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Commit 2d43f112 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
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Merge branch 'red' of 84.73.165.173:/home/tgr/repos/net-2.6

parents 6df71634 bdc450a0
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Showing with 891 additions and 771 deletions
include/linux/pkt_sched.h
View file @ 2d43f112
......@@ -93,6 +93,7 @@ struct tc_fifo_qopt
/* PRIO section */
#define TCQ_PRIO_BANDS 16
#define TCQ_MIN_PRIO_BANDS 2
struct tc_prio_qopt
{
......@@ -169,6 +170,7 @@ struct tc_red_qopt
unsigned char Scell_log; /* cell size for idle damping */
unsigned char flags;
#define TC_RED_ECN 1
#define TC_RED_HARDDROP 2
};
struct tc_red_xstats
......@@ -194,38 +196,34 @@ enum
#define TCA_GRED_MAX (__TCA_GRED_MAX - 1)
#define TCA_SET_OFF TCA_GRED_PARMS
struct tc_gred_qopt
{
__u32 limit; /* HARD maximal queue length (bytes)
*/
__u32 qth_min; /* Min average length threshold (bytes)
*/
__u32 qth_max; /* Max average length threshold (bytes)
*/
__u32 DP; /* upto 2^32 DPs */
__u32 backlog;
__u32 qave;
__u32 forced;
__u32 early;
__u32 other;
__u32 pdrop;
unsigned char Wlog; /* log(W) */
unsigned char Plog; /* log(P_max/(qth_max-qth_min)) */
unsigned char Scell_log; /* cell size for idle damping */
__u8 prio; /* prio of this VQ */
__u32 packets;
__u32 bytesin;
__u32 limit; /* HARD maximal queue length (bytes) */
__u32 qth_min; /* Min average length threshold (bytes) */
__u32 qth_max; /* Max average length threshold (bytes) */
__u32 DP; /* upto 2^32 DPs */
__u32 backlog;
__u32 qave;
__u32 forced;
__u32 early;
__u32 other;
__u32 pdrop;
__u8 Wlog; /* log(W) */
__u8 Plog; /* log(P_max/(qth_max-qth_min)) */
__u8 Scell_log; /* cell size for idle damping */
__u8 prio; /* prio of this VQ */
__u32 packets;
__u32 bytesin;
};
/* gred setup */
struct tc_gred_sopt
{
__u32 DPs;
__u32 def_DP;
__u8 grio;
__u8 pad1;
__u16 pad2;
__u32 DPs;
__u32 def_DP;
__u8 grio;
__u8 flags;
__u16 pad1;
};
/* HTB section */
......
include/net/inet_ecn.h
View file @ 2d43f112
......@@ -2,6 +2,7 @@
#define _INET_ECN_H_
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <net/dsfield.h>
enum {
......@@ -48,7 +49,7 @@ static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
(label) |= __constant_htons(INET_ECN_ECT_0 << 4); \
} while (0)
static inline void IP_ECN_set_ce(struct iphdr *iph)
static inline int IP_ECN_set_ce(struct iphdr *iph)
{
u32 check = iph->check;
u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
......@@ -61,7 +62,7 @@ static inline void IP_ECN_set_ce(struct iphdr *iph)
* INET_ECN_CE => 00
*/
if (!(ecn & 2))
return;
return !ecn;
/*
* The following gives us:
......@@ -72,6 +73,7 @@ static inline void IP_ECN_set_ce(struct iphdr *iph)
iph->check = check + (check>=0xFFFF);
iph->tos |= INET_ECN_CE;
return 1;
}
static inline void IP_ECN_clear(struct iphdr *iph)
......@@ -87,11 +89,12 @@ static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
struct ipv6hdr;
static inline void IP6_ECN_set_ce(struct ipv6hdr *iph)
static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
{
if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
return;
return 0;
*(u32*)iph |= htonl(INET_ECN_CE << 20);
return 1;
}
static inline void IP6_ECN_clear(struct ipv6hdr *iph)
......@@ -105,4 +108,21 @@ static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
}
static inline int INET_ECN_set_ce(struct sk_buff *skb)
{
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
if (skb->nh.raw + sizeof(struct iphdr) <= skb->tail)
return IP_ECN_set_ce(skb->nh.iph);
break;
case __constant_htons(ETH_P_IPV6):
if (skb->nh.raw + sizeof(struct ipv6hdr) <= skb->tail)
return IP6_ECN_set_ce(skb->nh.ipv6h);
break;
}
return 0;
}
#endif
include/net/red.h 0 → 100644
View file @ 2d43f112
#ifndef __NET_SCHED_RED_H
#define __NET_SCHED_RED_H
#include <linux/config.h>
#include <linux/types.h>
#include <net/pkt_sched.h>
#include <net/inet_ecn.h>
#include <net/dsfield.h>
/* Random Early Detection (RED) algorithm.
=======================================
Source: Sally Floyd and Van Jacobson, "Random Early Detection Gateways
for Congestion Avoidance", 1993, IEEE/ACM Transactions on Networking.
This file codes a "divisionless" version of RED algorithm
as written down in Fig.17 of the paper.
Short description.
------------------
When a new packet arrives we calculate the average queue length:
avg = (1-W)*avg + W*current_queue_len,
W is the filter time constant (chosen as 2^(-Wlog)), it controls
the inertia of the algorithm. To allow larger bursts, W should be
decreased.
if (avg > th_max) -> packet marked (dropped).
if (avg < th_min) -> packet passes.
if (th_min < avg < th_max) we calculate probability:
Pb = max_P * (avg - th_min)/(th_max-th_min)
and mark (drop) packet with this probability.
Pb changes from 0 (at avg==th_min) to max_P (avg==th_max).
max_P should be small (not 1), usually 0.01..0.02 is good value.
max_P is chosen as a number, so that max_P/(th_max-th_min)
is a negative power of two in order arithmetics to contain
only shifts.
Parameters, settable by user:
-----------------------------
qth_min - bytes (should be < qth_max/2)
qth_max - bytes (should be at least 2*qth_min and less limit)
Wlog - bits (<32) log(1/W).
Plog - bits (<32)
Plog is related to max_P by formula:
max_P = (qth_max-qth_min)/2^Plog;
F.e. if qth_max=128K and qth_min=32K, then Plog=22
corresponds to max_P=0.02
Scell_log
Stab
Lookup table for log((1-W)^(t/t_ave).
NOTES:
Upper bound on W.
-----------------
If you want to allow bursts of L packets of size S,
you should choose W:
L + 1 - th_min/S < (1-(1-W)^L)/W
th_min/S = 32 th_min/S = 4
log(W) L
-1 33
-2 35
-3 39
-4 46
-5 57
-6 75
-7 101
-8 135
-9 190
etc.
