Merge branch 'sched-Patches-from-out-of-tree-version-of-sch_cake'

Toke Høiland-Jørgensen says:

====================
sched: Patches from out-of-tree version of sch_cake

This series includes a couple of patches with updates from the out-of-tree
version of sch_cake. The first one is a fix to the fairness scheduling when
dual-mode fairness is enabled. The second patch is an additional feature flag
that allows using fwmark as a tin selector, as a convenience for people who want
to customise tin selection. The third patch is just a cleanup to the tin
selection logic.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_sched.h

@@ -1021,6 +1021,7 @@ enum {
 	TCA_CAKE_INGRESS,
 	TCA_CAKE_ACK_FILTER,
 	TCA_CAKE_SPLIT_GSO,
+	TCA_CAKE_FWMARK,
 	__TCA_CAKE_MAX
 };
 #define TCA_CAKE_MAX	(__TCA_CAKE_MAX - 1)

net/sched/sch_cake.c

@@ -138,8 +138,8 @@ struct cake_flow {
 struct cake_host {
 	u32 srchost_tag;
 	u32 dsthost_tag;
-	u16 srchost_refcnt;
-	u16 dsthost_refcnt;
+	u16 srchost_bulk_flow_count;
+	u16 dsthost_bulk_flow_count;
 };
 
 struct cake_heap_entry {
@@ -258,7 +258,8 @@ enum {
 	CAKE_FLAG_AUTORATE_INGRESS = BIT(1),
 	CAKE_FLAG_INGRESS	   = BIT(2),
 	CAKE_FLAG_WASH		   = BIT(3),
-	CAKE_FLAG_SPLIT_GSO	   = BIT(4)
+	CAKE_FLAG_SPLIT_GSO	   = BIT(4),
+	CAKE_FLAG_FWMARK	   = BIT(5)
 };
 
 /* COBALT operates the Codel and BLUE algorithms in parallel, in order to
@@ -746,8 +747,10 @@ static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
 		 * queue, accept the collision, update the host tags.
 		 */
 		q->way_collisions++;
-		q->hosts[q->flows[reduced_hash].srchost].srchost_refcnt--;
-		q->hosts[q->flows[reduced_hash].dsthost].dsthost_refcnt--;
+		if (q->flows[outer_hash + k].set == CAKE_SET_BULK) {
+			q->hosts[q->flows[reduced_hash].srchost].srchost_bulk_flow_count--;
+			q->hosts[q->flows[reduced_hash].dsthost].dsthost_bulk_flow_count--;
+		}
 		allocate_src = cake_dsrc(flow_mode);
 		allocate_dst = cake_ddst(flow_mode);
 found:
@@ -767,13 +770,14 @@ static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
 			}
 			for (i = 0; i < CAKE_SET_WAYS;
 				i++, k = (k + 1) % CAKE_SET_WAYS) {
-				if (!q->hosts[outer_hash + k].srchost_refcnt)
+				if (!q->hosts[outer_hash + k].srchost_bulk_flow_count)
 					break;
 			}
 			q->hosts[outer_hash + k].srchost_tag = srchost_hash;
 found_src:
 			srchost_idx = outer_hash + k;
-			q->hosts[srchost_idx].srchost_refcnt++;
+			if (q->flows[reduced_hash].set == CAKE_SET_BULK)
+				q->hosts[srchost_idx].srchost_bulk_flow_count++;
 			q->flows[reduced_hash].srchost = srchost_idx;
 		}
 
@@ -789,13 +793,14 @@ static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
 			}
 			for (i = 0; i < CAKE_SET_WAYS;
 			     i++, k = (k + 1) % CAKE_SET_WAYS) {
-				if (!q->hosts[outer_hash + k].dsthost_refcnt)
+				if (!q->hosts[outer_hash + k].dsthost_bulk_flow_count)
 					break;
 			}
 			q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
 found_dst:
 			dsthost_idx = outer_hash + k;
-			q->hosts[dsthost_idx].dsthost_refcnt++;
+			if (q->flows[reduced_hash].set == CAKE_SET_BULK)
+				q->hosts[dsthost_idx].dsthost_bulk_flow_count++;
 			q->flows[reduced_hash].dsthost = dsthost_idx;
 		}
 	}
@@ -1508,20 +1513,6 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
 	return idx + (tin << 16);
 }
 
