- 根目录:
- net
- sched
- sch_qfq.c
/*
* net/sched/sch_qfq.c Quick Fair Queueing Scheduler.
*
* Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/pkt_sched.h>
#include <net/sch_generic.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
/* Quick Fair Queueing
===================
Sources:
Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient
Packet Scheduling with Tight Bandwidth Distribution Guarantees."
See also:
http://retis.sssup.it/~fabio/linux/qfq/
*/
/*
Virtual time computations.
S, F and V are all computed in fixed point arithmetic with
FRAC_BITS decimal bits.
QFQ_MAX_INDEX is the maximum index allowed for a group. We need
one bit per index.
QFQ_MAX_WSHIFT is the maximum power of two supported as a weight.
The layout of the bits is as below:
[ MTU_SHIFT ][ FRAC_BITS ]
[ MAX_INDEX ][ MIN_SLOT_SHIFT ]
^.__grp->index = 0
*.__grp->slot_shift
where MIN_SLOT_SHIFT is derived by difference from the others.
The max group index corresponds to Lmax/w_min, where
Lmax=1<<MTU_SHIFT, w_min = 1 .
From this, and knowing how many groups (MAX_INDEX) we want,
we can derive the shift corresponding to each group.
Because we often need to compute
F = S + len/w_i and V = V + len/wsum
instead of storing w_i store the value
inv_w = (1<<FRAC_BITS)/w_i
so we can do F = S + len * inv_w * wsum.
We use W_TOT in the formulas so we can easily move between
static and adaptive weight sum.
The per-scheduler-instance data contain all the data structures
for the scheduler: bitmaps and bucket lists.
*/
/*
* Maximum number of consecutive slots occupied by backlogged classes
* inside a group.
*/
#define QFQ_MAX_SLOTS 32
/*
* Shifts used for class<->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
* group with the smallest index that can support the L_i / r_i configured
* for the class.
*
* grp->index is the index of the group; and grp->slot_shift
* is the shift for the corresponding (scaled) sigma_i.
*/
#define QFQ_MAX_INDEX 19
#define QFQ_MAX_WSHIFT 16
#define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT)
#define QFQ_MAX_WSUM (2*QFQ_MAX_WEIGHT)
#define FRAC_BITS 30 /* fixed point arithmetic */
#define ONE_FP (1UL << FRAC_BITS)
#define IWSUM (ONE_FP/QFQ_MAX_WSUM)
#define QFQ_MTU_SHIFT 11
#define QFQ_MIN_SLOT_SHIFT (FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX)
/*
* Possible group states. These values are used as indexes for the bitmaps
* array of struct qfq_queue.
*/
enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE };
struct qfq_group;
struct qfq_class {
struct Qdisc_class_common common;
unsigned int refcnt;
unsigned int filter_cnt;
struct gnet_stats_basic_packed bstats;
struct gnet_stats_queue qstats;
struct gnet_stats_rate_est rate_est;
struct Qdisc *qdisc;
struct hlist_node next; /* Link for the slot list. */
u64 S, F; /* flow timestamps (exact) */
/* group we belong to. In principle we would need the index,
* which is log_2(lmax/weight), but we never reference it
* directly, only the group.
*/
struct qfq_group *grp;
/* these are copied from the flowset. */
u32 inv_w; /* ONE_FP/weight */
u32 lmax; /* Max packet size for this flow. */
};
struct qfq_group {
u64 S, F; /* group timestamps (approx). */
unsigned int slot_shift; /* Slot shift. */
unsigned int index; /* Group index. */
unsigned int front; /* Index of the front slot. */
unsigned long full_slots; /* non-empty slots */
/* Array of RR lists of active classes. */
struct hlist_head slots[QFQ_MAX_SLOTS];
};
struct qfq_sched {
struct tcf_proto *filter_list;
struct Qdisc_class_hash clhash;
u64 V; /* Precise virtual time. */
u32 wsum; /* weight sum */
unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */
struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */
};
static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid)
{
struct qfq_sched *q = qdisc_priv(sch);
struct Qdisc_class_common *clc;
clc = qdisc_class_find(&q->clhash, classid);
if (clc == NULL)
return NULL;
return container_of(clc, struct qfq_class, common);
}
static void qfq_purge_queue(struct qfq_class *cl)
{
unsigned int len = cl->qdisc->q.qlen;
qdisc_reset(cl->qdisc);
qdisc_tree_decrease_qlen(cl->qdisc, len);
}
static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = {
[TCA_QFQ_WEIGHT] = { .type = NLA_U32 },
[TCA_QFQ_LMAX] = { .type = NLA_U32 },
};
/*
* Calculate a flow index, given its weight and maximum packet length.
