mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-08-21 16:19:00 +03:00
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33560 3c298f89-4303-0410-b956-a3cf2f4a3e73
758 lines
22 KiB
Diff
758 lines
22 KiB
Diff
From a93fd80d261f1dc2788442dba8dd5701363d3d6e Mon Sep 17 00:00:00 2001
|
|
From: Eric Dumazet <edumazet@google.com>
|
|
Date: Thu, 10 May 2012 07:51:25 +0000
|
|
Subject: [PATCH] codel: Controlled Delay AQM
|
|
|
|
commit 76e3cc126bb223013a6b9a0e2a51238d1ef2e409 upstream.
|
|
|
|
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");
|