*/
#define RED_STAB_SIZE 256
#define RED_STAB_MASK (RED_STAB_SIZE - 1)
struct red_stats
{
u32 prob_drop; /* Early probability drops */
u32 prob_mark; /* Early probability marks */
u32 forced_drop; /* Forced drops, qavg > max_thresh */
u32 forced_mark; /* Forced marks, qavg > max_thresh */
u32 pdrop; /* Drops due to queue limits */
u32 other; /* Drops due to drop() calls */
u32 backlog;
};
struct red_parms
{
/* Parameters */
u32 qth_min; /* Min avg length threshold: A scaled */
u32 qth_max; /* Max avg length threshold: A scaled */
u32 Scell_max;
u32 Rmask; /* Cached random mask, see red_rmask */
u8 Scell_log;
u8 Wlog; /* log(W) */
u8 Plog; /* random number bits */
u8 Stab[RED_STAB_SIZE];
/* Variables */
int qcount; /* Number of packets since last random
number generation */
u32 qR; /* Cached random number */
unsigned long qavg; /* Average queue length: A scaled */
psched_time_t qidlestart; /* Start of current idle period */
};
static inline u32 red_rmask(u8 Plog)
{
return Plog < 32 ? ((1 << Plog) - 1) : ~0UL;
}
static inline void red_set_parms(struct red_parms *p,
u32 qth_min, u32 qth_max, u8 Wlog, u8 Plog,
u8 Scell_log, u8 *stab)
{
/* Reset average queue length, the value is strictly bound
* to the parameters below, reseting hurts a bit but leaving
* it might result in an unreasonable qavg for a while. --TGR
*/
p->qavg = 0;
p->qcount = -1;
p->qth_min = qth_min << Wlog;
p->qth_max = qth_max << Wlog;
p->Wlog = Wlog;
p->Plog = Plog;
p->Rmask = red_rmask(Plog);
p->Scell_log = Scell_log;
p->Scell_max = (255 << Scell_log);
memcpy(p->Stab, stab, sizeof(p->Stab));
}
static inline int red_is_idling(struct red_parms *p)
{
return !PSCHED_IS_PASTPERFECT(p->qidlestart);
}
static inline void red_start_of_idle_period(struct red_parms *p)
{
PSCHED_GET_TIME(p->qidlestart);
}
static inline void red_end_of_idle_period(struct red_parms *p)
{
PSCHED_SET_PASTPERFECT(p->qidlestart);
}
static inline void red_restart(struct red_parms *p)
{
red_end_of_idle_period(p);
p->qavg = 0;
p->qcount = -1;
}
static inline unsigned long red_calc_qavg_from_idle_time(struct red_parms *p)
{
psched_time_t now;
long us_idle;
int shift;
PSCHED_GET_TIME(now);
us_idle = PSCHED_TDIFF_SAFE(now, p->qidlestart, p->Scell_max);
/*
* The problem: ideally, average length queue recalcultion should
* be done over constant clock intervals. This is too expensive, so
* that the calculation is driven by outgoing packets.
* When the queue is idle we have to model this clock by hand.
*
* SF+VJ proposed to "generate":
*
* m = idletime / (average_pkt_size / bandwidth)
*
* dummy packets as a burst after idle time, i.e.
*
* p->qavg *= (1-W)^m
*
* This is an apparently overcomplicated solution (f.e. we have to
* precompute a table to make this calculation in reasonable time)
* I believe that a simpler model may be used here,
* but it is field for experiments.
*/
shift = p->Stab[(us_idle >> p->Scell_log) & RED_STAB_MASK];
if (shift)
return p->qavg >> shift;
else {
/* Approximate initial part of exponent with linear function:
*
* (1-W)^m ~= 1-mW + ...
*
* Seems, it is the best solution to
* problem of too coarse exponent tabulation.
*/
us_idle = (p->qavg * us_idle) >> p->Scell_log;
if (us_idle < (p->qavg >> 1))
return p->qavg - us_idle;
else
return p->qavg >> 1;
}
}
static inline unsigned long red_calc_qavg_no_idle_time(struct red_parms *p,
unsigned int backlog)
{
/*
* NOTE: p->qavg is fixed point number with point at Wlog.
* The formula below is equvalent to floating point
* version:
*
* qavg = qavg*(1-W) + backlog*W;
*
* --ANK (980924)
*/
return p->qavg + (backlog - (p->qavg >> p->Wlog));
}
static inline unsigned long red_calc_qavg(struct red_parms *p,
unsigned int backlog)
{
if (!red_is_idling(p))
return red_calc_qavg_no_idle_time(p, backlog);
else
return red_calc_qavg_from_idle_time(p);
}
static inline u32 red_random(struct red_parms *p)
{
return net_random() & p->Rmask;
}
static inline int red_mark_probability(struct red_parms *p, unsigned long qavg)
{
/* The formula used below causes questions.
OK. qR is random number in the interval 0..Rmask
i.e. 0..(2^Plog). If we used floating point
arithmetics, it would be: (2^Plog)*rnd_num,
where rnd_num is less 1.
Taking into account, that qavg have fixed
point at Wlog, and Plog is related to max_P by
max_P = (qth_max-qth_min)/2^Plog; two lines
below have the following floating point equivalent:
max_P*(qavg - qth_min)/(qth_max-qth_min) < rnd/qcount
Any questions? --ANK (980924)
*/
return !(((qavg - p->qth_min) >> p->Wlog) * p->qcount < p->qR);
}
enum {
RED_BELOW_MIN_THRESH,
RED_BETWEEN_TRESH,
RED_ABOVE_MAX_TRESH,
};
static inline int red_cmp_thresh(struct red_parms *p, unsigned long qavg)
{
if (qavg < p->qth_min)
return RED_BELOW_MIN_THRESH;
else if (qavg >= p->qth_max)
return RED_ABOVE_MAX_TRESH;
else
return RED_BETWEEN_TRESH;
}
enum {
RED_DONT_MARK,
RED_PROB_MARK,
RED_HARD_MARK,
};
static inline int red_action(struct red_parms *p, unsigned long qavg)
{
switch (red_cmp_thresh(p, qavg)) {
case RED_BELOW_MIN_THRESH:
p->qcount = -1;
return RED_DONT_MARK;
case RED_BETWEEN_TRESH:
if (++p->qcount) {
if (red_mark_probability(p, qavg)) {
p->qcount = 0;
p->qR = red_random(p);
return RED_PROB_MARK;
}
} else
p->qR = red_random(p);
return RED_DONT_MARK;
case RED_ABOVE_MAX_TRESH:
p->qcount = -1;
return RED_HARD_MARK;
}
BUG();
return RED_DONT_MARK;
}
#endif
net/sched/sch_gred.c
View file @ 2d43f112
......@@ -15,247 +15,281 @@
* from Ren Liu
* - More error checks
*
*
*
* For all the glorious comments look at Alexey's sch_red.c
* For all the glorious comments look at include/net/red.h
*/
#include <linux/config.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/red.h>
#if 1 /* control */
#define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
#else
#define DPRINTK(format,args...)
#endif
#if 0 /* data */
#define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
#else
#define D2PRINTK(format,args...)