* index = log_2(maxlen/weight) but we need to apply the scaling.
* This is used only once at flow creation.
*/
static int qfq_calc_index(u32 inv_w, unsigned int maxlen)
{
u64 slot_size = (u64)maxlen * inv_w;
unsigned long size_map;
int index = 0;
size_map = slot_size >> QFQ_MIN_SLOT_SHIFT;
if (!size_map)
goto out;
index = __fls(size_map) + 1; /* basically a log_2 */
index -= !(slot_size - (1ULL << (index + QFQ_MIN_SLOT_SHIFT - 1)));
if (index < 0)
index = 0;
out:
pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n",
(unsigned long) ONE_FP/inv_w, maxlen, index);
return index;
}
static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
struct nlattr **tca, unsigned long *arg)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl = (struct qfq_class *)*arg;
struct nlattr *tb[TCA_QFQ_MAX + 1];
u32 weight, lmax, inv_w;
int i, err;
int delta_w;
if (tca[TCA_OPTIONS] == NULL) {
pr_notice("qfq: no options\n");
return -EINVAL;
}
err = nla_parse_nested(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], qfq_policy);
if (err < 0)
return err;
if (tb[TCA_QFQ_WEIGHT]) {
weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]);
if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) {
pr_notice("qfq: invalid weight %u\n", weight);
return -EINVAL;
}
} else
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]) {
lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
if (!lmax || lmax > (1UL << QFQ_MTU_SHIFT)) {
pr_notice("qfq: invalid max length %u\n", lmax);
return -EINVAL;
}
} else
lmax = 1UL << QFQ_MTU_SHIFT;
if (cl != NULL) {
if (tca[TCA_RATE]) {
err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
qdisc_root_sleeping_lock(sch),
tca[TCA_RATE]);
if (err)
return err;
}
if (inv_w != cl->inv_w) {
sch_tree_lock(sch);
q->wsum += delta_w;
cl->inv_w = inv_w;
sch_tree_unlock(sch);
}
return 0;
}
cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL);
if (cl == NULL)
return -ENOBUFS;
cl->refcnt = 1;
cl->common.classid = classid;
cl->lmax = lmax;
cl->inv_w = inv_w;
i = qfq_calc_index(cl->inv_w, cl->lmax);
cl->grp = &q->groups[i];
cl->qdisc = qdisc_create_dflt(sch->dev_queue,
&pfifo_qdisc_ops, classid);
if (cl->qdisc == NULL)
cl->qdisc = &noop_qdisc;
if (tca[TCA_RATE]) {
err = gen_new_estimator(&cl->bstats, &cl->rate_est,
qdisc_root_sleeping_lock(sch),
tca[TCA_RATE]);
if (err) {
qdisc_destroy(cl->qdisc);
kfree(cl);
return err;
}
}
q->wsum += weight;
sch_tree_lock(sch);
qdisc_class_hash_insert(&q->clhash, &cl->common);
sch_tree_unlock(sch);
qdisc_class_hash_grow(sch, &q->clhash);
*arg = (unsigned long)cl;
return 0;
}
static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl)
{
struct qfq_sched *q = qdisc_priv(sch);
if (cl->inv_w) {
q->wsum -= ONE_FP / cl->inv_w;
cl->inv_w = 0;
}
gen_kill_estimator(&cl->bstats, &cl->rate_est);
qdisc_destroy(cl->qdisc);
kfree(cl);
}
static int qfq_delete_class(struct Qdisc *sch, unsigned long arg)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl = (struct qfq_class *)arg;
if (cl->filter_cnt > 0)
return -EBUSY;
sch_tree_lock(sch);
qfq_purge_queue(cl);
qdisc_class_hash_remove(&q->clhash, &cl->common);
BUG_ON(--cl->refcnt == 0);
/*
* This shouldn't happen: we "hold" one cops->get() when called
* from tc_ctl_tclass; the destroy method is done from cops->put().
