perf record sleep
> > > sleep: missing operand
> > > Try 'sleep --help' for more information.
> > > [ perf record: Woken up 1 times to write data ]
> > > perf: util/maps.c:80: check_invariants: Assertion `RC_CHK_EQUAL(map__kmap(map)->kmaps, maps)' failed.
> > > Aborted (core dumped)
> > > root@number:~#
> > 
> > __maps__insert() does:
> > 
> >         if (dso && dso__kernel(dso)) {
> >                 struct kmap *kmap = map__kmap(new);
> > 
> >                 if (kmap)
> >                         kmap->kmaps = maps;
> >                 else
> >                         pr_err("Internal error: kernel dso with non kernel map\n");
> >         }
> > 
> > while maps__fixup_overlap_and_insert() doesn't.
> > 
> > It calls __maps__insert_sorted() that probably should do what
> > __maps__insert() does?
> 
> Ok, so I did the following patch but this case fails:
> 
> @@ -910,6 +928,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
>                                  */
>                                 map__put(maps_by_address[i]);
>                                 maps_by_address[i] = map__get(new);
> +                               map__set_kmap(new, maps);
>                                 check_invariants(maps);
>                                 return err;
>                         }
> 
> With:
> 
> perf: util/maps.c:110: check_invariants: Assertion `refcount_read(map__refcnt(map)) > 1' failed.
> 
> As:
> 
> 106				/*
> 107				 * Maps by name maps should be in maps_by_address, so
> 108				 * the reference count should be higher.
> 109				 */
> 110				assert(refcount_read(map__refcnt(map)) > 1);
> 
> Since it is just replacing the map in the maps_by_address and not
> touching on the maps_by_name? Thus the refcount is just 1:

Sounds like it.  Can you add this on top?

Thanks,
Namhyung


---8<---
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 09c9cc326c08d435..3aee0c9e8d421cef 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -797,7 +797,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 {
 	int err = 0;
 	FILE *fp = debug_file();
-	unsigned int i;
+	unsigned int i, ni;
 
 	if (!maps__maps_by_address_sorted(maps))
 		__maps__sort_by_address(maps);
@@ -808,6 +808,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 	 */
 	for (i = first_ending_after(maps, new); i < maps__nr_maps(maps); ) {
 		struct map **maps_by_address = maps__maps_by_address(maps);
+		struct map **maps_by_name = maps__maps_by_name(maps);
 		struct map *pos = maps_by_address[i];
 		struct map *before = NULL, *after = NULL;
 
@@ -827,6 +828,9 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 			map__fprintf(pos, fp);
 		}
 
+		if (maps_by_name)
+			ni = maps__by_name_index(maps, pos);
+
 		/*
 		 * Now check if we need to create new maps for areas not
 		 * overlapped by the new map:
@@ -871,6 +875,11 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 		if (before) {
 			map__put(maps_by_address[i]);
 			maps_by_address[i] = before;
+			if (maps_by_name) {
+				map__put(maps_by_name[ni]);
+				maps_by_name[ni] = map__get(before);
+			}
+
 			/* Maps are still ordered, go to next one. */
 			i++;
 			if (after) {
@@ -892,6 +901,10 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 			 */
 			map__put(maps_by_address[i]);
 			maps_by_address[i] = map__get(new);
+			if (maps_by_name) {
+				map__put(maps_by_name[ni]);
+				maps_by_name[ni] = map__get(new);
+			}
 			err = __maps__insert_sorted(maps, i + 1, after, NULL);
 			map__put(after);
 			check_invariants(maps);
@@ -910,6 +923,10 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 				 */
 				map__put(maps_by_address[i]);
 				maps_by_address[i] = map__get(new);
+				if (maps_by_name) {
+					map__put(maps_by_name[ni]);
+					maps_by_name[ni] = map__get(new);
+				}
 				check_invariants(maps);
 				return err;
 			}