#endif
#define GRED_DEF_PRIO (MAX_DPs / 2)
#define GRED_VQ_MASK (MAX_DPs - 1)
struct gred_sched_data;
struct gred_sched;
struct gred_sched_data
{
/* Parameters */
u32 limit; /* HARD maximal queue length */
u32 qth_min; /* Min average length threshold: A scaled */
u32 qth_max; /* Max average length threshold: A scaled */
u32 DP; /* the drop pramaters */
char Wlog; /* log(W) */
char Plog; /* random number bits */
u32 Scell_max;
u32 Rmask;
u32 bytesin; /* bytes seen on virtualQ so far*/
u32 packetsin; /* packets seen on virtualQ so far*/
u32 backlog; /* bytes on the virtualQ */
u32 forced; /* packets dropped for exceeding limits */
u32 early; /* packets dropped as a warning */
u32 other; /* packets dropped by invoking drop() */
u32 pdrop; /* packets dropped because we exceeded physical queue limits */
char Scell_log;
u8 Stab[256];
u8 prio; /* the prio of this vq */
/* Variables */
unsigned long qave; /* Average queue length: A scaled */
int qcount; /* Packets since last random number generation */
u32 qR; /* Cached random number */
psched_time_t qidlestart; /* Start of idle period */
u8 prio; /* the prio of this vq */
struct red_parms parms;
struct red_stats stats;
};
enum {
GRED_WRED_MODE = 1,
GRED_RIO_MODE,
};
struct gred_sched
{
struct gred_sched_data *tab[MAX_DPs];
u32 DPs;
u32 def;
u8 initd;
u8 grio;
u8 eqp;
unsigned long flags;
u32 red_flags;
u32 DPs;
u32 def;
struct red_parms wred_set;
};
static int
gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
static inline int gred_wred_mode(struct gred_sched *table)
{
psched_time_t now;
struct gred_sched_data *q=NULL;
struct gred_sched *t= qdisc_priv(sch);
unsigned long qave=0;
int i=0;
return test_bit(GRED_WRED_MODE, &table->flags);
}
static inline void gred_enable_wred_mode(struct gred_sched *table)
{
__set_bit(GRED_WRED_MODE, &table->flags);
}
static inline void gred_disable_wred_mode(struct gred_sched *table)
{
__clear_bit(GRED_WRED_MODE, &table->flags);
}
static inline int gred_rio_mode(struct gred_sched *table)
{
return test_bit(GRED_RIO_MODE, &table->flags);
}
static inline void gred_enable_rio_mode(struct gred_sched *table)
{
__set_bit(GRED_RIO_MODE, &table->flags);
}
static inline void gred_disable_rio_mode(struct gred_sched *table)
{
__clear_bit(GRED_RIO_MODE, &table->flags);
}
static inline int gred_wred_mode_check(struct Qdisc *sch)
{
struct gred_sched *table = qdisc_priv(sch);
int i;
if (!t->initd && skb_queue_len(&sch->q) < (sch->dev->tx_queue_len ? : 1)) {
D2PRINTK("NO GRED Queues setup yet! Enqueued anyway\n");
goto do_enqueue;
/* Really ugly O(n^2) but shouldn't be necessary too frequent. */
for (i = 0; i < table->DPs; i++) {
struct gred_sched_data *q = table->tab[i];
int n;
if (q == NULL)
continue;
for (n = 0; n < table->DPs; n++)
if (table->tab[n] && table->tab[n] != q &&
table->tab[n]->prio == q->prio)
return 1;
}
return 0;
}
static inline unsigned int gred_backlog(struct gred_sched *table,
struct gred_sched_data *q,
struct Qdisc *sch)
{
if (gred_wred_mode(table))
return sch->qstats.backlog;
else
return q->backlog;
}
static inline u16 tc_index_to_dp(struct sk_buff *skb)
{
return skb->tc_index & GRED_VQ_MASK;
}
static inline void gred_load_wred_set(struct gred_sched *table,
struct gred_sched_data *q)
{
q->parms.qavg = table->wred_set.qavg;
q->parms.qidlestart = table->wred_set.qidlestart;
}
static inline void gred_store_wred_set(struct gred_sched *table,
struct gred_sched_data *q)
{
table->wred_set.qavg = q->parms.qavg;
}
static inline int gred_use_ecn(struct gred_sched *t)
{
return t->red_flags & TC_RED_ECN;
}
if ( ((skb->tc_index&0xf) > (t->DPs -1)) || !(q=t->tab[skb->tc_index&0xf])) {
printk("GRED: setting to default (%d)\n ",t->def);
if (!(q=t->tab[t->def])) {
DPRINTK("GRED: setting to default FAILED! dropping!! "
"(%d)\n ", t->def);
goto drop;
static inline int gred_use_harddrop(struct gred_sched *t)
{
return t->red_flags & TC_RED_HARDDROP;
}
static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct gred_sched_data *q=NULL;
struct gred_sched *t= qdisc_priv(sch);
unsigned long qavg = 0;
u16 dp = tc_index_to_dp(skb);
if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
dp = t->def;
if ((q = t->tab[dp]) == NULL) {
/* Pass through packets not assigned to a DP
* if no default DP has been configured. This
* allows for DP flows to be left untouched.
*/
if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
return qdisc_enqueue_tail(skb, sch);
else
goto drop;
}
/* fix tc_index? --could be controvesial but needed for
requeueing */
skb->tc_index=(skb->tc_index&0xfffffff0) | t->def;
skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
}
D2PRINTK("gred_enqueue virtualQ 0x%x classid %x backlog %d "
"general backlog %d\n",skb->tc_index&0xf,sch->handle,q->backlog,
sch->qstats.backlog);
/* sum up all the qaves of prios <= to ours to get the new qave*/
if (!t->eqp && t->grio) {
for (i=0;i<t->DPs;i++) {
if ((!t->tab[i]) || (i==q->DP))
continue;
if ((t->tab[i]->prio < q->prio) && (PSCHED_IS_PASTPERFECT(t->tab[i]->qidlestart)))
qave +=t->tab[i]->qave;
/* sum up all the qaves of prios <= to ours to get the new qave */
if (!gred_wred_mode(t) && gred_rio_mode(t)) {
int i;
for (i = 0; i < t->DPs; i++) {
if (t->tab[i] && t->tab[i]->prio < q->prio &&
!red_is_idling(&t->tab[i]->parms))
qavg +=t->tab[i]->parms.qavg;
}
}
q->packetsin++;
q->bytesin+=skb->len;
q->bytesin += skb->len;
if (t->eqp && t->grio) {
qave=0;
q->qave=t->tab[t->def]->qave;
q->qidlestart=t->tab[t->def]->qidlestart;
}
if (gred_wred_mode(t))
gred_load_wred_set(t, q);
if (!PSCHED_IS_PASTPERFECT(q->qidlestart)) {
long us_idle;
PSCHED_GET_TIME(now);
us_idle = PSCHED_TDIFF_SAFE(now, q->qidlestart, q->Scell_max);
PSCHED_SET_PASTPERFECT(q->qidlestart);
q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
q->qave >>= q->Stab[(us_idle>>q->Scell_log)&0xFF];
} else {
if (t->eqp) {
q->qave += sch->qstats.backlog - (q->qave >> q->Wlog);
} else {
q->qave += q->backlog - (q->qave >> q->Wlog);
}
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
}
if (t->eqp && t->grio)
t->tab[t->def]->qave=q->qave;
if ((q->qave+qave) < q->qth_min) {
q->qcount = -1;
enqueue:
if (q->backlog + skb->len <= q->limit) {
q->backlog += skb->len;
do_enqueue:
