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Commit 462dbc91 authored by Paolo Valente's avatar Paolo Valente Committed by David S. Miller
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pkt_sched: QFQ Plus: fair-queueing service at DRR cost 

This patch turns QFQ into QFQ+, a variant of QFQ that provides the
following two benefits: 1) QFQ+ is faster than QFQ, 2) differently
from QFQ, QFQ+ correctly schedules also non-leaves classes in a
hierarchical setting. A detailed description of QFQ+, plus a
performance comparison with DRR and QFQ, can be found in [1].

[1] P. Valente, "Reducing the Execution Time of Fair-Queueing Schedulers"
http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdfSigned-off-by: default avatarPaolo Valente <paolo.valente@unimore.it>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 351f33d9
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net/sched/sch_qfq.c
View file @ 462dbc91
/* /*
* net/sched/sch_qfq.c Quick Fair Queueing Scheduler. * net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler.
* *
* Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente. * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
* Copyright (c) 2012 Paolo Valente.
* *
* This program is free software; you can redistribute it and/or * This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License * modify it under the terms of the GNU General Public License
...@@ -19,12 +20,18 @@ ...@@ -19,12 +20,18 @@
#include <net/pkt_cls.h> #include <net/pkt_cls.h>
/* Quick Fair Queueing /* Quick Fair Queueing Plus
=================== ========================
Sources: Sources:
Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient [1] Paolo Valente,
"Reducing the Execution Time of Fair-Queueing Schedulers."
http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf
Sources for QFQ:
[2] Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient
Packet Scheduling with Tight Bandwidth Distribution Guarantees." Packet Scheduling with Tight Bandwidth Distribution Guarantees."
See also: See also:
...@@ -33,6 +40,20 @@ ...@@ -33,6 +40,20 @@
/* /*
QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES
classes. Each aggregate is timestamped with a virtual start time S
and a virtual finish time F, and scheduled according to its
timestamps. S and F are computed as a function of a system virtual
time function V. The classes within each aggregate are instead
scheduled with DRR.
To speed up operations, QFQ+ divides also aggregates into a limited
number of groups. Which group a class belongs to depends on the
ratio between the maximum packet length for the class and the weight
of the class. Groups have their own S and F. In the end, QFQ+
schedules groups, then aggregates within groups, then classes within
aggregates. See [1] and [2] for a full description.
Virtual time computations. Virtual time computations.
S, F and V are all computed in fixed point arithmetic with S, F and V are all computed in fixed point arithmetic with
...@@ -76,27 +97,28 @@ ...@@ -76,27 +97,28 @@
#define QFQ_MAX_SLOTS 32 #define QFQ_MAX_SLOTS 32
/* /*
* Shifts used for class<->group mapping. We allow class weights that are * Shifts used for aggregate<->group mapping. We allow class weights that are
* in the range [1, 2^MAX_WSHIFT], and we try to map each class i to the * in the range [1, 2^MAX_WSHIFT], and we try to map each aggregate i to the
* group with the smallest index that can support the L_i / r_i configured * group with the smallest index that can support the L_i / r_i configured
* for the class. * for the classes in the aggregate.
* *
* grp->index is the index of the group; and grp->slot_shift * grp->index is the index of the group; and grp->slot_shift
* is the shift for the corresponding (scaled) sigma_i. * is the shift for the corresponding (scaled) sigma_i.
*/ */
#define QFQ_MAX_INDEX 24 #define QFQ_MAX_INDEX 24
#define QFQ_MAX_WSHIFT 12 #define QFQ_MAX_WSHIFT 10
#define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) #define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */
#define QFQ_MAX_WSUM (16*QFQ_MAX_WEIGHT) #define QFQ_MAX_WSUM (64*QFQ_MAX_WEIGHT)
#define FRAC_BITS 30 /* fixed point arithmetic */ #define FRAC_BITS 30 /* fixed point arithmetic */
#define ONE_FP (1UL << FRAC_BITS) #define ONE_FP (1UL << FRAC_BITS)
#define IWSUM (ONE_FP/QFQ_MAX_WSUM) #define IWSUM (ONE_FP/QFQ_MAX_WSUM)
#define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */ #define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */
#define QFQ_MIN_SLOT_SHIFT (FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX) #define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */
#define QFQ_MIN_LMAX 256 /* min possible lmax for a class */
#define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */
/* /*
* Possible group states. These values are used as indexes for the bitmaps * Possible group states. These values are used as indexes for the bitmaps
...@@ -106,6 +128,8 @@ enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE }; ...@@ -106,6 +128,8 @@ enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE };
struct qfq_group; struct qfq_group;
struct qfq_aggregate;
struct qfq_class { struct qfq_class {
struct Qdisc_class_common common; struct Qdisc_class_common common;
...@@ -116,7 +140,12 @@ struct qfq_class { ...@@ -116,7 +140,12 @@ struct qfq_class {
struct gnet_stats_queue qstats; struct gnet_stats_queue qstats;
struct gnet_stats_rate_est rate_est; struct gnet_stats_rate_est rate_est;
struct Qdisc *qdisc; struct Qdisc *qdisc;
struct list_head alist; /* Link for active-classes list. */
struct qfq_aggregate *agg; /* Parent aggregate. */
int deficit; /* DRR deficit counter. */
};
struct qfq_aggregate {
struct hlist_node next; /* Link for the slot list. */ struct hlist_node next; /* Link for the slot list. */
u64 S, F; /* flow timestamps (exact) */ u64 S, F; /* flow timestamps (exact) */
...@@ -127,8 +156,18 @@ struct qfq_class { ...@@ -127,8 +156,18 @@ struct qfq_class {
struct qfq_group *grp; struct qfq_group *grp;
/* these are copied from the flowset. */ /* these are copied from the flowset. */
u32 inv_w; /* ONE_FP/weight */ u32 class_weight; /* Weight of each class in this aggregate. */
u32 lmax; /* Max packet size for this flow. */ /* Max pkt size for the classes in this aggregate, DRR quantum. */
int lmax;
u32 inv_w; /* ONE_FP/(sum of weights of classes in aggr.). */
u32 budgetmax; /* Max budget for this aggregate. */
u32 initial_budget, budget; /* Initial and current budget. */
int num_classes; /* Number of classes in this aggr. */
struct list_head active; /* DRR queue of active classes. */
struct hlist_node nonfull_next; /* See nonfull_aggs in qfq_sched. */
}; };
struct qfq_group { struct qfq_group {
...@@ -138,7 +177,7 @@ struct qfq_group { ...@@ -138,7 +177,7 @@ struct qfq_group {
unsigned int front; /* Index of the front slot. */ unsigned int front; /* Index of the front slot. */
unsigned long full_slots; /* non-empty slots */ unsigned long full_slots; /* non-empty slots */
/* Array of RR lists of active classes. */ /* Array of RR lists of active aggregates. */
struct hlist_head slots[QFQ_MAX_SLOTS]; struct hlist_head slots[QFQ_MAX_SLOTS];
}; };
...@@ -146,13 +185,28 @@ struct qfq_sched { ...@@ -146,13 +185,28 @@ struct qfq_sched {
struct tcf_proto *filter_list; struct tcf_proto *filter_list;
struct Qdisc_class_hash clhash; struct Qdisc_class_hash clhash;
u64 V; /* Precise virtual time. */ u64 oldV, V; /* Precise virtual times. */
u32 wsum; /* weight sum */ struct qfq_aggregate *in_serv_agg; /* Aggregate being served. */
u32 num_active_agg; /* Num. of active aggregates */
u32 wsum; /* weight sum */
unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */ unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */
struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */ struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */
u32 min_slot_shift; /* Index of the group-0 bit in the bitmaps. */
u32 max_agg_classes; /* Max number of classes per aggr. */
struct hlist_head nonfull_aggs; /* Aggs with room for more classes. */
}; };
/*
* Possible reasons why the timestamps of an aggregate are updated
* enqueue: the aggregate switches from idle to active and must scheduled
* for service
* requeue: the aggregate finishes its budget, so it stops being served and
* must be rescheduled for service
*/
enum update_reason {enqueue, requeue};
static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid) static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
...@@ -182,18 +236,18 @@ static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = { ...@@ -182,18 +236,18 @@ static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = {
* index = log_2(maxlen/weight) but we need to apply the scaling. * index = log_2(maxlen/weight) but we need to apply the scaling.
