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authorEric Dumazet <edumazet@google.com>2016-06-06 09:37:15 -0700
committerDavid S. Miller <davem@davemloft.net>2016-06-07 16:37:13 -0700
commitf9eb8aea2a1e12fc2f584d1627deeb957435a801 (patch)
treebc3cf06664da45bc0e6ce9b5165dba534ed11751 /net
parent64151ae36ed93c45654069c8aff2a7f0125075e8 (diff)
net_sched: transform qdisc running bit into a seqcount
Instead of using a single bit (__QDISC___STATE_RUNNING) in sch->__state, use a seqcount. This adds lockdep support, but more importantly it will allow us to sample qdisc/class statistics without having to grab qdisc root lock. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/bluetooth/6lowpan.c2
-rw-r--r--net/core/dev.c2
-rw-r--r--net/ieee802154/6lowpan/core.c3
-rw-r--r--net/l2tp/l2tp_eth.c4
-rw-r--r--net/sched/sch_generic.c14
5 files changed, 20 insertions, 5 deletions
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 780089d75915..977a11e418d0 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -629,6 +629,7 @@ static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
static struct lock_class_key bt_tx_busylock;
static struct lock_class_key bt_netdev_xmit_lock_key;
+static struct lock_class_key bt_qdisc_running_key;
static void bt_set_lockdep_class_one(struct net_device *dev,
struct netdev_queue *txq,
@@ -641,6 +642,7 @@ static int bt_dev_init(struct net_device *dev)
{
netdev_for_each_tx_queue(dev, bt_set_lockdep_class_one, NULL);
dev->qdisc_tx_busylock = &bt_tx_busylock;
+ dev->qdisc_running_key = &bt_qdisc_running_key;
return 0;
}
diff --git a/net/core/dev.c b/net/core/dev.c
index 896b686d1966..e0bcc39f4a7d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3075,7 +3075,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
/*
* Heuristic to force contended enqueues to serialize on a
* separate lock before trying to get qdisc main lock.
- * This permits __QDISC___STATE_RUNNING owner to get the lock more
+ * This permits qdisc->running owner to get the lock more
* often and dequeue packets faster.
*/
contended = qdisc_is_running(q);
diff --git a/net/ieee802154/6lowpan/core.c b/net/ieee802154/6lowpan/core.c
index dd085db8580e..14aa5effd29a 100644
--- a/net/ieee802154/6lowpan/core.c
+++ b/net/ieee802154/6lowpan/core.c
@@ -60,6 +60,7 @@ static struct header_ops lowpan_header_ops = {
static struct lock_class_key lowpan_tx_busylock;
static struct lock_class_key lowpan_netdev_xmit_lock_key;
+static struct lock_class_key lowpan_qdisc_running_key;
static void lowpan_set_lockdep_class_one(struct net_device *ldev,
struct netdev_queue *txq,
@@ -73,6 +74,8 @@ static int lowpan_dev_init(struct net_device *ldev)
{
netdev_for_each_tx_queue(ldev, lowpan_set_lockdep_class_one, NULL);
ldev->qdisc_tx_busylock = &lowpan_tx_busylock;
+ ldev->qdisc_running_key = &lowpan_qdisc_running_key;
+
return 0;
}
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index e253c26f31ac..c00d72d182fa 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -68,6 +68,8 @@ static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
}
static struct lock_class_key l2tp_eth_tx_busylock;
+static struct lock_class_key l2tp_qdisc_running_key;
+
static int l2tp_eth_dev_init(struct net_device *dev)
{
struct l2tp_eth *priv = netdev_priv(dev);
@@ -76,6 +78,8 @@ static int l2tp_eth_dev_init(struct net_device *dev)
eth_hw_addr_random(dev);
eth_broadcast_addr(dev->broadcast);
dev->qdisc_tx_busylock = &l2tp_eth_tx_busylock;
+ dev->qdisc_running_key = &l2tp_qdisc_running_key;
+
return 0;
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 269dd71b3828..cebea73e70ac 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -110,7 +110,7 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
/*
* Transmit possibly several skbs, and handle the return status as
- * required. Holding the __QDISC___STATE_RUNNING bit guarantees that
+ * required. Owning running seqcount bit guarantees that
* only one CPU can execute this function.
*
* Returns to the caller:
@@ -137,10 +137,10 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
HARD_TX_UNLOCK(dev, txq);
} else {
- spin_lock(root_lock);
+ spin_lock_nested(root_lock, SINGLE_DEPTH_NESTING);
return qdisc_qlen(q);
}
- spin_lock(root_lock);
+ spin_lock_nested(root_lock, SINGLE_DEPTH_NESTING);
if (dev_xmit_complete(ret)) {
/* Driver sent out skb successfully or skb was consumed */
@@ -163,7 +163,7 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
/*
* NOTE: Called under qdisc_lock(q) with locally disabled BH.
*
- * __QDISC___STATE_RUNNING guarantees only one CPU can process
+ * running seqcount guarantees only one CPU can process
* this qdisc at a time. qdisc_lock(q) serializes queue accesses for
* this queue.
*
@@ -379,6 +379,7 @@ struct Qdisc noop_qdisc = {
.list = LIST_HEAD_INIT(noop_qdisc.list),
.q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
.dev_queue = &noop_netdev_queue,
+ .running = SEQCNT_ZERO(noop_qdisc.running),
.busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
};
EXPORT_SYMBOL(noop_qdisc);
@@ -537,6 +538,7 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = {
EXPORT_SYMBOL(pfifo_fast_ops);
static struct lock_class_key qdisc_tx_busylock;
+static struct lock_class_key qdisc_running_key;
struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
const struct Qdisc_ops *ops)
@@ -570,6 +572,10 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
lockdep_set_class(&sch->busylock,
dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+ seqcount_init(&sch->running);
+ lockdep_set_class(&sch->running,
+ dev->qdisc_running_key ?: &qdisc_running_key);
+
sch->ops = ops;
sch->enqueue = ops->enqueue;
sch->dequeue = ops->dequeue;