From 4df8374254ea9294dfe4b8c447a1b7eddc543dbf Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 13 Jul 2016 17:17:03 +0000 Subject: rcu: Convert rcutree to hotplug state machine Straight forward conversion to the state machine. Though the question arises whether this needs really all these state transitions to work. Signed-off-by: Thomas Gleixner Signed-off-by: Anna-Maria Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.982013161@linutronix.de Signed-off-by: Ingo Molnar --- kernel/rcu/tree.c | 105 +++++++++++++++++++++++++++--------------------------- 1 file changed, 52 insertions(+), 53 deletions(-) (limited to 'kernel/rcu') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f433959e9322..5d80925e7fc8 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1073,11 +1073,11 @@ EXPORT_SYMBOL_GPL(rcu_is_watching); * offline to continue to use RCU for one jiffy after marking itself * offline in the cpu_online_mask. This leniency is necessary given the * non-atomic nature of the online and offline processing, for example, - * the fact that a CPU enters the scheduler after completing the CPU_DYING - * notifiers. + * the fact that a CPU enters the scheduler after completing the teardown + * of the CPU. * - * This is also why RCU internally marks CPUs online during the - * CPU_UP_PREPARE phase and offline during the CPU_DEAD phase. + * This is also why RCU internally marks CPUs online during in the + * preparation phase and offline after the CPU has been taken down. * * Disable checking if in an NMI handler because we cannot safely report * errors from NMI handlers anyway. @@ -3806,12 +3806,58 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp) raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } -static void rcu_prepare_cpu(int cpu) +int rcutree_prepare_cpu(unsigned int cpu) { struct rcu_state *rsp; for_each_rcu_flavor(rsp) rcu_init_percpu_data(cpu, rsp); + + rcu_prepare_kthreads(cpu); + rcu_spawn_all_nocb_kthreads(cpu); + + return 0; +} + +static void rcutree_affinity_setting(unsigned int cpu, int outgoing) +{ + struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu); + + rcu_boost_kthread_setaffinity(rdp->mynode, outgoing); +} + +int rcutree_online_cpu(unsigned int cpu) +{ + sync_sched_exp_online_cleanup(cpu); + rcutree_affinity_setting(cpu, -1); + return 0; +} + +int rcutree_offline_cpu(unsigned int cpu) +{ + rcutree_affinity_setting(cpu, cpu); + return 0; +} + + +int rcutree_dying_cpu(unsigned int cpu) +{ + struct rcu_state *rsp; + + for_each_rcu_flavor(rsp) + rcu_cleanup_dying_cpu(rsp); + return 0; +} + +int rcutree_dead_cpu(unsigned int cpu) +{ + struct rcu_state *rsp; + + for_each_rcu_flavor(rsp) { + rcu_cleanup_dead_cpu(cpu, rsp); + do_nocb_deferred_wakeup(per_cpu_ptr(rsp->rda, cpu)); + } + return 0; } #ifdef CONFIG_HOTPLUG_CPU @@ -3851,52 +3897,6 @@ void rcu_report_dead(unsigned int cpu) } #endif -/* - * Handle CPU online/offline notification events. - */ -int rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - long cpu = (long)hcpu; - struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu); - struct rcu_node *rnp = rdp->mynode; - struct rcu_state *rsp; - - switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - rcu_prepare_cpu(cpu); - rcu_prepare_kthreads(cpu); - rcu_spawn_all_nocb_kthreads(cpu); - break; - case CPU_ONLINE: - case CPU_DOWN_FAILED: - sync_sched_exp_online_cleanup(cpu); - rcu_boost_kthread_setaffinity(rnp, -1); - break; - case CPU_DOWN_PREPARE: - rcu_boost_kthread_setaffinity(rnp, cpu); - break; - case CPU_DYING: - case CPU_DYING_FROZEN: - for_each_rcu_flavor(rsp) - rcu_cleanup_dying_cpu(rsp); - break; - case CPU_DEAD: - case CPU_DEAD_FROZEN: - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - for_each_rcu_flavor(rsp) { - rcu_cleanup_dead_cpu(cpu, rsp); - do_nocb_deferred_wakeup(per_cpu_ptr(rsp->rda, cpu)); - } - break; - default: - break; - } - return NOTIFY_OK; -} - static int rcu_pm_notify(struct notifier_block *self, unsigned long action, void *hcpu) { @@ -4208,10 +4208,9 @@ void __init rcu_init(void) * this is called early in boot, before either interrupts * or the scheduler are operational. */ - cpu_notifier(rcu_cpu_notify, 0); pm_notifier(rcu_pm_notify, 0); for_each_online_cpu(cpu) - rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); + rcutree_prepare_cpu(cpu); } #include "tree_exp.h" -- cgit v1.2.3