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perf symbols: Stop using map->groups, we can use kmaps instead

tip: perf/core tip-bot2 for Arnaldo Carvalho de Melo 1 participant 1 message Nov 15, 2019 1 message not in the archive perf events

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The following commit has been merged into the perf/core branch of tip:

Commit-ID:     f2baa060cd766f4e585339423891e0063179d702
Gitweb:        https://git.kernel.org/tip/f2baa060cd766f4e585339423891e0063179d702
Author:        Arnaldo Carvalho de Melo <[email protected]>
AuthorDate:    Mon, 04 Nov 2019 16:09:48 -03:00
Committer:     Arnaldo Carvalho de Melo <[email protected]>
CommitterDate: Tue, 12 Nov 2019 08:20:53 -03:00

perf symbols: Stop using map->groups, we can use kmaps instead

To test that that function is being called I just added a probe on that place, enabled it via 'perf trace' asking for at most 16 levels of backtraces, system wide, and then ran 'perf top' on another xterm, voilà:

  # perf probe -x ~/bin/perf dso__process_kernel_symbol
  Added new event:
    probe_perf:dso__process_kernel_symbol (on dso__process_kernel_symbol in /home/acme/bin/perf)

You can now use it in all perf tools, such as:

perf record -e probe_perf:dso__process_kernel_symbol -aR sleep 1

  # perf trace -e probe_perf:dso__process_kernel_symbol/max-stack=16/ --max-events=2
  # perf trace -e probe_perf:dso__process_kernel_symbol/max-stack=16/ --max-events=2
       0.000 :17345/17345 probe_perf:dso__process_kernel_symbol(__probe_ip: 5680224)
                                         dso__process_kernel_symbol (/home/acme/bin/perf)
                                         dso__load_vmlinux (/home/acme/bin/perf)
                                         dso__load_vmlinux_path (/home/acme/bin/perf)
                                         dso__load (/home/acme/bin/perf)
                                         map__load (/home/acme/bin/perf)
                                         thread__find_map (/home/acme/bin/perf)
                                         machine__resolve (/home/acme/bin/perf)
                                         deliver_event (/home/acme/bin/perf)
                                         __ordered_events__flush.part.0 (/home/acme/bin/perf)
                                         process_thread (/home/acme/bin/perf)
                                         start_thread (/usr/lib64/libpthread-2.29.so)
       0.064 :17345/17345 probe_perf:dso__process_kernel_symbol(__probe_ip: 5680224)
                                         dso__process_kernel_symbol (/home/acme/bin/perf)
                                         dso__load_vmlinux (/home/acme/bin/perf)
                                         dso__load_vmlinux_path (/home/acme/bin/perf)
                                         dso__load (/home/acme/bin/perf)
                                         map__load (/home/acme/bin/perf)
                                         thread__find_map (/home/acme/bin/perf)
                                         machine__resolve (/home/acme/bin/perf)
                                         deliver_event (/home/acme/bin/perf)
                                         __ordered_events__flush.part.0 (/home/acme/bin/perf)
                                         process_thread (/home/acme/bin/perf)
                                         start_thread (/usr/lib64/libpthread-2.29.so)
  #
  # perf stat -e probe_perf:dso__process_kernel_symbol
  ^C
   Performance counter stats for 'system wide':
           107,308      probe_perf:dso__process_kernel_symbol

       8.215399813 seconds time elapsed

#

---
 tools/perf/util/symbol-elf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
tools/perf/util/symbol-elf.c +1 -1
index 66f4be1..16776d5 100644
@@ -934,7 +934,7 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 		 * we still are sure to have a reference to this DSO via
 		 * *curr_map->dso.
 		 */
-		dsos__add(&map->groups->machine->dsos, curr_dso);
+		dsos__add(&kmaps->machine->dsos, curr_dso);
 		/* kmaps already got it */
 		map__put(curr_map);
 		dso__set_loaded(curr_dso);