summaryrefslogtreecommitdiff
path: root/tools/rcu/rcu-cbs.py
blob: f8b461b9eaa71903eded9f60e8ef0af88986fb5d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
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));