-static void cake_wash_diffserv(struct sk_buff *skb)
-{
-	switch (skb->protocol) {
-	case htons(ETH_P_IP):
-		ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
-		break;
-	case htons(ETH_P_IPV6):
-		ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
-		break;
-	default:
-		break;
-	}
-}
-
 static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
 {
 	u8 dscp;
@@ -1553,25 +1544,32 @@ static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
 {
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 tin;
+	u8 dscp;
+
+	/* Tin selection: Default to diffserv-based selection, allow overriding
+	 * using firewall marks or skb->priority.
+	 */
+	dscp = cake_handle_diffserv(skb,
+				    q->rate_flags & CAKE_FLAG_WASH);
+
+	if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
+		tin = 0;
 
-	if (TC_H_MAJ(skb->priority) == sch->handle &&
-	    TC_H_MIN(skb->priority) > 0 &&
-	    TC_H_MIN(skb->priority) <= q->tin_cnt) {
+	else if (q->rate_flags & CAKE_FLAG_FWMARK && /* use fw mark */
+		 skb->mark &&
+		 skb->mark <= q->tin_cnt)
+		tin = q->tin_order[skb->mark - 1];
+
+	else if (TC_H_MAJ(skb->priority) == sch->handle &&
+		 TC_H_MIN(skb->priority) > 0 &&
+		 TC_H_MIN(skb->priority) <= q->tin_cnt)
 		tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
 
-		if (q->rate_flags & CAKE_FLAG_WASH)
-			cake_wash_diffserv(skb);
-	} else if (q->tin_mode != CAKE_DIFFSERV_BESTEFFORT) {
-		/* extract the Diffserv Precedence field, if it exists */
-		/* and clear DSCP bits if washing */
-		tin = q->tin_index[cake_handle_diffserv(skb,
-				q->rate_flags & CAKE_FLAG_WASH)];
+	else {
+		tin = q->tin_index[dscp];
+
 		if (unlikely(tin >= q->tin_cnt))
 			tin = 0;
-	} else {
-		tin = 0;
-		if (q->rate_flags & CAKE_FLAG_WASH)
-			cake_wash_diffserv(skb);
 	}
 
 	return &q->tins[tin];
@@ -1794,20 +1792,30 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		b->sparse_flow_count++;
 
 		if (cake_dsrc(q->flow_mode))
-			host_load = max(host_load, srchost->srchost_refcnt);
+			host_load = max(host_load, srchost->srchost_bulk_flow_count);
 
 		if (cake_ddst(q->flow_mode))
-			host_load = max(host_load, dsthost->dsthost_refcnt);
+			host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
 
 		flow->deficit = (b->flow_quantum *
 				 quantum_div[host_load]) >> 16;
 	} else if (flow->set == CAKE_SET_SPARSE_WAIT) {
+		struct cake_host *srchost = &b->hosts[flow->srchost];
+		struct cake_host *dsthost = &b->hosts[flow->dsthost];
+
 		/* this flow was empty, accounted as a sparse flow, but actually
 		 * in the bulk rotation.
 		 */
 		flow->set = CAKE_SET_BULK;
 		b->sparse_flow_count--;
 		b->bulk_flow_count++;
+
+		if (cake_dsrc(q->flow_mode))
+			srchost->srchost_bulk_flow_count++;
+
+		if (cake_ddst(q->flow_mode))
+			dsthost->dsthost_bulk_flow_count++;
+
 	}
 
 	if (q->buffer_used > q->buffer_max_used)
@@ -1975,23 +1983,8 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 	dsthost = &b->hosts[flow->dsthost];
 	host_load = 1;
 
