Merge remote-tracking branch 'net-next/master' into mac80211-next

Resolve the merge conflict between Felix's/my and Toke's patches
coming into the tree through net and mac80211-next respectively.
Most of Felix's changes go away due to Toke's new infrastructure
work, my patch changes to "goto begin" (the label wasn't there
before) instead of returning NULL so flow control towards drivers
is preserved better.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 37 insertions, 6 deletions

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index dc52cc1..18e7524 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -86,6 +86,7 @@ struct fq_sched_data {
 
 	struct rb_root	delayed;	/* for rate limited flows */
 	u64		time_next_delayed_flow;
+	unsigned long	unthrottle_latency_ns;
 
 	struct fq_flow	internal;	/* for non classified or high prio packets */
 	u32		quantum;
@@ -94,6 +95,7 @@ struct fq_sched_data {
 	u32		flow_max_rate;	/* optional max rate per flow */
 	u32		flow_plimit;	/* max packets per flow */
 	u32		orphan_mask;	/* mask for orphaned skb */
+	u32		low_rate_threshold;
 	struct rb_root	*fq_root;
 	u8		rate_enable;
 	u8		fq_trees_log;
@@ -407,11 +409,19 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 
 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 {
+	unsigned long sample;
 	struct rb_node *p;
 
 	if (q->time_next_delayed_flow > now)
 		return;
 
+	/* Update unthrottle latency EWMA.
+	 * This is cheap and can help diagnosing timer/latency problems.
+	 */
+	sample = (unsigned long)(now - q->time_next_delayed_flow);
+	q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
+	q->unthrottle_latency_ns += sample >> 3;
+
 	q->time_next_delayed_flow = ~0ULL;
 	while ((p = rb_first(&q->delayed)) != NULL) {
 		struct fq_flow *f = container_of(p, struct fq_flow, rate_node);
@@ -433,7 +443,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 	struct fq_flow_head *head;
 	struct sk_buff *skb;
 	struct fq_flow *f;
-	u32 rate;
+	u32 rate, plen;
 
 	skb = fq_dequeue_head(sch, &q->internal);
 	if (skb)
@@ -482,7 +492,7 @@ begin:
 	prefetch(&skb->end);
 	f->credit -= qdisc_pkt_len(skb);
 
-	if (f->credit > 0 || !q->rate_enable)
+	if (!q->rate_enable)
 		goto out;
 
 	/* Do not pace locally generated ack packets */
@@ -493,8 +503,15 @@ begin:
 	if (skb->sk)
 		rate = min(skb->sk->sk_pacing_rate, rate);
 
+	if (rate <= q->low_rate_threshold) {
+		f->credit = 0;
+		plen = qdisc_pkt_len(skb);
+	} else {
+		plen = max(qdisc_pkt_len(skb), q->quantum);
+		if (f->credit > 0)
+			goto out;
+	}
 	if (rate != ~0U) {
-		u32 plen = max(qdisc_pkt_len(skb), q->quantum);
 		u64 len = (u64)plen * NSEC_PER_SEC;
 
 		if (likely(rate))
@@ -507,7 +524,12 @@ begin:
 			len = NSEC_PER_SEC;
 			q->stat_pkts_too_long++;
 		}
-
+		/* Account for schedule/timers drifts.
+		 * f->time_next_packet was set when prior packet was sent,
+		 * and current time (@now) can be too late by tens of us.
+		 */
+		if (f->time_next_packet)
+			len -= min(len/2, now - f->time_next_packet);
 		f->time_next_packet = now + len;
 	}
 out:
@@ -662,6 +684,7 @@ static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 	[TCA_FQ_FLOW_MAX_RATE]		= { .type = NLA_U32 },
 	[TCA_FQ_BUCKETS_LOG]		= { .type = NLA_U32 },
 	[TCA_FQ_FLOW_REFILL_DELAY]	= { .type = NLA_U32 },
+	[TCA_FQ_LOW_RATE_THRESHOLD]	= { .type = NLA_U32 },
 };
 
 static int fq_change(struct Qdisc *sch, struct nlattr *opt)
@@ -716,6 +739,10 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt)
 	if (tb[TCA_FQ_FLOW_MAX_RATE])
 		q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 
+	if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
+		q->low_rate_threshold =
+			nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
+
 	if (tb[TCA_FQ_RATE_ENABLE]) {
 		u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 
@@ -774,6 +801,7 @@ static int fq_init(struct Qdisc *sch, struct nlattr *opt)
 	q->initial_quantum	= 10 * psched_mtu(qdisc_dev(sch));
 	q->flow_refill_delay	= msecs_to_jiffies(40);
 	q->flow_max_rate	= ~0U;
+	q->time_next_delayed_flow = ~0ULL;
 	q->rate_enable		= 1;
 	q->new_flows.first	= NULL;
 	q->old_flows.first	= NULL;
@@ -781,6 +809,7 @@ static int fq_init(struct Qdisc *sch, struct nlattr *opt)
 	q->fq_root		= NULL;
 	q->fq_trees_log		= ilog2(1024);
 	q->orphan_mask		= 1024 - 1;
+	q->low_rate_threshold	= 550000 / 8;
 	qdisc_watchdog_init(&q->watchdog, sch);
 
 	if (opt)
@@ -811,6 +840,8 @@ static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 	    nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 			jiffies_to_usecs(q->flow_refill_delay)) ||
 	    nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
+	    nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
+			q->low_rate_threshold) ||
 	    nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 		goto nla_put_failure;
 
@@ -838,8 +869,8 @@ static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 	st.flows		  = q->flows;
 	st.inactive_flows	  = q->inactive_flows;
 	st.throttled_flows	  = q->throttled_flows;
-	st.pad			  = 0;
-
+	st.unthrottle_latency_ns  = min_t(unsigned long,
+					  q->unthrottle_latency_ns, ~0U);
 	sch_tree_unlock(sch);
 
 	return gnet_stats_copy_app(d, &st, sizeof(st));