Commit 3d906ef1 authored Jun 23, 2009 by Peter Zijlstra Committed by Ingo Molnar Jun 23, 2009

perf_counter tools: Handle overlapping MMAP events



Martin Schwidefsky reported "perf report" symbol resolution
problems on S390.

Since we only report MMAP, not MUNMAP, we have to deal with
overlapping maps.

We used to simply throw out the old map on the assumption whole
maps got unmapped. This obviously doesn't deal with partial
unmaps. However it appears some dynamic linkers do fancy
partial unmaps (s390), so do something more elaborate and
truncate the old maps, only removing them when they've been
fully covered.

This resolves (part of) the S390 symbol resolution problems.

Reported-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Tested-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent dee41206

tools/perf/builtin-report.c

+21 −3

Original line number	Diff line number	Diff line
		@@ -400,11 +400,29 @@ static void thread__insert_map(struct thread self, struct map map)

		list_for_each_entry_safe(pos, tmp, &self->maps, node) {
		if (map__overlap(pos, map)) {
		if (verbose >= 2) {
		printf("overlapping maps:\n");
		map__fprintf(map, stdout);
		map__fprintf(pos, stdout);
		}

		if (map->start <= pos->start && map->end > pos->start)
		pos->start = map->end;

		if (map->end >= pos->end && map->start < pos->end)
		pos->end = map->start;

		if (verbose >= 2) {
		printf("after collision:\n");
		map__fprintf(pos, stdout);
		}

		if (pos->start >= pos->end) {
		list_del_init(&pos->node);
		/* XXX leaks dsos */
		free(pos);
		}
		}
		}

		list_add_tail(&map->node, &self->maps);
		}

Admin message