kernel: add codel and fq_codel to generic 3.3 patch set (based on patch by Dave Täht)

Codel is a new AQM algorithm and RED replacement designed by
Kathie Nichols and Van Jacobson, and published in ACM queue:

http://queue.acm.org/detail.cfm?id=2209336

Codel stands for "Controlled Delay", and needs no knobs in the
general case, twiddled, for optimum results. It aims for 5ms of
delay, at most, when in use.

Additionally,

fq_codel (by eric dumazet) builds on codel to provide fair queuing
superior to what could be had with SFQ, and drop behavior saner
than RED, BLUE, or choke.

These patches are backported from net-next and are known to work
on Linux 3.3.4 and later.

Includes updates to codel for better portability and speed

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@31756 3c298f89-4303-0410-b956-a3cf2f4a3e73

8 files changed, 2050 insertions, 1 deletions

diff --git a/target/linux/generic/patches-3.2/309-optimize_mips_memcpy_memset_cache.patch b/target/linux/generic/patches-3.2/309-optimize_mips_memcpy_memset_cache.patch
new file mode 100644
index 000000000..f3eebc6c2
--- /dev/null
+++ b/target/linux/generic/patches-3.2/309-optimize_mips_memcpy_memset_cache.patch
@@ -0,0 +1,109 @@
+--- a/arch/mips/lib/memset.S
++++ b/arch/mips/lib/memset.S
+@@ -19,6 +19,8 @@
+ #define LONG_S_R sdr
+ #endif
+ 
++#include "prefetch.h"
++
+ #define EX(insn,reg,addr,handler)			\
+ 9:	insn	reg, addr;				\
+ 	.section __ex_table,"a"; 			\
+@@ -75,6 +77,8 @@ FEXPORT(__bzero)
+ 	bnez		t0, .Lsmall_memset
+ 	 andi		t0, a0, LONGMASK	/* aligned? */
+ 
++	prefetch_store a0, a2, t2, t3, t4
++
+ #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
+ 	beqz		t0, 1f
+ 	 PTR_SUBU	t0, LONGSIZE		/* alignment in bytes */
+--- a/arch/mips/include/asm/processor.h
++++ b/arch/mips/include/asm/processor.h
+@@ -354,7 +354,7 @@ unsigned long get_wchan(struct task_stru
+ #define prefetch(x) __builtin_prefetch((x), 0, 1)
+ 
+ #define ARCH_HAS_PREFETCHW
+-#define prefetchw(x) __builtin_prefetch((x), 1, 1)
++#define prefetchw(x) do {} while (0)
+ 
+ #endif
+ 
+--- /dev/null
++++ b/arch/mips/lib/prefetch.h
+@@ -0,0 +1,35 @@
++/*
++ * This file is subject to the terms and conditions of the GNU General Public
++ * License.  See the file "COPYING" in the main directory of this archive
++ * for more details.
++ *
++ * Copyright (C) 2012  Felix Fietkau <nbd@openwrt.org>
++ */
++
++.macro	prefetch_store	dst, size, temp1, temp2, temp3
++#ifdef CONFIG_CPU_MIPS32
++	li		\temp1, ((1 << CONFIG_MIPS_L1_CACHE_SHIFT) - 1)
++	nor		\temp1, \temp1, \temp1
++
++	and		\temp2, \size, \temp1
++	beqz		\temp2, 2f
++	 nop
++
++	move		\temp2, \dst
++	PTR_ADDIU	\temp2, ((1 << CONFIG_MIPS_L1_CACHE_SHIFT) - 1)
++	and		\temp2, \temp2, \temp1
++
++	move		\temp3, \dst
++	PTR_ADDU	\temp3, \size
++	and		\temp3, \temp3, \temp1
++
++1:	beq		\temp2, \temp3, 2f
++	 nop
++
++	pref		30, 0(\temp2)
++
++	b		1b
++	  PTR_ADDIU	\temp2, (1 << CONFIG_MIPS_L1_CACHE_SHIFT)
++2:
++#endif
++.endm
+--- a/arch/mips/lib/memcpy.S
++++ b/arch/mips/lib/memcpy.S
+@@ -182,6 +182,8 @@
+ 	.set	at=v1
+ #endif
+ 
++#include "prefetch.h"
++
+ /*
+  * A combined memcpy/__copy_user
+  * __copy_user sets len to 0 for success; else to an upper bound of
+@@ -199,6 +201,8 @@ FEXPORT(__copy_user)
+ 	 */
+ #define rem t8
+ 
++	prefetch_store a0, a2, t0, t1, t2
++
+ 	R10KCBARRIER(0(ra))
+ 	/*
+ 	 * The "issue break"s below are very approximate.
+--- a/arch/mips/lib/memcpy-inatomic.S
++++ b/arch/mips/lib/memcpy-inatomic.S
+@@ -182,6 +182,8 @@
+ 	.set	at=v1
+ #endif
+ 
++#include "prefetch.h"
++
+ /*
+  * A combined memcpy/__copy_user
+  * __copy_user sets len to 0 for success; else to an upper bound of
+@@ -196,6 +198,8 @@ LEAF(__copy_user_inatomic)
+ 	 */
+ #define rem t8
+ 
++	prefetch_store dst, len, t0, t1, t2
++
+ 	/*
+ 	 * The "issue break"s below are very approximate.
+ 	 * Issue delays for dcache fills will perturb the schedule, as will
diff --git a/target/linux/generic/patches-3.3/040-Controlled-Delay-AQM.patch b/target/linux/generic/patches-3.3/040-Controlled-Delay-AQM.patch
new file mode 100644
index 000000000..5848d2fda
--- /dev/null
+++ b/target/linux/generic/patches-3.3/040-Controlled-Delay-AQM.patch
@@ -0,0 +1,755 @@
+From 76e3cc126bb223013a6b9a0e2a51238d1ef2e409 Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Thu, 10 May 2012 07:51:25 +0000
+Subject: [PATCH 01/41] codel: Controlled Delay AQM
+
+An implementation of CoDel AQM, from Kathleen Nichols and Van Jacobson.
+
+http://queue.acm.org/detail.cfm?id=2209336
+
+This AQM main input is no longer queue size in bytes or packets, but the
+delay packets stay in (FIFO) queue.
+
+As we don't have infinite memory, we still can drop packets in enqueue()
+in case of massive load, but mean of CoDel is to drop packets in
+dequeue(), using a control law based on two simple parameters :
+
+target : target sojourn time (default 5ms)
+interval : width of moving time window (default 100ms)
+
+Based on initial work from Dave Taht.
+
+Refactored to help future codel inclusion as a plugin for other linux
+qdisc (FQ_CODEL, ...), like RED.
+
+include/net/codel.h contains codel algorithm as close as possible than
+Kathleen reference.
+
+net/sched/sch_codel.c contains the linux qdisc specific glue.
+
+Separate structures permit a memory efficient implementation of fq_codel
+(to be sent as a separate work) : Each flow has its own struct
+codel_vars.
+
+timestamps are taken at enqueue() time with 1024 ns precision, allowing
+a range of 2199 seconds in queue, and 100Gb links support. iproute2 uses
+usec as base unit.
+
+Selected packets are dropped, unless ECN is enabled and packets can get
+ECN mark instead.
+
+Tested from 2Mb to 10Gb speeds with no particular problems, on ixgbe and
+tg3 drivers (BQL enabled).
+
+Usage: tc qdisc ... codel [ limit PACKETS ] [ target TIME ]
+                          [ interval TIME ] [ ecn ]
+
+qdisc codel 10: parent 1:1 limit 2000p target 3.0ms interval 60.0ms ecn
+ Sent 13347099587 bytes 8815805 pkt (dropped 0, overlimits 0 requeues 0)
+ rate 202365Kbit 16708pps backlog 113550b 75p requeues 0
+  count 116 lastcount 98 ldelay 4.3ms dropping drop_next 816us
+  maxpacket 1514 ecn_mark 84399 drop_overlimit 0
+
+CoDel must be seen as a base module, and should be used keeping in mind
+there is still a FIFO queue. So a typical setup will probably need a
+hierarchy of several qdiscs and packet classifiers to be able to meet
+whatever constraints a user might have.
+
+One possible example would be to use fq_codel, which combines Fair
+Queueing and CoDel, in replacement of sfq / sfq_red.
+
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: Dave Taht <dave.taht@bufferbloat.net>
+Cc: Kathleen Nichols <nichols@pollere.com>
+Cc: Van Jacobson <van@pollere.net>
+Cc: Tom Herbert <therbert@google.com>
+Cc: Matt Mathis <mattmathis@google.com>
+Cc: Yuchung Cheng <ycheng@google.com>
+Cc: Stephen Hemminger <shemminger@vyatta.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ include/linux/pkt_sched.h |   26 ++++
+ include/net/codel.h       |  332 +++++++++++++++++++++++++++++++++++++++++++++
+ net/sched/Kconfig         |   11 ++
+ net/sched/Makefile        |    1 +
+ net/sched/sch_codel.c     |  275 +++++++++++++++++++++++++++++++++++++
+ 5 files changed, 645 insertions(+)
+ create mode 100644 include/net/codel.h
+ create mode 100644 net/sched/sch_codel.c
+
+--- a/include/linux/pkt_sched.h
++++ b/include/linux/pkt_sched.h
+@@ -633,4 +633,30 @@ struct tc_qfq_stats {
+ 	__u32 lmax;
+ };
+ 
++/* CODEL */
++
++enum {
++	TCA_CODEL_UNSPEC,
++	TCA_CODEL_TARGET,
++	TCA_CODEL_LIMIT,
++	TCA_CODEL_INTERVAL,
++	TCA_CODEL_ECN,
++	__TCA_CODEL_MAX
++};
++
++#define TCA_CODEL_MAX	(__TCA_CODEL_MAX - 1)
++
++struct tc_codel_xstats {
++	__u32	maxpacket; /* largest packet we've seen so far */
++	__u32	count;	   /* how many drops we've done since the last time we
++			    * entered dropping state
++			    */
++	__u32	lastcount; /* count at entry to dropping state */
++	__u32	ldelay;    /* in-queue delay seen by most recently dequeued packet */
++	__s32	drop_next; /* time to drop next packet */
++	__u32	drop_overlimit; /* number of time max qdisc packet limit was hit */
++	__u32	ecn_mark;  /* number of packets we ECN marked instead of dropped */
++	__u32	dropping;  /* are we in dropping state ? */
++};
++
+ #endif
+--- /dev/null
++++ b/include/net/codel.h
+@@ -0,0 +1,332 @@
++#ifndef __NET_SCHED_CODEL_H
++#define __NET_SCHED_CODEL_H
++
++/*
++ * Codel - The Controlled-Delay Active Queue Management algorithm
++ *
++ *  Copyright (C) 2011-2012 Kathleen Nichols <nichols@pollere.com>
++ *  Copyright (C) 2011-2012 Van Jacobson <van@pollere.net>
++ *  Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net>
++ *  Copyright (C) 2012 Eric Dumazet <edumazet@google.com>
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions, and the following disclaimer,
++ *    without modification.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ * 3. The names of the authors may not be used to endorse or promote products
++ *    derived from this software without specific prior written permission.
