[patch net-next v4 00/11] couple of net/sched fixes+improvements

[patch net-next v4 00/11] couple of net/sched fixes+improvements

[Jiri Pirko]

v3->v4:
 - cache mtu_ptokens value instead of compute in by psched_l2t_ns in fast path
   (patch "act_police: improved accuracy at high rates" and
    patch "tbf: fix value set for q->ptokens")

v2->v3:
 - fixed schedule while atomic issue
   (patch "act_police: improved accuracy at high rates")

v1->v2:
 - made struct psched_ratecfg const in params of couple of inline functions
   (patch "sch: make htb_rate_cfg and functions around that generic")
 - fixes misspelled "peak"
   (patch "tbf: improved accuracy at high rates")
 - added last 4 patches to this set

Jiri Pirko (11):
  htb: use PSCHED_TICKS2NS()
  htb: fix values in opt dump
  htb: remove pointless first initialization of buffer and cbuffer
  htb: initialize cl->tokens and cl->ctokens correctly
  sch: make htb_rate_cfg and functions around that generic
  tbf: improved accuracy at high rates
  tbf: ignore max_size check for gso skbs
  tbf: fix value set for q->ptokens
  act_police: move struct tcf_police to act_police.c
  act_police: improved accuracy at high rates
  act_police: remove <=mtu check for gso skbs

 include/net/act_api.h     |  15 -------
 include/net/sch_generic.h |  19 +++++++++
 net/sched/act_police.c    | 100 ++++++++++++++++++++++++++++------------------
 net/sched/sch_generic.c   |  37 +++++++++++++++++
 net/sched/sch_htb.c       |  80 +++++++------------------------------
 net/sched/sch_tbf.c       |  73 ++++++++++++++++-----------------
 6 files changed, 169 insertions(+), 155 deletions(-)

-- 
1.8.1.2

[patch net-next v4 01/11] htb: use PSCHED_TICKS2NS()

[Jiri Pirko]

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_htb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 51561ea..476992c 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1512,8 +1512,8 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 	htb_precompute_ratedata(&cl->rate);
 	htb_precompute_ratedata(&cl->ceil);
 
-	cl->buffer = hopt->buffer << PSCHED_SHIFT;
-	cl->cbuffer = hopt->buffer << PSCHED_SHIFT;
+	cl->buffer = PSCHED_TICKS2NS(hopt->buffer);
+	cl->cbuffer = PSCHED_TICKS2NS(hopt->buffer);
 
 	sch_tree_unlock(sch);
 
-- 
1.8.1.2

[patch net-next v4 02/11] htb: fix values in opt dump

[Jiri Pirko]

in htb_change_class() cl->buffer and cl->buffer are stored in ns.
So in dump, convert them back to psched ticks.

Note this was introduced by:
commit 56b765b79e9a78dc7d3f8850ba5e5567205a3ecd
    htb: improved accuracy at high rates

Please consider this for -net/-stable.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_htb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 476992c..14a83dc 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1135,9 +1135,9 @@ static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
 	memset(&opt, 0, sizeof(opt));
 
 	opt.rate.rate = cl->rate.rate_bps >> 3;
-	opt.buffer = cl->buffer;
+	opt.buffer = PSCHED_NS2TICKS(cl->buffer);
 	opt.ceil.rate = cl->ceil.rate_bps >> 3;
-	opt.cbuffer = cl->cbuffer;
+	opt.cbuffer = PSCHED_NS2TICKS(cl->cbuffer);
 	opt.quantum = cl->quantum;
 	opt.prio = cl->prio;
 	opt.level = cl->level;
-- 
1.8.1.2

[patch net-next v4 03/11] htb: remove pointless first initialization of buffer and cbuffer

[Jiri Pirko]

these are initialized correctly couple of lines later in the function.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_htb.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 14a83dc..547912e9 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1503,9 +1503,6 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 			cl->prio = TC_HTB_NUMPRIO - 1;
 	}
 
-	cl->buffer = hopt->buffer;
-	cl->cbuffer = hopt->cbuffer;
-
 	cl->rate.rate_bps = (u64)hopt->rate.rate << 3;
 	cl->ceil.rate_bps = (u64)hopt->ceil.rate << 3;
 