* This is used only once at flow creation. * This is used only once at flow creation.
*/ */
static int qfq_calc_index(u32 inv_w, unsigned int maxlen) static int qfq_calc_index(u32 inv_w, unsigned int maxlen, u32 min_slot_shift)
{ {
u64 slot_size = (u64)maxlen * inv_w; u64 slot_size = (u64)maxlen * inv_w;
unsigned long size_map; unsigned long size_map;
int index = 0; int index = 0;
size_map = slot_size >> QFQ_MIN_SLOT_SHIFT; size_map = slot_size >> min_slot_shift;
if (!size_map) if (!size_map)
goto out; goto out;
index = __fls(size_map) + 1; /* basically a log_2 */ index = __fls(size_map) + 1; /* basically a log_2 */
index -= !(slot_size - (1ULL << (index + QFQ_MIN_SLOT_SHIFT - 1))); index -= !(slot_size - (1ULL << (index + min_slot_shift - 1)));
if (index < 0) if (index < 0)
index = 0; index = 0;
...@@ -204,66 +258,150 @@ static int qfq_calc_index(u32 inv_w, unsigned int maxlen) ...@@ -204,66 +258,150 @@ static int qfq_calc_index(u32 inv_w, unsigned int maxlen)
return index; return index;
} }
/* Length of the next packet (0 if the queue is empty). */ static void qfq_deactivate_agg(struct qfq_sched *, struct qfq_aggregate *);
static unsigned int qdisc_peek_len(struct Qdisc *sch) static void qfq_activate_agg(struct qfq_sched *, struct qfq_aggregate *,
enum update_reason);
static void qfq_init_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
u32 lmax, u32 weight)
{ {
struct sk_buff *skb; INIT_LIST_HEAD(&agg->active);
hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs);
agg->lmax = lmax;
agg->class_weight = weight;
}
static struct qfq_aggregate *qfq_find_agg(struct qfq_sched *q,
u32 lmax, u32 weight)
{
struct qfq_aggregate *agg;
struct hlist_node *n;
hlist_for_each_entry(agg, n, &q->nonfull_aggs, nonfull_next)
if (agg->lmax == lmax && agg->class_weight == weight)
return agg;
return NULL;
}
skb = sch->ops->peek(sch); /* Update aggregate as a function of the new number of classes. */
return skb ? qdisc_pkt_len(skb) : 0; static void qfq_update_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
int new_num_classes)
{
u32 new_agg_weight;
if (new_num_classes == q->max_agg_classes)
hlist_del_init(&agg->nonfull_next);
if (agg->num_classes > new_num_classes &&
new_num_classes == q->max_agg_classes - 1) /* agg no more full */
hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs);
agg->budgetmax = new_num_classes * agg->lmax;
new_agg_weight = agg->class_weight * new_num_classes;
agg->inv_w = ONE_FP/new_agg_weight;
if (agg->grp == NULL) {
int i = qfq_calc_index(agg->inv_w, agg->budgetmax,
q->min_slot_shift);
agg->grp = &q->groups[i];
}
q->wsum +=
(int) agg->class_weight * (new_num_classes - agg->num_classes);
agg->num_classes = new_num_classes;
}
/* Add class to aggregate. */
static void qfq_add_to_agg(struct qfq_sched *q,
struct qfq_aggregate *agg,
struct qfq_class *cl)
{
cl->agg = agg;
qfq_update_agg(q, agg, agg->num_classes+1);
if (cl->qdisc->q.qlen > 0) { /* adding an active class */
list_add_tail(&cl->alist, &agg->active);
if (list_first_entry(&agg->active, struct qfq_class, alist) ==
cl && q->in_serv_agg != agg) /* agg was inactive */
qfq_activate_agg(q, agg, enqueue); /* schedule agg */
}
} }
static void qfq_deactivate_class(struct qfq_sched *, struct qfq_class *); static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *);
static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl,
unsigned int len);
static void qfq_update_class_params(struct qfq_sched *q, struct qfq_class *cl, static void qfq_destroy_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
u32 lmax, u32 inv_w, int delta_w)
{ {
int i; if (!hlist_unhashed(&agg->nonfull_next))
hlist_del_init(&agg->nonfull_next);
if (q->in_serv_agg == agg)
q->in_serv_agg = qfq_choose_next_agg(q);
kfree(agg);
}
/* update qfq-specific data */ /* Deschedule class from within its parent aggregate. */
cl->lmax = lmax; static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl)
cl->inv_w = inv_w; {
i = qfq_calc_index(cl->inv_w, cl->lmax); struct qfq_aggregate *agg = cl->agg;
cl->grp = &q->groups[i];
q->wsum += delta_w; list_del(&cl->alist); /* remove from RR queue of the aggregate */
if (list_empty(&agg->active)) /* agg is now inactive */
qfq_deactivate_agg(q, agg);
} }
static void qfq_update_reactivate_class(struct qfq_sched *q, /* Remove class from its parent aggregate. */
struct qfq_class *cl, static void qfq_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl)
u32 inv_w, u32 lmax, int delta_w)
{ {
bool need_reactivation = false; struct qfq_aggregate *agg = cl->agg;
int i = qfq_calc_index(inv_w, lmax);
if (&q->groups[i] != cl->grp && cl->qdisc->q.qlen > 0) { cl->agg = NULL;
/* if (agg->num_classes == 1) { /* agg being emptied, destroy it */
* shift cl->F back, to not charge the qfq_destroy_agg(q, agg);
* class for the not-yet-served head return;
* packet
*/
cl->F = cl->S;
/* remove class from its slot in the old group */
qfq_deactivate_class(q, cl);
need_reactivation = true;
} }
qfq_update_agg(q, agg, agg->num_classes-1);
}
qfq_update_class_params(q, cl, lmax, inv_w, delta_w); /* Deschedule class and remove it from its parent aggregate. */
static void qfq_deact_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl)
{
if (cl->qdisc->q.qlen > 0) /* class is active */
qfq_deactivate_class(q, cl);
if (need_reactivation) /* activate in new group */ qfq_rm_from_agg(q, cl);