++ *
++ * Alternatively, provided that this notice is retained in full, this
++ * software may be distributed under the terms of the GNU General
++ * Public License ("GPL") version 2, in which case the provisions of the
++ * GPL apply INSTEAD OF those given above.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
++ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
++ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
++ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
++ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
++ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
++ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
++ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
++ * DAMAGE.
++ *
++ */
++
++#include <linux/types.h>
++#include <linux/ktime.h>
++#include <linux/skbuff.h>
++#include <net/pkt_sched.h>
++#include <net/inet_ecn.h>
++
++/* Controlling Queue Delay (CoDel) algorithm
++ * =========================================
++ * Source : Kathleen Nichols and Van Jacobson
++ * http://queue.acm.org/detail.cfm?id=2209336
++ *
++ * Implemented on linux by Dave Taht and Eric Dumazet
++ */
++
++
++/* CoDel uses a 1024 nsec clock, encoded in u32
++ * This gives a range of 2199 seconds, because of signed compares
++ */
++typedef u32 codel_time_t;
++typedef s32 codel_tdiff_t;
++#define CODEL_SHIFT 10
++#define MS2TIME(a) ((a * NSEC_PER_MSEC) >> CODEL_SHIFT)
++
++static inline codel_time_t codel_get_time(void)
++{
++	u64 ns = ktime_to_ns(ktime_get());
++
++	return ns >> CODEL_SHIFT;
++}
++
++#define codel_time_after(a, b)		((s32)(a) - (s32)(b) > 0)
++#define codel_time_after_eq(a, b)	((s32)(a) - (s32)(b) >= 0)
++#define codel_time_before(a, b)		((s32)(a) - (s32)(b) < 0)
++#define codel_time_before_eq(a, b)	((s32)(a) - (s32)(b) <= 0)
++
++/* Qdiscs using codel plugin must use codel_skb_cb in their own cb[] */
++struct codel_skb_cb {
++	codel_time_t enqueue_time;
++};
++
++static struct codel_skb_cb *get_codel_cb(const struct sk_buff *skb)
++{
++	qdisc_cb_private_validate(skb, sizeof(struct codel_skb_cb));
++	return (struct codel_skb_cb *)qdisc_skb_cb(skb)->data;
++}
++
++static codel_time_t codel_get_enqueue_time(const struct sk_buff *skb)
++{
++	return get_codel_cb(skb)->enqueue_time;
++}
++
++static void codel_set_enqueue_time(struct sk_buff *skb)
++{
++	get_codel_cb(skb)->enqueue_time = codel_get_time();
++}
++
++static inline u32 codel_time_to_us(codel_time_t val)
++{
++	u64 valns = ((u64)val << CODEL_SHIFT);
++
++	do_div(valns, NSEC_PER_USEC);
++	return (u32)valns;
++}
++
++/**
++ * struct codel_params - contains codel parameters
++ * @target:	target queue size (in time units)
++ * @interval:	width of moving time window
++ * @ecn:	is Explicit Congestion Notification enabled
++ */
++struct codel_params {
++	codel_time_t	target;
++	codel_time_t	interval;
++	bool		ecn;
++};
++
++/**
++ * struct codel_vars - contains codel variables
++ * @count:		how many drops we've done since the last time we
++ *			entered dropping state
++ * @lastcount:		count at entry to dropping state
++ * @dropping:		set to true if in dropping state
++ * @first_above_time:	when we went (or will go) continuously above target
++ *			for interval
++ * @drop_next:		time to drop next packet, or when we dropped last
++ * @ldelay:		sojourn time of last dequeued packet
++ */
++struct codel_vars {
++	u32		count;
++	u32		lastcount;
++	bool		dropping;
++	codel_time_t	first_above_time;
++	codel_time_t	drop_next;
++	codel_time_t	ldelay;
++};
++
++/**
++ * struct codel_stats - contains codel shared variables and stats
++ * @maxpacket:	largest packet we've seen so far
++ * @drop_count:	temp count of dropped packets in dequeue()
++ * ecn_mark:	number of packets we ECN marked instead of dropping
++ */
++struct codel_stats {
++	u32		maxpacket;
++	u32		drop_count;
++	u32		ecn_mark;
++};
++
++static void codel_params_init(struct codel_params *params)
++{
++	params->interval = MS2TIME(100);
++	params->target = MS2TIME(5);
++	params->ecn = false;
++}
++
++static void codel_vars_init(struct codel_vars *vars)
++{
++	vars->drop_next = 0;
++	vars->first_above_time = 0;
++	vars->dropping = false; /* exit dropping state */
++	vars->count = 0;
++	vars->lastcount = 0;
++}
++
++static void codel_stats_init(struct codel_stats *stats)
++{
++	stats->maxpacket = 256;
++}
++
++/* return interval/sqrt(x) with good precision
++ * relies on int_sqrt(unsigned long x) kernel implementation
++ */
++static u32 codel_inv_sqrt(u32 _interval, u32 _x)
++{
++	u64 interval = _interval;
++	unsigned long x = _x;
++
++	/* Scale operands for max precision */
++
++#if BITS_PER_LONG == 64
++	x <<= 32; /* On 64bit arches, we can prescale x by 32bits */
++	interval <<= 16;
++#endif
++
++	while (x < (1UL << (BITS_PER_LONG - 2))) {
++		x <<= 2;
++		interval <<= 1;
++	}
++	do_div(interval, int_sqrt(x));
++	return (u32)interval;
++}
++
++static codel_time_t codel_control_law(codel_time_t t,
++				      codel_time_t interval,
++				      u32 count)
++{
++	return t + codel_inv_sqrt(interval, count);
++}
++
++
++static bool codel_should_drop(struct sk_buff *skb,
++			      unsigned int *backlog,
++			      struct codel_vars *vars,
++			      struct codel_params *params,
++			      struct codel_stats *stats,
++			      codel_time_t now)
++{
++	bool ok_to_drop;
++
++	if (!skb) {
++		vars->first_above_time = 0;
++		return false;
++	}
++
++	vars->ldelay = now - codel_get_enqueue_time(skb);
++	*backlog -= qdisc_pkt_len(skb);
++
++	if (unlikely(qdisc_pkt_len(skb) > stats->maxpacket))
++		stats->maxpacket = qdisc_pkt_len(skb);
++
++	if (codel_time_before(vars->ldelay, params->target) ||
++	    *backlog <= stats->maxpacket) {
++		/* went below - stay below for at least interval */
++		vars->first_above_time = 0;
++		return false;
++	}
++	ok_to_drop = false;
++	if (vars->first_above_time == 0) {
++		/* just went above from below. If we stay above
++		 * for at least interval we'll say it's ok to drop
++		 */
++		vars->first_above_time = now + params->interval;
++	} else if (codel_time_after(now, vars->first_above_time)) {
++		ok_to_drop = true;
++	}
++	return ok_to_drop;
++}
++
++typedef struct sk_buff * (*codel_skb_dequeue_t)(struct codel_vars *vars,
++						struct Qdisc *sch);
++
++static struct sk_buff *codel_dequeue(struct Qdisc *sch,
++				     struct codel_params *params,
++				     struct codel_vars *vars,
++				     struct codel_stats *stats,
++				     codel_skb_dequeue_t dequeue_func,
++				     u32 *backlog)
++{
++	struct sk_buff *skb = dequeue_func(vars, sch);
++	codel_time_t now;
++	bool drop;
++
++	if (!skb) {
++		vars->dropping = false;
++		return skb;
++	}
++	now = codel_get_time();
++	drop = codel_should_drop(skb, backlog, vars, params, stats, now);
++	if (vars->dropping) {
++		if (!drop) {
++			/* sojourn time below target - leave dropping state */
++			vars->dropping = false;
++		} else if (codel_time_after_eq(now, vars->drop_next)) {
++			/* It's time for the next drop. Drop the current
++			 * packet and dequeue the next. The dequeue might
++			 * take us out of dropping state.
++			 * If not, schedule the next drop.
++			 * A large backlog might result in drop rates so high
++			 * that the next drop should happen now,
++			 * hence the while loop.
