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Message-ID: <20190522160657.GF30271@kernel.org> Date: Wed, 22 May 2019 13:06:57 -0300 From: Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> To: Jiri Olsa <jolsa@...nel.org> Cc: Adrian Hunter <adrian.hunter@...el.com>, lkml <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Stanislav Fomichev <sdf@...ichev.me>, Song Liu <songliubraving@...com>, Andi Kleen <ak@...ux.intel.com> Subject: Re: [PATCH 08/12] perf tools: Preserve eBPF maps when loading kcore Em Wed, May 08, 2019 at 03:20:06PM +0200, Jiri Olsa escreveu: > We need to preserve eBPF maps even if they are > covered by kcore, because we need to access > eBPF dso for source data. So, I reordered this one with the previous, as to get the output you added to 07/12 we need what is in 08/12, and they are otherwise completely independent, right? - Arnaldo > Adding map_groups__merge_in function to do that. > It merges map into map_groups by splitting the > new map within the existing map regions. > > Suggested-by: Adrian Hunter <adrian.hunter@...el.com> > Link: http://lkml.kernel.org/n/tip-mlu13e9zl6rbsz4fa00x7mfa@git.kernel.org > Signed-off-by: Jiri Olsa <jolsa@...nel.org> > --- > tools/perf/util/symbol.c | 97 ++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 93 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > index 5cbad55cd99d..29780fcd049c 100644 > --- a/tools/perf/util/symbol.c > +++ b/tools/perf/util/symbol.c > @@ -1166,6 +1166,85 @@ static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data) > return 0; > } > > +/* > + * Merges map into map_groups by splitting the new map > + * within the existing map regions. > + */ > +static int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map) > +{ > + struct map *old_map; > + LIST_HEAD(merged); > + > + for (old_map = map_groups__first(kmaps); old_map; > + old_map = map_groups__next(old_map)) { > + > + /* no overload with this one */ > + if (new_map->end < old_map->start || > + new_map->start >= old_map->end) > + continue; > + > + if (new_map->start < old_map->start) { > + /* > + * |new...... > + * |old.... > + */ > + if (new_map->end < old_map->end) { > + /* > + * |new......| -> |new..| > + * |old....| -> |old....| > + */ > + new_map->end = old_map->start; > + } else { > + /* > + * |new.............| -> |new..| |new..| > + * |old....| -> |old....| > + */ > + struct map *m = map__clone(new_map); > + > + if (!m) > + return -ENOMEM; > + > + m->end = old_map->start; > + list_add_tail(&m->node, &merged); > + new_map->start = old_map->end; > + } > + } else { > + /* > + * |new...... > + * |old.... > + */ > + if (new_map->end < old_map->end) { > + /* > + * |new..| -> x > + * |old.........| -> |old.........| > + */ > + map__put(new_map); > + new_map = NULL; > + break; > + } else { > + /* > + * |new......| -> |new...| > + * |old....| -> |old....| > + */ > + new_map->start = old_map->end; > + } > + } > + } > + > + while (!list_empty(&merged)) { > + old_map = list_entry(merged.next, struct map, node); > + list_del_init(&old_map->node); > + map_groups__insert(kmaps, old_map); > + map__put(old_map); > + } > + > + if (new_map) { > + map_groups__insert(kmaps, new_map); > + map__put(new_map); > + } > + return 0; > +} > + > static int dso__load_kcore(struct dso *dso, struct map *map, > const char *kallsyms_filename) > { > @@ -1222,7 +1301,12 @@ 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) > + /* > + * We need to preserve eBPF maps even if they are > + * covered by kcore, because we need to access > + * eBPF dso for source data. > + */ > + if (old_map != map && !__map__is_bpf_prog(old_map)) > map_groups__remove(kmaps, old_map); > old_map = next; > } > @@ -1256,11 +1340,16 @@ static int dso__load_kcore(struct dso *dso, struct map *map, > map_groups__remove(kmaps, map); > map_groups__insert(kmaps, map); > map__put(map); > + map__put(new_map); > } else { > - map_groups__insert(kmaps, new_map); > + /* > + * Merge kcore map into existing maps, > + * and ensure that current maps (eBPF) > + * stay intact. > + */ > + if (map_groups__merge_in(kmaps, new_map)) > + goto out_err; > } > - > - map__put(new_map); > } > > if (machine__is(machine, "x86_64")) { > -- > 2.20.1 -- - Arnaldo
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