qfq_activate_class(q, cl, qdisc_peek_len(cl->qdisc));
} }
/* Move class to a new aggregate, matching the new class weight and/or lmax */
static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight,
u32 lmax)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight);
if (new_agg == NULL) { /* create new aggregate */
new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC);
if (new_agg == NULL)
return -ENOBUFS;
qfq_init_agg(q, new_agg, lmax, weight);
}
qfq_deact_rm_from_agg(q, cl);
qfq_add_to_agg(q, new_agg, cl);
return 0;
}
static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
struct nlattr **tca, unsigned long *arg) struct nlattr **tca, unsigned long *arg)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl = (struct qfq_class *)*arg; struct qfq_class *cl = (struct qfq_class *)*arg;
bool existing = false;
struct nlattr *tb[TCA_QFQ_MAX + 1]; struct nlattr *tb[TCA_QFQ_MAX + 1];
struct qfq_aggregate *new_agg = NULL;
u32 weight, lmax, inv_w; u32 weight, lmax, inv_w;
int err; int err;
int delta_w; int delta_w;
...@@ -286,15 +424,6 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, ...@@ -286,15 +424,6 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
} else } else
weight = 1; weight = 1;
inv_w = ONE_FP / weight;
weight = ONE_FP / inv_w;
delta_w = weight - (cl ? ONE_FP / cl->inv_w : 0);
if (q->wsum + delta_w > QFQ_MAX_WSUM) {
pr_notice("qfq: total weight out of range (%u + %u)\n",
delta_w, q->wsum);
return -EINVAL;
}
if (tb[TCA_QFQ_LMAX]) { if (tb[TCA_QFQ_LMAX]) {
lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) { if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) {
...@@ -304,7 +433,23 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, ...@@ -304,7 +433,23 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
} else } else
lmax = psched_mtu(qdisc_dev(sch)); lmax = psched_mtu(qdisc_dev(sch));
if (cl != NULL) { inv_w = ONE_FP / weight;
weight = ONE_FP / inv_w;
if (cl != NULL &&
lmax == cl->agg->lmax &&
weight == cl->agg->class_weight)
return 0; /* nothing to change */
delta_w = weight - (cl ? cl->agg->class_weight : 0);
if (q->wsum + delta_w > QFQ_MAX_WSUM) {
pr_notice("qfq: total weight out of range (%d + %u)\n",
delta_w, q->wsum);
return -EINVAL;
}
if (cl != NULL) { /* modify existing class */
if (tca[TCA_RATE]) { if (tca[TCA_RATE]) {
err = gen_replace_estimator(&cl->bstats, &cl->rate_est, err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
qdisc_root_sleeping_lock(sch), qdisc_root_sleeping_lock(sch),
...@@ -312,25 +457,18 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, ...@@ -312,25 +457,18 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
if (err) if (err)
return err; return err;
} }
existing = true;
if (lmax == cl->lmax && inv_w == cl->inv_w) goto set_change_agg;
return 0; /* nothing to update */
sch_tree_lock(sch);
qfq_update_reactivate_class(q, cl, inv_w, lmax, delta_w);
sch_tree_unlock(sch);
return 0;
} }
/* create and init new class */
cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL); cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL);
if (cl == NULL) if (cl == NULL)
return -ENOBUFS; return -ENOBUFS;
cl->refcnt = 1; cl->refcnt = 1;
cl->common.classid = classid; cl->common.classid = classid;
cl->deficit = lmax;
qfq_update_class_params(q, cl, lmax, inv_w, delta_w);
cl->qdisc = qdisc_create_dflt(sch->dev_queue, cl->qdisc = qdisc_create_dflt(sch->dev_queue,
&pfifo_qdisc_ops, classid); &pfifo_qdisc_ops, classid);
...@@ -341,11 +479,8 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, ...@@ -341,11 +479,8 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
err = gen_new_estimator(&cl->bstats, &cl->rate_est, err = gen_new_estimator(&cl->bstats, &cl->rate_est,
qdisc_root_sleeping_lock(sch), qdisc_root_sleeping_lock(sch),
tca[TCA_RATE]); tca[TCA_RATE]);
if (err) { if (err)
qdisc_destroy(cl->qdisc); goto destroy_class;
kfree(cl);
return err;
}
} }
sch_tree_lock(sch); sch_tree_lock(sch);
...@@ -354,19 +489,39 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, ...@@ -354,19 +489,39 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
qdisc_class_hash_grow(sch, &q->clhash); qdisc_class_hash_grow(sch, &q->clhash);
set_change_agg:
sch_tree_lock(sch);
new_agg = qfq_find_agg(q, lmax, weight);
if (new_agg == NULL) { /* create new aggregate */
sch_tree_unlock(sch);
new_agg = kzalloc(sizeof(*new_agg), GFP_KERNEL);
if (new_agg == NULL) {
err = -ENOBUFS;
gen_kill_estimator(&cl->bstats, &cl->rate_est);
goto destroy_class;
}
sch_tree_lock(sch);
qfq_init_agg(q, new_agg, lmax, weight);
}
if (existing)
qfq_deact_rm_from_agg(q, cl);
qfq_add_to_agg(q, new_agg, cl);
sch_tree_unlock(sch);
*arg = (unsigned long)cl; *arg = (unsigned long)cl;
return 0; return 0;
destroy_class:
qdisc_destroy(cl->qdisc);
kfree(cl);
return err;
} }
static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl) static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
if (cl->inv_w) { qfq_rm_from_agg(q, cl);
q->wsum -= ONE_FP / cl->inv_w;
cl->inv_w = 0;
}
gen_kill_estimator(&cl->bstats, &cl->rate_est); gen_kill_estimator(&cl->bstats, &cl->rate_est);
qdisc_destroy(cl->qdisc); qdisc_destroy(cl->qdisc);
kfree(cl); kfree(cl);
...@@ -481,8 +636,8 @@ static int qfq_dump_class(struct Qdisc *sch, unsigned long arg, ...@@ -481,8 +636,8 @@ static int qfq_dump_class(struct Qdisc *sch, unsigned long arg,