-- 
1.8.1.2

[patch net-next v4 04/11] htb: initialize cl->tokens and cl->ctokens correctly

[Jiri Pirko]

These are in ns so convert from ticks to ns.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_htb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 547912e9..2b22544 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1459,8 +1459,8 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 		cl->parent = parent;
 
 		/* set class to be in HTB_CAN_SEND state */
-		cl->tokens = hopt->buffer;
-		cl->ctokens = hopt->cbuffer;
+		cl->tokens = PSCHED_TICKS2NS(hopt->buffer);
+		cl->ctokens = PSCHED_TICKS2NS(hopt->cbuffer);
 		cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC;	/* 1min */
 		cl->t_c = psched_get_time();
 		cl->cmode = HTB_CAN_SEND;
-- 
1.8.1.2

[patch net-next v4 05/11] sch: make htb_rate_cfg and functions around that generic

[Jiri Pirko]

As it is going to be used in tbf as well, push these to generic code.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 include/net/sch_generic.h | 19 ++++++++++++++
 net/sched/sch_generic.c   | 37 +++++++++++++++++++++++++++
 net/sched/sch_htb.c       | 65 +++++++----------------------------------------
 3 files changed, 65 insertions(+), 56 deletions(-)

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 2d06c2a..2761c90 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -679,4 +679,23 @@ static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask,
 }
 #endif
 
+struct psched_ratecfg {
+	u64 rate_bps;
+	u32 mult;
+	u32 shift;
+};
+
+static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
+				unsigned int len)
+{
+	return ((u64)len * r->mult) >> r->shift;
+}
+
+extern void psched_ratecfg_precompute(struct psched_ratecfg *r, u32 rate);
+
+static inline u32 psched_ratecfg_getrate(const struct psched_ratecfg *r)
+{
+	return r->rate_bps >> 3;
+}
+
 #endif
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 5d81a44..ffad481 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -25,6 +25,7 @@
 #include <linux/rcupdate.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <net/sch_generic.h>
 #include <net/pkt_sched.h>
 #include <net/dst.h>
 
@@ -896,3 +897,39 @@ void dev_shutdown(struct net_device *dev)
 
 	WARN_ON(timer_pending(&dev->watchdog_timer));
 }
+
+void psched_ratecfg_precompute(struct psched_ratecfg *r, u32 rate)
+{
+	u64 factor;
+	u64 mult;
+	int shift;
+
+	r->rate_bps = rate << 3;
+	r->shift = 0;
+	r->mult = 1;
+	/*
+	 * Calibrate mult, shift so that token counting is accurate
+	 * for smallest packet size (64 bytes).  Token (time in ns) is
+	 * computed as (bytes * 8) * NSEC_PER_SEC / rate_bps.  It will
+	 * work as long as the smallest packet transfer time can be
+	 * accurately represented in nanosec.
+	 */
+	if (r->rate_bps > 0) {
+		/*
+		 * Higher shift gives better accuracy.  Find the largest
+		 * shift such that mult fits in 32 bits.
+		 */
+		for (shift = 0; shift < 16; shift++) {
+			r->shift = shift;
+			factor = 8LLU * NSEC_PER_SEC * (1 << r->shift);
+			mult = div64_u64(factor, r->rate_bps);
+			if (mult > UINT_MAX)
+				break;
+		}
+
+		r->shift = shift - 1;
+		factor = 8LLU * NSEC_PER_SEC * (1 << r->shift);
+		r->mult = div64_u64(factor, r->rate_bps);
+	}
+}
+EXPORT_SYMBOL(psched_ratecfg_precompute);
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 2b22544..03c2692 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -38,6 +38,7 @@
 #include <linux/workqueue.h>
 #include <linux/slab.h>
 #include <net/netlink.h>
+#include <net/sch_generic.h>
 #include <net/pkt_sched.h>
 
 /* HTB algorithm.
@@ -71,12 +72,6 @@ enum htb_cmode {
 	HTB_CAN_SEND		/* class can send */
 };
 
-struct htb_rate_cfg {
-	u64 rate_bps;
-	u32 mult;
-	u32 shift;
-};
-
 /* interior & leaf nodes; props specific to leaves are marked L: */
 struct htb_class {
 	struct Qdisc_class_common common;
@@ -124,8 +119,8 @@ struct htb_class {
 	int filter_cnt;
 
