64 строки
1.4 KiB
C
64 строки
1.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* RCU CPU stall warnings for normal RCU grace periods
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*
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* Copyright IBM Corporation, 2019
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*
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* Author: Paul E. McKenney <paulmck@linux.ibm.com>
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*/
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#ifdef CONFIG_PROVE_RCU
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#define RCU_STALL_DELAY_DELTA (5 * HZ)
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#else
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#define RCU_STALL_DELAY_DELTA 0
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#endif
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int rcu_jiffies_till_stall_check(void)
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{
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int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout);
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/*
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* Limit check must be consistent with the Kconfig limits
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* for CONFIG_RCU_CPU_STALL_TIMEOUT.
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*/
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if (till_stall_check < 3) {
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WRITE_ONCE(rcu_cpu_stall_timeout, 3);
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till_stall_check = 3;
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} else if (till_stall_check > 300) {
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WRITE_ONCE(rcu_cpu_stall_timeout, 300);
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till_stall_check = 300;
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}
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return till_stall_check * HZ + RCU_STALL_DELAY_DELTA;
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}
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EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check);
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void rcu_sysrq_start(void)
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{
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if (!rcu_cpu_stall_suppress)
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rcu_cpu_stall_suppress = 2;
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}
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void rcu_sysrq_end(void)
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{
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if (rcu_cpu_stall_suppress == 2)
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rcu_cpu_stall_suppress = 0;
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}
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static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
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{
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rcu_cpu_stall_suppress = 1;
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return NOTIFY_DONE;
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}
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static struct notifier_block rcu_panic_block = {
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.notifier_call = rcu_panic,
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};
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static int __init check_cpu_stall_init(void)
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{
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atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block);
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return 0;
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}
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early_initcall(check_cpu_stall_init);
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