++			 */
++			while (vars->dropping &&
++			       codel_time_after_eq(now, vars->drop_next)) {
++				if (++vars->count == 0) /* avoid zero divides */
++					vars->count = ~0U;
++				if (params->ecn && INET_ECN_set_ce(skb)) {
++					stats->ecn_mark++;
++					vars->drop_next =
++						codel_control_law(vars->drop_next,
++								  params->interval,
++								  vars->count);
++					goto end;
++				}
++				qdisc_drop(skb, sch);
++				stats->drop_count++;
++				skb = dequeue_func(vars, sch);
++				if (!codel_should_drop(skb, backlog,
++						       vars, params, stats, now)) {
++					/* leave dropping state */
++					vars->dropping = false;
++				} else {
++					/* and schedule the next drop */
++					vars->drop_next =
++						codel_control_law(vars->drop_next,
++								  params->interval,
++								  vars->count);
++				}
++			}
++		}
++	} else if (drop) {
++		if (params->ecn && INET_ECN_set_ce(skb)) {
++			stats->ecn_mark++;
++		} else {
++			qdisc_drop(skb, sch);
++			stats->drop_count++;
++
++			skb = dequeue_func(vars, sch);
++			drop = codel_should_drop(skb, backlog, vars, params,
++						 stats, now);
++		}
++		vars->dropping = true;
++		/* if min went above target close to when we last went below it
++		 * assume that the drop rate that controlled the queue on the
++		 * last cycle is a good starting point to control it now.
++		 */
++		if (codel_time_before(now - vars->drop_next,
++				      16 * params->interval)) {
++			vars->count = (vars->count - vars->lastcount) | 1;
++		} else {
++			vars->count = 1;
++		}
++		vars->lastcount = vars->count;
++		vars->drop_next = codel_control_law(now, params->interval,
++						    vars->count);
++	}
++end:
++	return skb;
++}
++#endif
+--- a/net/sched/Kconfig
++++ b/net/sched/Kconfig
+@@ -250,6 +250,17 @@ config NET_SCH_QFQ
+ 
+ 	  If unsure, say N.
+ 
++config NET_SCH_CODEL
++	tristate "Controlled Delay AQM (CODEL)"
++	help
++	  Say Y here if you want to use the Controlled Delay (CODEL)
++	  packet scheduling algorithm.
++
++	  To compile this driver as a module, choose M here: the module
++	  will be called sch_codel.
++
++	  If unsure, say N.
++
+ config NET_SCH_INGRESS
+ 	tristate "Ingress Qdisc"
+ 	depends on NET_CLS_ACT
+--- a/net/sched/Makefile
++++ b/net/sched/Makefile
+@@ -36,6 +36,7 @@ obj-$(CONFIG_NET_SCH_DRR)	+= sch_drr.o
+ obj-$(CONFIG_NET_SCH_MQPRIO)	+= sch_mqprio.o
+ obj-$(CONFIG_NET_SCH_CHOKE)	+= sch_choke.o
+ obj-$(CONFIG_NET_SCH_QFQ)	+= sch_qfq.o
++obj-$(CONFIG_NET_SCH_CODEL)	+= sch_codel.o
+ 
+ obj-$(CONFIG_NET_CLS_U32)	+= cls_u32.o
+ obj-$(CONFIG_NET_CLS_ROUTE4)	+= cls_route.o
+--- /dev/null
++++ b/net/sched/sch_codel.c
+@@ -0,0 +1,275 @@
++/*
++ * Codel - The Controlled-Delay Active Queue Management algorithm
++ *
++ *  Copyright (C) 2011-2012 Kathleen Nichols <nichols@pollere.com>
++ *  Copyright (C) 2011-2012 Van Jacobson <van@pollere.net>
++ *
++ *  Implemented on linux by :
++ *  Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net>
++ *  Copyright (C) 2012 Eric Dumazet <edumazet@google.com>
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions, and the following disclaimer,
++ *    without modification.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ * 3. The names of the authors may not be used to endorse or promote products
++ *    derived from this software without specific prior written permission.
++ *
++ * Alternatively, provided that this notice is retained in full, this
++ * software may be distributed under the terms of the GNU General
++ * Public License ("GPL") version 2, in which case the provisions of the
++ * GPL apply INSTEAD OF those given above.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
++ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
++ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
++ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
++ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
++ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
++ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
++ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
++ * DAMAGE.
++ *
++ */
++
++#include <linux/module.h>
++#include <linux/slab.h>
++#include <linux/types.h>
++#include <linux/kernel.h>
++#include <linux/errno.h>
++#include <linux/skbuff.h>
++#include <net/pkt_sched.h>
++#include <net/codel.h>
++
++
++#define DEFAULT_CODEL_LIMIT 1000
++
++struct codel_sched_data {
++	struct codel_params	params;
++	struct codel_vars	vars;
++	struct codel_stats	stats;
++	u32			drop_overlimit;
++};
++
++/* This is the specific function called from codel_dequeue()
++ * to dequeue a packet from queue. Note: backlog is handled in
++ * codel, we dont need to reduce it here.
++ */
++static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch)
++{
++	struct sk_buff *skb = __skb_dequeue(&sch->q);
++
++	prefetch(&skb->end); /* we'll need skb_shinfo() */
++	return skb;
++}
++
++static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch)
++{
++	struct codel_sched_data *q = qdisc_priv(sch);
++	struct sk_buff *skb;
++
++	skb = codel_dequeue(sch, &q->params, &q->vars, &q->stats,
++			    dequeue, &sch->qstats.backlog);
++	/* We cant call qdisc_tree_decrease_qlen() if our qlen is 0,
++	 * or HTB crashes. Defer it for next round.
++	 */
++	if (q->stats.drop_count && sch->q.qlen) {
++		qdisc_tree_decrease_qlen(sch, q->stats.drop_count);
++		q->stats.drop_count = 0;
++	}
++	if (skb)
++		qdisc_bstats_update(sch, skb);
++	return skb;
++}
++
++static int codel_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
++{
++	struct codel_sched_data *q;
++
++	if (likely(qdisc_qlen(sch) < sch->limit)) {
++		codel_set_enqueue_time(skb);
++		return qdisc_enqueue_tail(skb, sch);
++	}
++	q = qdisc_priv(sch);
++	q->drop_overlimit++;
++	return qdisc_drop(skb, sch);
++}
++
++static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = {
++	[TCA_CODEL_TARGET]	= { .type = NLA_U32 },
++	[TCA_CODEL_LIMIT]	= { .type = NLA_U32 },
++	[TCA_CODEL_INTERVAL]	= { .type = NLA_U32 },
++	[TCA_CODEL_ECN]		= { .type = NLA_U32 },
++};
++
++static int codel_change(struct Qdisc *sch, struct nlattr *opt)
++{
++	struct codel_sched_data *q = qdisc_priv(sch);
++	struct nlattr *tb[TCA_CODEL_MAX + 1];
++	unsigned int qlen;
++	int err;
++
++	if (!opt)
++		return -EINVAL;
++
++	err = nla_parse_nested(tb, TCA_CODEL_MAX, opt, codel_policy);
++	if (err < 0)
++		return err;
++
++	sch_tree_lock(sch);
++
++	if (tb[TCA_CODEL_TARGET]) {
++		u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
++
++		q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
++	}
++
++	if (tb[TCA_CODEL_INTERVAL]) {
++		u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
++
++		q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT;
++	}
++
++	if (tb[TCA_CODEL_LIMIT])
++		sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]);
++
++	if (tb[TCA_CODEL_ECN])
++		q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
++
++	qlen = sch->q.qlen;
++	while (sch->q.qlen > sch->limit) {
++		struct sk_buff *skb = __skb_dequeue(&sch->q);
++
++		sch->qstats.backlog -= qdisc_pkt_len(skb);
++		qdisc_drop(skb, sch);
++	}
++	qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
++
++	sch_tree_unlock(sch);
++	return 0;
++}
++
++static int codel_init(struct Qdisc *sch, struct nlattr *opt)
++{
++	struct codel_sched_data *q = qdisc_priv(sch);
++
++	sch->limit = DEFAULT_CODEL_LIMIT;
++
++	codel_params_init(&q->params);
++	codel_vars_init(&q->vars);
++	codel_stats_init(&q->stats);
++
++	if (opt) {
++		int err = codel_change(sch, opt);
++
++		if (err)
++			return err;
++	}
++
++	if (sch->limit >= 1)
++		sch->flags |= TCQ_F_CAN_BYPASS;
++	else
++		sch->flags &= ~TCQ_F_CAN_BYPASS;
++
++	return 0;
++}
++
++static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
++{
++	struct codel_sched_data *q = qdisc_priv(sch);
++	struct nlattr *opts;
++
++	opts = nla_nest_start(skb, TCA_OPTIONS);
++	if (opts == NULL)
++		goto nla_put_failure;
++
++	if (nla_put_u32(skb, TCA_CODEL_TARGET,
++			codel_time_to_us(q->params.target)) ||
++	    nla_put_u32(skb, TCA_CODEL_LIMIT,
++			sch->limit) ||
++	    nla_put_u32(skb, TCA_CODEL_INTERVAL,
++			codel_time_to_us(q->params.interval)) ||
++	    nla_put_u32(skb, TCA_CODEL_ECN,
++			q->params.ecn))
++		goto nla_put_failure;
++
++	return nla_nest_end(skb, opts);
++
++nla_put_failure:
++	nla_nest_cancel(skb, opts);
++	return -1;
++}
++
++static int codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
++{
++	const struct codel_sched_data *q = qdisc_priv(sch);
++	struct tc_codel_xstats st = {
++		.maxpacket	= q->stats.maxpacket,
++		.count		= q->vars.count,
++		.lastcount	= q->vars.lastcount,
++		.drop_overlimit = q->drop_overlimit,
++		.ldelay		= codel_time_to_us(q->vars.ldelay),
++		.dropping	= q->vars.dropping,
++		.ecn_mark	= q->stats.ecn_mark,
++	};
++
++	if (q->vars.dropping) {
++		codel_tdiff_t delta = q->vars.drop_next - codel_get_time();
++
++		if (delta >= 0)
++			st.drop_next = codel_time_to_us(delta);
++		else
++			st.drop_next = -codel_time_to_us(-delta);
++	}
++
++	return gnet_stats_copy_app(d, &st, sizeof(st));
++}
++
++static void codel_reset(struct Qdisc *sch)
++{
++	struct codel_sched_data *q = qdisc_priv(sch);
++
++	qdisc_reset_queue(sch);
++	codel_vars_init(&q->vars);
++}
++
++static struct Qdisc_ops codel_qdisc_ops __read_mostly = {
++	.id		=	"codel",
++	.priv_size	=	sizeof(struct codel_sched_data),
++
++	.enqueue	=	codel_qdisc_enqueue,
++	.dequeue	=	codel_qdisc_dequeue,
++	.peek		=	qdisc_peek_dequeued,
++	.init		=	codel_init,
++	.reset		=	codel_reset,
++	.change 	=	codel_change,
++	.dump		=	codel_dump,
++	.dump_stats	=	codel_dump_stats,
++	.owner		=	THIS_MODULE,
++};
++
++static int __init codel_module_init(void)
++{
++	return register_qdisc(&codel_qdisc_ops);
++}
++
++static void __exit codel_module_exit(void)
++{
++	unregister_qdisc(&codel_qdisc_ops);
++}
++
++module_init(codel_module_init)
++module_exit(codel_module_exit)
++
++MODULE_DESCRIPTION("Controlled Delay queue discipline");
++MODULE_AUTHOR("Dave Taht");
++MODULE_AUTHOR("Eric Dumazet");
++MODULE_LICENSE("Dual BSD/GPL");
diff --git a/target/linux/generic/patches-3.3/041-codel-use-Newton-method-instead-of-sqrt-and-divides.patch b/target/linux/generic/patches-3.3/041-codel-use-Newton-method-instead-of-sqrt-and-divides.patch
new file mode 100644
index 000000000..97401bb12
--- /dev/null
+++ b/target/linux/generic/patches-3.3/041-codel-use-Newton-method-instead-of-sqrt-and-divides.patch
@@ -0,0 +1,183 @@
+From 536edd67109df5e0cdb2c4ee759e9bade7976367 Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Sat, 12 May 2012 03:32:13 +0000
+Subject: [PATCH 37/41] codel: use Newton method instead of sqrt() and divides
+
+As Van pointed out, interval/sqrt(count) can be implemented using
+multiplies only.