 	/* token bucket parameters */
-	struct htb_rate_cfg rate;
-	struct htb_rate_cfg ceil;
+	struct psched_ratecfg rate;
+	struct psched_ratecfg ceil;
 	s64 buffer, cbuffer;	/* token bucket depth/rate */
 	psched_tdiff_t mbuffer;	/* max wait time */
 	s64 tokens, ctokens;	/* current number of tokens */
@@ -168,45 +163,6 @@ struct htb_sched {
 	struct work_struct work;
 };
 
-static u64 l2t_ns(struct htb_rate_cfg *r, unsigned int len)
-{
-	return ((u64)len * r->mult) >> r->shift;
-}
-
-static void htb_precompute_ratedata(struct htb_rate_cfg *r)
-{
-	u64 factor;
-	u64 mult;
-	int shift;
-
-	r->shift = 0;
-	r->mult = 1;
-	/*
-	 * Calibrate mult, shift so that token counting is accurate
-	 * for smallest packet size (64 bytes).  Token (time in ns) is
-	 * computed as (bytes * 8) * NSEC_PER_SEC / rate_bps.  It will
-	 * work as long as the smallest packet transfer time can be
-	 * accurately represented in nanosec.
-	 */
-	if (r->rate_bps > 0) {
-		/*
-		 * Higher shift gives better accuracy.  Find the largest
-		 * shift such that mult fits in 32 bits.
-		 */
-		for (shift = 0; shift < 16; shift++) {
-			r->shift = shift;
-			factor = 8LLU * NSEC_PER_SEC * (1 << r->shift);
-			mult = div64_u64(factor, r->rate_bps);
-			if (mult > UINT_MAX)
-				break;
-		}
-
-		r->shift = shift - 1;
-		factor = 8LLU * NSEC_PER_SEC * (1 << r->shift);
-		r->mult = div64_u64(factor, r->rate_bps);
-	}
-}
-
 /* find class in global hash table using given handle */
 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
 {
@@ -632,7 +588,7 @@ static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, s64 diff)
 
 	if (toks > cl->buffer)
 		toks = cl->buffer;
-	toks -= (s64) l2t_ns(&cl->rate, bytes);
+	toks -= (s64) psched_l2t_ns(&cl->rate, bytes);
 	if (toks <= -cl->mbuffer)
 		toks = 1 - cl->mbuffer;
 
@@ -645,7 +601,7 @@ static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
 
 	if (toks > cl->cbuffer)
 		toks = cl->cbuffer;
-	toks -= (s64) l2t_ns(&cl->ceil, bytes);
+	toks -= (s64) psched_l2t_ns(&cl->ceil, bytes);
 	if (toks <= -cl->mbuffer)
 		toks = 1 - cl->mbuffer;
 
@@ -1134,9 +1090,9 @@ static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
 
 	memset(&opt, 0, sizeof(opt));
 
-	opt.rate.rate = cl->rate.rate_bps >> 3;
+	opt.rate.rate = psched_ratecfg_getrate(&cl->rate);
 	opt.buffer = PSCHED_NS2TICKS(cl->buffer);
-	opt.ceil.rate = cl->ceil.rate_bps >> 3;
+	opt.ceil.rate = psched_ratecfg_getrate(&cl->ceil);
 	opt.cbuffer = PSCHED_NS2TICKS(cl->cbuffer);
 	opt.quantum = cl->quantum;
 	opt.prio = cl->prio;
@@ -1503,11 +1459,8 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 			cl->prio = TC_HTB_NUMPRIO - 1;
 	}
 
-	cl->rate.rate_bps = (u64)hopt->rate.rate << 3;
-	cl->ceil.rate_bps = (u64)hopt->ceil.rate << 3;
-
-	htb_precompute_ratedata(&cl->rate);
-	htb_precompute_ratedata(&cl->ceil);
+	psched_ratecfg_precompute(&cl->rate, hopt->rate.rate);
+	psched_ratecfg_precompute(&cl->ceil, hopt->ceil.rate);
 
 	cl->buffer = PSCHED_TICKS2NS(hopt->buffer);
 	cl->cbuffer = PSCHED_TICKS2NS(hopt->buffer);
-- 
1.8.1.2

[patch net-next v4 06/11] tbf: improved accuracy at high rates

[Jiri Pirko]

Current TBF uses rate table computed by the "tc" userspace program,
which has the following issue:

The rate table has 256 entries to map packet lengths to
token (time units).  With TSO sized packets, the 256 entry granularity
leads to loss/gain of rate, making the token bucket inaccurate.

