Messages in this thread | | | Date | Wed, 2 Sep 2015 14:46:16 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf tools: Don't write to evsel if parser doesn't collect evsel |
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On Wed, Sep 02, 2015 at 08:05:54PM +0800, pi3orama wrote:
SNIP
> >>> perf_evlist__splice_list_tail(evlist, &data.list, entries); > >>> evlist->nr_groups += data.nr_groups; > >>> - last = perf_evlist__last(evlist); > >>> - last->cmdline_group_boundary = true; > >>> return 0; > >>> } > >>> @@ -1252,7 +1262,13 @@ foreach_evsel_in_last_glob(struct perf_evlist *evlist, > >>> struct perf_evsel *last = NULL; > >>> int err; > >>> - if (evlist->nr_entries > 0) > >>> + /* > >>> + * Don't return when list_empty, give func a chance to report > >>> + * error when it found last == NULL. > >>> + * > >>> + * So no need to WARN here, let *func do this. > >>> + */ > >>> + if (!list_empty(&evlist->entries)) > > > > why is it better than to check evlist->nr_entries? > > evlist->nr_entries is equivalent to !list_empty(&evlist->entries) in here, right? > > > > By checking list we won't rely on the assumption that nr_entries reflects the > actual number of elements in that list, makes the logic of this code more compact. > Don't you think so? > > At this point they are equivalent, but the whole patch is preventive action.
ok, fair enough ;-)
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks, jirka
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