__skb_queue_tail(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->bstats.bytes += skb->len;
sch->bstats.packets++;
return 0;
} else {
q->pdrop++;
}
if (gred_wred_mode(t))
gred_store_wred_set(t, q);
drop:
kfree_skb(skb);
sch->qstats.drops++;
return NET_XMIT_DROP;
}
if ((q->qave+qave) >= q->qth_max) {
q->qcount = -1;
sch->qstats.overlimits++;
q->forced++;
goto drop;
switch (red_action(&q->parms, q->parms.qavg + qavg)) {
case RED_DONT_MARK:
break;
case RED_PROB_MARK:
sch->qstats.overlimits++;
if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
q->stats.prob_drop++;
goto congestion_drop;
}
q->stats.prob_mark++;
break;
case RED_HARD_MARK:
sch->qstats.overlimits++;
if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
!INET_ECN_set_ce(skb)) {
q->stats.forced_drop++;
goto congestion_drop;
}
q->stats.forced_mark++;
break;
}
if (++q->qcount) {
if ((((qave+q->qave) - q->qth_min)>>q->Wlog)*q->qcount < q->qR)
goto enqueue;
q->qcount = 0;
q->qR = net_random()&q->Rmask;
sch->qstats.overlimits++;
q->early++;
goto drop;
if (q->backlog + skb->len <= q->limit) {
q->backlog += skb->len;
return qdisc_enqueue_tail(skb, sch);
}
q->qR = net_random()&q->Rmask;
goto enqueue;
q->stats.pdrop++;
drop:
return qdisc_drop(skb, sch);
congestion_drop:
qdisc_drop(skb, sch);
return NET_XMIT_CN;
}
static int
gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
static int gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
{
struct gred_sched *t = qdisc_priv(sch);
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
q= t->tab[(skb->tc_index&0xf)];
/* error checking here -- probably unnecessary */
PSCHED_SET_PASTPERFECT(q->qidlestart);
__skb_queue_head(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->qstats.requeues++;
q->backlog += skb->len;
return 0;
u16 dp = tc_index_to_dp(skb);
if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
if (net_ratelimit())
printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
"for requeue, screwing up backlog.\n",
tc_index_to_dp(skb));
} else {
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
q->backlog += skb->len;
}
return qdisc_requeue(skb, sch);
}
static struct sk_buff *
gred_dequeue(struct Qdisc* sch)
static struct sk_buff *gred_dequeue(struct Qdisc* sch)
{
struct sk_buff *skb;
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
struct gred_sched *t = qdisc_priv(sch);
skb = qdisc_dequeue_head(sch);
skb = __skb_dequeue(&sch->q);
if (skb) {
sch->qstats.backlog -= skb->len;
q= t->tab[(skb->tc_index&0xf)];
if (q) {
q->backlog -= skb->len;
if (!q->backlog && !t->eqp)
PSCHED_GET_TIME(q->qidlestart);
struct gred_sched_data *q;
u16 dp = tc_index_to_dp(skb);
if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
if (net_ratelimit())
printk(KERN_WARNING "GRED: Unable to relocate "
"VQ 0x%x after dequeue, screwing up "
"backlog.\n", tc_index_to_dp(skb));
} else {
D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",skb->tc_index&0xf);
q->backlog -= skb->len;
if (!q->backlog && !gred_wred_mode(t))
red_start_of_idle_period(&q->parms);
}
return skb;
}
if (t->eqp) {
q= t->tab[t->def];
if (!q)
D2PRINTK("no default VQ set: Results will be "
"screwed up\n");
else
PSCHED_GET_TIME(q->qidlestart);
}
if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
red_start_of_idle_period(&t->wred_set);
return NULL;
}
......@@ -263,36 +297,34 @@ gred_dequeue(struct Qdisc* sch)
static unsigned int gred_drop(struct Qdisc* sch)
{
struct sk_buff *skb;
struct gred_sched *t = qdisc_priv(sch);
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
skb = __skb_dequeue_tail(&sch->q);
skb = qdisc_dequeue_tail(sch);
if (skb) {
unsigned int len = skb->len;
sch->qstats.backlog -= len;
sch->qstats.drops++;
q= t->tab[(skb->tc_index&0xf)];
if (q) {
q->backlog -= len;
q->other++;
if (!q->backlog && !t->eqp)
PSCHED_GET_TIME(q->qidlestart);
struct gred_sched_data *q;
u16 dp = tc_index_to_dp(skb);
if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
if (net_ratelimit())
printk(KERN_WARNING "GRED: Unable to relocate "
"VQ 0x%x while dropping, screwing up "
"backlog.\n", tc_index_to_dp(skb));
} else {
D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",skb->tc_index&0xf);
q->backlog -= len;
q->stats.other++;
if (!q->backlog && !gred_wred_mode(t))
red_start_of_idle_period(&q->parms);
}
kfree_skb(skb);
qdisc_drop(skb, sch);
return len;
}
q=t->tab[t->def];
if (!q) {
D2PRINTK("no default VQ set: Results might be screwed up\n");
return 0;
}
if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
red_start_of_idle_period(&t->wred_set);
PSCHED_GET_TIME(q->qidlestart);
return 0;
}
......@@ -300,293 +332,241 @@ static unsigned int gred_drop(struct Qdisc* sch)
static void gred_reset(struct Qdisc* sch)
{
int i;
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
struct gred_sched *t = qdisc_priv(sch);
qdisc_reset_queue(sch);
__skb_queue_purge(&sch->q);
for (i = 0; i < t->DPs; i++) {
struct gred_sched_data *q = t->tab[i];
sch->qstats.backlog = 0;
if (!q)
continue;
for (i=0;i<t->DPs;i++) {
q= t->tab[i];
if (!q)
continue;
PSCHED_SET_PASTPERFECT(q->qidlestart);
q->qave = 0;
q->qcount = -1;
red_restart(&q->parms);
q->backlog = 0;
q->other=0;
q->forced=0;
q->pdrop=0;
q->early=0;
}
}
static int gred_change(struct Qdisc *sch, struct rtattr *opt)
static inline void gred_destroy_vq(struct gred_sched_data *q)
{
kfree(q);
}
static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
{
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q;
struct tc_gred_qopt *ctl;
struct tc_gred_sopt *sopt;
struct rtattr *tb[TCA_GRED_STAB];
struct rtattr *tb2[TCA_GRED_DPS];
int i;
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_STAB, opt))
if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
return -EINVAL;
if (tb[TCA_GRED_PARMS-1] == 0 && tb[TCA_GRED_STAB-1] == 0) {
rtattr_parse_nested(tb2, TCA_GRED_DPS, opt);
sopt = RTA_DATA(dps);
if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
return -EINVAL;
if (tb2[TCA_GRED_DPS-1] == 0)
return -EINVAL;
sch_tree_lock(sch);
table->DPs = sopt->DPs;
table->def = sopt->def_DP;
table->red_flags = sopt->flags;
/*
* Every entry point to GRED is synchronized with the above code
* and the DP is checked against DPs, i.e. shadowed VQs can no
* longer be found so we can unlock right here.