Thus, instead of relying on rate table, this patch explicitly computes
the time and accounts for packet transmission times with nanosecond
granularity.

This is a followup to 56b765b79e9a78dc7d3f8850ba5e5567205a3ecd

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_tbf.c | 60 ++++++++++++++++++++++++++---------------------------
 1 file changed, 29 insertions(+), 31 deletions(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 4b056c15..e05710a 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -19,6 +19,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <net/netlink.h>
+#include <net/sch_generic.h>
 #include <net/pkt_sched.h>
 
 
@@ -100,23 +101,21 @@
 struct tbf_sched_data {
 /* Parameters */
 	u32		limit;		/* Maximal length of backlog: bytes */
-	u32		buffer;		/* Token bucket depth/rate: MUST BE >= MTU/B */
+	s64		buffer;		/* Token bucket depth/rate: MUST BE >= MTU/B */
 	u32		mtu;
 	u32		max_size;
-	struct qdisc_rate_table	*R_tab;
-	struct qdisc_rate_table	*P_tab;
+	struct psched_ratecfg rate;
+	struct psched_ratecfg peak;
+	bool peak_present;
 
 /* Variables */
-	long	tokens;			/* Current number of B tokens */
-	long	ptokens;		/* Current number of P tokens */
+	s64	tokens;			/* Current number of B tokens */
+	s64	ptokens;		/* Current number of P tokens */
 	psched_time_t	t_c;		/* Time check-point */
 	struct Qdisc	*qdisc;		/* Inner qdisc, default - bfifo queue */
 	struct qdisc_watchdog watchdog;	/* Watchdog timer */
 };
 
-#define L2T(q, L)   qdisc_l2t((q)->R_tab, L)
-#define L2T_P(q, L) qdisc_l2t((q)->P_tab, L)
-
 static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct tbf_sched_data *q = qdisc_priv(sch);
@@ -157,23 +156,23 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
 
 	if (skb) {
 		psched_time_t now;
-		long toks;
-		long ptoks = 0;
+		s64 toks;
+		s64 ptoks = 0;
 		unsigned int len = qdisc_pkt_len(skb);
 
-		now = psched_get_time();
-		toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
+		now = ktime_to_ns(ktime_get());
+		toks = min_t(s64, now - q->t_c, q->buffer);
 
-		if (q->P_tab) {
+		if (q->peak_present) {
 			ptoks = toks + q->ptokens;
 			if (ptoks > (long)q->mtu)
 				ptoks = q->mtu;
-			ptoks -= L2T_P(q, len);
+			ptoks -= (s64) psched_l2t_ns(&q->peak, len);
 		}
 		toks += q->tokens;
-		if (toks > (long)q->buffer)
+		if (toks > q->buffer)
 			toks = q->buffer;
-		toks -= L2T(q, len);
+		toks -= (s64) psched_l2t_ns(&q->rate, len);
 
 		if ((toks|ptoks) >= 0) {
 			skb = qdisc_dequeue_peeked(q->qdisc);
@@ -214,7 +213,7 @@ static void tbf_reset(struct Qdisc *sch)
 
 	qdisc_reset(q->qdisc);
 	sch->q.qlen = 0;
-	q->t_c = psched_get_time();
+	q->t_c = ktime_to_ns(ktime_get());
 	q->tokens = q->buffer;
 	q->ptokens = q->mtu;
 	qdisc_watchdog_cancel(&q->watchdog);
@@ -295,12 +294,17 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
 	q->limit = qopt->limit;
 	q->mtu = qopt->mtu;
 	q->max_size = max_size;
-	q->buffer = qopt->buffer;
+	q->buffer = PSCHED_TICKS2NS(qopt->buffer);
 	q->tokens = q->buffer;
 	q->ptokens = q->mtu;
 
