Re: [PATCH 08/30] perf tools: Propagate cpu maps through the evlist

Arnaldo Carvalho de Melo
2015-06-15T19:52:19Z

Em Sun, Jun 14, 2015 at 10:19:23AM +0200, Jiri Olsa escreveu:
> Propagate evlist's cpu_map object through all the evsel objects,
> while keeping already configured evsel->cpus.
>
> It'll be handy to access evsel's cpus directly
> in following patches.
>
> Link: http://lkml.kernel.org/n/tip-myadl53clbkjvzeqolwp95w0@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/evlist.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index f7d80ca58136..c0d3058c1868 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1085,6 +1085,28 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
> return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false);
> }
>
> +static int propagate_maps(struct perf_evlist *evlist, struct target *target)

Please rename this to perf_evlist__set_maps()

> +{
> + struct perf_evsel *evsel;

> + evlist__for_each(evlist, evsel) {
> + /*
> + * We already have cpus for evsel (via PMU sysfs) so

If we already...

> + * keep it, if there's no target cpu list defined.
^ The comma here confused me
> + */
> + if (evsel->cpus && target->cpu_list)
> + cpu_map__put(evsel->cpus);

If you drop the reference, and then will test it... use a
cpu_map__zput(&evsel->cpus), so that after the put you don't access
something you don't hold a reference for anymore...

But the logic is still confusing! Can you try to rewrite it in a more
clear way?

> + if (!evsel->cpus || target->cpu_list)
> + evsel->cpus = cpu_map__get(evlist->cpus);

Something like:

if (evsel->cpus) {
something
} else {
something else
}
> +
> + if (!evsel->cpus)
> + return -ENOMEM;

Where was that we tried to allocate memory in this operation?

> + }
> +
> + return 0;
> +}
> +
> int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
> {
> evlist->threads = thread_map__new_str(target->pid, target->tid,
> @@ -1101,7 +1123,7 @@ int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
> if (evlist->cpus == NULL)
> goto out_delete_threads;
>
> - return 0;
> + return propagate_maps(evlist, target);
>
> out_delete_threads:
> thread_map__put(evlist->threads);
> --
> 1.9.3