From 12fae71b184dade2cedf154bbc8fd7870c5cd71c Mon Sep 17 00:00:00 2001 From: Tianyi Gou Date: Tue, 26 Jun 2012 10:11:05 -0600 Subject: net: sched: Schedule PRIO qdisc when flow control released The PRIO qdisc supports flow control, such that packet dequeue can be disabled based on boolean flag 'enable_flow'. When flow is re-enabled, the latency for new packets arriving at network driver is high. To reduce the delay in scheduling packets, the qdisc will now invoke __netif_schedule() to expedite dequeue. This significantly reduces the latency of packets arriving at network driver. Change-Id: Ic5fe3faf86f177300d3018b9f60974ba3811641c CRs-Fixed: 355156 Acked-by: Jimi Shah Signed-off-by: Tianyi Gou --- net/sched/sch_prio.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c index a8891a51af34..59ef2daf652c 100644 --- a/net/sched/sch_prio.c +++ b/net/sched/sch_prio.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -178,6 +179,7 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt) struct prio_sched_data *q = qdisc_priv(sch); struct tc_prio_qopt *qopt; int i; + int flow_change = 0; if (nla_len(opt) < sizeof(*qopt)) return -EINVAL; @@ -192,7 +194,10 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt) } sch_tree_lock(sch); - q->enable_flow = qopt->enable_flow; + if (q->enable_flow != qopt->enable_flow) { + q->enable_flow = qopt->enable_flow; + flow_change = 1; + } q->bands = qopt->bands; memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); @@ -227,6 +232,13 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt) } } } + + /* Schedule qdisc when flow re-enabled */ + if (flow_change && q->enable_flow) { + if (!test_bit(__QDISC_STATE_DEACTIVATED, + &sch->state)) + __netif_schedule(qdisc_root(sch)); + } return 0; } -- cgit v1.2.3