+
+http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots
+
+This patch implements the Newton method and reciprocal divide.
+
+Total cost is 15 cycles instead of 120 on my Corei5 machine (64bit
+kernel).
+
+There is a small 'error' for count values < 5, but we don't really care.
+
+I reuse a hole in struct codel_vars :
+ - pack the dropping boolean into one bit
+ - use 31bit to store the reciprocal value of sqrt(count).
+
+Suggested-by: Van Jacobson <van@pollere.net>
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Cc: Dave Taht <dave.taht@bufferbloat.net>
+Cc: Kathleen Nichols <nichols@pollere.com>
+Cc: Tom Herbert <therbert@google.com>
+Cc: Matt Mathis <mattmathis@google.com>
+Cc: Yuchung Cheng <ycheng@google.com>
+Cc: Nandita Dukkipati <nanditad@google.com>
+Cc: Stephen Hemminger <shemminger@vyatta.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ include/net/codel.h |   68 ++++++++++++++++++++++++++++-----------------------
+ 1 file changed, 37 insertions(+), 31 deletions(-)
+
+--- a/include/net/codel.h
++++ b/include/net/codel.h
+@@ -46,6 +46,7 @@
+ #include <linux/skbuff.h>
+ #include <net/pkt_sched.h>
+ #include <net/inet_ecn.h>
++#include <linux/reciprocal_div.h>
+ 
+ /* Controlling Queue Delay (CoDel) algorithm
+  * =========================================
+@@ -123,6 +124,7 @@ struct codel_params {
+  *			entered dropping state
+  * @lastcount:		count at entry to dropping state
+  * @dropping:		set to true if in dropping state
++ * @rec_inv_sqrt:	reciprocal value of sqrt(count) >> 1
+  * @first_above_time:	when we went (or will go) continuously above target
+  *			for interval
+  * @drop_next:		time to drop next packet, or when we dropped last
+@@ -131,7 +133,8 @@ struct codel_params {
+ struct codel_vars {
+ 	u32		count;
+ 	u32		lastcount;
+-	bool		dropping;
++	bool		dropping:1;
++	u32		rec_inv_sqrt:31;
+ 	codel_time_t	first_above_time;
+ 	codel_time_t	drop_next;
+ 	codel_time_t	ldelay;
+@@ -158,11 +161,7 @@ static void codel_params_init(struct cod
+ 
+ static void codel_vars_init(struct codel_vars *vars)
+ {
+-	vars->drop_next = 0;
+-	vars->first_above_time = 0;
+-	vars->dropping = false; /* exit dropping state */
+-	vars->count = 0;
+-	vars->lastcount = 0;
++	memset(vars, 0, sizeof(*vars));
+ }
+ 
+ static void codel_stats_init(struct codel_stats *stats)
+@@ -170,38 +169,37 @@ static void codel_stats_init(struct code
+ 	stats->maxpacket = 256;
+ }
+ 
+-/* return interval/sqrt(x) with good precision
+- * relies on int_sqrt(unsigned long x) kernel implementation
++/*
++ * http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots
++ * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
++ *
++ * Here, invsqrt is a fixed point number (< 1.0), 31bit mantissa)
+  */
+-static u32 codel_inv_sqrt(u32 _interval, u32 _x)
++static void codel_Newton_step(struct codel_vars *vars)
+ {
+-	u64 interval = _interval;
+-	unsigned long x = _x;
+-
+-	/* Scale operands for max precision */
++	u32 invsqrt = vars->rec_inv_sqrt;
++	u32 invsqrt2 = ((u64)invsqrt * invsqrt) >> 31;
++	u64 val = (3LL << 31) - ((u64)vars->count * invsqrt2);
+ 
+-#if BITS_PER_LONG == 64
+-	x <<= 32; /* On 64bit arches, we can prescale x by 32bits */
+-	interval <<= 16;
+-#endif
++	val = (val * invsqrt) >> 32;
+ 
+-	while (x < (1UL << (BITS_PER_LONG - 2))) {
+-		x <<= 2;
+-		interval <<= 1;
+-	}
+-	do_div(interval, int_sqrt(x));
+-	return (u32)interval;
++	vars->rec_inv_sqrt = val;
+ }
+ 
++/*
++ * CoDel control_law is t + interval/sqrt(count)
++ * We maintain in rec_inv_sqrt the reciprocal value of sqrt(count) to avoid
++ * both sqrt() and divide operation.
++ */
+ static codel_time_t codel_control_law(codel_time_t t,
+ 				      codel_time_t interval,
+-				      u32 count)
++				      u32 rec_inv_sqrt)
+ {
+-	return t + codel_inv_sqrt(interval, count);
++	return t + reciprocal_divide(interval, rec_inv_sqrt << 1);
+ }
+ 
+ 
+-static bool codel_should_drop(struct sk_buff *skb,
++static bool codel_should_drop(const struct sk_buff *skb,
+ 			      unsigned int *backlog,
+ 			      struct codel_vars *vars,
+ 			      struct codel_params *params,
+@@ -274,14 +272,16 @@ static struct sk_buff *codel_dequeue(str
+ 			 */
+ 			while (vars->dropping &&
+ 			       codel_time_after_eq(now, vars->drop_next)) {
+-				if (++vars->count == 0) /* avoid zero divides */
+-					vars->count = ~0U;
++				vars->count++; /* dont care of possible wrap
++						* since there is no more divide
++						*/
++				codel_Newton_step(vars);
+ 				if (params->ecn && INET_ECN_set_ce(skb)) {
+ 					stats->ecn_mark++;
+ 					vars->drop_next =
+ 						codel_control_law(vars->drop_next,
+ 								  params->interval,
+-								  vars->count);
++								  vars->rec_inv_sqrt);
+ 					goto end;
+ 				}
+ 				qdisc_drop(skb, sch);
+@@ -296,7 +296,7 @@ static struct sk_buff *codel_dequeue(str
+ 					vars->drop_next =
+ 						codel_control_law(vars->drop_next,
+ 								  params->interval,
+-								  vars->count);
++								  vars->rec_inv_sqrt);
+ 				}
+ 			}
+ 		}
+@@ -319,12 +319,18 @@ static struct sk_buff *codel_dequeue(str
+ 		if (codel_time_before(now - vars->drop_next,
+ 				      16 * params->interval)) {
+ 			vars->count = (vars->count - vars->lastcount) | 1;
++			/* we dont care if rec_inv_sqrt approximation
++			 * is not very precise :
++			 * Next Newton steps will correct it quadratically.
++			 */
++			codel_Newton_step(vars);
+ 		} else {
+ 			vars->count = 1;
++			vars->rec_inv_sqrt = 0x7fffffff;
+ 		}
+ 		vars->lastcount = vars->count;
+ 		vars->drop_next = codel_control_law(now, params->interval,
+-						    vars->count);
++						    vars->rec_inv_sqrt);
+ 	}
+ end:
+ 	return skb;
diff --git a/target/linux/generic/patches-3.3/042-fq_codel-Fair-Queue-Codel-AQM.patch b/target/linux/generic/patches-3.3/042-fq_codel-Fair-Queue-Codel-AQM.patch
new file mode 100644
index 000000000..44f208a7e
--- /dev/null
+++ b/target/linux/generic/patches-3.3/042-fq_codel-Fair-Queue-Codel-AQM.patch
@@ -0,0 +1,837 @@
+From 4b549a2ef4bef9965d97cbd992ba67930cd3e0fe Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Fri, 11 May 2012 09:30:50 +0000
+Subject: [PATCH 38/41] fq_codel: Fair Queue Codel AQM
+
+Fair Queue Codel packet scheduler
+
+Principles :
+
+- Packets are classified (internal classifier or external) on flows.
