[PATCH v2 1/2] net_sched: add size table functions

[PATCH v2 1/2] net_sched: add size table functions

[Jussi Kivilinna]

Patch adds size table that is similiar to rate table, with difference that
size table stores link layer packet size. It's needed for HFSC link
layer adaption patch as it converts skb->len to link layer packet size
directly, unlike HTB/CFQ/etc that convert packet length to link layer
transfer time using rate tables.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
---

 include/linux/pkt_sched.h |   10 ++++++++++
 include/net/pkt_sched.h   |    3 +++
 include/net/sch_generic.h |   23 ++++++++++++++++++++++
 net/sched/sch_api.c       |   47 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index dbb7ac3..b8366fb 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -85,6 +85,16 @@ struct tc_ratespec
 
 #define TC_RTAB_SIZE	1024
 
+struct tc_sizespec {
+	unsigned char	cell_log;
+	unsigned char	size_log;
+	unsigned short	overhead;
+	short		cell_align;
+	unsigned short	mpu;
+};
+
+#define TC_STAB_SIZE	1024
+
 /* FIFO section */
 
 struct tc_fifo_qopt
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 46fb4d8..b032488 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -78,7 +78,10 @@ extern struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
 extern struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
 extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
 		struct nlattr *tab);
+extern struct qdisc_size_table *qdisc_get_stab(struct tc_sizespec *s,
+		struct nlattr *tab);
 extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
+extern void qdisc_put_stab(struct qdisc_size_table *tab);
 
 extern void __qdisc_run(struct net_device *dev);
 
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ab502ec..32b6865 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -23,6 +23,13 @@ struct qdisc_rate_table
 	int		refcnt;
 };
 
+struct qdisc_size_table {
+	struct tc_sizespec szopts;
+	u16		data[512];
+	struct qdisc_size_table *next;
+	int		refcnt;
+};
+
 struct Qdisc
 {
 	int 			(*enqueue)(struct sk_buff *skb, struct Qdisc *dev);
@@ -316,6 +323,22 @@ static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
 	return rtab->data[slot];
 }
 
+/* Length to link layer size lookup in a qdisc_size_table, to determine how
+   what size packet takes on link layer.
+ */
+static inline u32 qdisc_linklayer_sz(struct qdisc_size_table *stab, u32 pktlen)
+{
+	int slot = pktlen + stab->szopts.cell_align + stab->szopts.overhead;
+	unsigned char size_log = stab->szopts.size_log;
+	if (unlikely(slot < 0))
+		slot = 0;
+	slot >>= stab->szopts.cell_log;
+	if (unlikely(slot > 511))
+		return ((u32)stab->data[511] << size_log) * (slot >> 9) +
+			((u32)stab->data[slot & 0x1FF] << size_log);
+	return (u32)stab->data[slot] << size_log;
+}
+
 #ifdef CONFIG_NET_CLS_ACT
 static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask)
 {
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index c40773c..de25928 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -277,6 +277,53 @@ void qdisc_put_rtab(struct qdisc_rate_table *tab)
 }
 EXPORT_SYMBOL(qdisc_put_rtab);
 
+static struct qdisc_size_table *qdisc_stab_list;
+
+struct qdisc_size_table *qdisc_get_stab(struct tc_sizespec *s,
+					struct nlattr *tab)
+{
+	struct qdisc_size_table *stab;
+
+	for (stab = qdisc_stab_list; stab; stab = stab->next) {
+		if (memcmp(&stab->szopts, s, sizeof(struct tc_sizespec)) == 0) {
+			stab->refcnt++;
+			return stab;
+		}
+	}
+
+	if (tab == NULL || s->cell_log == 0 || nla_len(tab) != TC_STAB_SIZE)
+		return NULL;
+
+	stab = kmalloc(sizeof(*stab), GFP_KERNEL);
+	if (stab) {
+		stab->szopts = *s;
+		stab->refcnt = 1;
+		memcpy(stab->data, nla_data(tab), TC_STAB_SIZE);
+		stab->next = qdisc_stab_list;
+		qdisc_stab_list = stab;
+	}
+	return stab;
+}
+EXPORT_SYMBOL(qdisc_get_stab);
+
+void qdisc_put_stab(struct qdisc_size_table *tab)
+{
+	struct qdisc_size_table *stab, **stabp;
+
+	if (!tab || --tab->refcnt)
+		return;
+
+	for (stabp = &qdisc_stab_list; (stab = *stabp) != NULL;
+							stabp = &stab->next) {
+		if (stab == tab) {
+			*stabp = stab->next;
+			kfree(stab);
+			return;
+		}
+	}
+}
+EXPORT_SYMBOL(qdisc_put_stab);
+
 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
 {
 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,

[PATCH v2 2/2] hfsc: add link layer overhead adaption

[Jussi Kivilinna]

CBQ and HTB have options for emulating overhead of underlying link layer
(mpu/overhead/linklayer options). This patch makes sch_hfsc use size table
to emulate link layer overhead.