nest = nla_nest_start(skb, TCA_OPTIONS); nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL) if (nest == NULL)
goto nla_put_failure; goto nla_put_failure;
if (nla_put_u32(skb, TCA_QFQ_WEIGHT, ONE_FP/cl->inv_w) || if (nla_put_u32(skb, TCA_QFQ_WEIGHT, cl->agg->class_weight) ||
nla_put_u32(skb, TCA_QFQ_LMAX, cl->lmax)) nla_put_u32(skb, TCA_QFQ_LMAX, cl->agg->lmax))
goto nla_put_failure; goto nla_put_failure;
return nla_nest_end(skb, nest); return nla_nest_end(skb, nest);
...@@ -500,8 +655,8 @@ static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg, ...@@ -500,8 +655,8 @@ static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
memset(&xstats, 0, sizeof(xstats)); memset(&xstats, 0, sizeof(xstats));
cl->qdisc->qstats.qlen = cl->qdisc->q.qlen; cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
xstats.weight = ONE_FP/cl->inv_w; xstats.weight = cl->agg->class_weight;
xstats.lmax = cl->lmax; xstats.lmax = cl->agg->lmax;
if (gnet_stats_copy_basic(d, &cl->bstats) < 0 || if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
...@@ -652,16 +807,16 @@ static void qfq_unblock_groups(struct qfq_sched *q, int index, u64 old_F) ...@@ -652,16 +807,16 @@ static void qfq_unblock_groups(struct qfq_sched *q, int index, u64 old_F)
* perhaps * perhaps
* *
old_V ^= q->V; old_V ^= q->V;
old_V >>= QFQ_MIN_SLOT_SHIFT; old_V >>= q->min_slot_shift;
if (old_V) { if (old_V) {
... ...
} }
* *
*/ */
static void qfq_make_eligible(struct qfq_sched *q, u64 old_V) static void qfq_make_eligible(struct qfq_sched *q)
{ {
unsigned long vslot = q->V >> QFQ_MIN_SLOT_SHIFT; unsigned long vslot = q->V >> q->min_slot_shift;
unsigned long old_vslot = old_V >> QFQ_MIN_SLOT_SHIFT; unsigned long old_vslot = q->oldV >> q->min_slot_shift;
if (vslot != old_vslot) { if (vslot != old_vslot) {
unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1; unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1;
...@@ -672,34 +827,38 @@ static void qfq_make_eligible(struct qfq_sched *q, u64 old_V) ...@@ -672,34 +827,38 @@ static void qfq_make_eligible(struct qfq_sched *q, u64 old_V)
/* /*
* If the weight and lmax (max_pkt_size) of the classes do not change, * The index of the slot in which the aggregate is to be inserted must
* then QFQ guarantees that the slot index is never higher than * not be higher than QFQ_MAX_SLOTS-2. There is a '-2' and not a '-1'
* 2 + ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) * (QFQ_MAX_WEIGHT/QFQ_MAX_WSUM). * because the start time of the group may be moved backward by one
* slot after the aggregate has been inserted, and this would cause
* non-empty slots to be right-shifted by one position.
* *
* With the current values of the above constants, the index is * If the weight and lmax (max_pkt_size) of the classes do not change,
* then guaranteed to never be higher than 2 + 256 * (1 / 16) = 18. * then QFQ+ does meet the above contraint according to the current
* values of its parameters. In fact, if the weight and lmax of the
* classes do not change, then, from the theory, QFQ+ guarantees that
* the slot index is never higher than
* 2 + QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) *
* (QFQ_MAX_WEIGHT/QFQ_MAX_WSUM) = 2 + 8 * 128 * (1 / 64) = 18
* *
* When the weight of a class is increased or the lmax of the class is * When the weight of a class is increased or the lmax of the class is
* decreased, a new class with smaller slot size may happen to be * decreased, a new aggregate with smaller slot size than the original
* activated. The activation of this class should be properly delayed * parent aggregate of the class may happen to be activated. The
* to when the service of the class has finished in the ideal system * activation of this aggregate should be properly delayed to when the
* tracked by QFQ. If the activation of the class is not delayed to * service of the class has finished in the ideal system tracked by
* this reference time instant, then this class may be unjustly served * QFQ+. If the activation of the aggregate is not delayed to this
* before other classes waiting for service. This may cause * reference time instant, then this aggregate may be unjustly served
* (unfrequently) the above bound to the slot index to be violated for * before other aggregates waiting for service. This may cause the
* some of these unlucky classes. * above bound to the slot index to be violated for some of these
* unlucky aggregates.
* *
* Instead of delaying the activation of the new class, which is quite * Instead of delaying the activation of the new aggregate, which is
* complex, the following inaccurate but simple solution is used: if * quite complex, the following inaccurate but simple solution is used:
* the slot index is higher than QFQ_MAX_SLOTS-2, then the timestamps * if the slot index is higher than QFQ_MAX_SLOTS-2, then the
* of the class are shifted backward so as to let the slot index * timestamps of the aggregate are shifted backward so as to let the
* become equal to QFQ_MAX_SLOTS-2. This threshold is used because, if * slot index become equal to QFQ_MAX_SLOTS-2.
* the slot index is above it, then the data structure implementing
* the bucket list either gets immediately corrupted or may get
* corrupted on a possible next packet arrival that causes the start
* time of the group to be shifted backward.