+- This is a Stochastic model (as we use a hash, several flows might
+                              be hashed on same slot)
+- Each flow has a CoDel managed queue.
+- Flows are linked onto two (Round Robin) lists,
+  so that new flows have priority on old ones.
+
+- For a given flow, packets are not reordered (CoDel uses a FIFO)
+- head drops only.
+- ECN capability is on by default.
+- Very low memory footprint (64 bytes per flow)
+
+tc qdisc ... fq_codel [ limit PACKETS ] [ flows number ]
+                      [ target TIME ] [ interval TIME ] [ noecn ]
+                      [ quantum BYTES ]
+
+defaults : 1024 flows, 10240 packets limit, quantum : device MTU
+           target : 5ms (CoDel default)
+           interval : 100ms (CoDel default)
+
+Impressive results on load :
+
+class htb 1:1 root leaf 10: prio 0 quantum 1514 rate 200000Kbit ceil 200000Kbit burst 1475b/8 mpu 0b overhead 0b cburst 1475b/8 mpu 0b overhead 0b level 0
+ Sent 43304920109 bytes 33063109 pkt (dropped 0, overlimits 0 requeues 0)
+ rate 201691Kbit 28595pps backlog 0b 312p requeues 0
+ lended: 33063109 borrowed: 0 giants: 0
+ tokens: -912 ctokens: -912
+
+class fq_codel 10:1735 parent 10:
+ (dropped 1292, overlimits 0 requeues 0)
+ backlog 15140b 10p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
+class fq_codel 10:4524 parent 10:
+ (dropped 1291, overlimits 0 requeues 0)
+ backlog 16654b 11p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
+class fq_codel 10:4e74 parent 10:
+ (dropped 1290, overlimits 0 requeues 0)
+ backlog 6056b 4p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 6.4ms dropping drop_next 92.0ms
+class fq_codel 10:628a parent 10:
+ (dropped 1289, overlimits 0 requeues 0)
+ backlog 7570b 5p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 5.4ms dropping drop_next 90.9ms
+class fq_codel 10:a4b3 parent 10:
+ (dropped 302, overlimits 0 requeues 0)
+ backlog 16654b 11p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
+class fq_codel 10:c3c2 parent 10:
+ (dropped 1284, overlimits 0 requeues 0)
+ backlog 13626b 9p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
+class fq_codel 10:d331 parent 10:
+ (dropped 299, overlimits 0 requeues 0)
+ backlog 15140b 10p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.0ms
+class fq_codel 10:d526 parent 10:
+ (dropped 12160, overlimits 0 requeues 0)
+ backlog 35870b 211p requeues 0
+  deficit 1508 count 12160 lastcount 1 ldelay 15.3ms dropping drop_next 247us
+class fq_codel 10:e2c6 parent 10:
+ (dropped 1288, overlimits 0 requeues 0)
+ backlog 15140b 10p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
+class fq_codel 10:eab5 parent 10:
+ (dropped 1285, overlimits 0 requeues 0)
+ backlog 16654b 11p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
+class fq_codel 10:f220 parent 10:
+ (dropped 1289, overlimits 0 requeues 0)
+ backlog 15140b 10p requeues 0
+  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
+
+qdisc htb 1: root refcnt 6 r2q 10 default 1 direct_packets_stat 0 ver 3.17
+ Sent 43331086547 bytes 33092812 pkt (dropped 0, overlimits 66063544 requeues 71)
+ rate 201697Kbit 28602pps backlog 0b 260p requeues 71
+qdisc fq_codel 10: parent 1:1 limit 10240p flows 65536 target 5.0ms interval 100.0ms ecn
+ Sent 43331086547 bytes 33092812 pkt (dropped 949359, overlimits 0 requeues 0)
+ rate 201697Kbit 28602pps backlog 189352b 260p requeues 0
+  maxpacket 1514 drop_overlimit 0 new_flow_count 5582 ecn_mark 125593
+  new_flows_len 0 old_flows_len 11
+
+PING 172.30.42.18 (172.30.42.18) 56(84) bytes of data.
+64 bytes from 172.30.42.18: icmp_req=1 ttl=64 time=0.227 ms
+64 bytes from 172.30.42.18: icmp_req=2 ttl=64 time=0.165 ms
+64 bytes from 172.30.42.18: icmp_req=3 ttl=64 time=0.166 ms
+64 bytes from 172.30.42.18: icmp_req=4 ttl=64 time=0.151 ms
+64 bytes from 172.30.42.18: icmp_req=5 ttl=64 time=0.164 ms
+64 bytes from 172.30.42.18: icmp_req=6 ttl=64 time=0.172 ms
+64 bytes from 172.30.42.18: icmp_req=7 ttl=64 time=0.175 ms
+64 bytes from 172.30.42.18: icmp_req=8 ttl=64 time=0.183 ms
+64 bytes from 172.30.42.18: icmp_req=9 ttl=64 time=0.158 ms
+64 bytes from 172.30.42.18: icmp_req=10 ttl=64 time=0.200 ms
+
+10 packets transmitted, 10 received, 0% packet loss, time 8999ms
+rtt min/avg/max/mdev = 0.151/0.176/0.227/0.022 ms
+
+Much better than SFQ because of priority given to new flows, and fast
+path dirtying less cache lines.
+
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ include/linux/pkt_sched.h |   54 ++++
+ net/sched/Kconfig         |   11 +
+ net/sched/Makefile        |    1 +
+ net/sched/sch_fq_codel.c  |  624 +++++++++++++++++++++++++++++++++++++++++++++
+ 4 files changed, 690 insertions(+)
+ create mode 100644 net/sched/sch_fq_codel.c
+
+--- a/include/linux/pkt_sched.h
++++ b/include/linux/pkt_sched.h
+@@ -659,4 +659,58 @@ struct tc_codel_xstats {
+ 	__u32	dropping;  /* are we in dropping state ? */
+ };
+ 
++/* FQ_CODEL */
++
++enum {
++	TCA_FQ_CODEL_UNSPEC,
++	TCA_FQ_CODEL_TARGET,
++	TCA_FQ_CODEL_LIMIT,
++	TCA_FQ_CODEL_INTERVAL,
++	TCA_FQ_CODEL_ECN,
++	TCA_FQ_CODEL_FLOWS,
++	TCA_FQ_CODEL_QUANTUM,
++	__TCA_FQ_CODEL_MAX
++};
++
++#define TCA_FQ_CODEL_MAX	(__TCA_FQ_CODEL_MAX - 1)
++
++enum {
++	TCA_FQ_CODEL_XSTATS_QDISC,
++	TCA_FQ_CODEL_XSTATS_CLASS,
++};
++
++struct tc_fq_codel_qd_stats {
++	__u32	maxpacket;	/* largest packet we've seen so far */
++	__u32	drop_overlimit; /* number of time max qdisc
++				 * packet limit was hit
++				 */
++	__u32	ecn_mark;	/* number of packets we ECN marked
++				 * instead of being dropped
++				 */
++	__u32	new_flow_count; /* number of time packets
++				 * created a 'new flow'
++				 */
++	__u32	new_flows_len;	/* count of flows in new list */
++	__u32	old_flows_len;	/* count of flows in old list */
++};
++
++struct tc_fq_codel_cl_stats {
++	__s32	deficit;
++	__u32	ldelay;		/* in-queue delay seen by most recently
++				 * dequeued packet
++				 */
++	__u32	count;
++	__u32	lastcount;
++	__u32	dropping;
++	__s32	drop_next;
++};
++
++struct tc_fq_codel_xstats {
++	__u32	type;
++	union {
++		struct tc_fq_codel_qd_stats qdisc_stats;
++		struct tc_fq_codel_cl_stats class_stats;
++	};
++};
++
+ #endif
+--- a/net/sched/Kconfig
++++ b/net/sched/Kconfig
+@@ -261,6 +261,17 @@ config NET_SCH_CODEL
+ 
+ 	  If unsure, say N.
+ 
++config NET_SCH_FQ_CODEL
++	tristate "Fair Queue Controlled Delay AQM (FQ_CODEL)"
++	help
++	  Say Y here if you want to use the FQ Controlled Delay (FQ_CODEL)
++	  packet scheduling algorithm.
++
++	  To compile this driver as a module, choose M here: the module
++	  will be called sch_fq_codel.
++
++	  If unsure, say N.
++
+ config NET_SCH_INGRESS
+ 	tristate "Ingress Qdisc"
+ 	depends on NET_CLS_ACT
+--- a/net/sched/Makefile
++++ b/net/sched/Makefile
+@@ -37,6 +37,7 @@ obj-$(CONFIG_NET_SCH_MQPRIO)	+= sch_mqpr
+ obj-$(CONFIG_NET_SCH_CHOKE)	+= sch_choke.o
+ obj-$(CONFIG_NET_SCH_QFQ)	+= sch_qfq.o
+ obj-$(CONFIG_NET_SCH_CODEL)	+= sch_codel.o
++obj-$(CONFIG_NET_SCH_FQ_CODEL)	+= sch_fq_codel.o
+ 
+ obj-$(CONFIG_NET_CLS_U32)	+= cls_u32.o
+ obj-$(CONFIG_NET_CLS_ROUTE4)	+= cls_route.o
+--- /dev/null
++++ b/net/sched/sch_fq_codel.c
+@@ -0,0 +1,624 @@
++/*
++ * Fair Queue CoDel discipline
++ *
++ *	This program is free software; you can redistribute it and/or
++ *	modify it under the terms of the GNU General Public License
++ *	as published by the Free Software Foundation; either version
++ *	2 of the License, or (at your option) any later version.