Patch uses size table to convert packet length to emulated link layer packet
length. Converted packet length is passed to hfsc calculations instead of
real. If size table isn't passed to kernel, hfsc works as before.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
---

 include/linux/pkt_sched.h |    2 +
 net/sched/sch_hfsc.c      |  116 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 93 insertions(+), 25 deletions(-)

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index b8366fb..43c11f2 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -326,6 +326,8 @@ enum
 	TCA_HFSC_RSC,
 	TCA_HFSC_FSC,
 	TCA_HFSC_USC,
+	TCA_HFSC_SZOPTS,
+	TCA_HFSC_STAB,
 	__TCA_HFSC_MAX,
 };
 
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index fdfaa3f..de958aa 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -128,6 +128,8 @@ struct hfsc_class
 	struct list_head siblings;	/* sibling classes */
 	struct list_head children;	/* child classes */
 	struct Qdisc	*qdisc;		/* leaf qdisc */
+	struct qdisc_size_table *stab;	/* size table used for link layer
+					   overhead adaption */
 
 	struct rb_node el_node;		/* qdisc's eligible tree member */
 	struct rb_root vt_tree;		/* active children sorted by cl_vt */
@@ -496,6 +498,14 @@ sc2isc(struct tc_service_curve *sc, struct internal_sc *isc)
 	isc->ism2 = m2ism(sc->m2);
 }
 
+/* convert packet length to link layer packet length */
+static unsigned int get_linklayer_len(struct hfsc_class *cl, unsigned int len)
+{
+	if (unlikely(!len) || likely(!cl->stab))
+		return len;
+	return qdisc_linklayer_sz(cl->stab, len);
+}
+
 /*
  * initialize the runtime service curve with the given internal
  * service curve starting at (x, y).
@@ -987,9 +997,11 @@ hfsc_change_usc(struct hfsc_class *cl, struct tc_service_curve *usc,
 }
 
 static const struct nla_policy hfsc_policy[TCA_HFSC_MAX + 1] = {
-	[TCA_HFSC_RSC]	= { .len = sizeof(struct tc_service_curve) },
-	[TCA_HFSC_FSC]	= { .len = sizeof(struct tc_service_curve) },
-	[TCA_HFSC_USC]	= { .len = sizeof(struct tc_service_curve) },
+	[TCA_HFSC_RSC]		= { .len = sizeof(struct tc_service_curve) },
+	[TCA_HFSC_FSC]		= { .len = sizeof(struct tc_service_curve) },
+	[TCA_HFSC_USC]		= { .len = sizeof(struct tc_service_curve) },
+	[TCA_HFSC_SZOPTS]	= { .len = sizeof(struct tc_sizespec) },
+	[TCA_HFSC_STAB]		= { .type = NLA_BINARY, .len = TC_STAB_SIZE },
 };
 
 static int
@@ -1000,18 +1012,21 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 	struct hfsc_class *cl = (struct hfsc_class *)*arg;
 	struct hfsc_class *parent = NULL;
 	struct nlattr *opt = tca[TCA_OPTIONS];
-	struct nlattr *tb[TCA_HFSC_MAX + 1];
+	struct nlattr *tb[TCA_HFSC_STAB + 1];
 	struct tc_service_curve *rsc = NULL, *fsc = NULL, *usc = NULL;
+	struct tc_sizespec *szopts = NULL;
+	struct qdisc_size_table *stab = NULL;
 	u64 cur_time;
 	int err;
 
 	if (opt == NULL)
 		return -EINVAL;
 
-	err = nla_parse_nested(tb, TCA_HFSC_MAX, opt, hfsc_policy);
+	err = nla_parse_nested(tb, TCA_HFSC_STAB, opt, hfsc_policy);
 	if (err < 0)
 		return err;
 
+	err = -EINVAL;
 	if (tb[TCA_HFSC_RSC]) {
 		rsc = nla_data(tb[TCA_HFSC_RSC]);
 		if (rsc->m1 == 0 && rsc->m2 == 0)
@@ -1030,12 +1045,18 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 			usc = NULL;
 	}
 
+	if (tb[TCA_HFSC_SZOPTS]) {
+		szopts = nla_data(tb[TCA_HFSC_SZOPTS]);
+		stab = qdisc_get_stab(szopts, tb[TCA_HFSC_STAB]);
+	}
+
 	if (cl != NULL) {
 		if (parentid) {
+			err = -EINVAL;
 			if (cl->cl_parent && cl->cl_parent->classid != parentid)
-				return -EINVAL;
+				goto failure;
 			if (cl->cl_parent == NULL && parentid != TC_H_ROOT)
-				return -EINVAL;
+				goto failure;
 		}
 		cur_time = psched_get_time();
 
@@ -1047,9 +1068,14 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 		if (usc != NULL)
 			hfsc_change_usc(cl, usc, cur_time);
 
+		if (cl->stab)
+			qdisc_put_stab(cl->stab);
+		cl->stab = stab;
+
 		if (cl->qdisc->q.qlen != 0) {
 			if (cl->cl_flags & HFSC_RSC)
-				update_ed(cl, qdisc_peek_len(cl->qdisc));
+				update_ed(cl, get_linklayer_len(cl,
+						qdisc_peek_len(cl->qdisc)));
 			if (cl->cl_flags & HFSC_FSC)
 				update_vf(cl, 0, cur_time);
 		}
@@ -1062,27 +1088,39 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 		return 0;
 	}
 