*/ */
static void qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl, static void qfq_slot_insert(struct qfq_group *grp, struct qfq_aggregate *agg,
u64 roundedS) u64 roundedS)
{ {
u64 slot = (roundedS - grp->S) >> grp->slot_shift; u64 slot = (roundedS - grp->S) >> grp->slot_shift;
...@@ -708,22 +867,22 @@ static void qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl, ...@@ -708,22 +867,22 @@ static void qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl,
if (unlikely(slot > QFQ_MAX_SLOTS - 2)) { if (unlikely(slot > QFQ_MAX_SLOTS - 2)) {
u64 deltaS = roundedS - grp->S - u64 deltaS = roundedS - grp->S -
((u64)(QFQ_MAX_SLOTS - 2)<<grp->slot_shift); ((u64)(QFQ_MAX_SLOTS - 2)<<grp->slot_shift);
cl->S -= deltaS; agg->S -= deltaS;
cl->F -= deltaS; agg->F -= deltaS;
slot = QFQ_MAX_SLOTS - 2; slot = QFQ_MAX_SLOTS - 2;
} }
i = (grp->front + slot) % QFQ_MAX_SLOTS; i = (grp->front + slot) % QFQ_MAX_SLOTS;
hlist_add_head(&cl->next, &grp->slots[i]); hlist_add_head(&agg->next, &grp->slots[i]);
__set_bit(slot, &grp->full_slots); __set_bit(slot, &grp->full_slots);
} }
/* Maybe introduce hlist_first_entry?? */ /* Maybe introduce hlist_first_entry?? */
static struct qfq_class *qfq_slot_head(struct qfq_group *grp) static struct qfq_aggregate *qfq_slot_head(struct qfq_group *grp)
{ {
return hlist_entry(grp->slots[grp->front].first, return hlist_entry(grp->slots[grp->front].first,
struct qfq_class, next); struct qfq_aggregate, next);
} }
/* /*
...@@ -731,20 +890,20 @@ static struct qfq_class *qfq_slot_head(struct qfq_group *grp) ...@@ -731,20 +890,20 @@ static struct qfq_class *qfq_slot_head(struct qfq_group *grp)
*/ */
static void qfq_front_slot_remove(struct qfq_group *grp) static void qfq_front_slot_remove(struct qfq_group *grp)
{ {
struct qfq_class *cl = qfq_slot_head(grp); struct qfq_aggregate *agg = qfq_slot_head(grp);
BUG_ON(!cl); BUG_ON(!agg);
hlist_del(&cl->next); hlist_del(&agg->next);
if (hlist_empty(&grp->slots[grp->front])) if (hlist_empty(&grp->slots[grp->front]))
__clear_bit(0, &grp->full_slots); __clear_bit(0, &grp->full_slots);
} }
/* /*
* Returns the first full queue in a group. As a side effect, * Returns the first aggregate in the first non-empty bucket of the
* adjust the bucket list so the first non-empty bucket is at * group. As a side effect, adjusts the bucket list so the first
* position 0 in full_slots. * non-empty bucket is at position 0 in full_slots.
*/ */
static struct qfq_class *qfq_slot_scan(struct qfq_group *grp) static struct qfq_aggregate *qfq_slot_scan(struct qfq_group *grp)
{ {
unsigned int i; unsigned int i;
...@@ -780,7 +939,7 @@ static void qfq_slot_rotate(struct qfq_group *grp, u64 roundedS) ...@@ -780,7 +939,7 @@ static void qfq_slot_rotate(struct qfq_group *grp, u64 roundedS)
grp->front = (grp->front - i) % QFQ_MAX_SLOTS; grp->front = (grp->front - i) % QFQ_MAX_SLOTS;
} }
static void qfq_update_eligible(struct qfq_sched *q, u64 old_V) static void qfq_update_eligible(struct qfq_sched *q)
{ {
struct qfq_group *grp; struct qfq_group *grp;
unsigned long ineligible; unsigned long ineligible;
...@@ -792,137 +951,226 @@ static void qfq_update_eligible(struct qfq_sched *q, u64 old_V) ...@@ -792,137 +951,226 @@ static void qfq_update_eligible(struct qfq_sched *q, u64 old_V)
if (qfq_gt(grp->S, q->V)) if (qfq_gt(grp->S, q->V))
q->V = grp->S; q->V = grp->S;
} }
qfq_make_eligible(q, old_V); qfq_make_eligible(q);
} }
} }
/* /* Dequeue head packet of the head class in the DRR queue of the aggregate. */
* Updates the class, returns true if also the group needs to be updated. static void agg_dequeue(struct qfq_aggregate *agg,
*/ struct qfq_class *cl, unsigned int len)
static bool qfq_update_class(struct qfq_group *grp, struct qfq_class *cl)
{ {
unsigned int len = qdisc_peek_len(cl->qdisc); qdisc_dequeue_peeked(cl->qdisc);
cl->S = cl->F; cl->deficit -= (int) len;
if (!len)
qfq_front_slot_remove(grp); /* queue is empty */
else {
u64 roundedS;
cl->F = cl->S + (u64)len * cl->inv_w; if (cl->qdisc->q.qlen == 0) /* no more packets, remove from list */
roundedS = qfq_round_down(cl->S, grp->slot_shift); list_del(&cl->alist);
if (roundedS == grp->S) else if (cl->deficit < qdisc_pkt_len(cl->qdisc->ops->peek(cl->qdisc))) {
return false; cl->deficit += agg->lmax;
list_move_tail(&cl->alist, &agg->active);
qfq_front_slot_remove(grp);
qfq_slot_insert(grp, cl, roundedS);
} }
}
static inline struct sk_buff *qfq_peek_skb(struct qfq_aggregate *agg,
struct qfq_class **cl,
unsigned int *len)
{
struct sk_buff *skb;
return true; *cl = list_first_entry(&agg->active, struct qfq_class, alist);
skb = (*cl)->qdisc->ops->peek((*cl)->qdisc);
if (skb == NULL)
WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n");
else
*len = qdisc_pkt_len(skb);
return skb;
}
/* Update F according to the actual service received by the aggregate. */
static inline void charge_actual_service(struct qfq_aggregate *agg)
{
/* compute the service received by the aggregate */
u32 service_received = agg->initial_budget - agg->budget;
agg->F = agg->S + (u64)service_received * agg->inv_w;
} }
static struct sk_buff *qfq_dequeue(struct Qdisc *sch) static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp; struct qfq_aggregate *in_serv_agg = q->in_serv_agg;
struct qfq_class *cl; struct qfq_class *cl;
struct sk_buff *skb; struct sk_buff *skb = NULL;
unsigned int len; /* next-packet len, 0 means no more active classes in in-service agg */
u64 old_V; unsigned int len = 0;
if (!q->bitmaps[ER]) if (in_serv_agg == NULL)
return NULL; return NULL;
grp = qfq_ffs(q, q->bitmaps[ER]); if (!list_empty(&in_serv_agg->active))
skb = qfq_peek_skb(in_serv_agg, &cl, &len);
cl = qfq_slot_head(grp); /*
skb = qdisc_dequeue_peeked(cl->qdisc); * If there are no active classes in the in-service aggregate,
if (!skb) { * or if the aggregate has not enough budget to serve its next
WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n"); * class, then choose the next aggregate to serve.
return NULL; */
if (len == 0 || in_serv_agg->budget < len) {
charge_actual_service(in_serv_agg);
/* recharge the budget of the aggregate */
in_serv_agg->initial_budget = in_serv_agg->budget =
in_serv_agg->budgetmax;
if (!list_empty(&in_serv_agg->active))
/*
* Still active: reschedule for
* service. Possible optimization: if no other
* aggregate is active, then there is no point
* in rescheduling this aggregate, and we can
* just keep it as the in-service one. This
* should be however a corner case, and to
* handle it, we would need to maintain an
* extra num_active_aggs field.
