net: factorize sync-rcu call in unregister_netdevice_many
Add dev_close_many and dev_deactivate_many to factorize another
sync-rcu operation on the netdevice unregister path.
$ modprobe dummy numdummies=10000
$ ip link set dev dummy* up
$ time rmmod dummy
Without the patch With the patch
real 0m 24.63s real 0m 5.15s
user 0m 0.00s user 0m 0.00s
sys 0m 6.05s sys 0m 5.14s
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 0918834..34dc598 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -810,20 +810,35 @@
return false;
}
-void dev_deactivate(struct net_device *dev)
+void dev_deactivate_many(struct list_head *head)
{
- netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc);
- if (dev_ingress_queue(dev))
- dev_deactivate_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
+ struct net_device *dev;
- dev_watchdog_down(dev);
+ list_for_each_entry(dev, head, unreg_list) {
+ netdev_for_each_tx_queue(dev, dev_deactivate_queue,
+ &noop_qdisc);
+ if (dev_ingress_queue(dev))
+ dev_deactivate_queue(dev, dev_ingress_queue(dev),
+ &noop_qdisc);
+
+ dev_watchdog_down(dev);
+ }
/* Wait for outstanding qdisc-less dev_queue_xmit calls. */
synchronize_rcu();
/* Wait for outstanding qdisc_run calls. */
- while (some_qdisc_is_busy(dev))
- yield();
+ list_for_each_entry(dev, head, unreg_list)
+ while (some_qdisc_is_busy(dev))
+ yield();
+}
+
+void dev_deactivate(struct net_device *dev)
+{
+ LIST_HEAD(single);
+
+ list_add(&dev->unreg_list, &single);
+ dev_deactivate_many(&single);
}
static void dev_init_scheduler_queue(struct net_device *dev,