47 lines
1.1 KiB
Python
47 lines
1.1 KiB
Python
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#!/usr/bin/env drgn
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# SPDX-License-Identifier: GPL-2.0+
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#
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# Dump out the number of RCU callbacks outstanding.
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#
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# On older kernels having multiple flavors of RCU, this dumps out the
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# number of callbacks for the most heavily used flavor.
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#
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# Usage: sudo drgn rcu-cbs.py
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#
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# Copyright (C) 2021 Facebook, Inc.
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#
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# Authors: Paul E. McKenney <paulmck@kernel.org>
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import sys
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import drgn
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from drgn import NULL, Object
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from drgn.helpers.linux import *
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def get_rdp0(prog):
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try:
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rdp0 = prog.variable('rcu_preempt_data', 'kernel/rcu/tree.c');
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except LookupError:
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rdp0 = NULL;
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if rdp0 == NULL:
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try:
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rdp0 = prog.variable('rcu_sched_data',
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'kernel/rcu/tree.c');
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except LookupError:
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rdp0 = NULL;
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if rdp0 == NULL:
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rdp0 = prog.variable('rcu_data', 'kernel/rcu/tree.c');
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return rdp0.address_of_();
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rdp0 = get_rdp0(prog);
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# Sum up RCU callbacks.
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sum = 0;
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for cpu in for_each_possible_cpu(prog):
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rdp = per_cpu_ptr(rdp0, cpu);
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len = rdp.cblist.len.value_();
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# print("CPU " + str(cpu) + " RCU callbacks: " + str(len));
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sum += len;
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print("Number of RCU callbacks in flight: " + str(sum));
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