[tip:perf/urgent] perf c2c: Fix c2c report for empty numa node

[tip-bot for Jiri Olsa]

Commit-ID:  e34c940245437f36d2c492edd1f8237eff391064
Gitweb:     https://git.kernel.org/tip/e34c940245437f36d2c492edd1f8237eff391064
Author:     Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Tue, 5 Mar 2019 16:25:29 +0100
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 6 Mar 2019 18:15:24 -0300

perf c2c: Fix c2c report for empty numa node

Ravi Bangoria reported that we fail with an empty NUMA node with the
following message:

  $ lscpu
  NUMA node0 CPU(s):
  NUMA node1 CPU(s):   0-4

  $ sudo ./perf c2c report
  node/cpu topology bugFailed setup nodes

Fix this by detecting the empty node and keeping its CPU set empty.

Reported-by: Nageswara R Sastry <nasastry@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jonas Rabenstein <jonas.rabenstein@xxxxxxxxxxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20190305152536.21035-2-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-c2c.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 4272763a5e96..9e6cc868bdb4 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2056,6 +2056,12 @@ static int setup_nodes(struct perf_session *session)
 		if (!set)
 			return -ENOMEM;
 
+		nodes[node] = set;
+
+		/* empty node, skip */
+		if (cpu_map__empty(map))
+			continue;
+
 		for (cpu = 0; cpu < map->nr; cpu++) {
 			set_bit(map->map[cpu], set);
 
@@ -2064,8 +2070,6 @@ static int setup_nodes(struct perf_session *session)
 
 			cpu2node[map->map[cpu]] = node;
 		}
-
-		nodes[node] = set;
 	}
 
 	setup_nodes_header();