115 lines
3.3 KiB
Diff
115 lines
3.3 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Tue, 12 Jul 2011 15:38:34 +0200
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Subject: net: Use skbufhead with raw lock
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.4-rc6-rt1/patches-4.4-rc6-rt1.tar.xz
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Use the rps lock as rawlock so we can keep irq-off regions. It looks low
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latency. However we can't kfree() from this context therefore we defer this
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to the softirq and use the tofree_queue list for it (similar to process_queue).
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/netdevice.h | 1 +
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include/linux/skbuff.h | 7 +++++++
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net/core/dev.c | 19 +++++++++++++------
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3 files changed, 21 insertions(+), 6 deletions(-)
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--- a/include/linux/netdevice.h
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+++ b/include/linux/netdevice.h
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@@ -2546,6 +2546,7 @@ struct softnet_data {
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unsigned int dropped;
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struct sk_buff_head input_pkt_queue;
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struct napi_struct backlog;
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+ struct sk_buff_head tofree_queue;
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};
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--- a/include/linux/skbuff.h
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+++ b/include/linux/skbuff.h
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@@ -203,6 +203,7 @@ struct sk_buff_head {
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__u32 qlen;
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spinlock_t lock;
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+ raw_spinlock_t raw_lock;
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};
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struct sk_buff;
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@@ -1463,6 +1464,12 @@ static inline void skb_queue_head_init(s
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__skb_queue_head_init(list);
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}
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+static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
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+{
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+ raw_spin_lock_init(&list->raw_lock);
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+ __skb_queue_head_init(list);
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+}
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+
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static inline void skb_queue_head_init_class(struct sk_buff_head *list,
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struct lock_class_key *class)
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{
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--- a/net/core/dev.c
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+++ b/net/core/dev.c
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@@ -207,14 +207,14 @@ static inline struct hlist_head *dev_ind
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static inline void rps_lock(struct softnet_data *sd)
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{
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#ifdef CONFIG_RPS
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- spin_lock(&sd->input_pkt_queue.lock);
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+ raw_spin_lock(&sd->input_pkt_queue.raw_lock);
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#endif
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}
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static inline void rps_unlock(struct softnet_data *sd)
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{
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#ifdef CONFIG_RPS
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- spin_unlock(&sd->input_pkt_queue.lock);
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+ raw_spin_unlock(&sd->input_pkt_queue.raw_lock);
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#endif
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}
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@@ -4045,7 +4045,7 @@ static void flush_backlog(void *arg)
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skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
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if (skb->dev == dev) {
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__skb_unlink(skb, &sd->input_pkt_queue);
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- kfree_skb(skb);
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+ __skb_queue_tail(&sd->tofree_queue, skb);
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input_queue_head_incr(sd);
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}
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}
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@@ -4054,10 +4054,13 @@ static void flush_backlog(void *arg)
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skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
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if (skb->dev == dev) {
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__skb_unlink(skb, &sd->process_queue);
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- kfree_skb(skb);
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+ __skb_queue_tail(&sd->tofree_queue, skb);
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input_queue_head_incr(sd);
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}
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}
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+
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+ if (!skb_queue_empty(&sd->tofree_queue))
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+ raise_softirq_irqoff(NET_RX_SOFTIRQ);
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}
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static int napi_gro_complete(struct sk_buff *skb)
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@@ -7464,6 +7467,9 @@ static int dev_cpu_callback(struct notif
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netif_rx_ni(skb);
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input_queue_head_incr(oldsd);
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}
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+ while ((skb = __skb_dequeue(&oldsd->tofree_queue))) {
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+ kfree_skb(skb);
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+ }
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return NOTIFY_OK;
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}
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@@ -7765,8 +7771,9 @@ static int __init net_dev_init(void)
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for_each_possible_cpu(i) {
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struct softnet_data *sd = &per_cpu(softnet_data, i);
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- skb_queue_head_init(&sd->input_pkt_queue);
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- skb_queue_head_init(&sd->process_queue);
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+ skb_queue_head_init_raw(&sd->input_pkt_queue);
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+ skb_queue_head_init_raw(&sd->process_queue);
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+ skb_queue_head_init_raw(&sd->tofree_queue);
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INIT_LIST_HEAD(&sd->poll_list);
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sd->output_queue_tailp = &sd->output_queue;
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#ifdef CONFIG_RPS
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