++ *
++ *  Copyright (C) 2012 Eric Dumazet <edumazet@google.com>
++ */
++
++#include <linux/module.h>
++#include <linux/types.h>
++#include <linux/kernel.h>
++#include <linux/jiffies.h>
++#include <linux/string.h>
++#include <linux/in.h>
++#include <linux/errno.h>
++#include <linux/init.h>
++#include <linux/skbuff.h>
++#include <linux/jhash.h>
++#include <linux/slab.h>
++#include <linux/vmalloc.h>
++#include <net/netlink.h>
++#include <net/pkt_sched.h>
++#include <net/flow_keys.h>
++#include <net/codel.h>
++
++/*	Fair Queue CoDel.
++ *
++ * Principles :
++ * Packets are classified (internal classifier or external) on flows.
++ * This is a Stochastic model (as we use a hash, several flows
++ *			       might be hashed on same slot)
++ * Each flow has a CoDel managed queue.
++ * Flows are linked onto two (Round Robin) lists,
++ * so that new flows have priority on old ones.
++ *
++ * For a given flow, packets are not reordered (CoDel uses a FIFO)
++ * head drops only.
++ * ECN capability is on by default.
++ * Low memory footprint (64 bytes per flow)
++ */
++
++struct fq_codel_flow {
++	struct sk_buff	  *head;
++	struct sk_buff	  *tail;
++	struct list_head  flowchain;
++	int		  deficit;
++	u32		  dropped; /* number of drops (or ECN marks) on this flow */
++	struct codel_vars cvars;
++}; /* please try to keep this structure <= 64 bytes */
++
++struct fq_codel_sched_data {
++	struct tcf_proto *filter_list;	/* optional external classifier */
++	struct fq_codel_flow *flows;	/* Flows table [flows_cnt] */
++	u32		*backlogs;	/* backlog table [flows_cnt] */
++	u32		flows_cnt;	/* number of flows */
++	u32		perturbation;	/* hash perturbation */
++	u32		quantum;	/* psched_mtu(qdisc_dev(sch)); */
++	struct codel_params cparams;
++	struct codel_stats cstats;
++	u32		drop_overlimit;
++	u32		new_flow_count;
++
++	struct list_head new_flows;	/* list of new flows */
++	struct list_head old_flows;	/* list of old flows */
++};
++
++static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q,
++				  const struct sk_buff *skb)
++{
++	struct flow_keys keys;
++	unsigned int hash;
++
++	skb_flow_dissect(skb, &keys);
++	hash = jhash_3words((__force u32)keys.dst,
++			    (__force u32)keys.src ^ keys.ip_proto,
++			    (__force u32)keys.ports, q->perturbation);
++	return ((u64)hash * q->flows_cnt) >> 32;
++}
++
++static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
++				      int *qerr)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct tcf_result res;
++	int result;
++
++	if (TC_H_MAJ(skb->priority) == sch->handle &&
++	    TC_H_MIN(skb->priority) > 0 &&
++	    TC_H_MIN(skb->priority) <= q->flows_cnt)
++		return TC_H_MIN(skb->priority);
++
++	if (!q->filter_list)
++		return fq_codel_hash(q, skb) + 1;
++
++	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
++	result = tc_classify(skb, q->filter_list, &res);
++	if (result >= 0) {
++#ifdef CONFIG_NET_CLS_ACT
++		switch (result) {
++		case TC_ACT_STOLEN:
++		case TC_ACT_QUEUED:
++			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
++		case TC_ACT_SHOT:
++			return 0;
++		}
++#endif
++		if (TC_H_MIN(res.classid) <= q->flows_cnt)
++			return TC_H_MIN(res.classid);
++	}
++	return 0;
++}
++
++/* helper functions : might be changed when/if skb use a standard list_head */
++
++/* remove one skb from head of slot queue */
++static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow)
++{
++	struct sk_buff *skb = flow->head;
++
++	flow->head = skb->next;
++	skb->next = NULL;
++	return skb;
++}
++
++/* add skb to flow queue (tail add) */
++static inline void flow_queue_add(struct fq_codel_flow *flow,
++				  struct sk_buff *skb)
++{
++	if (flow->head == NULL)
++		flow->head = skb;
++	else
++		flow->tail->next = skb;
++	flow->tail = skb;
++	skb->next = NULL;
++}
++
++static unsigned int fq_codel_drop(struct Qdisc *sch)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct sk_buff *skb;
++	unsigned int maxbacklog = 0, idx = 0, i, len;
++	struct fq_codel_flow *flow;
++
++	/* Queue is full! Find the fat flow and drop packet from it.
++	 * This might sound expensive, but with 1024 flows, we scan
++	 * 4KB of memory, and we dont need to handle a complex tree
++	 * in fast path (packet queue/enqueue) with many cache misses.
++	 */
++	for (i = 0; i < q->flows_cnt; i++) {
++		if (q->backlogs[i] > maxbacklog) {
++			maxbacklog = q->backlogs[i];
++			idx = i;
++		}
++	}
++	flow = &q->flows[idx];
++	skb = dequeue_head(flow);
++	len = qdisc_pkt_len(skb);
++	q->backlogs[idx] -= len;
++	kfree_skb(skb);
++	sch->q.qlen--;
++	sch->qstats.drops++;
++	sch->qstats.backlog -= len;
++	flow->dropped++;
++	return idx;
++}
++
++static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	unsigned int idx;
++	struct fq_codel_flow *flow;
++	int uninitialized_var(ret);
++
++	idx = fq_codel_classify(skb, sch, &ret);
++	if (idx == 0) {
++		if (ret & __NET_XMIT_BYPASS)
++			sch->qstats.drops++;
++		kfree_skb(skb);
++		return ret;
++	}
++	idx--;
++
++	codel_set_enqueue_time(skb);
++	flow = &q->flows[idx];
++	flow_queue_add(flow, skb);
++	q->backlogs[idx] += qdisc_pkt_len(skb);
++	sch->qstats.backlog += qdisc_pkt_len(skb);
++
++	if (list_empty(&flow->flowchain)) {
++		list_add_tail(&flow->flowchain, &q->new_flows);
++		codel_vars_init(&flow->cvars);
++		q->new_flow_count++;
++		flow->deficit = q->quantum;
++		flow->dropped = 0;
++	}
++	if (++sch->q.qlen < sch->limit)
++		return NET_XMIT_SUCCESS;
++
++	q->drop_overlimit++;
++	/* Return Congestion Notification only if we dropped a packet
++	 * from this flow.
++	 */
++	if (fq_codel_drop(sch) == idx)
++		return NET_XMIT_CN;
++
++	/* As we dropped a packet, better let upper stack know this */
++	qdisc_tree_decrease_qlen(sch, 1);
++	return NET_XMIT_SUCCESS;
++}
++
++/* This is the specific function called from codel_dequeue()
++ * to dequeue a packet from queue. Note: backlog is handled in
++ * codel, we dont need to reduce it here.
++ */
++static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch)
++{
++	struct fq_codel_flow *flow;
++	struct sk_buff *skb = NULL;
++
++	flow = container_of(vars, struct fq_codel_flow, cvars);
++	if (flow->head) {
++		skb = dequeue_head(flow);
++		sch->qstats.backlog -= qdisc_pkt_len(skb);
++		sch->q.qlen--;
++	}
++	return skb;
++}
++
++static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct sk_buff *skb;
++	struct fq_codel_flow *flow;
++	struct list_head *head;
++	u32 prev_drop_count, prev_ecn_mark;
++
++begin:
++	head = &q->new_flows;
++	if (list_empty(head)) {
++		head = &q->old_flows;
++		if (list_empty(head))
++			return NULL;
++	}
++	flow = list_first_entry(head, struct fq_codel_flow, flowchain);
++
++	if (flow->deficit <= 0) {
++		flow->deficit += q->quantum;
++		list_move_tail(&flow->flowchain, &q->old_flows);
++		goto begin;
++	}
++
++	prev_drop_count = q->cstats.drop_count;
++	prev_ecn_mark = q->cstats.ecn_mark;
++
++	skb = codel_dequeue(sch, &q->cparams, &flow->cvars, &q->cstats,
++			    dequeue, &q->backlogs[flow - q->flows]);
++
++	flow->dropped += q->cstats.drop_count - prev_drop_count;
++	flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
++
++	if (!skb) {
++		/* force a pass through old_flows to prevent starvation */
++		if ((head == &q->new_flows) && !list_empty(&q->old_flows))
++			list_move_tail(&flow->flowchain, &q->old_flows);
++		else
++			list_del_init(&flow->flowchain);
++		goto begin;
++	}
++	qdisc_bstats_update(sch, skb);
++	flow->deficit -= qdisc_pkt_len(skb);
++	/* We cant call qdisc_tree_decrease_qlen() if our qlen is 0,
++	 * or HTB crashes. Defer it for next round.