*/
sch_tree_unlock(sch);
if (sopt->grio) {
gred_enable_rio_mode(table);
gred_disable_wred_mode(table);
if (gred_wred_mode_check(sch))
gred_enable_wred_mode(table);
} else {
gred_disable_rio_mode(table);
gred_disable_wred_mode(table);
}
sopt = RTA_DATA(tb2[TCA_GRED_DPS-1]);
table->DPs=sopt->DPs;
table->def=sopt->def_DP;
table->grio=sopt->grio;
table->initd=0;
/* probably need to clear all the table DP entries as well */
return 0;
}
for (i = table->DPs; i < MAX_DPs; i++) {
if (table->tab[i]) {
printk(KERN_WARNING "GRED: Warning: Destroying "
"shadowed VQ 0x%x\n", i);
gred_destroy_vq(table->tab[i]);
table->tab[i] = NULL;
}
}
return 0;
}
if (!table->DPs || tb[TCA_GRED_PARMS-1] == 0 || tb[TCA_GRED_STAB-1] == 0 ||
RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
return -EINVAL;
static inline int gred_change_vq(struct Qdisc *sch, int dp,
struct tc_gred_qopt *ctl, int prio, u8 *stab)
{
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q;
ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
if (ctl->DP > MAX_DPs-1 ) {
/* misbehaving is punished! Put in the default drop probability */
DPRINTK("\nGRED: DP %u not in the proper range fixed. New DP "
"set to default at %d\n",ctl->DP,table->def);
ctl->DP=table->def;
}
if (table->tab[ctl->DP] == NULL) {
table->tab[ctl->DP]=kmalloc(sizeof(struct gred_sched_data),
GFP_KERNEL);
if (NULL == table->tab[ctl->DP])
if (table->tab[dp] == NULL) {
table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
if (table->tab[dp] == NULL)
return -ENOMEM;
memset(table->tab[ctl->DP], 0, (sizeof(struct gred_sched_data)));
}
q= table->tab[ctl->DP];
if (table->grio) {
if (ctl->prio <=0) {
if (table->def && table->tab[table->def]) {
DPRINTK("\nGRED: DP %u does not have a prio"
"setting default to %d\n",ctl->DP,
table->tab[table->def]->prio);
q->prio=table->tab[table->def]->prio;
} else {
DPRINTK("\nGRED: DP %u does not have a prio"
" setting default to 8\n",ctl->DP);
q->prio=8;
}
} else {
q->prio=ctl->prio;
}
} else {
q->prio=8;
memset(table->tab[dp], 0, sizeof(*q));
}
q->DP=ctl->DP;
q->Wlog = ctl->Wlog;
q->Plog = ctl->Plog;
q = table->tab[dp];
q->DP = dp;
q->prio = prio;
q->limit = ctl->limit;
q->Scell_log = ctl->Scell_log;
q->Rmask = ctl->Plog < 32 ? ((1<<ctl->Plog) - 1) : ~0UL;
q->Scell_max = (255<<q->Scell_log);
q->qth_min = ctl->qth_min<<ctl->Wlog;
q->qth_max = ctl->qth_max<<ctl->Wlog;
q->qave=0;
q->backlog=0;
q->qcount = -1;
q->other=0;
q->forced=0;
q->pdrop=0;
q->early=0;
PSCHED_SET_PASTPERFECT(q->qidlestart);
memcpy(q->Stab, RTA_DATA(tb[TCA_GRED_STAB-1]), 256);
if ( table->initd && table->grio) {
/* this looks ugly but it's not in the fast path */
for (i=0;i<table->DPs;i++) {
if ((!table->tab[i]) || (i==q->DP) )
continue;
if (table->tab[i]->prio == q->prio ){
/* WRED mode detected */
table->eqp=1;
break;
}
}
}
if (!table->initd) {
table->initd=1;
/*
the first entry also goes into the default until
over-written
*/
if (table->tab[table->def] == NULL) {
table->tab[table->def]=
kmalloc(sizeof(struct gred_sched_data), GFP_KERNEL);
if (NULL == table->tab[table->def])
return -ENOMEM;
memset(table->tab[table->def], 0,
(sizeof(struct gred_sched_data)));
}
q= table->tab[table->def];
q->DP=table->def;
q->Wlog = ctl->Wlog;
q->Plog = ctl->Plog;
q->limit = ctl->limit;
q->Scell_log = ctl->Scell_log;
q->Rmask = ctl->Plog < 32 ? ((1<<ctl->Plog) - 1) : ~0UL;
q->Scell_max = (255<<q->Scell_log);
q->qth_min = ctl->qth_min<<ctl->Wlog;
q->qth_max = ctl->qth_max<<ctl->Wlog;
if (table->grio)
q->prio=table->tab[ctl->DP]->prio;
else
q->prio=8;
q->qcount = -1;
PSCHED_SET_PASTPERFECT(q->qidlestart);
memcpy(q->Stab, RTA_DATA(tb[TCA_GRED_STAB-1]), 256);
}
return 0;
if (q->backlog == 0)
red_end_of_idle_period(&q->parms);
red_set_parms(&q->parms,
ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
ctl->Scell_log, stab);
return 0;
}
static int gred_init(struct Qdisc *sch, struct rtattr *opt)
static int gred_change(struct Qdisc *sch, struct rtattr *opt)
{
struct gred_sched *table = qdisc_priv(sch);
struct tc_gred_sopt *sopt;
struct rtattr *tb[TCA_GRED_STAB];
struct rtattr *tb2[TCA_GRED_DPS];
struct tc_gred_qopt *ctl;
struct rtattr *tb[TCA_GRED_MAX];
int err = -EINVAL, prio = GRED_DEF_PRIO;
u8 *stab;
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_STAB, opt))
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
return -EINVAL;
if (tb[TCA_GRED_PARMS-1] == 0 && tb[TCA_GRED_STAB-1] == 0) {
rtattr_parse_nested(tb2, TCA_GRED_DPS, opt);
if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
return gred_change_table_def(sch, opt);
if (tb[TCA_GRED_PARMS-1] == NULL ||
RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
tb[TCA_GRED_STAB-1] == NULL ||
RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
return -EINVAL;
ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
if (ctl->DP >= table->DPs)
goto errout;
if (tb2[TCA_GRED_DPS-1] == 0)
return -EINVAL;
if (gred_rio_mode(table)) {
if (ctl->prio == 0) {
int def_prio = GRED_DEF_PRIO;
sopt = RTA_DATA(tb2[TCA_GRED_DPS-1]);
table->DPs=sopt->DPs;
table->def=sopt->def_DP;
table->grio=sopt->grio;
table->initd=0;
return 0;
if (table->tab[table->def])
def_prio = table->tab[table->def]->prio;
printk(KERN_DEBUG "GRED: DP %u does not have a prio "
"setting default to %d\n", ctl->DP, def_prio);
prio = def_prio;
} else
prio = ctl->prio;
}
sch_tree_lock(sch);
err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
if (err < 0)
goto errout_locked;
if (gred_rio_mode(table)) {
gred_disable_wred_mode(table);
if (gred_wred_mode_check(sch))
gred_enable_wred_mode(table);
}
DPRINTK("\n GRED_INIT error!\n");
return -EINVAL;
err = 0;
errout_locked:
sch_tree_unlock(sch);
errout:
return err;
}