-	swap(q->R_tab, rtab);
-	swap(q->P_tab, ptab);
+	psched_ratecfg_precompute(&q->rate, rtab->rate.rate);
+	if (ptab) {
+		psched_ratecfg_precompute(&q->peak, ptab->rate.rate);
+		q->peak_present = true;
+	} else {
+		q->peak_present = false;
+	}
 
 	sch_tree_unlock(sch);
 	err = 0;
@@ -319,7 +323,7 @@ static int tbf_init(struct Qdisc *sch, struct nlattr *opt)
 	if (opt == NULL)
 		return -EINVAL;
 
-	q->t_c = psched_get_time();
+	q->t_c = ktime_to_ns(ktime_get());
 	qdisc_watchdog_init(&q->watchdog, sch);
 	q->qdisc = &noop_qdisc;
 
@@ -331,12 +335,6 @@ static void tbf_destroy(struct Qdisc *sch)
 	struct tbf_sched_data *q = qdisc_priv(sch);
 
 	qdisc_watchdog_cancel(&q->watchdog);
-
-	if (q->P_tab)
-		qdisc_put_rtab(q->P_tab);
-	if (q->R_tab)
-		qdisc_put_rtab(q->R_tab);
-
 	qdisc_destroy(q->qdisc);
 }
 
@@ -352,13 +350,13 @@ static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	opt.limit = q->limit;
-	opt.rate = q->R_tab->rate;
-	if (q->P_tab)
-		opt.peakrate = q->P_tab->rate;
+	opt.rate.rate = psched_ratecfg_getrate(&q->rate);
+	if (q->peak_present)
+		opt.peakrate.rate = psched_ratecfg_getrate(&q->peak);
 	else
 		memset(&opt.peakrate, 0, sizeof(opt.peakrate));
 	opt.mtu = q->mtu;
-	opt.buffer = q->buffer;
+	opt.buffer = PSCHED_NS2TICKS(q->buffer);
 	if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
-- 
1.8.1.2

[patch net-next v4 07/11] tbf: ignore max_size check for gso skbs

[Jiri Pirko]

This check made bigger packets incorrectly dropped. Remove this
limitation for gso skbs.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_tbf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index e05710a..dc562a8 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -121,7 +121,7 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	struct tbf_sched_data *q = qdisc_priv(sch);
 	int ret;
 
-	if (qdisc_pkt_len(skb) > q->max_size)
+	if (qdisc_pkt_len(skb) > q->max_size && !skb_is_gso(skb))
 		return qdisc_reshape_fail(skb, sch);
 
 	ret = qdisc_enqueue(skb, q->qdisc);
-- 
1.8.1.2

Re: [patch net-next v4 07/11] tbf: ignore max_size check for gso skbs

[Jiri Pirko]

Hmm. I think that this approach might not be correct after all. This
might break existing setups when user is taking gso into account and
adjust mtu and burst accordingly. After more thorough study, I'm under
impression that gso skbs should not be handled in any different way.

Thoughts?


Sun, Feb 10, 2013 at 11:52:15AM CET, jiri@resnulli.us wrote:
>This check made bigger packets incorrectly dropped. Remove this
>limitation for gso skbs.
>
>Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>Acked-by: Eric Dumazet <edumazet@google.com>
>---
> net/sched/sch_tbf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
>index e05710a..dc562a8 100644
>--- a/net/sched/sch_tbf.c
>+++ b/net/sched/sch_tbf.c
>@@ -121,7 +121,7 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
> 	struct tbf_sched_data *q = qdisc_priv(sch);
> 	int ret;
> 
>-	if (qdisc_pkt_len(skb) > q->max_size)
>+	if (qdisc_pkt_len(skb) > q->max_size && !skb_is_gso(skb))
> 		return qdisc_reshape_fail(skb, sch);
> 
> 	ret = qdisc_enqueue(skb, q->qdisc);
>-- 
>1.8.1.2
>

Re: [patch net-next v4 07/11] tbf: ignore max_size check for gso skbs

[David Miller]

From: Jiri Pirko <jiri@resnulli.us>
Date: Mon, 11 Feb 2013 22:02:20 +0100

> Hmm. I think that this approach might not be correct after all. This
> might break existing setups when user is taking gso into account and
> adjust mtu and burst accordingly. After more thorough study, I'm under
> impression that gso skbs should not be handled in any different way.
> 
> Thoughts?