*/
qfq_activate_agg(q, in_serv_agg, requeue);
else if (sch->q.qlen == 0) { /* no aggregate to serve */
q->in_serv_agg = NULL;
return NULL;
}
/*
* If we get here, there are other aggregates queued:
* choose the new aggregate to serve.
*/
in_serv_agg = q->in_serv_agg = qfq_choose_next_agg(q);
skb = qfq_peek_skb(in_serv_agg, &cl, &len);
} }
if (!skb)
return NULL;
sch->q.qlen--; sch->q.qlen--;
qdisc_bstats_update(sch, skb); qdisc_bstats_update(sch, skb);
old_V = q->V; agg_dequeue(in_serv_agg, cl, len);
len = qdisc_pkt_len(skb); in_serv_agg->budget -= len;
q->V += (u64)len * IWSUM; q->V += (u64)len * IWSUM;
pr_debug("qfq dequeue: len %u F %lld now %lld\n", pr_debug("qfq dequeue: len %u F %lld now %lld\n",
len, (unsigned long long) cl->F, (unsigned long long) q->V); len, (unsigned long long) in_serv_agg->F,
(unsigned long long) q->V);
if (qfq_update_class(grp, cl)) { return skb;
u64 old_F = grp->F; }
cl = qfq_slot_scan(grp); static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *q)
if (!cl) {
__clear_bit(grp->index, &q->bitmaps[ER]); struct qfq_group *grp;
else { struct qfq_aggregate *agg, *new_front_agg;
u64 roundedS = qfq_round_down(cl->S, grp->slot_shift); u64 old_F;
unsigned int s;
if (grp->S == roundedS) qfq_update_eligible(q);
goto skip_unblock; q->oldV = q->V;
grp->S = roundedS;
grp->F = roundedS + (2ULL << grp->slot_shift); if (!q->bitmaps[ER])
__clear_bit(grp->index, &q->bitmaps[ER]); return NULL;
s = qfq_calc_state(q, grp);
__set_bit(grp->index, &q->bitmaps[s]); grp = qfq_ffs(q, q->bitmaps[ER]);
} old_F = grp->F;
agg = qfq_slot_head(grp);
qfq_unblock_groups(q, grp->index, old_F); /* agg starts to be served, remove it from schedule */
qfq_front_slot_remove(grp);
new_front_agg = qfq_slot_scan(grp);
if (new_front_agg == NULL) /* group is now inactive, remove from ER */
__clear_bit(grp->index, &q->bitmaps[ER]);
else {
u64 roundedS = qfq_round_down(new_front_agg->S,
grp->slot_shift);
unsigned int s;
if (grp->S == roundedS)
return agg;
grp->S = roundedS;
grp->F = roundedS + (2ULL << grp->slot_shift);
__clear_bit(grp->index, &q->bitmaps[ER]);
s = qfq_calc_state(q, grp);
__set_bit(grp->index, &q->bitmaps[s]);
} }
skip_unblock: qfq_unblock_groups(q, grp->index, old_F);
qfq_update_eligible(q, old_V);
return skb; return agg;
} }
/* /*
* Assign a reasonable start time for a new flow k in group i. * Assign a reasonable start time for a new aggregate in group i.
* Admissible values for \hat(F) are multiples of \sigma_i * Admissible values for \hat(F) are multiples of \sigma_i
* no greater than V+\sigma_i . Larger values mean that * no greater than V+\sigma_i . Larger values mean that
* we had a wraparound so we consider the timestamp to be stale. * we had a wraparound so we consider the timestamp to be stale.
* *
* If F is not stale and F >= V then we set S = F. * If F is not stale and F >= V then we set S = F.
* Otherwise we should assign S = V, but this may violate * Otherwise we should assign S = V, but this may violate
* the ordering in ER. So, if we have groups in ER, set S to * the ordering in EB (see [2]). So, if we have groups in ER,
* the F_j of the first group j which would be blocking us. * set S to the F_j of the first group j which would be blocking us.
* We are guaranteed not to move S backward because * We are guaranteed not to move S backward because
* otherwise our group i would still be blocked. * otherwise our group i would still be blocked.
*/ */
static void qfq_update_start(struct qfq_sched *q, struct qfq_class *cl) static void qfq_update_start(struct qfq_sched *q, struct qfq_aggregate *agg)
{ {
unsigned long mask; unsigned long mask;
u64 limit, roundedF; u64 limit, roundedF;
int slot_shift = cl->grp->slot_shift; int slot_shift = agg->grp->slot_shift;
roundedF = qfq_round_down(cl->F, slot_shift); roundedF = qfq_round_down(agg->F, slot_shift);
limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift); limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift);
if (!qfq_gt(cl->F, q->V) || qfq_gt(roundedF, limit)) { if (!qfq_gt(agg->F, q->V) || qfq_gt(roundedF, limit)) {
/* timestamp was stale */ /* timestamp was stale */
mask = mask_from(q->bitmaps[ER], cl->grp->index); mask = mask_from(q->bitmaps[ER], agg->grp->index);
if (mask) { if (mask) {
struct qfq_group *next = qfq_ffs(q, mask); struct qfq_group *next = qfq_ffs(q, mask);
if (qfq_gt(roundedF, next->F)) { if (qfq_gt(roundedF, next->F)) {
if (qfq_gt(limit, next->F)) if (qfq_gt(limit, next->F))
cl->S = next->F; agg->S = next->F;
else /* preserve timestamp correctness */ else /* preserve timestamp correctness */
cl->S = limit; agg->S = limit;
return; return;
} }
} }
cl->S = q->V; agg->S = q->V;
} else /* timestamp is not stale */ } else /* timestamp is not stale */
cl->S = cl->F; agg->S = agg->F;
} }
/*
* Update the timestamps of agg before scheduling/rescheduling it for
* service. In particular, assign to agg->F its maximum possible
* value, i.e., the virtual finish time with which the aggregate
* should be labeled if it used all its budget once in service.
