workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/tools/perf/util/find-map.c b/tools/perf/util/find-map.c
new file mode 100644
index 000000000..7b2300588
--- /dev/null
+++ b/tools/perf/util/find-map.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+static int find_map(void **start, void **end, const char *name)
+{
+	FILE *maps;
+	char line[128];
+	int found = 0;
+
+	maps = fopen("/proc/self/maps", "r");
+	if (!maps) {
+		fprintf(stderr, "cannot open maps\n");
+		return -1;
+	}
+
+	while (!found && fgets(line, sizeof(line), maps)) {
+		int m = -1;
+
+		/* We care only about private r-x mappings. */
+		if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
+				start, end, &m))
+			continue;
+		if (m < 0)
+			continue;
+
+		if (!strncmp(&line[m], name, strlen(name)))
+			found = 1;
+	}
+
+	fclose(maps);
+	return !found;
+}