*/
sch_tree_unlock(sch);
return 0;
}
static unsigned long qfq_get_class(struct Qdisc *sch, u32 classid)
{
struct qfq_class *cl = qfq_find_class(sch, classid);
if (cl != NULL)
cl->refcnt++;
return (unsigned long)cl;
}
static void qfq_put_class(struct Qdisc *sch, unsigned long arg)
{
struct qfq_class *cl = (struct qfq_class *)arg;
if (--cl->refcnt == 0)
qfq_destroy_class(sch, cl);
}
static struct tcf_proto **qfq_tcf_chain(struct Qdisc *sch, unsigned long cl)
{
struct qfq_sched *q = qdisc_priv(sch);
if (cl)
return NULL;
return &q->filter_list;
}
static unsigned long qfq_bind_tcf(struct Qdisc *sch, unsigned long parent,
u32 classid)
{
struct qfq_class *cl = qfq_find_class(sch, classid);
if (cl != NULL)
cl->filter_cnt++;
return (unsigned long)cl;
}
static void qfq_unbind_tcf(struct Qdisc *sch, unsigned long arg)
{
struct qfq_class *cl = (struct qfq_class *)arg;
cl->filter_cnt--;
}
static int qfq_graft_class(struct Qdisc *sch, unsigned long arg,
struct Qdisc *new, struct Qdisc **old)
{
struct qfq_class *cl = (struct qfq_class *)arg;
if (new == NULL) {
new = qdisc_create_dflt(sch->dev_queue,
&pfifo_qdisc_ops, cl->common.classid);
if (new == NULL)
new = &noop_qdisc;
}
sch_tree_lock(sch);
qfq_purge_queue(cl);
*old = cl->qdisc;
cl->qdisc = new;
sch_tree_unlock(sch);
return 0;
}
static struct Qdisc *qfq_class_leaf(struct Qdisc *sch, unsigned long arg)
{
struct qfq_class *cl = (struct qfq_class *)arg;
return cl->qdisc;
}
static int qfq_dump_class(struct Qdisc *sch, unsigned long arg,
struct sk_buff *skb, struct tcmsg *tcm)
{
struct qfq_class *cl = (struct qfq_class *)arg;
struct nlattr *nest;
tcm->tcm_parent = TC_H_ROOT;
tcm->tcm_handle = cl->common.classid;
tcm->tcm_info = cl->qdisc->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
NLA_PUT_U32(skb, TCA_QFQ_WEIGHT, ONE_FP/cl->inv_w);
NLA_PUT_U32(skb, TCA_QFQ_LMAX, cl->lmax);
return nla_nest_end(skb, nest);
nla_put_failure:
nla_nest_cancel(skb, nest);
return -EMSGSIZE;
}
static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
struct gnet_dump *d)
{
struct qfq_class *cl = (struct qfq_class *)arg;
struct tc_qfq_stats xstats;
memset(&xstats, 0, sizeof(xstats));
cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
xstats.weight = ONE_FP/cl->inv_w;
xstats.lmax = cl->lmax;
if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
return -1;
return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
}
static void qfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl;
struct hlist_node *n;
unsigned int i;
if (arg->stop)
return;
for (i = 0; i < q->clhash.hashsize; i++) {
hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
int *qerr)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl;
struct tcf_result res;
int result;
if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
pr_debug("qfq_classify: found %d\n", skb->priority);
cl = qfq_find_class(sch, skb->priority);
if (cl != NULL)
return cl;
}
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
result = tc_classify(skb, q->filter_list, &res);
if (result >= 0) {
#ifdef CONFIG_NET_CLS_ACT
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
#endif
cl = (struct qfq_class *)res.class;
if (cl == NULL)
cl = qfq_find_class(sch, res.classid);
return cl;
}
return NULL;
}
/* Generic comparison function, handling wraparound. */
static inline int qfq_gt(u64 a, u64 b)
{
return (s64)(a - b) > 0;
}
/* Round a precise timestamp to its slotted value. */
static inline u64 qfq_round_down(u64 ts, unsigned int shift)
{
return ts & ~((1ULL << shift) - 1);
}
/* return the pointer to the group with lowest index in the bitmap */
static inline struct qfq_group *qfq_ffs(struct qfq_sched *q,
unsigned long bitmap)
{
int index = __ffs(bitmap);
return &q->groups[index];
}
/* Calculate a mask to mimic what would be ffs_from(). */
static inline unsigned long mask_from(unsigned long bitmap, int from)
{
return bitmap & ~((1UL << from) - 1);
}
/*
* The state computation relies on ER=0, IR=1, EB=2, IB=3
* First compute eligibility comparing grp->S, q->V,
* then check if someone is blocking us and possibly add EB
*/
static int qfq_calc_state(struct qfq_sched *q, const struct qfq_group *grp)
{
/* if S > V we are not eligible */
unsigned int state = qfq_gt(grp->S, q->V);
unsigned long mask = mask_from(q->bitmaps[ER], grp->index);
struct qfq_group *next;
if (mask) {
next = qfq_ffs(q, mask);
if (qfq_gt(grp->F, next->F))
state |= EB;
}
return state;
}
/*
* In principle
* q->bitmaps[dst] |= q->bitmaps[src] & mask;
* q->bitmaps[src] &= ~mask;
* but we should make sure that src != dst
*/
static inline void qfq_move_groups(struct qfq_sched *q, unsigned long mask,
int src, int dst)
{
q->bitmaps[dst] |= q->bitmaps[src] & mask;
q->bitmaps[src] &= ~mask;
}
static void qfq_unblock_groups(struct qfq_sched *q, int index, u64 old_F)
{
unsigned long mask = mask_from(q->bitmaps[ER], index + 1);
struct qfq_group *next;
if (mask) {
next = qfq_ffs(q, mask);
if (!qfq_gt(next->F, old_F))
return;
}
mask = (1UL << index) - 1;
qfq_move_groups(q, mask, EB, ER);
qfq_move_groups(q, mask, IB, IR);
}
/*
* perhaps
*
old_V ^= q->V;
old_V >>= QFQ_MIN_SLOT_SHIFT;
if (old_V) {
...