++	 */
++	if (q->cstats.drop_count && sch->q.qlen) {
++		qdisc_tree_decrease_qlen(sch, q->cstats.drop_count);
++		q->cstats.drop_count = 0;
++	}
++	return skb;
++}
++
++static void fq_codel_reset(struct Qdisc *sch)
++{
++	struct sk_buff *skb;
++
++	while ((skb = fq_codel_dequeue(sch)) != NULL)
++		kfree_skb(skb);
++}
++
++static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
++	[TCA_FQ_CODEL_TARGET]	= { .type = NLA_U32 },
++	[TCA_FQ_CODEL_LIMIT]	= { .type = NLA_U32 },
++	[TCA_FQ_CODEL_INTERVAL]	= { .type = NLA_U32 },
++	[TCA_FQ_CODEL_ECN]	= { .type = NLA_U32 },
++	[TCA_FQ_CODEL_FLOWS]	= { .type = NLA_U32 },
++	[TCA_FQ_CODEL_QUANTUM]	= { .type = NLA_U32 },
++};
++
++static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct nlattr *tb[TCA_FQ_CODEL_MAX + 1];
++	int err;
++
++	if (!opt)
++		return -EINVAL;
++
++	err = nla_parse_nested(tb, TCA_FQ_CODEL_MAX, opt, fq_codel_policy);
++	if (err < 0)
++		return err;
++	if (tb[TCA_FQ_CODEL_FLOWS]) {
++		if (q->flows)
++			return -EINVAL;
++		q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]);
++		if (!q->flows_cnt ||
++		    q->flows_cnt > 65536)
++			return -EINVAL;
++	}
++	sch_tree_lock(sch);
++
++	if (tb[TCA_FQ_CODEL_TARGET]) {
++		u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
++
++		q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
++	}
++
++	if (tb[TCA_FQ_CODEL_INTERVAL]) {
++		u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
++
++		q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT;
++	}
++
++	if (tb[TCA_FQ_CODEL_LIMIT])
++		sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]);
++
++	if (tb[TCA_FQ_CODEL_ECN])
++		q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]);
++
++	if (tb[TCA_FQ_CODEL_QUANTUM])
++		q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM]));
++
++	while (sch->q.qlen > sch->limit) {
++		struct sk_buff *skb = fq_codel_dequeue(sch);
++
++		kfree_skb(skb);
++		q->cstats.drop_count++;
++	}
++	qdisc_tree_decrease_qlen(sch, q->cstats.drop_count);
++	q->cstats.drop_count = 0;
++
++	sch_tree_unlock(sch);
++	return 0;
++}
++
++static void *fq_codel_zalloc(size_t sz)
++{
++	void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN);
++
++	if (!ptr)
++		ptr = vzalloc(sz);
++	return ptr;
++}
++
++static void fq_codel_free(void *addr)
++{
++	if (addr) {
++		if (is_vmalloc_addr(addr))
++			vfree(addr);
++		else
++			kfree(addr);
++	}
++}
++
++static void fq_codel_destroy(struct Qdisc *sch)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++
++	tcf_destroy_chain(&q->filter_list);
++	fq_codel_free(q->backlogs);
++	fq_codel_free(q->flows);
++}
++
++static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	int i;
++
++	sch->limit = 10*1024;
++	q->flows_cnt = 1024;
++	q->quantum = psched_mtu(qdisc_dev(sch));
++	q->perturbation = net_random();
++	INIT_LIST_HEAD(&q->new_flows);
++	INIT_LIST_HEAD(&q->old_flows);
++	codel_params_init(&q->cparams);
++	codel_stats_init(&q->cstats);
++	q->cparams.ecn = true;
++
++	if (opt) {
++		int err = fq_codel_change(sch, opt);
++		if (err)
++			return err;
++	}
++
++	if (!q->flows) {
++		q->flows = fq_codel_zalloc(q->flows_cnt *
++					   sizeof(struct fq_codel_flow));
++		if (!q->flows)
++			return -ENOMEM;
++		q->backlogs = fq_codel_zalloc(q->flows_cnt * sizeof(u32));
++		if (!q->backlogs) {
++			fq_codel_free(q->flows);
++			return -ENOMEM;
++		}
++		for (i = 0; i < q->flows_cnt; i++) {
++			struct fq_codel_flow *flow = q->flows + i;
++
++			INIT_LIST_HEAD(&flow->flowchain);
++		}
++	}
++	if (sch->limit >= 1)
++		sch->flags |= TCQ_F_CAN_BYPASS;
++	else
++		sch->flags &= ~TCQ_F_CAN_BYPASS;
++	return 0;
++}
++
++static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct nlattr *opts;
++
++	opts = nla_nest_start(skb, TCA_OPTIONS);
++	if (opts == NULL)
++		goto nla_put_failure;
++
++	if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
++			codel_time_to_us(q->cparams.target)) ||
++	    nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
++			sch->limit) ||
++	    nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
++			codel_time_to_us(q->cparams.interval)) ||
++	    nla_put_u32(skb, TCA_FQ_CODEL_ECN,
++			q->cparams.ecn) ||
++	    nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
++			q->quantum) ||
++	    nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
++			q->flows_cnt))
++		goto nla_put_failure;
++
++	nla_nest_end(skb, opts);
++	return skb->len;
++
++nla_put_failure:
++	return -1;
++}
++
++static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	struct tc_fq_codel_xstats st = {
++		.type				= TCA_FQ_CODEL_XSTATS_QDISC,
++		.qdisc_stats.maxpacket		= q->cstats.maxpacket,
++		.qdisc_stats.drop_overlimit	= q->drop_overlimit,
++		.qdisc_stats.ecn_mark		= q->cstats.ecn_mark,
++		.qdisc_stats.new_flow_count	= q->new_flow_count,
++	};
++	struct list_head *pos;
++
++	list_for_each(pos, &q->new_flows)
++		st.qdisc_stats.new_flows_len++;
++
++	list_for_each(pos, &q->old_flows)
++		st.qdisc_stats.old_flows_len++;
++
++	return gnet_stats_copy_app(d, &st, sizeof(st));
++}
++
++static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg)
++{
++	return NULL;
++}
++
++static unsigned long fq_codel_get(struct Qdisc *sch, u32 classid)
++{
++	return 0;
++}
++
++static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent,
++			      u32 classid)
++{
++	/* we cannot bypass queue discipline anymore */
++	sch->flags &= ~TCQ_F_CAN_BYPASS;
++	return 0;
++}
++
++static void fq_codel_put(struct Qdisc *q, unsigned long cl)
++{
++}
++
++static struct tcf_proto **fq_codel_find_tcf(struct Qdisc *sch, unsigned long cl)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++
++	if (cl)
++		return NULL;
++	return &q->filter_list;
++}
++
++static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl,
++			  struct sk_buff *skb, struct tcmsg *tcm)
++{
++	tcm->tcm_handle |= TC_H_MIN(cl);
++	return 0;
++}
++
++static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl,
++				     struct gnet_dump *d)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	u32 idx = cl - 1;
++	struct gnet_stats_queue qs = { 0 };
++	struct tc_fq_codel_xstats xstats;
++
++	if (idx < q->flows_cnt) {
++		const struct fq_codel_flow *flow = &q->flows[idx];
++		const struct sk_buff *skb = flow->head;
++
++		memset(&xstats, 0, sizeof(xstats));
++		xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
++		xstats.class_stats.deficit = flow->deficit;
++		xstats.class_stats.ldelay =
++			codel_time_to_us(flow->cvars.ldelay);
++		xstats.class_stats.count = flow->cvars.count;
++		xstats.class_stats.lastcount = flow->cvars.lastcount;
++		xstats.class_stats.dropping = flow->cvars.dropping;
++		if (flow->cvars.dropping) {
++			codel_tdiff_t delta = flow->cvars.drop_next -
++					      codel_get_time();
++
++			xstats.class_stats.drop_next = (delta >= 0) ?
