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SubjectRe: [PATCH v4 06/22] perf map: Move map list node into symbol
Em Sun, Mar 19, 2023 at 08:37:54PM -0700, Ian Rogers escreveu:
> Using a perf map as a list node is only done in symbol. Move the
> list_node struct into symbol as a single pointer to the map. This
> makes reference count behavior more obvious and easy to check.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/map.h | 5 +--
> tools/perf/util/symbol.c | 90 ++++++++++++++++++++++++++--------------
> 2 files changed, 60 insertions(+), 35 deletions(-)
>
> diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> index 3dcfe06db6b3..2879cae05ee0 100644
> --- a/tools/perf/util/map.h
> +++ b/tools/perf/util/map.h
> @@ -16,10 +16,7 @@ struct maps;
> struct machine;
>
> struct map {
> - union {
> - struct rb_node rb_node;
> - struct list_head node;
> - };
> + struct rb_node rb_node;
> u64 start;
> u64 end;
> bool erange_warned:1;
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index a458aa8b87bb..2676a163e237 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -48,6 +48,11 @@ static bool symbol__is_idle(const char *name);
> int vmlinux_path__nr_entries;
> char **vmlinux_path;
>
> +struct map_list_node {
> + struct list_head node;
> + struct map *map;
> +};
> +
> struct symbol_conf symbol_conf = {
> .nanosecs = false,
> .use_modules = true,
> @@ -1219,16 +1224,22 @@ struct kcore_mapfn_data {
> static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
> {
> struct kcore_mapfn_data *md = data;
> - struct map *map;
> + struct map_list_node *list_node;
> +
> + list_node = malloc(sizeof(*list_node));
> + if (list_node == NULL)
> + return -ENOMEM;

So this is open coding map_list_node__new(), can we have it defined
right after the struct map_list_node definition?

I've applied the 1-5 patches in this series to my local branch, testing
now.

- Arnaldo

>
> - map = map__new2(start, md->dso);
> - if (map == NULL)
> + list_node->map = map__new2(start, md->dso);
> + if (list_node->map == NULL) {
> + free(list_node);
> return -ENOMEM;
> + }
>
> - map->end = map->start + len;
> - map->pgoff = pgoff;
> + list_node->map->end = list_node->map->start + len;
> + list_node->map->pgoff = pgoff;
>
> - list_add(&map->node, &md->maps);
> + list_add(&list_node->node, &md->maps);
>
> return 0;
> }
> @@ -1264,12 +1275,19 @@ int maps__merge_in(struct maps *kmaps, struct map *new_map)
> * |new.............| -> |new..| |new..|
> * |old....| -> |old....|
> */
> - struct map *m = map__clone(new_map);
> + struct map_list_node *m;
>
> + m = malloc(sizeof(*m));
> if (!m)
> return -ENOMEM;
>
> - m->end = old_map->start;
> + m->map = map__clone(new_map);
> + if (!m->map) {
> + free(m);
> + return -ENOMEM;
> + }
> +
> + m->map->end = old_map->start;
> list_add_tail(&m->node, &merged);
> new_map->pgoff += old_map->end - new_map->start;
> new_map->start = old_map->end;
> @@ -1299,10 +1317,13 @@ int maps__merge_in(struct maps *kmaps, struct map *new_map)
> }
>
> while (!list_empty(&merged)) {
> - old_map = list_entry(merged.next, struct map, node);
> - list_del_init(&old_map->node);
> - maps__insert(kmaps, old_map);
> - map__put(old_map);
> + struct map_list_node *old_node;
> +
> + old_node = list_entry(merged.next, struct map_list_node, node);
> + list_del_init(&old_node->node);
> + maps__insert(kmaps, old_node->map);
> + map__put(old_node->map);
> + free(old_node);
> }
>
> if (new_map) {
> @@ -1317,7 +1338,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
> {
> struct maps *kmaps = map__kmaps(map);
> struct kcore_mapfn_data md;
> - struct map *old_map, *new_map, *replacement_map = NULL, *next;
> + struct map *old_map, *replacement_map = NULL, *next;
> struct machine *machine;
> bool is_64_bit;
> int err, fd;
> @@ -1378,11 +1399,12 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
> /* Find the kernel map using the '_stext' symbol */
> if (!kallsyms__get_function_start(kallsyms_filename, "_stext", &stext)) {
> u64 replacement_size = 0;
> + struct map_list_node *new_node;
>
> - list_for_each_entry(new_map, &md.maps, node) {
> - u64 new_size = new_map->end - new_map->start;
> + list_for_each_entry(new_node, &md.maps, node) {
> + u64 new_size = new_node->map->end - new_node->map->start;
>
> - if (!(stext >= new_map->start && stext < new_map->end))
> + if (!(stext >= new_node->map->start && stext < new_node->map->end))
> continue;
>
> /*
> @@ -1392,40 +1414,43 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
> * falls within more than one in the list.
> */
> if (!replacement_map || new_size < replacement_size) {
> - replacement_map = new_map;
> + replacement_map = new_node->map;
> replacement_size = new_size;
> }
> }
> }
>
> if (!replacement_map)
> - replacement_map = list_entry(md.maps.next, struct map, node);
> + replacement_map = list_entry(md.maps.next, struct map_list_node, node)->map;
>
> /* Add new maps */
> while (!list_empty(&md.maps)) {
> - new_map = list_entry(md.maps.next, struct map, node);
> - list_del_init(&new_map->node);
> - if (new_map == replacement_map) {
> - map->start = new_map->start;
> - map->end = new_map->end;
> - map->pgoff = new_map->pgoff;
> - map->map_ip = new_map->map_ip;
> - map->unmap_ip = new_map->unmap_ip;
> + struct map_list_node *new_node;
> +
> + new_node = list_entry(md.maps.next, struct map_list_node, node);
> + list_del_init(&new_node->node);
> + if (new_node->map == replacement_map) {
> + map->start = new_node->map->start;
> + map->end = new_node->map->end;
> + map->pgoff = new_node->map->pgoff;
> + map->map_ip = new_node->map->map_ip;
> + map->unmap_ip = new_node->map->unmap_ip;
> /* Ensure maps are correctly ordered */
> map__get(map);
> maps__remove(kmaps, map);
> maps__insert(kmaps, map);
> map__put(map);
> - map__put(new_map);
> + map__put(new_node->map);
> } else {
> /*
> * Merge kcore map into existing maps,
> * and ensure that current maps (eBPF)
> * stay intact.
> */
> - if (maps__merge_in(kmaps, new_map))
> + if (maps__merge_in(kmaps, new_node->map))
> goto out_err;
> }
> + free(new_node);
> }
>
> if (machine__is(machine, "x86_64")) {
> @@ -1462,9 +1487,12 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
>
> out_err:
> while (!list_empty(&md.maps)) {
> - map = list_entry(md.maps.next, struct map, node);
> - list_del_init(&map->node);
> - map__put(map);
> + struct map_list_node *list_node;
> +
> + list_node = list_entry(md.maps.next, struct map_list_node, node);
> + list_del_init(&list_node->node);
> + map__put(list_node->map);
> + free(list_node);
> }
> close(fd);
> return -EINVAL;
> --
> 2.40.0.rc1.284.g88254d51c5-goog
>

--

- Arnaldo

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