diff options
Diffstat (limited to 'debian/patches-rt/0197-net-Use-skbufhead-with-raw-lock.patch')
| -rw-r--r-- | debian/patches-rt/0197-net-Use-skbufhead-with-raw-lock.patch | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/debian/patches-rt/0197-net-Use-skbufhead-with-raw-lock.patch b/debian/patches-rt/0197-net-Use-skbufhead-with-raw-lock.patch new file mode 100644 index 000000000..f54ab15b6 --- /dev/null +++ b/debian/patches-rt/0197-net-Use-skbufhead-with-raw-lock.patch @@ -0,0 +1,148 @@ +From 8c4af88efcc296bc2daa2be90fbea82190799883 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 12 Jul 2011 15:38:34 +0200 +Subject: [PATCH 197/347] net: Use skbufhead with raw lock +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +Use the rps lock as rawlock so we can keep irq-off regions. It looks low +latency. However we can't kfree() from this context therefore we defer this +to the softirq and use the tofree_queue list for it (similar to process_queue). + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +--- + include/linux/netdevice.h | 1 + + include/linux/skbuff.h | 7 +++++++ + net/core/dev.c | 26 ++++++++++++++++++++------ + 3 files changed, 28 insertions(+), 6 deletions(-) + +diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h +index 8d48b352ee74..d893dc112afc 100644 +--- a/include/linux/netdevice.h ++++ b/include/linux/netdevice.h +@@ -2990,6 +2990,7 @@ struct softnet_data { + unsigned int dropped; + struct sk_buff_head input_pkt_queue; + struct napi_struct backlog; ++ struct sk_buff_head tofree_queue; + + }; + +diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h +index f97734f34746..3ede4f0eac10 100644 +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -287,6 +287,7 @@ struct sk_buff_head { + + __u32 qlen; + spinlock_t lock; ++ raw_spinlock_t raw_lock; + }; + + struct sk_buff; +@@ -1735,6 +1736,12 @@ static inline void skb_queue_head_init(struct sk_buff_head *list) + __skb_queue_head_init(list); + } + ++static inline void skb_queue_head_init_raw(struct sk_buff_head *list) ++{ ++ raw_spin_lock_init(&list->raw_lock); ++ __skb_queue_head_init(list); ++} ++ + static inline void skb_queue_head_init_class(struct sk_buff_head *list, + struct lock_class_key *class) + { +diff --git a/net/core/dev.c b/net/core/dev.c +index 315bdaf00ac8..c279375fa5b9 100644 +--- a/net/core/dev.c ++++ b/net/core/dev.c +@@ -219,14 +219,14 @@ 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 + } + +@@ -5858,7 +5858,9 @@ static int process_backlog(struct napi_struct *napi, int quota) + while (again) { + struct sk_buff *skb; + ++ local_irq_disable(); + while ((skb = __skb_dequeue(&sd->process_queue))) { ++ local_irq_enable(); + rcu_read_lock(); + __netif_receive_skb(skb); + rcu_read_unlock(); +@@ -5866,9 +5868,9 @@ static int process_backlog(struct napi_struct *napi, int quota) + if (++work >= quota) + return work; + ++ local_irq_disable(); + } + +- local_irq_disable(); + rps_lock(sd); + if (skb_queue_empty(&sd->input_pkt_queue)) { + /* +@@ -6341,13 +6343,21 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) + unsigned long time_limit = jiffies + + usecs_to_jiffies(netdev_budget_usecs); + int budget = netdev_budget; ++ struct sk_buff_head tofree_q; ++ struct sk_buff *skb; + LIST_HEAD(list); + LIST_HEAD(repoll); + ++ __skb_queue_head_init(&tofree_q); ++ + local_irq_disable(); ++ skb_queue_splice_init(&sd->tofree_queue, &tofree_q); + list_splice_init(&sd->poll_list, &list); + local_irq_enable(); + ++ while ((skb = __skb_dequeue(&tofree_q))) ++ kfree_skb(skb); ++ + for (;;) { + struct napi_struct *n; + +@@ -9545,10 +9555,13 @@ static int dev_cpu_dead(unsigned int oldcpu) + netif_rx_ni(skb); + input_queue_head_incr(oldsd); + } +- while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) { ++ while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) { + netif_rx_ni(skb); + input_queue_head_incr(oldsd); + } ++ while ((skb = __skb_dequeue(&oldsd->tofree_queue))) { ++ kfree_skb(skb); ++ } + + return 0; + } +@@ -9859,8 +9872,9 @@ static int __init net_dev_init(void) + + INIT_WORK(flush, flush_backlog); + +- 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); + #ifdef CONFIG_XFRM_OFFLOAD + skb_queue_head_init(&sd->xfrm_backlog); + #endif +-- +2.36.1 + |