static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
static int gred_init(struct Qdisc *sch, struct rtattr *opt)
{
unsigned long qave;
struct rtattr *rta;
struct tc_gred_qopt *opt = NULL ;
struct tc_gred_qopt *dst;
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q;
int i;
unsigned char *b = skb->tail;
struct rtattr *tb[TCA_GRED_MAX];
rta = (struct rtattr*)b;
RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
return -EINVAL;
opt=kmalloc(sizeof(struct tc_gred_qopt)*MAX_DPs, GFP_KERNEL);
if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
return -EINVAL;
if (opt == NULL) {
DPRINTK("gred_dump:failed to malloc for %Zd\n",
sizeof(struct tc_gred_qopt)*MAX_DPs);
goto rtattr_failure;
}
return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
}
memset(opt, 0, (sizeof(struct tc_gred_qopt))*table->DPs);
static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct gred_sched *table = qdisc_priv(sch);
struct rtattr *parms, *opts = NULL;
int i;
struct tc_gred_sopt sopt = {
.DPs = table->DPs,
.def_DP = table->def,
.grio = gred_rio_mode(table),
.flags = table->red_flags,
};
if (!table->initd) {
DPRINTK("NO GRED Queues setup!\n");
}
opts = RTA_NEST(skb, TCA_OPTIONS);
RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
parms = RTA_NEST(skb, TCA_GRED_PARMS);
for (i = 0; i < MAX_DPs; i++) {
struct gred_sched_data *q = table->tab[i];
struct tc_gred_qopt opt;
for (i=0;i<MAX_DPs;i++) {
dst= &opt[i];
q= table->tab[i];
memset(&opt, 0, sizeof(opt));
if (!q) {
/* hack -- fix at some point with proper message
This is how we indicate to tc that there is no VQ
at this DP */
dst->DP=MAX_DPs+i;
continue;
opt.DP = MAX_DPs + i;
goto append_opt;
}
dst->limit=q->limit;
dst->qth_min=q->qth_min>>q->Wlog;
dst->qth_max=q->qth_max>>q->Wlog;
dst->DP=q->DP;
dst->backlog=q->backlog;
if (q->qave) {
if (table->eqp && table->grio) {
q->qidlestart=table->tab[table->def]->qidlestart;
q->qave=table->tab[table->def]->qave;
}
if (!PSCHED_IS_PASTPERFECT(q->qidlestart)) {
long idle;
psched_time_t now;
PSCHED_GET_TIME(now);
idle = PSCHED_TDIFF_SAFE(now, q->qidlestart, q->Scell_max);
qave = q->qave >> q->Stab[(idle>>q->Scell_log)&0xFF];
dst->qave = qave >> q->Wlog;
} else {
dst->qave = q->qave >> q->Wlog;
}
} else {
dst->qave = 0;
opt.limit = q->limit;
opt.DP = q->DP;
opt.backlog = q->backlog;
opt.prio = q->prio;
opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
opt.Wlog = q->parms.Wlog;
opt.Plog = q->parms.Plog;
opt.Scell_log = q->parms.Scell_log;
opt.other = q->stats.other;
opt.early = q->stats.prob_drop;
opt.forced = q->stats.forced_drop;
opt.pdrop = q->stats.pdrop;
opt.packets = q->packetsin;
opt.bytesin = q->bytesin;
if (gred_wred_mode(table)) {
q->parms.qidlestart =
table->tab[table->def]->parms.qidlestart;
q->parms.qavg = table->tab[table->def]->parms.qavg;
}
dst->Wlog = q->Wlog;
dst->Plog = q->Plog;
dst->Scell_log = q->Scell_log;
dst->other = q->other;
dst->forced = q->forced;
dst->early = q->early;
dst->pdrop = q->pdrop;
dst->prio = q->prio;
dst->packets=q->packetsin;
dst->bytesin=q->bytesin;
opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
append_opt:
RTA_APPEND(skb, sizeof(opt), &opt);
}
RTA_PUT(skb, TCA_GRED_PARMS, sizeof(struct tc_gred_qopt)*MAX_DPs, opt);
rta->rta_len = skb->tail - b;
RTA_NEST_END(skb, parms);
kfree(opt);
return skb->len;
return RTA_NEST_END(skb, opts);
rtattr_failure:
if (opt)
kfree(opt);
DPRINTK("gred_dump: FAILURE!!!!\n");
/* also free the opt struct here */
skb_trim(skb, b - skb->data);
return -1;
return RTA_NEST_CANCEL(skb, opts);
}
static void gred_destroy(struct Qdisc *sch)
......@@ -594,15 +574,13 @@ static void gred_destroy(struct Qdisc *sch)
struct gred_sched *table = qdisc_priv(sch);
int i;
for (i = 0;i < table->DPs; i++) {
for (i = 0; i < table->DPs; i++) {
if (table->tab[i])
kfree(table->tab[i]);
gred_destroy_vq(table->tab[i]);
}
}
static struct Qdisc_ops gred_qdisc_ops = {
.next = NULL,
.cl_ops = NULL,
.id = "gred",
.priv_size = sizeof(struct gred_sched),
.enqueue = gred_enqueue,
......@@ -621,10 +599,13 @@ static int __init gred_module_init(void)
{
return register_qdisc(&gred_qdisc_ops);
}
static void __exit gred_module_exit(void)
static void __exit gred_module_exit(void)
{
unregister_qdisc(&gred_qdisc_ops);
}
module_init(gred_module_init)
module_exit(gred_module_exit)
MODULE_LICENSE("GPL");
net/sched/sch_red.c
View file @ 2d43f112
......@@ -9,76 +9,23 @@
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* Changes:
* J Hadi Salim <hadi@nortel.com> 980914: computation fixes
* J Hadi Salim 980914: computation fixes
* Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
* J Hadi Salim <hadi@nortelnetworks.com> 980816: ECN support
* J Hadi Salim 980816: ECN support
*/
#include <linux/config.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/inet_ecn.h>
#include <net/dsfield.h>
#include <net/red.h>
/* Random Early Detection (RED) algorithm.
=======================================
Source: Sally Floyd and Van Jacobson, "Random Early Detection Gateways
for Congestion Avoidance", 1993, IEEE/ACM Transactions on Networking.
This file codes a "divisionless" version of RED algorithm
as written down in Fig.17 of the paper.
Short description.
------------------
When a new packet arrives we calculate the average queue length:
avg = (1-W)*avg + W*current_queue_len,
W is the filter time constant (chosen as 2^(-Wlog)), it controls
the inertia of the algorithm. To allow larger bursts, W should be
decreased.
if (avg > th_max) -> packet marked (dropped).
if (avg < th_min) -> packet passes.
if (th_min < avg < th_max) we calculate probability:
Pb = max_P * (avg - th_min)/(th_max-th_min)
and mark (drop) packet with this probability.