I really think userspace should be ignorant of GSO to the maximum
extent to which that is possible.

[patch net-next v4 08/11] tbf: fix value set for q->ptokens

[Jiri Pirko]

q->ptokens is in ns and we are assigning q->mtu directly to it. That is
wrong. psched_l2t_ns() should be used to compute correct value.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 net/sched/sch_tbf.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index dc562a8..0ac6224 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -111,6 +111,7 @@ struct tbf_sched_data {
 /* Variables */
 	s64	tokens;			/* Current number of B tokens */
 	s64	ptokens;		/* Current number of P tokens */
+	s64	mtu_ptokens;
 	psched_time_t	t_c;		/* Time check-point */
 	struct Qdisc	*qdisc;		/* Inner qdisc, default - bfifo queue */
 	struct qdisc_watchdog watchdog;	/* Watchdog timer */
@@ -165,8 +166,8 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
 
 		if (q->peak_present) {
 			ptoks = toks + q->ptokens;
-			if (ptoks > (long)q->mtu)
-				ptoks = q->mtu;
+			if (ptoks > q->mtu_ptokens)
+				ptoks = q->mtu_ptokens;
 			ptoks -= (s64) psched_l2t_ns(&q->peak, len);
 		}
 		toks += q->tokens;
@@ -215,7 +216,8 @@ static void tbf_reset(struct Qdisc *sch)
 	sch->q.qlen = 0;
 	q->t_c = ktime_to_ns(ktime_get());
 	q->tokens = q->buffer;
-	q->ptokens = q->mtu;
+	if (q->peak_present)
+		q->ptokens = q->mtu_ptokens;
 	qdisc_watchdog_cancel(&q->watchdog);
 }
 
@@ -296,11 +298,12 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
 	q->max_size = max_size;
 	q->buffer = PSCHED_TICKS2NS(qopt->buffer);
 	q->tokens = q->buffer;
-	q->ptokens = q->mtu;
 
 	psched_ratecfg_precompute(&q->rate, rtab->rate.rate);
 	if (ptab) {
 		psched_ratecfg_precompute(&q->peak, ptab->rate.rate);
+		q->mtu_ptokens = (s64) psched_l2t_ns(&q->peak, q->mtu);
+		q->ptokens = q->mtu_ptokens;
 		q->peak_present = true;
 	} else {
 		q->peak_present = false;
-- 
1.8.1.2

[patch net-next v4 09/11] act_police: move struct tcf_police to act_police.c

[Jiri Pirko]

It's not used anywhere else, so move it.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 include/net/act_api.h  | 15 ---------------
 net/sched/act_police.c | 15 +++++++++++++++
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 112c25c..06ef7e9 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -35,21 +35,6 @@ struct tcf_common {
 #define tcf_lock	common.tcfc_lock
 #define tcf_rcu		common.tcfc_rcu
 
-struct tcf_police {
-	struct tcf_common	common;
-	int			tcfp_result;
-	u32			tcfp_ewma_rate;
-	u32			tcfp_burst;
-	u32			tcfp_mtu;
-	u32			tcfp_toks;
-	u32			tcfp_ptoks;
-	psched_time_t		tcfp_t_c;
-	struct qdisc_rate_table	*tcfp_R_tab;
-	struct qdisc_rate_table	*tcfp_P_tab;
-};
-#define to_police(pc)	\
-	container_of(pc, struct tcf_police, common)
-
 struct tcf_hashinfo {
 	struct tcf_common	**htab;
 	unsigned int		hmask;
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 8dbd695..378a649 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -22,6 +22,21 @@
 #include <net/act_api.h>
 #include <net/netlink.h>
 
+struct tcf_police {
+	struct tcf_common	common;
+	int			tcfp_result;
+	u32			tcfp_ewma_rate;
+	u32			tcfp_burst;
+	u32			tcfp_mtu;
+	u32			tcfp_toks;
+	u32			tcfp_ptoks;
+	psched_time_t		tcfp_t_c;
+	struct qdisc_rate_table	*tcfp_R_tab;
+	struct qdisc_rate_table	*tcfp_P_tab;
+};
+#define to_police(pc)	\
+	container_of(pc, struct tcf_police, common)
+
 #define L2T(p, L)   qdisc_l2t((p)->tcfp_R_tab, L)
 #define L2T_P(p, L) qdisc_l2t((p)->tcfp_P_tab, L)
 
-- 
1.8.1.2

[patch net-next v4 10/11] act_police: improved accuracy at high rates

[Jiri Pirko]

Current act_police uses rate table computed by the "tc" userspace program,
which has the following issue:

The rate table has 256 entries to map packet lengths to
token (time units).  With TSO sized packets, the 256 entry granularity
leads to loss/gain of rate, making the token bucket inaccurate.

