2 files changed, 94 insertions, 0 deletions
diff --git a/tools/rcu/extract-stall.sh b/tools/rcu/extract-stall.sh
new file mode 100755
index 0000000000..08a39ad443
--- /dev/null
+++ b/tools/rcu/extract-stall.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+
+usage() {
+	echo Extract any RCU CPU stall warnings present in specified file.
+	echo Filter out clocksource lines.  Note that preceding-lines excludes the
+	echo initial line of the stall warning but trailing-lines includes it.
+	echo
+	echo Usage: $(basename $0) dmesg-file [ preceding-lines [ trailing-lines ] ]
+	echo
+	echo Error: $1
+}
+
+# Terminate the script, if the argument is missing
+
+if test -f "$1" && test -r "$1"
+then
+	:
+else
+	usage "Console log file \"$1\" missing or unreadable."
+	exit 1
+fi
+
+echo $1
+preceding_lines="${2-3}"
+trailing_lines="${3-10}"
+
+awk -v preceding_lines="$preceding_lines" -v trailing_lines="$trailing_lines" '
+suffix <= 0 {
+	for (i = preceding_lines; i > 0; i--)
+		last[i] = last[i - 1];
+	last[0] = $0;
+}
+
+suffix > 0 {
+	print $0;
+	suffix--;
+	if (suffix <= 0)
+		print "";
+}
+
+suffix <= 0 && /detected stall/ {
+	for (i = preceding_lines; i >= 0; i--)
+		if (last[i] != "")
+			print last[i];
+	suffix = trailing_lines;
+}' < "$1" | tr -d '\015' | grep -v clocksource
+
diff --git a/tools/rcu/rcu-cbs.py b/tools/rcu/rcu-cbs.py
new file mode 100644
index 0000000000..f8b461b9ea
--- /dev/null
+++ b/tools/rcu/rcu-cbs.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env drgn
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Dump out the number of RCU callbacks outstanding.
+#
+# On older kernels having multiple flavors of RCU, this dumps out the
+# number of callbacks for the most heavily used flavor.
+#
+# Usage: sudo drgn rcu-cbs.py
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+import sys
+import drgn
+from drgn import NULL, Object
+from drgn.helpers.linux import *
+
+def get_rdp0(prog):
+	try:
+		rdp0 = prog.variable('rcu_preempt_data', 'kernel/rcu/tree.c');
+	except LookupError:
+		rdp0 = NULL;
+
+	if rdp0 == NULL:
+		try:
+			rdp0 = prog.variable('rcu_sched_data',
+					     'kernel/rcu/tree.c');
+		except LookupError:
+			rdp0 = NULL;
+
+	if rdp0 == NULL:
+		rdp0 = prog.variable('rcu_data', 'kernel/rcu/tree.c');
+	return rdp0.address_of_();
+
+rdp0 = get_rdp0(prog);
+
+# Sum up RCU callbacks.
+sum = 0;
+for cpu in for_each_possible_cpu(prog):
+	rdp = per_cpu_ptr(rdp0, cpu);
+	len = rdp.cblist.len.value_();
+	# print("CPU " + str(cpu) + " RCU callbacks: " + str(len));
+	sum += len;
+print("Number of RCU callbacks in flight: " + str(sum));