Pb changes from 0 (at avg==th_min) to max_P (avg==th_max).
max_P should be small (not 1), usually 0.01..0.02 is good value.
max_P is chosen as a number, so that max_P/(th_max-th_min)
is a negative power of two in order arithmetics to contain
only shifts.
Parameters, settable by user:
/* Parameters, settable by user:
-----------------------------
limit - bytes (must be > qth_max + burst)
......@@ -89,243 +36,93 @@ Short description.
arbitrarily high (well, less than ram size)
Really, this limit will never be reached
if RED works correctly.
qth_min - bytes (should be < qth_max/2)
qth_max - bytes (should be at least 2*qth_min and less limit)
Wlog - bits (<32) log(1/W).
Plog - bits (<32)
Plog is related to max_P by formula:
max_P = (qth_max-qth_min)/2^Plog;
F.e. if qth_max=128K and qth_min=32K, then Plog=22
corresponds to max_P=0.02
Scell_log
Stab
Lookup table for log((1-W)^(t/t_ave).
NOTES:
Upper bound on W.
-----------------
If you want to allow bursts of L packets of size S,
you should choose W:
L + 1 - th_min/S < (1-(1-W)^L)/W
th_min/S = 32 th_min/S = 4
log(W) L
-1 33
-2 35
-3 39
-4 46
-5 57
-6 75
-7 101
-8 135
-9 190
etc.
*/
struct red_sched_data
{
/* Parameters */
u32 limit; /* HARD maximal queue length */
u32 qth_min; /* Min average length threshold: A scaled */
u32 qth_max; /* Max average length threshold: A scaled */
u32 Rmask;
u32 Scell_max;
unsigned char flags;
char Wlog; /* log(W) */
char Plog; /* random number bits */
char Scell_log;
u8 Stab[256];
/* Variables */
unsigned long qave; /* Average queue length: A scaled */
int qcount; /* Packets since last random number generation */
u32 qR; /* Cached random number */
psched_time_t qidlestart; /* Start of idle period */
struct tc_red_xstats st;
u32 limit; /* HARD maximal queue length */
unsigned char flags;
struct red_parms parms;
struct red_stats stats;
};
static int red_ecn_mark(struct sk_buff *skb)
static inline int red_use_ecn(struct red_sched_data *q)
{
if (skb->nh.raw + 20 > skb->tail)
return 0;
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
if (INET_ECN_is_not_ect(skb->nh.iph->tos))
return 0;
IP_ECN_set_ce(skb->nh.iph);
return 1;
case __constant_htons(ETH_P_IPV6):
if (INET_ECN_is_not_ect(ipv6_get_dsfield(skb->nh.ipv6h)))
return 0;
IP6_ECN_set_ce(skb->nh.ipv6h);
return 1;
default:
return 0;
}
return q->flags & TC_RED_ECN;
}
static int
red_enqueue(struct sk_buff *skb, struct Qdisc* sch)
static inline int red_use_harddrop(struct red_sched_data *q)
{
return q->flags & TC_RED_HARDDROP;
}
static int red_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct red_sched_data *q = qdisc_priv(sch);
psched_time_t now;
q->parms.qavg = red_calc_qavg(&q->parms, sch->qstats.backlog);
if (!PSCHED_IS_PASTPERFECT(q->qidlestart)) {
long us_idle;
int shift;
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
PSCHED_GET_TIME(now);
us_idle = PSCHED_TDIFF_SAFE(now, q->qidlestart, q->Scell_max);
PSCHED_SET_PASTPERFECT(q->qidlestart);
switch (red_action(&q->parms, q->parms.qavg)) {
case RED_DONT_MARK:
break;
/*
The problem: ideally, average length queue recalcultion should
be done over constant clock intervals. This is too expensive, so that
the calculation is driven by outgoing packets.
When the queue is idle we have to model this clock by hand.
SF+VJ proposed to "generate" m = idletime/(average_pkt_size/bandwidth)
dummy packets as a burst after idle time, i.e.
q->qave *= (1-W)^m
This is an apparently overcomplicated solution (f.e. we have to precompute
a table to make this calculation in reasonable time)
I believe that a simpler model may be used here,
but it is field for experiments.
*/
shift = q->Stab[us_idle>>q->Scell_log];
if (shift) {
q->qave >>= shift;
} else {
/* Approximate initial part of exponent
with linear function:
(1-W)^m ~= 1-mW + ...
Seems, it is the best solution to
problem of too coarce exponent tabulation.
*/
us_idle = (q->qave * us_idle)>>q->Scell_log;
if (us_idle < q->qave/2)
q->qave -= us_idle;
else
q->qave >>= 1;
}
} else {
q->qave += sch->qstats.backlog - (q->qave >> q->Wlog);
/* NOTE:
q->qave is fixed point number with point at Wlog.
The formulae above is equvalent to floating point
version:
qave = qave*(1-W) + sch->qstats.backlog*W;
--ANK (980924)
*/
}
case RED_PROB_MARK:
sch->qstats.overlimits++;
if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
q->stats.prob_drop++;
goto congestion_drop;
}
if (q->qave < q->qth_min) {
q->qcount = -1;
enqueue:
if (sch->qstats.backlog + skb->len <= q->limit) {
__skb_queue_tail(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->bstats.bytes += skb->len;
sch->bstats.packets++;
return NET_XMIT_SUCCESS;
} else {
q->st.pdrop++;
}
kfree_skb(skb);
sch->qstats.drops++;
return NET_XMIT_DROP;
}
if (q->qave >= q->qth_max) {
q->qcount = -1;
sch->qstats.overlimits++;
mark:
if (!(q->flags&TC_RED_ECN) || !red_ecn_mark(skb)) {
q->st.early++;
goto drop;
}
q->st.marked++;
goto enqueue;
}
q->stats.prob_mark++;
break;
case RED_HARD_MARK:
sch->qstats.overlimits++;
if (red_use_harddrop(q) || !red_use_ecn(q) ||
!INET_ECN_set_ce(skb)) {
q->stats.forced_drop++;
goto congestion_drop;
}
if (++q->qcount) {
/* The formula used below causes questions.
OK. qR is random number in the interval 0..Rmask
i.e. 0..(2^Plog). If we used floating point
arithmetics, it would be: (2^Plog)*rnd_num,
where rnd_num is less 1.