*/
static inline void
qfq_update_agg_ts(struct qfq_sched *q,
struct qfq_aggregate *agg, enum update_reason reason)
{
if (reason != requeue)
qfq_update_start(q, agg);
else /* just charge agg for the service received */
agg->S = agg->F;
agg->F = agg->S + (u64)agg->budgetmax * agg->inv_w;
}
static void qfq_schedule_agg(struct qfq_sched *, struct qfq_aggregate *);
static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl; struct qfq_class *cl;
struct qfq_aggregate *agg;
int err = 0; int err = 0;
cl = qfq_classify(skb, sch, &err); cl = qfq_classify(skb, sch, &err);
...@@ -934,11 +1182,13 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) ...@@ -934,11 +1182,13 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
} }
pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid);
if (unlikely(cl->lmax < qdisc_pkt_len(skb))) { if (unlikely(cl->agg->lmax < qdisc_pkt_len(skb))) {
pr_debug("qfq: increasing maxpkt from %u to %u for class %u", pr_debug("qfq: increasing maxpkt from %u to %u for class %u",
cl->lmax, qdisc_pkt_len(skb), cl->common.classid); cl->agg->lmax, qdisc_pkt_len(skb), cl->common.classid);
qfq_update_reactivate_class(q, cl, cl->inv_w, err = qfq_change_agg(sch, cl, cl->agg->class_weight,
qdisc_pkt_len(skb), 0); qdisc_pkt_len(skb));
if (err)
return err;
} }
err = qdisc_enqueue(skb, cl->qdisc); err = qdisc_enqueue(skb, cl->qdisc);
...@@ -954,35 +1204,50 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) ...@@ -954,35 +1204,50 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
bstats_update(&cl->bstats, skb); bstats_update(&cl->bstats, skb);
++sch->q.qlen; ++sch->q.qlen;
/* If the new skb is not the head of queue, then done here. */ agg = cl->agg;
if (cl->qdisc->q.qlen != 1) /* if the queue was not empty, then done here */
if (cl->qdisc->q.qlen != 1) {
if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) &&
list_first_entry(&agg->active, struct qfq_class, alist)
== cl && cl->deficit < qdisc_pkt_len(skb))
list_move_tail(&cl->alist, &agg->active);
return err; return err;
}
/* schedule class for service within the aggregate */
cl->deficit = agg->lmax;
list_add_tail(&cl->alist, &agg->active);
/* If reach this point, queue q was idle */ if (list_first_entry(&agg->active, struct qfq_class, alist) != cl)
qfq_activate_class(q, cl, qdisc_pkt_len(skb)); return err; /* aggregate was not empty, nothing else to do */
/* recharge budget */
agg->initial_budget = agg->budget = agg->budgetmax;
qfq_update_agg_ts(q, agg, enqueue);
if (q->in_serv_agg == NULL)
q->in_serv_agg = agg;
else if (agg != q->in_serv_agg)
qfq_schedule_agg(q, agg);
return err; return err;
} }
/* /*
* Handle class switch from idle to backlogged. * Schedule aggregate according to its timestamps.
*/ */
static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl, static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
unsigned int pkt_len)
{ {
struct qfq_group *grp = cl->grp; struct qfq_group *grp = agg->grp;
u64 roundedS; u64 roundedS;
int s; int s;
qfq_update_start(q, cl); roundedS = qfq_round_down(agg->S, grp->slot_shift);
/* compute new finish time and rounded start. */
cl->F = cl->S + (u64)pkt_len * cl->inv_w;
roundedS = qfq_round_down(cl->S, grp->slot_shift);
/* /*
* insert cl in the correct bucket. * Insert agg in the correct bucket.
* If cl->S >= grp->S we don't need to adjust the * If agg->S >= grp->S we don't need to adjust the
* bucket list and simply go to the insertion phase. * bucket list and simply go to the insertion phase.
* Otherwise grp->S is decreasing, we must make room * Otherwise grp->S is decreasing, we must make room
* in the bucket list, and also recompute the group state. * in the bucket list, and also recompute the group state.
...@@ -990,10 +1255,10 @@ static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl, ...@@ -990,10 +1255,10 @@ static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl,
* was in ER make sure to adjust V. * was in ER make sure to adjust V.
*/ */
if (grp->full_slots) { if (grp->full_slots) {
if (!qfq_gt(grp->S, cl->S)) if (!qfq_gt(grp->S, agg->S))
goto skip_update; goto skip_update;
/* create a slot for this cl->S */ /* create a slot for this agg->S */
qfq_slot_rotate(grp, roundedS); qfq_slot_rotate(grp, roundedS);
/* group was surely ineligible, remove */ /* group was surely ineligible, remove */
__clear_bit(grp->index, &q->bitmaps[IR]); __clear_bit(grp->index, &q->bitmaps[IR]);
...@@ -1008,46 +1273,61 @@ static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl, ...@@ -1008,46 +1273,61 @@ static void qfq_activate_class(struct qfq_sched *q, struct qfq_class *cl,
pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n", pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n",
s, q->bitmaps[s], s, q->bitmaps[s],
(unsigned long long) cl->S, (unsigned long long) agg->S,
(unsigned long long) cl->F, (unsigned long long) agg->F,
(unsigned long long) q->V); (unsigned long long) q->V);
skip_update: skip_update:
qfq_slot_insert(grp, cl, roundedS); qfq_slot_insert(grp, agg, roundedS);
} }
/* Update agg ts and schedule agg for service */
static void qfq_activate_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
enum update_reason reason)
{
qfq_update_agg_ts(q, agg, reason);
qfq_schedule_agg(q, agg);
}
static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp, static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp,
struct qfq_class *cl) struct qfq_aggregate *agg)
{ {
unsigned int i, offset; unsigned int i, offset;
u64 roundedS; u64 roundedS;
roundedS = qfq_round_down(cl->S, grp->slot_shift); roundedS = qfq_round_down(agg->S, grp->slot_shift);
offset = (roundedS - grp->S) >> grp->slot_shift; offset = (roundedS - grp->S) >> grp->slot_shift;
i = (grp->front + offset) % QFQ_MAX_SLOTS; i = (grp->front + offset) % QFQ_MAX_SLOTS;
hlist_del(&cl->next); hlist_del(&agg->next);
if (hlist_empty(&grp->slots[i])) if (hlist_empty(&grp->slots[i]))
__clear_bit(offset, &grp->full_slots); __clear_bit(offset, &grp->full_slots);
} }
/* /*
* called to forcibly destroy a queue. * Called to forcibly deschedule an aggregate. If the aggregate is
* If the queue is not in the front bucket, or if it has * not in the front bucket, or if the latter has other aggregates in
* other queues in the front bucket, we can simply remove * the front bucket, we can simply remove the aggregate with no other
* the queue with no other side effects. * side effects.
* Otherwise we must propagate the event up. * Otherwise we must propagate the event up.
