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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>
This commit is contained in:
Peter Zijlstra 2009-06-23 11:23:07 +02:00 committed by Ingo Molnar
parent dee412066a
commit 3d906ef10a
1 changed files with 21 additions and 3 deletions
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24
tools/perf/builtin-report.c
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@ -400,9 +400,27 @@ 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)) {
list_del_init(&pos->node);
/* XXX leaks dsos */
free(pos);
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);
free(pos);
}
}
}