Taking into account, that qave have fixed
point at Wlog, and Plog is related to max_P by
max_P = (qth_max-qth_min)/2^Plog; two lines
below have the following floating point equivalent:
max_P*(qave - qth_min)/(qth_max-qth_min) < rnd/qcount
Any questions? --ANK (980924)
*/
if (((q->qave - q->qth_min)>>q->Wlog)*q->qcount < q->qR)
goto enqueue;
q->qcount = 0;
q->qR = net_random()&q->Rmask;
sch->qstats.overlimits++;
goto mark;
q->stats.forced_mark++;
break;
}
q->qR = net_random()&q->Rmask;
goto enqueue;
drop:
kfree_skb(skb);
sch->qstats.drops++;
if (sch->qstats.backlog + skb->len <= q->limit)
return qdisc_enqueue_tail(skb, sch);
q->stats.pdrop++;
return qdisc_drop(skb, sch);
congestion_drop:
qdisc_drop(skb, sch);
return NET_XMIT_CN;
}
static int
red_requeue(struct sk_buff *skb, struct Qdisc* sch)
static int red_requeue(struct sk_buff *skb, struct Qdisc* sch)
{
struct red_sched_data *q = qdisc_priv(sch);
PSCHED_SET_PASTPERFECT(q->qidlestart);
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
__skb_queue_head(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->qstats.requeues++;
return 0;
return qdisc_requeue(skb, sch);
}
static struct sk_buff *
red_dequeue(struct Qdisc* sch)
static struct sk_buff * red_dequeue(struct Qdisc* sch)
{
struct sk_buff *skb;
struct red_sched_data *q = qdisc_priv(sch);
skb = __skb_dequeue(&sch->q);
if (skb) {
sch->qstats.backlog -= skb->len;
return skb;
}
PSCHED_GET_TIME(q->qidlestart);
return NULL;
skb = qdisc_dequeue_head(sch);
if (skb == NULL && !red_is_idling(&q->parms))
red_start_of_idle_period(&q->parms);
return skb;
}
static unsigned int red_drop(struct Qdisc* sch)
......@@ -333,16 +130,17 @@ static unsigned int red_drop(struct Qdisc* sch)
struct sk_buff *skb;
struct red_sched_data *q = qdisc_priv(sch);
skb = __skb_dequeue_tail(&sch->q);
skb = qdisc_dequeue_tail(sch);
if (skb) {
unsigned int len = skb->len;
sch->qstats.backlog -= len;
sch->qstats.drops++;
q->st.other++;
kfree_skb(skb);
q->stats.other++;
qdisc_drop(skb, sch);
return len;
}
PSCHED_GET_TIME(q->qidlestart);
if (!red_is_idling(&q->parms))
red_start_of_idle_period(&q->parms);
return 0;
}
......@@ -350,43 +148,38 @@ static void red_reset(struct Qdisc* sch)
{
struct red_sched_data *q = qdisc_priv(sch);
__skb_queue_purge(&sch->q);
sch->qstats.backlog = 0;
PSCHED_SET_PASTPERFECT(q->qidlestart);
q->qave = 0;
q->qcount = -1;
qdisc_reset_queue(sch);
red_restart(&q->parms);
}
static int red_change(struct Qdisc *sch, struct rtattr *opt)
{
struct red_sched_data *q = qdisc_priv(sch);
struct rtattr *tb[TCA_RED_STAB];
struct rtattr *tb[TCA_RED_MAX];
struct tc_red_qopt *ctl;
if (opt == NULL ||
rtattr_parse_nested(tb, TCA_RED_STAB, opt) ||
tb[TCA_RED_PARMS-1] == 0 || tb[TCA_RED_STAB-1] == 0 ||
if (opt == NULL || rtattr_parse_nested(tb, TCA_RED_MAX, opt))
return -EINVAL;
if (tb[TCA_RED_PARMS-1] == NULL ||
RTA_PAYLOAD(tb[TCA_RED_PARMS-1]) < sizeof(*ctl) ||
RTA_PAYLOAD(tb[TCA_RED_STAB-1]) < 256)
tb[TCA_RED_STAB-1] == NULL ||
RTA_PAYLOAD(tb[TCA_RED_STAB-1]) < RED_STAB_SIZE)
return -EINVAL;
ctl = RTA_DATA(tb[TCA_RED_PARMS-1]);
sch_tree_lock(sch);
q->flags = ctl->flags;
q->Wlog = ctl->Wlog;
q->Plog = ctl->Plog;
q->Rmask = ctl->Plog < 32 ? ((1<<ctl->Plog) - 1) : ~0UL;
q->Scell_log = ctl->Scell_log;
q->Scell_max = (255<<q->Scell_log);
q->qth_min = ctl->qth_min<<ctl->Wlog;
q->qth_max = ctl->qth_max<<ctl->Wlog;
q->limit = ctl->limit;
memcpy(q->Stab, RTA_DATA(tb[TCA_RED_STAB-1]), 256);
q->qcount = -1;
red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
ctl->Plog, ctl->Scell_log,
RTA_DATA(tb[TCA_RED_STAB-1]));
if (skb_queue_empty(&sch->q))
PSCHED_SET_PASTPERFECT(q->qidlestart);
red_end_of_idle_period(&q->parms);
sch_tree_unlock(sch);
return 0;
}
......@@ -399,39 +192,39 @@ static int red_init(struct Qdisc* sch, struct rtattr *opt)
static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct red_sched_data *q = qdisc_priv(sch);
unsigned char *b = skb->tail;
struct rtattr *rta;
struct tc_red_qopt opt;
rta = (struct rtattr*)b;
RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
opt.limit = q->limit;
opt.qth_min = q->qth_min>>q->Wlog;
opt.qth_max = q->qth_max>>q->Wlog;
opt.Wlog = q->Wlog;
opt.Plog = q->Plog;
opt.Scell_log = q->Scell_log;
opt.flags = q->flags;
struct rtattr *opts = NULL;
struct tc_red_qopt opt = {
.limit = q->limit,
.flags = q->flags,
.qth_min = q->parms.qth_min >> q->parms.Wlog,
.qth_max = q->parms.qth_max >> q->parms.Wlog,
.Wlog = q->parms.Wlog,
.Plog = q->parms.Plog,
.Scell_log = q->parms.Scell_log,
};
opts = RTA_NEST(skb, TCA_OPTIONS);
RTA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt);
rta->rta_len = skb->tail - b;
return skb->len;
return RTA_NEST_END(skb, opts);
rtattr_failure:
skb_trim(skb, b - skb->data);
return -1;
return RTA_NEST_CANCEL(skb, opts);
}
static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct red_sched_data *q = qdisc_priv(sch);
return gnet_stats_copy_app(d, &q->st, sizeof(q->st));
struct tc_red_xstats st = {
.early = q->stats.prob_drop + q->stats.forced_drop,
.pdrop = q->stats.pdrop,
.other = q->stats.other,
.marked = q->stats.prob_mark + q->stats.forced_mark,
};
return gnet_stats_copy_app(d, &st, sizeof(st));
}
static struct Qdisc_ops red_qdisc_ops = {
.next = NULL,
.cl_ops = NULL,
.id = "red",
.priv_size = sizeof(struct red_sched_data),
.enqueue = red_enqueue,
......@@ -450,10 +243,13 @@ static int __init red_module_init(void)
{
return register_qdisc(&red_qdisc_ops);
}
static void __exit red_module_exit(void)
static void __exit red_module_exit(void)
{
unregister_qdisc(&red_qdisc_ops);
}
module_init(red_module_init)
module_exit(red_module_exit)
MODULE_LICENSE("GPL");
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