Thus, instead of relying on rate table, this patch explicitly computes
the time and accounts for packet transmission times with nanosecond
granularity.

This is a followup to 56b765b79e9a78dc7d3f8850ba5e5567205a3ecd

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 net/sched/act_police.c | 95 +++++++++++++++++++++++++++-----------------------
 1 file changed, 51 insertions(+), 44 deletions(-)

diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 378a649..71bf4f5 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -26,20 +26,20 @@ struct tcf_police {
 	struct tcf_common	common;
 	int			tcfp_result;
 	u32			tcfp_ewma_rate;
-	u32			tcfp_burst;
+	s64			tcfp_burst;
 	u32			tcfp_mtu;
-	u32			tcfp_toks;
-	u32			tcfp_ptoks;
+	s64			tcfp_toks;
+	s64			tcfp_ptoks;
+	s64			tcfp_mtu_ptoks;
 	psched_time_t		tcfp_t_c;
-	struct qdisc_rate_table	*tcfp_R_tab;
-	struct qdisc_rate_table	*tcfp_P_tab;
+	struct psched_ratecfg	rate;
+	bool			rate_present;
+	struct psched_ratecfg	peak;
+	bool			peak_present;
 };
 #define to_police(pc)	\
 	container_of(pc, struct tcf_police, common)
 
-#define L2T(p, L)   qdisc_l2t((p)->tcfp_R_tab, L)
-#define L2T_P(p, L) qdisc_l2t((p)->tcfp_P_tab, L)
-
 #define POL_TAB_MASK     15
 static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1];
 static u32 police_idx_gen;
@@ -123,10 +123,6 @@ static void tcf_police_destroy(struct tcf_police *p)
 			write_unlock_bh(&police_lock);
 			gen_kill_estimator(&p->tcf_bstats,
 					   &p->tcf_rate_est);
-			if (p->tcfp_R_tab)
-				qdisc_put_rtab(p->tcfp_R_tab);
-			if (p->tcfp_P_tab)
-				qdisc_put_rtab(p->tcfp_P_tab);
 			/*
 			 * gen_estimator est_timer() might access p->tcf_lock
 			 * or bstats, wait a RCU grace period before freeing p
@@ -227,26 +223,36 @@ override:
 	}
 
 	/* No failure allowed after this point */
-	if (R_tab != NULL) {
-		qdisc_put_rtab(police->tcfp_R_tab);
-		police->tcfp_R_tab = R_tab;
+	police->tcfp_mtu = parm->mtu;
+	if (police->tcfp_mtu == 0) {
+		police->tcfp_mtu = ~0;
+		if (R_tab)
+			police->tcfp_mtu = 255 << R_tab->rate.cell_log;
+	}
+	if (R_tab) {
+		police->rate_present = true;
+		psched_ratecfg_precompute(&police->rate, R_tab->rate.rate);
+		qdisc_put_rtab(R_tab);
+	} else {
+		police->rate_present = false;
 	}
-	if (P_tab != NULL) {
-		qdisc_put_rtab(police->tcfp_P_tab);
-		police->tcfp_P_tab = P_tab;
+	if (P_tab) {
+		police->peak_present = true;
+		psched_ratecfg_precompute(&police->peak, P_tab->rate.rate);
+		qdisc_put_rtab(P_tab);
+	} else {
+		police->peak_present = false;
 	}
 
 	if (tb[TCA_POLICE_RESULT])
 		police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
-	police->tcfp_toks = police->tcfp_burst = parm->burst;
-	police->tcfp_mtu = parm->mtu;
-	if (police->tcfp_mtu == 0) {
-		police->tcfp_mtu = ~0;
-		if (police->tcfp_R_tab)
-			police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log;
+	police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
+	police->tcfp_toks = police->tcfp_burst;
+	if (police->peak_present) {
+		police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
+							     police->tcfp_mtu);
+		police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 	}
-	if (police->tcfp_P_tab)
-		police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu);
 	police->tcf_action = parm->action;
 
 	if (tb[TCA_POLICE_AVRATE])
@@ -256,7 +262,7 @@ override:
 	if (ret != ACT_P_CREATED)
 		return ret;
 