*/ */
static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) static void qfq_deactivate_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
{ {
struct qfq_group *grp = cl->grp; struct qfq_group *grp = agg->grp;
unsigned long mask; unsigned long mask;
u64 roundedS; u64 roundedS;
int s; int s;
cl->F = cl->S; if (agg == q->in_serv_agg) {
qfq_slot_remove(q, grp, cl); charge_actual_service(agg);
q->in_serv_agg = qfq_choose_next_agg(q);
return;
}
agg->F = agg->S;
qfq_slot_remove(q, grp, agg);
if (!grp->full_slots) { if (!grp->full_slots) {
__clear_bit(grp->index, &q->bitmaps[IR]); __clear_bit(grp->index, &q->bitmaps[IR]);
...@@ -1066,8 +1346,8 @@ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) ...@@ -1066,8 +1346,8 @@ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl)
} }
__clear_bit(grp->index, &q->bitmaps[ER]); __clear_bit(grp->index, &q->bitmaps[ER]);
} else if (hlist_empty(&grp->slots[grp->front])) { } else if (hlist_empty(&grp->slots[grp->front])) {
cl = qfq_slot_scan(grp); agg = qfq_slot_scan(grp);
roundedS = qfq_round_down(cl->S, grp->slot_shift); roundedS = qfq_round_down(agg->S, grp->slot_shift);
if (grp->S != roundedS) { if (grp->S != roundedS) {
__clear_bit(grp->index, &q->bitmaps[ER]); __clear_bit(grp->index, &q->bitmaps[ER]);
__clear_bit(grp->index, &q->bitmaps[IR]); __clear_bit(grp->index, &q->bitmaps[IR]);
...@@ -1080,7 +1360,7 @@ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) ...@@ -1080,7 +1360,7 @@ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl)
} }
} }
qfq_update_eligible(q, q->V); qfq_update_eligible(q);
} }
static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg) static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg)
...@@ -1092,6 +1372,32 @@ static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg) ...@@ -1092,6 +1372,32 @@ static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg)
qfq_deactivate_class(q, cl); qfq_deactivate_class(q, cl);
} }
static unsigned int qfq_drop_from_slot(struct qfq_sched *q,
struct hlist_head *slot)
{
struct qfq_aggregate *agg;
struct hlist_node *n;
struct qfq_class *cl;
unsigned int len;
hlist_for_each_entry(agg, n, slot, next) {
list_for_each_entry(cl, &agg->active, alist) {
if (!cl->qdisc->ops->drop)
continue;
len = cl->qdisc->ops->drop(cl->qdisc);
if (len > 0) {
if (cl->qdisc->q.qlen == 0)
qfq_deactivate_class(q, cl);
return len;
}
}
}
return 0;
}
static unsigned int qfq_drop(struct Qdisc *sch) static unsigned int qfq_drop(struct Qdisc *sch)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
...@@ -1101,24 +1407,13 @@ static unsigned int qfq_drop(struct Qdisc *sch) ...@@ -1101,24 +1407,13 @@ static unsigned int qfq_drop(struct Qdisc *sch)
for (i = 0; i <= QFQ_MAX_INDEX; i++) { for (i = 0; i <= QFQ_MAX_INDEX; i++) {
grp = &q->groups[i]; grp = &q->groups[i];
for (j = 0; j < QFQ_MAX_SLOTS; j++) { for (j = 0; j < QFQ_MAX_SLOTS; j++) {
struct qfq_class *cl; len = qfq_drop_from_slot(q, &grp->slots[j]);
struct hlist_node *n; if (len > 0) {
sch->q.qlen--;
hlist_for_each_entry(cl, n, &grp->slots[j], next) { return len;
if (!cl->qdisc->ops->drop)
continue;
len = cl->qdisc->ops->drop(cl->qdisc);
if (len > 0) {
sch->q.qlen--;
if (!cl->qdisc->q.qlen)
qfq_deactivate_class(q, cl);
return len;
}
} }
} }
} }
return 0; return 0;
...@@ -1129,44 +1424,51 @@ static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt) ...@@ -1129,44 +1424,51 @@ static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp; struct qfq_group *grp;
int i, j, err; int i, j, err;
u32 max_cl_shift, maxbudg_shift, max_classes;
err = qdisc_class_hash_init(&q->clhash); err = qdisc_class_hash_init(&q->clhash);
if (err < 0) if (err < 0)
return err; return err;
if (qdisc_dev(sch)->tx_queue_len + 1 > QFQ_MAX_AGG_CLASSES)
max_classes = QFQ_MAX_AGG_CLASSES;
else
max_classes = qdisc_dev(sch)->tx_queue_len + 1;
/* max_cl_shift = floor(log_2(max_classes)) */
max_cl_shift = __fls(max_classes);
q->max_agg_classes = 1<<max_cl_shift;
/* maxbudg_shift = log2(max_len * max_classes_per_agg) */
maxbudg_shift = QFQ_MTU_SHIFT + max_cl_shift;
q->min_slot_shift = FRAC_BITS + maxbudg_shift - QFQ_MAX_INDEX;
for (i = 0; i <= QFQ_MAX_INDEX; i++) { for (i = 0; i <= QFQ_MAX_INDEX; i++) {
grp = &q->groups[i]; grp = &q->groups[i];
grp->index = i; grp->index = i;
grp->slot_shift = QFQ_MTU_SHIFT + FRAC_BITS grp->slot_shift = q->min_slot_shift + i;
- (QFQ_MAX_INDEX - i);
for (j = 0; j < QFQ_MAX_SLOTS; j++) for (j = 0; j < QFQ_MAX_SLOTS; j++)
INIT_HLIST_HEAD(&grp->slots[j]); INIT_HLIST_HEAD(&grp->slots[j]);
} }
INIT_HLIST_HEAD(&q->nonfull_aggs);
return 0; return 0;
} }
static void qfq_reset_qdisc(struct Qdisc *sch) static void qfq_reset_qdisc(struct Qdisc *sch)
{ {
struct qfq_sched *q = qdisc_priv(sch); struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
struct qfq_class *cl; struct qfq_class *cl;
struct hlist_node *n, *tmp; struct hlist_node *n;
unsigned int i, j; unsigned int i;
for (i = 0; i <= QFQ_MAX_INDEX; i++) { for (i = 0; i < q->clhash.hashsize; i++) {
grp = &q->groups[i]; hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
for (j = 0; j < QFQ_MAX_SLOTS; j++) { if (cl->qdisc->q.qlen > 0)
hlist_for_each_entry_safe(cl, n, tmp,
&grp->slots[j], next) {
qfq_deactivate_class(q, cl); qfq_deactivate_class(q, cl);
}
}
}
for (i = 0; i < q->clhash.hashsize; i++) {
hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode)
qdisc_reset(cl->qdisc); qdisc_reset(cl->qdisc);
}
} }
sch->q.qlen = 0; sch->q.qlen = 0;
} }
......
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