}
*
*/
static void qfq_make_eligible(struct qfq_sched *q, u64 old_V)
{
unsigned long vslot = q->V >> QFQ_MIN_SLOT_SHIFT;
unsigned long old_vslot = old_V >> QFQ_MIN_SLOT_SHIFT;
if (vslot != old_vslot) {
unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1;
qfq_move_groups(q, mask, IR, ER);
qfq_move_groups(q, mask, IB, EB);
}
}
/*
* XXX we should make sure that slot becomes less than 32.
* This is guaranteed by the input values.
* roundedS is always cl->S rounded on grp->slot_shift bits.
*/
static void qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl,
u64 roundedS)
{
u64 slot = (roundedS - grp->S) >> grp->slot_shift;
unsigned int i = (grp->front + slot) % QFQ_MAX_SLOTS;
hlist_add_head(&cl->next, &grp->slots[i]);
__set_bit(slot, &grp->full_slots);
}
/* Maybe introduce hlist_first_entry?? */
static struct qfq_class *qfq_slot_head(struct qfq_group *grp)
{
return hlist_entry(grp->slots[grp->front].first,
struct qfq_class, next);
}
/*
* remove the entry from the slot
*/
static void qfq_front_slot_remove(struct qfq_group *grp)
{
struct qfq_class *cl = qfq_slot_head(grp);
BUG_ON(!cl);
hlist_del(&cl->next);
if (hlist_empty(&grp->slots[grp->front]))
__clear_bit(0, &grp->full_slots);
}
/*
* Returns the first full queue in a group. As a side effect,
* adjust the bucket list so the first non-empty bucket is at
* position 0 in full_slots.
*/
static struct qfq_class *qfq_slot_scan(struct qfq_group *grp)
{
unsigned int i;
pr_debug("qfq slot_scan: grp %u full %#lx\n",
grp->index, grp->full_slots);
if (grp->full_slots == 0)
return NULL;
i = __ffs(grp->full_slots); /* zero based */
if (i > 0) {
grp->front = (grp->front + i) % QFQ_MAX_SLOTS;
grp->full_slots >>= i;
}
return qfq_slot_head(grp);
}
/*
* adjust the bucket list. When the start time of a group decreases,
* we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to
* move the objects. The mask of occupied slots must be shifted
* because we use ffs() to find the first non-empty slot.
* This covers decreases in the group's start time, but what about
* increases of the start time ?
* Here too we should make sure that i is less than 32
*/
static void qfq_slot_rotate(struct qfq_group *grp, u64 roundedS)
{
unsigned int i = (grp->S - roundedS) >> grp->slot_shift;
grp->full_slots <<= i;
grp->front = (grp->front - i) % QFQ_MAX_SLOTS;
}
static void qfq_update_eligible(struct qfq_sched *q, u64 old_V)
{
struct qfq_group *grp;
unsigned long ineligible;
ineligible = q->bitmaps[IR] | q->bitmaps[IB];
if (ineligible) {
if (!q->bitmaps[ER]) {
grp = qfq_ffs(q, ineligible);
if (qfq_gt(grp->S, q->V))
q->V = grp->S;
}
qfq_make_eligible(q, old_V);
}
}
/* What is length of next packet in queue (0 if queue is empty) */
static unsigned int qdisc_peek_len(struct Qdisc *sch)
{
struct sk_buff *skb;
skb = sch->ops->peek(sch);
return skb ? qdisc_pkt_len(skb) : 0;
}
/*
* Updates the class, returns true if also the group needs to be updated.