-	police->tcfp_t_c = psched_get_time();
+	police->tcfp_t_c = ktime_to_ns(ktime_get());
 	police->tcf_index = parm->index ? parm->index :
 		tcf_hash_new_index(&police_idx_gen, &police_hash_info);
 	h = tcf_hash(police->tcf_index, POL_TAB_MASK);
@@ -303,8 +309,8 @@ static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 {
 	struct tcf_police *police = a->priv;
 	psched_time_t now;
-	long toks;
-	long ptoks = 0;
+	s64 toks;
+	s64 ptoks = 0;
 
 	spin_lock(&police->tcf_lock);
 
@@ -320,24 +326,25 @@ static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 	}
 
 	if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
-		if (police->tcfp_R_tab == NULL) {
+		if (!police->rate_present) {
 			spin_unlock(&police->tcf_lock);
 			return police->tcfp_result;
 		}
 
-		now = psched_get_time();
-		toks = psched_tdiff_bounded(now, police->tcfp_t_c,
-					    police->tcfp_burst);
-		if (police->tcfp_P_tab) {
+		now = ktime_to_ns(ktime_get());
+		toks = min_t(s64, now - police->tcfp_t_c,
+			     police->tcfp_burst);
+		if (police->peak_present) {
 			ptoks = toks + police->tcfp_ptoks;
-			if (ptoks > (long)L2T_P(police, police->tcfp_mtu))
-				ptoks = (long)L2T_P(police, police->tcfp_mtu);
-			ptoks -= L2T_P(police, qdisc_pkt_len(skb));
+			if (ptoks > police->tcfp_mtu_ptoks)
+				ptoks = police->tcfp_mtu_ptoks;
+			ptoks -= (s64) psched_l2t_ns(&police->peak,
+						     qdisc_pkt_len(skb));
 		}
 		toks += police->tcfp_toks;
-		if (toks > (long)police->tcfp_burst)
+		if (toks > police->tcfp_burst)
 			toks = police->tcfp_burst;
-		toks -= L2T(police, qdisc_pkt_len(skb));
+		toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 		if ((toks|ptoks) >= 0) {
 			police->tcfp_t_c = now;
 			police->tcfp_toks = toks;
@@ -363,15 +370,15 @@ tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 		.index = police->tcf_index,
 		.action = police->tcf_action,
 		.mtu = police->tcfp_mtu,
-		.burst = police->tcfp_burst,
+		.burst = PSCHED_NS2TICKS(police->tcfp_burst),
 		.refcnt = police->tcf_refcnt - ref,
 		.bindcnt = police->tcf_bindcnt - bind,
 	};
 
-	if (police->tcfp_R_tab)
-		opt.rate = police->tcfp_R_tab->rate;
-	if (police->tcfp_P_tab)
-		opt.peakrate = police->tcfp_P_tab->rate;
+	if (police->rate_present)
+		opt.rate.rate = psched_ratecfg_getrate(&police->rate);
+	if (police->peak_present)
+		opt.peakrate.rate = psched_ratecfg_getrate(&police->peak);
 	if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 		goto nla_put_failure;
 	if (police->tcfp_result &&
-- 
1.8.1.2

[patch net-next v4 11/11] act_police: remove <=mtu check for gso skbs

[Jiri Pirko]

This check made bigger packets incorrectly dropped. Remove this
limitation for gso skbs.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 net/sched/act_police.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 71bf4f5..e11eca9 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -325,7 +325,7 @@ static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 		return police->tcf_action;
 	}
 
-	if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
+	if (qdisc_pkt_len(skb) <= police->tcfp_mtu || skb_is_gso(skb)) {
 		if (!police->rate_present) {
 			spin_unlock(&police->tcf_lock);
 			return police->tcfp_result;
-- 
1.8.1.2