++				codel_time_to_us(delta) :
++				-codel_time_to_us(-delta);
++		}
++		while (skb) {
++			qs.qlen++;
++			skb = skb->next;
++		}
++		qs.backlog = q->backlogs[idx];
++		qs.drops = flow->dropped;
++	}
++	if (gnet_stats_copy_queue(d, &qs) < 0)
++		return -1;
++	if (idx < q->flows_cnt)
++		return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
++	return 0;
++}
++
++static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg)
++{
++	struct fq_codel_sched_data *q = qdisc_priv(sch);
++	unsigned int i;
++
++	if (arg->stop)
++		return;
++
++	for (i = 0; i < q->flows_cnt; i++) {
++		if (list_empty(&q->flows[i].flowchain) ||
++		    arg->count < arg->skip) {
++			arg->count++;
++			continue;
++		}
++		if (arg->fn(sch, i + 1, arg) < 0) {
++			arg->stop = 1;
++			break;
++		}
++		arg->count++;
++	}
++}
++
++static const struct Qdisc_class_ops fq_codel_class_ops = {
++	.leaf		=	fq_codel_leaf,
++	.get		=	fq_codel_get,
++	.put		=	fq_codel_put,
++	.tcf_chain	=	fq_codel_find_tcf,
++	.bind_tcf	=	fq_codel_bind,
++	.unbind_tcf	=	fq_codel_put,
++	.dump		=	fq_codel_dump_class,
++	.dump_stats	=	fq_codel_dump_class_stats,
++	.walk		=	fq_codel_walk,
++};
++
++static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = {
++	.cl_ops		=	&fq_codel_class_ops,
++	.id		=	"fq_codel",
++	.priv_size	=	sizeof(struct fq_codel_sched_data),
++	.enqueue	=	fq_codel_enqueue,
++	.dequeue	=	fq_codel_dequeue,
++	.peek		=	qdisc_peek_dequeued,
++	.drop		=	fq_codel_drop,
++	.init		=	fq_codel_init,
++	.reset		=	fq_codel_reset,
++	.destroy	=	fq_codel_destroy,
++	.change		=	fq_codel_change,
++	.dump		=	fq_codel_dump,
++	.dump_stats =	fq_codel_dump_stats,
++	.owner		=	THIS_MODULE,
++};
++
++static int __init fq_codel_module_init(void)
++{
++	return register_qdisc(&fq_codel_qdisc_ops);
++}
++
++static void __exit fq_codel_module_exit(void)
++{
++	unregister_qdisc(&fq_codel_qdisc_ops);
++}
++
++module_init(fq_codel_module_init)
++module_exit(fq_codel_module_exit)
++MODULE_AUTHOR("Eric Dumazet");
++MODULE_LICENSE("GPL");
diff --git a/target/linux/generic/patches-3.3/043-net-codel-Add-missing-include-linux-prefetch.h.patch b/target/linux/generic/patches-3.3/043-net-codel-Add-missing-include-linux-prefetch.h.patch
new file mode 100644
index 000000000..cb2a72af8
--- /dev/null
+++ b/target/linux/generic/patches-3.3/043-net-codel-Add-missing-include-linux-prefetch.h.patch
@@ -0,0 +1,31 @@
+From ce5b4b977127ee20c3f9c3fd3637cd3796f649f5 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert@linux-m68k.org>
+Date: Mon, 14 May 2012 09:47:05 +0000
+Subject: [PATCH 44/50] net/codel: Add missing #include <linux/prefetch.h>
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+m68k allmodconfig:
+
+net/sched/sch_codel.c: In function ‘dequeue’:
+net/sched/sch_codel.c:70: error: implicit declaration of function ‘prefetch’
+make[1]: *** [net/sched/sch_codel.o] Error 1
+
+Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
+Acked-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sched/sch_codel.c |    1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/net/sched/sch_codel.c
++++ b/net/sched/sch_codel.c
+@@ -46,6 +46,7 @@
+ #include <linux/kernel.h>
+ #include <linux/errno.h>
+ #include <linux/skbuff.h>
++#include <linux/prefetch.h>
+ #include <net/pkt_sched.h>
+ #include <net/codel.h>
+ 
diff --git a/target/linux/generic/patches-3.3/044-net-codel-fix-build-errors.patch b/target/linux/generic/patches-3.3/044-net-codel-fix-build-errors.patch
new file mode 100644
index 000000000..36f16d2bf
--- /dev/null
+++ b/target/linux/generic/patches-3.3/044-net-codel-fix-build-errors.patch
@@ -0,0 +1,49 @@
+From 669d67bf777def468970f2dcba1537edf3b2d329 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <levinsasha928@gmail.com>
+Date: Mon, 14 May 2012 11:57:06 +0000
+Subject: [PATCH 45/50] net: codel: fix build errors
+
+Fix the following build error:
+
+net/sched/sch_fq_codel.c: In function 'fq_codel_dump_stats':
+net/sched/sch_fq_codel.c:464:3: error: unknown field 'qdisc_stats' specified in initializer
+net/sched/sch_fq_codel.c:464:3: warning: missing braces around initializer
+net/sched/sch_fq_codel.c:464:3: warning: (near initialization for 'st.<anonymous>')
+net/sched/sch_fq_codel.c:465:3: error: unknown field 'qdisc_stats' specified in initializer
+net/sched/sch_fq_codel.c:465:3: warning: excess elements in struct initializer
+net/sched/sch_fq_codel.c:465:3: warning: (near initialization for 'st')
+net/sched/sch_fq_codel.c:466:3: error: unknown field 'qdisc_stats' specified in initializer
+net/sched/sch_fq_codel.c:466:3: warning: excess elements in struct initializer
+net/sched/sch_fq_codel.c:466:3: warning: (near initialization for 'st')
+net/sched/sch_fq_codel.c:467:3: error: unknown field 'qdisc_stats' specified in initializer
+net/sched/sch_fq_codel.c:467:3: warning: excess elements in struct initializer
+net/sched/sch_fq_codel.c:467:3: warning: (near initialization for 'st')
+make[1]: *** [net/sched/sch_fq_codel.o] Error 1
+
+Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sched/sch_fq_codel.c |    9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+--- a/net/sched/sch_fq_codel.c
++++ b/net/sched/sch_fq_codel.c
+@@ -461,13 +461,14 @@ static int fq_codel_dump_stats(struct Qd
+ 	struct fq_codel_sched_data *q = qdisc_priv(sch);
+ 	struct tc_fq_codel_xstats st = {
+ 		.type				= TCA_FQ_CODEL_XSTATS_QDISC,
+-		.qdisc_stats.maxpacket		= q->cstats.maxpacket,
+-		.qdisc_stats.drop_overlimit	= q->drop_overlimit,
+-		.qdisc_stats.ecn_mark		= q->cstats.ecn_mark,
+-		.qdisc_stats.new_flow_count	= q->new_flow_count,
+ 	};
+ 	struct list_head *pos;
+ 
++	st.qdisc_stats.maxpacket = q->cstats.maxpacket;
++	st.qdisc_stats.drop_overlimit = q->drop_overlimit;
++	st.qdisc_stats.ecn_mark = q->cstats.ecn_mark;
++	st.qdisc_stats.new_flow_count = q->new_flow_count;
++
+ 	list_for_each(pos, &q->new_flows)
+ 		st.qdisc_stats.new_flows_len++;
+ 
diff --git a/target/linux/generic/patches-3.3/045-codel-use-u16-field-instead-of-31bits-for-rec_inv_sq.patch b/target/linux/generic/patches-3.3/045-codel-use-u16-field-instead-of-31bits-for-rec_inv_sq.patch
new file mode 100644
index 000000000..814aebc61
--- /dev/null
+++ b/target/linux/generic/patches-3.3/045-codel-use-u16-field-instead-of-31bits-for-rec_inv_sq.patch
@@ -0,0 +1,85 @@
+From 6ff272c9ad65eda219cd975b9da2dbc31cc812ee Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <eric.dumazet@gmail.com>
+Date: Sat, 12 May 2012 21:23:23 +0000
+Subject: [PATCH 46/50] codel: use u16 field instead of 31bits for
+ rec_inv_sqrt
+
+David pointed out gcc might generate poor code with 31bit fields.
+
+Using u16 is more than enough and permits a better code output.
+
+Also make the code intent more readable using constants, fixed point arithmetic
+not being trivial for everybody.
+
+Suggested-by: David Miller <davem@davemloft.net>
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ include/net/codel.h |   25 +++++++++++++++----------
+ 1 file changed, 15 insertions(+), 10 deletions(-)
+
+--- a/include/net/codel.h
++++ b/include/net/codel.h
+@@ -133,13 +133,17 @@ struct codel_params {
+ struct codel_vars {
+ 	u32		count;
+ 	u32		lastcount;
+-	bool		dropping:1;
+-	u32		rec_inv_sqrt:31;
++	bool		dropping;
++	u16		rec_inv_sqrt;
+ 	codel_time_t	first_above_time;
+ 	codel_time_t	drop_next;
+ 	codel_time_t	ldelay;
+ };
+ 
++#define REC_INV_SQRT_BITS (8 * sizeof(u16)) /* or sizeof_in_bits(rec_inv_sqrt) */
++/* needed shift to get a Q0.32 number from rec_inv_sqrt */
++#define REC_INV_SQRT_SHIFT (32 - REC_INV_SQRT_BITS)
++
+ /**
+  * struct codel_stats - contains codel shared variables and stats
+  * @maxpacket:	largest packet we've seen so far
+@@ -173,17 +177,18 @@ static void codel_stats_init(struct code
+  * http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Iterative_methods_for_reciprocal_square_roots
+  * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
+  *
+- * Here, invsqrt is a fixed point number (< 1.0), 31bit mantissa)
++ * Here, invsqrt is a fixed point number (< 1.0), 32bit mantissa, aka Q0.32
+  */
+ static void codel_Newton_step(struct codel_vars *vars)
+ {
+-	u32 invsqrt = vars->rec_inv_sqrt;
+-	u32 invsqrt2 = ((u64)invsqrt * invsqrt) >> 31;
+-	u64 val = (3LL << 31) - ((u64)vars->count * invsqrt2);
++	u32 invsqrt = ((u32)vars->rec_inv_sqrt) << REC_INV_SQRT_SHIFT;
++	u32 invsqrt2 = ((u64)invsqrt * invsqrt) >> 32;
++	u64 val = (3LL << 32) - ((u64)vars->count * invsqrt2);
+ 
+-	val = (val * invsqrt) >> 32;
++	val >>= 2; /* avoid overflow in following multiply */
++	val = (val * invsqrt) >> (32 - 2 + 1);
+ 
+-	vars->rec_inv_sqrt = val;
++	vars->rec_inv_sqrt = val >> REC_INV_SQRT_SHIFT;
+ }
+ 
+ /*
+@@ -195,7 +200,7 @@ static codel_time_t codel_control_law(co
+ 				      codel_time_t interval,
+ 				      u32 rec_inv_sqrt)
+ {
+-	return t + reciprocal_divide(interval, rec_inv_sqrt << 1);
++	return t + reciprocal_divide(interval, rec_inv_sqrt << REC_INV_SQRT_SHIFT);
+ }
+ 
+ 
+@@ -326,7 +331,7 @@ static struct sk_buff *codel_dequeue(str
+ 			codel_Newton_step(vars);
+ 		} else {
+ 			vars->count = 1;
+-			vars->rec_inv_sqrt = 0x7fffffff;
++			vars->rec_inv_sqrt = ~0U >> REC_INV_SQRT_SHIFT;
+ 		}
+ 		vars->lastcount = vars->count;
+ 		vars->drop_next = codel_control_law(now, params->interval,
diff --git a/target/linux/generic/patches-3.3/621-sched_act_connmark.patch b/target/linux/generic/patches-3.3/621-sched_act_connmark.patch
index 157421d20..eceec0a1e 100644
--- a/target/linux/generic/patches-3.3/621-sched_act_connmark.patch
+++ b/target/linux/generic/patches-3.3/621-sched_act_connmark.patch
@@ -140,7 +140,7 @@
 +module_exit(connmark_cleanup_module);
 --- a/net/sched/Kconfig
 +++ b/net/sched/Kconfig
-@@ -602,6 +602,19 @@ config NET_ACT_CSUM
+@@ -624,6 +624,19 @@ config NET_ACT_CSUM
  	  To compile this code as a module, choose M here: the
  	  module will be called act_csum.