On 16/04/19 7:01 PM, Jiri Olsa wrote: > Maps in kcore do not cover bpf maps, so we can't just > remove everything. Keeping all kernel maps, which are > not covered by kcore maps.
Memory for jited-bpf is allocated from the same area that is used for modules. In the case of /proc/kcore, that entire area is mapped, so there won't be any bpf-maps that are not covered. For copies of kcore made by 'perf buildid-cache' the same would be true for any bpf that got allocated in between modules. But shouldn't the bpf map supersede the kcore map for the address range that it maps? I guess that would mean splitting the kcore map, truncating the first piece and inserting the bpf map in between. > > Link: http://lkml.kernel.org/n/[email protected] > Signed-off-by: Jiri Olsa <[email protected]> > --- > tools/perf/util/symbol.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > index 5cbad55cd99d..96738a7a8c14 100644 > --- a/tools/perf/util/symbol.c > +++ b/tools/perf/util/symbol.c > @@ -1166,6 +1166,18 @@ static int kcore_mapfn(u64 start, u64 len, u64 pgoff, > void *data) > return 0; > } > > +static bool in_kcore(struct kcore_mapfn_data *md, struct map *map) > +{ > + struct map *iter; > + > + list_for_each_entry(iter, &md->maps, node) { > + if ((map->start >= iter->start) && (map->start < iter->end)) > + return true; > + } > + > + return false; > +} > + > static int dso__load_kcore(struct dso *dso, struct map *map, > const char *kallsyms_filename) > { > @@ -1222,7 +1234,7 @@ static int dso__load_kcore(struct dso *dso, struct map > *map, > while (old_map) { > struct map *next = map_groups__next(old_map); > > - if (old_map != map) > + if (old_map != map && !in_kcore(&md, old_map)) > map_groups__remove(kmaps, old_map); > old_map = next; > } >
