Re: [tip:perf/urgent] perf hists: Fix determination of a callchain node's childlessness

Andres Freund
2016-04-16T19:46:19Z

Hi,

Perhaps this should also go into stable? It'd be nice to fix that
regression for 4.4 and 4.5.

Regards,

Andres

On 2016-03-30 23:33:37 -0700, tip-bot for Andres Freund wrote:
> Commit-ID: 909890355507e92bdaf648e73870f6b5df606da8
> Gitweb: http://git.kernel.org/tip/909890355507e92bdaf648e73870f6b5df606da8
> Author: Andres Freund <andres@anarazel.de>
> AuthorDate: Wed, 30 Mar 2016 21:02:45 +0200
> Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
> CommitDate: Wed, 30 Mar 2016 18:08:39 -0300
>
> perf hists: Fix determination of a callchain node's childlessness
>
> The 4b3a3212233a ("perf hists browser: Support flat callchains") commit
> over-aggressively tried to optimize callchain_node__init_have_children().
>
> That lead to --tui mode not allowing to expand call chain elements if a
> call chain element had only one parent. That's why --inverted callgraphs
> looked halfway sane, but plain ones didn't.
>
> Revert that individual optimization, it wasn't really related to the
> rest of the commit.
>
> Signed-off-by: Andres Freund <andres@anarazel.de>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Fixes: 4b3a3212233a ("perf hists browser: Support flat callchains")
> Link: http://lkml.kernel.org/r/20160330190245.GB13305@awork2.anarazel.de
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/ui/browsers/hists.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index 4b98165..2a83414 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -337,7 +337,7 @@ static void callchain_node__init_have_children(struct callchain_node *node,
> chain = list_entry(node->val.next, struct callchain_list, list);
> chain->has_children = has_sibling;
>
> - if (node->val.next != node->val.prev) {
> + if (!list_empty(&node->val)) {
> chain = list_entry(node->val.prev, struct callchain_list, list);
> chain->has_children = !RB_EMPTY_ROOT(&node->rb_root);
> }