-	if (parentid == TC_H_ROOT)
-		return -EEXIST;
+	if (parentid == TC_H_ROOT) {
+		err = -EEXIST;
+		goto failure;
+	}
 
 	parent = &q->root;
 	if (parentid) {
 		parent = hfsc_find_class(parentid, sch);
-		if (parent == NULL)
-			return -ENOENT;
+		if (parent == NULL) {
+			err = -ENOENT;
+			goto failure;
+		}
 	}
 
-	if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0)
-		return -EINVAL;
-	if (hfsc_find_class(classid, sch))
-		return -EEXIST;
+	if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0) {
+		err = -EINVAL;
+		goto failure;
+	}
+	if (hfsc_find_class(classid, sch)) {
+		err = -EEXIST;
+		goto failure;
+	}
 
-	if (rsc == NULL && fsc == NULL)
-		return -EINVAL;
+	if (rsc == NULL && fsc == NULL) {
+		err = -EINVAL;
+		goto failure;
+	}
 
 	cl = kzalloc(sizeof(struct hfsc_class), GFP_KERNEL);
-	if (cl == NULL)
-		return -ENOBUFS;
+	if (cl == NULL) {
+		err = -ENOBUFS;
+		goto failure;
+	}
 
 	if (rsc != NULL)
 		hfsc_change_rsc(cl, rsc, 0);
@@ -1109,6 +1147,9 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 		hfsc_purge_queue(sch, parent);
 	hfsc_adjust_levels(parent);
 	cl->cl_pcvtoff = parent->cl_cvtoff;
+	if (cl->stab)
+		qdisc_put_stab(cl->stab);
+	cl->stab = stab;
 	sch_tree_unlock(sch);
 
 	if (tca[TCA_RATE])
@@ -1116,6 +1157,10 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 				  &sch->dev->queue_lock, tca[TCA_RATE]);
 	*arg = (unsigned long)cl;
 	return 0;
+failure:
+	if (stab)
+		qdisc_put_stab(stab);
+	return err;
 }
 
 static void
@@ -1126,6 +1171,8 @@ hfsc_destroy_class(struct Qdisc *sch, struct hfsc_class *cl)
 	tcf_destroy_chain(cl->filter_list);
 	qdisc_destroy(cl->qdisc);
 	gen_kill_estimator(&cl->bstats, &cl->rate_est);
+	if (cl->stab)
+		qdisc_put_stab(cl->stab);
 	if (cl != &q->root)
 		kfree(cl);
 }
@@ -1338,6 +1385,21 @@ hfsc_dump_curves(struct sk_buff *skb, struct hfsc_class *cl)
 	return -1;
 }
 
+static inline int
+hfsc_dump_szopts(struct sk_buff *skb, struct hfsc_class *cl)
+{
+	if (!cl->stab)
+		return 0;
+
+	NLA_PUT(skb, TCA_HFSC_SZOPTS, sizeof(cl->stab->szopts),
+		&cl->stab->szopts);
+
+	return skb->len;
+
+ nla_put_failure:
+	return -1;
+}
+
 static int
 hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,
 		struct tcmsg *tcm)
@@ -1355,6 +1417,8 @@ hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,
 		goto nla_put_failure;
 	if (hfsc_dump_curves(skb, cl) < 0)
 		goto nla_put_failure;
+	if (hfsc_dump_szopts(skb, cl) < 0)
+		goto nla_put_failure;
 	nla_nest_end(skb, nest);
 	return skb->len;
 
@@ -1588,7 +1652,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	}
 
 	if (cl->qdisc->q.qlen == 1)
-		set_active(cl, len);
+		set_active(cl, get_linklayer_len(cl, len));
 
 	cl->bstats.packets++;
 	cl->bstats.bytes += len;
@@ -1606,7 +1670,7 @@ hfsc_dequeue(struct Qdisc *sch)
 	struct hfsc_class *cl;
 	struct sk_buff *skb;
 	u64 cur_time;
-	unsigned int next_len;
+	unsigned int next_len, cur_len;
 	int realtime = 0;
 
 	if (sch->q.qlen == 0)
@@ -1643,14 +1707,16 @@ hfsc_dequeue(struct Qdisc *sch)
 		return NULL;
 	}
 
-	update_vf(cl, skb->len, cur_time);
+	cur_len = get_linklayer_len(cl, skb->len);
+	update_vf(cl, cur_len, cur_time);
 	if (realtime)
-		cl->cl_cumul += skb->len;
+		cl->cl_cumul += cur_len;
 
 	if (cl->qdisc->q.qlen != 0) {
 		if (cl->cl_flags & HFSC_RSC) {
 			/* update ed */
-			next_len = qdisc_peek_len(cl->qdisc);
+			next_len = get_linklayer_len(cl,
+						qdisc_peek_len(cl->qdisc));
 			if (realtime)
 				update_ed(cl, next_len);
 			else