sched: add head drop fifo queue
This adds an additional queuing strategy, called pfifo_head_drop,
to remove the oldest skb in the case of an overflow within the queue -
the head element - instead of the last skb (tail). To remove the oldest
skb in congested situations is useful for sensor network environments
where newer packets reflect the superior information.
Reviewed-by: Florian Westphal <fw@strlen.de>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 75fd1c6..6cd4910 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1707,6 +1707,7 @@
{
register_qdisc(&pfifo_qdisc_ops);
register_qdisc(&bfifo_qdisc_ops);
+ register_qdisc(&pfifo_head_drop_qdisc_ops);
register_qdisc(&mq_qdisc_ops);
proc_net_fops_create(&init_net, "psched", 0, &psched_fops);