-	if (cake_dsrc(q->flow_mode))
-		host_load = max(host_load, srchost->srchost_refcnt);
-
-	if (cake_ddst(q->flow_mode))
-		host_load = max(host_load, dsthost->dsthost_refcnt);
-
-	WARN_ON(host_load > CAKE_QUEUES);
-
 	/* flow isolation (DRR++) */
 	if (flow->deficit <= 0) {
-		/* The shifted prandom_u32() is a way to apply dithering to
-		 * avoid accumulating roundoff errors
-		 */
-		flow->deficit += (b->flow_quantum * quantum_div[host_load] +
-				  (prandom_u32() >> 16)) >> 16;
-		list_move_tail(&flow->flowchain, &b->old_flows);
-
 		/* Keep all flows with deficits out of the sparse and decaying
 		 * rotations.  No non-empty flow can go into the decaying
 		 * rotation, so they can't get deficits
@@ -2000,6 +1993,13 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 			if (flow->head) {
 				b->sparse_flow_count--;
 				b->bulk_flow_count++;
+
+				if (cake_dsrc(q->flow_mode))
+					srchost->srchost_bulk_flow_count++;
+
+				if (cake_ddst(q->flow_mode))
+					dsthost->dsthost_bulk_flow_count++;
+
 				flow->set = CAKE_SET_BULK;
 			} else {
 				/* we've moved it to the bulk rotation for
@@ -2009,6 +2009,22 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 				flow->set = CAKE_SET_SPARSE_WAIT;
 			}
 		}
+
+		if (cake_dsrc(q->flow_mode))
+			host_load = max(host_load, srchost->srchost_bulk_flow_count);
+
+		if (cake_ddst(q->flow_mode))
+			host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
+
+		WARN_ON(host_load > CAKE_QUEUES);
+
+		/* The shifted prandom_u32() is a way to apply dithering to
+		 * avoid accumulating roundoff errors
+		 */
+		flow->deficit += (b->flow_quantum * quantum_div[host_load] +
+				  (prandom_u32() >> 16)) >> 16;
+		list_move_tail(&flow->flowchain, &b->old_flows);
+
 		goto retry;
 	}
 
@@ -2029,6 +2045,13 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 					       &b->decaying_flows);
 				if (flow->set == CAKE_SET_BULK) {
 					b->bulk_flow_count--;
+
+					if (cake_dsrc(q->flow_mode))
+						srchost->srchost_bulk_flow_count--;
+
+					if (cake_ddst(q->flow_mode))
+						dsthost->dsthost_bulk_flow_count--;
+
 					b->decaying_flow_count++;
 				} else if (flow->set == CAKE_SET_SPARSE ||
 					   flow->set == CAKE_SET_SPARSE_WAIT) {
@@ -2042,14 +2065,19 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 				if (flow->set == CAKE_SET_SPARSE ||
 				    flow->set == CAKE_SET_SPARSE_WAIT)
 					b->sparse_flow_count--;
-				else if (flow->set == CAKE_SET_BULK)
+				else if (flow->set == CAKE_SET_BULK) {
 					b->bulk_flow_count--;
-				else
+
+					if (cake_dsrc(q->flow_mode))
+						srchost->srchost_bulk_flow_count--;
+
+					if (cake_ddst(q->flow_mode))
+						dsthost->dsthost_bulk_flow_count--;
+
+				} else
 					b->decaying_flow_count--;
 
 				flow->set = CAKE_SET_NONE;
-				srchost->srchost_refcnt--;
-				dsthost->dsthost_refcnt--;
 			}
 			goto begin;
 		}
@@ -2590,6 +2618,13 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 			q->rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
 	}
 
+	if (tb[TCA_CAKE_FWMARK]) {
+		if (!!nla_get_u32(tb[TCA_CAKE_FWMARK]))
+			q->rate_flags |= CAKE_FLAG_FWMARK;
+		else
+			q->rate_flags &= ~CAKE_FLAG_FWMARK;
+	}
+
 	if (q->tins) {
 		sch_tree_lock(sch);
 		cake_reconfigure(sch);
@@ -2749,6 +2784,10 @@ static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
 			!!(q->rate_flags & CAKE_FLAG_SPLIT_GSO)))
 		goto nla_put_failure;
 
+	if (nla_put_u32(skb, TCA_CAKE_FWMARK,
+			!!(q->rate_flags & CAKE_FLAG_FWMARK)))
+		goto nla_put_failure;
+
 	return nla_nest_end(skb, opts);
 
 nla_put_failure: