diff options
Diffstat (limited to 'kernel/rcu/tree_stall.h')
| -rw-r--r-- | kernel/rcu/tree_stall.h | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 2443d1d4a6dc..49544f932279 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -8,6 +8,7 @@ */ #include <linux/kvm_para.h> +#include <linux/rcu_notifier.h> ////////////////////////////////////////////////////////////////////////////// // @@ -770,6 +771,7 @@ static void check_cpu_stall(struct rcu_data *rdp) if (kvm_check_and_clear_guest_paused()) return; + rcu_stall_notifier_call_chain(RCU_STALL_NOTIFY_NORM, (void *)j - gps); if (self_detected) { /* We haven't checked in, so go dump stack. */ print_cpu_stall(gps); @@ -790,7 +792,7 @@ static void check_cpu_stall(struct rcu_data *rdp) ////////////////////////////////////////////////////////////////////////////// // -// RCU forward-progress mechanisms, including of callback invocation. +// RCU forward-progress mechanisms, including for callback invocation. /* @@ -1042,3 +1044,58 @@ static int __init rcu_sysrq_init(void) return 0; } early_initcall(rcu_sysrq_init); + + +////////////////////////////////////////////////////////////////////////////// +// +// RCU CPU stall-warning notifiers + +static ATOMIC_NOTIFIER_HEAD(rcu_cpu_stall_notifier_list); + +/** + * rcu_stall_chain_notifier_register - Add an RCU CPU stall notifier + * @n: Entry to add. + * + * Adds an RCU CPU stall notifier to an atomic notifier chain. + * The @action passed to a notifier will be @RCU_STALL_NOTIFY_NORM or + * friends. The @data will be the duration of the stalled grace period, + * in jiffies, coerced to a void* pointer. + * + * Returns 0 on success, %-EEXIST on error. + */ +int rcu_stall_chain_notifier_register(struct notifier_block *n) +{ + return atomic_notifier_chain_register(&rcu_cpu_stall_notifier_list, n); +} +EXPORT_SYMBOL_GPL(rcu_stall_chain_notifier_register); + +/** + * rcu_stall_chain_notifier_unregister - Remove an RCU CPU stall notifier + * @n: Entry to add. + * + * Removes an RCU CPU stall notifier from an atomic notifier chain. + * + * Returns zero on success, %-ENOENT on failure. + */ +int rcu_stall_chain_notifier_unregister(struct notifier_block *n) +{ + return atomic_notifier_chain_unregister(&rcu_cpu_stall_notifier_list, n); +} +EXPORT_SYMBOL_GPL(rcu_stall_chain_notifier_unregister); + +/* + * rcu_stall_notifier_call_chain - Call functions in an RCU CPU stall notifier chain + * @val: Value passed unmodified to notifier function + * @v: Pointer passed unmodified to notifier function + * + * Calls each function in the RCU CPU stall notifier chain in turn, which + * is an atomic call chain. See atomic_notifier_call_chain() for more + * information. + * + * This is for use within RCU, hence the omission of the extra asterisk + * to indicate a non-kerneldoc format header comment. + */ +int rcu_stall_notifier_call_chain(unsigned long val, void *v) +{ + return atomic_notifier_call_chain(&rcu_cpu_stall_notifier_list, val, v); +} |