diff options
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8e880c09ab59..f52ff7241041 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -640,6 +640,7 @@ void __rcu_irq_enter_check_tick(void) } raw_spin_unlock_rcu_node(rdp->mynode); } +NOKPROBE_SYMBOL(__rcu_irq_enter_check_tick); #endif /* CONFIG_NO_HZ_FULL */ /* @@ -1955,7 +1956,6 @@ rcu_report_qs_rdp(struct rcu_data *rdp) { unsigned long flags; unsigned long mask; - bool needwake = false; bool needacc = false; struct rcu_node *rnp; @@ -1987,7 +1987,12 @@ rcu_report_qs_rdp(struct rcu_data *rdp) * NOCB kthreads have their own way to deal with that... */ if (!rcu_rdp_is_offloaded(rdp)) { - needwake = rcu_accelerate_cbs(rnp, rdp); + /* + * The current GP has not yet ended, so it + * should not be possible for rcu_accelerate_cbs() + * to return true. So complain, but don't awaken. + */ + WARN_ON_ONCE(rcu_accelerate_cbs(rnp, rdp)); } else if (!rcu_segcblist_completely_offloaded(&rdp->cblist)) { /* * ...but NOCB kthreads may miss or delay callbacks acceleration @@ -1999,8 +2004,6 @@ rcu_report_qs_rdp(struct rcu_data *rdp) rcu_disable_urgency_upon_qs(rdp); rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags); /* ^^^ Released rnp->lock */ - if (needwake) - rcu_gp_kthread_wake(); if (needacc) { rcu_nocb_lock_irqsave(rdp, flags); @@ -2131,6 +2134,8 @@ static void rcu_do_batch(struct rcu_data *rdp) break; } } else { + // In rcuoc context, so no worries about depriving + // other softirq vectors of CPU cycles. local_bh_enable(); lockdep_assert_irqs_enabled(); cond_resched_tasks_rcu_qs(); @@ -3024,6 +3029,18 @@ need_offload_krc(struct kfree_rcu_cpu *krcp) return !!READ_ONCE(krcp->head); } +static bool +need_wait_for_krwp_work(struct kfree_rcu_cpu_work *krwp) +{ + int i; + + for (i = 0; i < FREE_N_CHANNELS; i++) + if (!list_empty(&krwp->bulk_head_free[i])) + return true; + + return !!krwp->head_free; +} + static int krc_count(struct kfree_rcu_cpu *krcp) { int sum = atomic_read(&krcp->head_count); @@ -3107,15 +3124,14 @@ static void kfree_rcu_monitor(struct work_struct *work) for (i = 0; i < KFREE_N_BATCHES; i++) { struct kfree_rcu_cpu_work *krwp = &(krcp->krw_arr[i]); - // Try to detach bulk_head or head and attach it over any - // available corresponding free channel. It can be that - // a previous RCU batch is in progress, it means that - // immediately to queue another one is not possible so - // in that case the monitor work is rearmed. - if ((!list_empty(&krcp->bulk_head[0]) && list_empty(&krwp->bulk_head_free[0])) || - (!list_empty(&krcp->bulk_head[1]) && list_empty(&krwp->bulk_head_free[1])) || - (READ_ONCE(krcp->head) && !krwp->head_free)) { + // Try to detach bulk_head or head and attach it, only when + // all channels are free. Any channel is not free means at krwp + // there is on-going rcu work to handle krwp's free business. + if (need_wait_for_krwp_work(krwp)) + continue; + // kvfree_rcu_drain_ready() might handle this krcp, if so give up. + if (need_offload_krc(krcp)) { // Channel 1 corresponds to the SLAB-pointer bulk path. // Channel 2 corresponds to vmalloc-pointer bulk path. for (j = 0; j < FREE_N_CHANNELS; j++) { @@ -4940,9 +4956,8 @@ void __init rcu_init(void) else qovld_calc = qovld; - // Kick-start any polled grace periods that started early. - if (!(per_cpu_ptr(&rcu_data, cpu)->mynode->exp_seq_poll_rq & 0x1)) - (void)start_poll_synchronize_rcu_expedited(); + // Kick-start in case any polled grace periods started early. + (void)start_poll_synchronize_rcu_expedited(); rcu_test_sync_prims(); } |