diff options
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 70 |
1 files changed, 60 insertions, 10 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index c25d453b2803..11ad67cbc63a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -220,14 +220,14 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex) static inline void rps_lock(struct softnet_data *sd) { #ifdef CONFIG_RPS - spin_lock(&sd->input_pkt_queue.lock); + raw_spin_lock(&sd->input_pkt_queue.raw_lock); #endif } static inline void rps_unlock(struct softnet_data *sd) { #ifdef CONFIG_RPS - spin_unlock(&sd->input_pkt_queue.lock); + raw_spin_unlock(&sd->input_pkt_queue.raw_lock); #endif } @@ -1783,6 +1783,7 @@ static inline void __netif_reschedule(struct Qdisc *q) sd->output_queue_tailp = &q->next_sched; raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_restore(flags); + preempt_check_resched_rt(); } void __netif_schedule(struct Qdisc *q) @@ -1804,6 +1805,7 @@ void dev_kfree_skb_irq(struct sk_buff *skb) sd->completion_queue = skb; raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_restore(flags); + preempt_check_resched_rt(); } } EXPORT_SYMBOL(dev_kfree_skb_irq); @@ -2903,6 +2905,7 @@ enqueue: rps_unlock(sd); local_irq_restore(flags); + preempt_check_resched_rt(); atomic_long_inc(&skb->dev->rx_dropped); kfree_skb(skb); @@ -2966,16 +2969,46 @@ int netif_rx_ni(struct sk_buff *skb) { int err; - preempt_disable(); + migrate_disable(); err = netif_rx(skb); if (local_softirq_pending()) - do_softirq(); - preempt_enable(); + thread_do_softirq(); + migrate_enable(); return err; } EXPORT_SYMBOL(netif_rx_ni); +#ifdef CONFIG_PREEMPT_RT_FULL +/* + * RT runs ksoftirqd as a real time thread and the root_lock is a + * "sleeping spinlock". If the trylock fails then we can go into an + * infinite loop when ksoftirqd preempted the task which actually + * holds the lock, because we requeue q and raise NET_TX softirq + * causing ksoftirqd to loop forever. + * + * It's safe to use spin_lock on RT here as softirqs run in thread + * context and cannot deadlock against the thread which is holding + * root_lock. + * + * On !RT the trylock might fail, but there we bail out from the + * softirq loop after 10 attempts which we can't do on RT. And the + * task holding root_lock cannot be preempted, so the only downside of + * that trylock is that we need 10 loops to decide that we should have + * given up in the first one :) + */ +static inline int take_root_lock(spinlock_t *lock) +{ + spin_lock(lock); + return 1; +} +#else +static inline int take_root_lock(spinlock_t *lock) +{ + return spin_trylock(lock); +} +#endif + static void net_tx_action(struct softirq_action *h) { struct softnet_data *sd = &__get_cpu_var(softnet_data); @@ -3014,7 +3047,7 @@ static void net_tx_action(struct softirq_action *h) head = head->next_sched; root_lock = qdisc_lock(q); - if (spin_trylock(root_lock)) { + if (take_root_lock(root_lock)) { smp_mb__before_clear_bit(); clear_bit(__QDISC_STATE_SCHED, &q->state); @@ -3333,7 +3366,7 @@ static void flush_backlog(void *arg) skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) { if (skb->dev == dev) { __skb_unlink(skb, &sd->input_pkt_queue); - kfree_skb(skb); + __skb_queue_tail(&sd->tofree_queue, skb); input_queue_head_incr(sd); } } @@ -3342,10 +3375,13 @@ static void flush_backlog(void *arg) skb_queue_walk_safe(&sd->process_queue, skb, tmp) { if (skb->dev == dev) { __skb_unlink(skb, &sd->process_queue); - kfree_skb(skb); + __skb_queue_tail(&sd->tofree_queue, skb); input_queue_head_incr(sd); } } + + if (!skb_queue_empty(&sd->tofree_queue)) + raise_softirq_irqoff(NET_RX_SOFTIRQ); } static int napi_gro_complete(struct sk_buff *skb) @@ -3683,6 +3719,7 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd) } else #endif local_irq_enable(); + preempt_check_resched_rt(); } static int process_backlog(struct napi_struct *napi, int quota) @@ -3755,6 +3792,7 @@ void __napi_schedule(struct napi_struct *n) local_irq_save(flags); ____napi_schedule(&__get_cpu_var(softnet_data), n); local_irq_restore(flags); + preempt_check_resched_rt(); } EXPORT_SYMBOL(__napi_schedule); @@ -3829,10 +3867,17 @@ static void net_rx_action(struct softirq_action *h) struct softnet_data *sd = &__get_cpu_var(softnet_data); unsigned long time_limit = jiffies + 2; int budget = netdev_budget; + struct sk_buff *skb; void *have; local_irq_disable(); + while ((skb = __skb_dequeue(&sd->tofree_queue))) { + local_irq_enable(); + kfree_skb(skb); + local_irq_disable(); + } + while (!list_empty(&sd->poll_list)) { struct napi_struct *n; int work, weight; @@ -6249,6 +6294,7 @@ static int dev_cpu_callback(struct notifier_block *nfb, raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_enable(); + preempt_check_resched_rt(); /* Process offline CPU's input_pkt_queue */ while ((skb = __skb_dequeue(&oldsd->process_queue))) { @@ -6259,6 +6305,9 @@ static int dev_cpu_callback(struct notifier_block *nfb, netif_rx(skb); input_queue_head_incr(oldsd); } + while ((skb = __skb_dequeue(&oldsd->tofree_queue))) { + kfree_skb(skb); + } return NOTIFY_OK; } @@ -6522,8 +6571,9 @@ static int __init net_dev_init(void) struct softnet_data *sd = &per_cpu(softnet_data, i); memset(sd, 0, sizeof(*sd)); - skb_queue_head_init(&sd->input_pkt_queue); - skb_queue_head_init(&sd->process_queue); + skb_queue_head_init_raw(&sd->input_pkt_queue); + skb_queue_head_init_raw(&sd->process_queue); + skb_queue_head_init_raw(&sd->tofree_queue); sd->completion_queue = NULL; INIT_LIST_HEAD(&sd->poll_list); sd->output_queue = NULL; |