*/
static bool qfq_update_class(struct qfq_group *grp, struct qfq_class *cl)
{
unsigned int len = qdisc_peek_len(cl->qdisc);
cl->S = cl->F;
if (!len)
qfq_front_slot_remove(grp); /* queue is empty */
else {
u64 roundedS;
cl->F = cl->S + (u64)len * cl->inv_w;
roundedS = qfq_round_down(cl->S, grp->slot_shift);
if (roundedS == grp->S)
return false;
qfq_front_slot_remove(grp);
qfq_slot_insert(grp, cl, roundedS);
}
return true;
}
static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
struct qfq_class *cl;
struct sk_buff *skb;
unsigned int len;
u64 old_V;
if (!q->bitmaps[ER])
return NULL;
grp = qfq_ffs(q, q->bitmaps[ER]);
cl = qfq_slot_head(grp);
skb = qdisc_dequeue_peeked(cl->qdisc);
if (!skb) {
WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n");
return NULL;
}
sch->q.qlen--;
qdisc_bstats_update(sch, skb);
old_V = q->V;
len = qdisc_pkt_len(skb);
q->V += (u64)len * IWSUM;
pr_debug("qfq dequeue: len %u F %lld now %lld\n",
len, (unsigned long long) cl->F, (unsigned long long) q->V);
if (qfq_update_class(grp, cl)) {
u64 old_F = grp->F;
cl = qfq_slot_scan(grp);
if (!cl)
__clear_bit(grp->index, &q->bitmaps[ER]);
else {
u64 roundedS = qfq_round_down(cl->S, grp->slot_shift);
unsigned int s;
if (grp->S == roundedS)
goto skip_unblock;
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]);
}
qfq_unblock_groups(q, grp->index, old_F);
}
skip_unblock:
qfq_update_eligible(q, old_V);
return skb;
}
/*
* Assign a reasonable start time for a new flow k in group i.
* Admissible values for \hat(F) are multiples of \sigma_i
* no greater than V+\sigma_i . Larger values mean that
* 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.
* 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 F_j of the first group j which would be blocking us.
* We are guaranteed not to move S backward because
* otherwise our group i would still be blocked.
*/
static void qfq_update_start(struct qfq_sched *q, struct qfq_class *cl)
{
unsigned long mask;
u64 limit, roundedF;
int slot_shift = cl->grp->slot_shift;
roundedF = qfq_round_down(cl->F, slot_shift);
limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift);
if (!qfq_gt(cl->F, q->V) || qfq_gt(roundedF, limit)) {
/* timestamp was stale */
mask = mask_from(q->bitmaps[ER], cl->grp->index);
if (mask) {
struct qfq_group *next = qfq_ffs(q, mask);
if (qfq_gt(roundedF, next->F)) {
if (qfq_gt(limit, next->F))
cl->S = next->F;
else /* preserve timestamp correctness */
cl->S = limit;
return;
}
}
cl->S = q->V;
} else /* timestamp is not stale */
cl->S = cl->F;
}
static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
struct qfq_class *cl;
int err;
u64 roundedS;
int s;
cl = qfq_classify(skb, sch, &err);
if (cl == NULL) {
if (err & __NET_XMIT_BYPASS)
sch->qstats.drops++;
kfree_skb(skb);
return err;
}
pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid);
err = qdisc_enqueue(skb, cl->qdisc);
if (unlikely(err != NET_XMIT_SUCCESS)) {
pr_debug("qfq_enqueue: enqueue failed %d\n", err);
if (net_xmit_drop_count(err)) {
cl->qstats.drops++;
sch->qstats.drops++;
}
return err;
}
bstats_update(&cl->bstats, skb);
++sch->q.qlen;
/* If the new skb is not the head of queue, then done here. */
if (cl->qdisc->q.qlen != 1)
return err;
/* If reach this point, queue q was idle */
grp = cl->grp;
qfq_update_start(q, cl);
/* compute new finish time and rounded start. */
cl->F = cl->S + (u64)qdisc_pkt_len(skb) * cl->inv_w;
roundedS = qfq_round_down(cl->S, grp->slot_shift);
/*
* insert cl in the correct bucket.
* If cl->S >= grp->S we don't need to adjust the
* bucket list and simply go to the insertion phase.
* Otherwise grp->S is decreasing, we must make room
* in the bucket list, and also recompute the group state.
* Finally, if there were no flows in this group and nobody
* was in ER make sure to adjust V.
*/
if (grp->full_slots) {
if (!qfq_gt(grp->S, cl->S))
goto skip_update;
/* create a slot for this cl->S */
qfq_slot_rotate(grp, roundedS);
/* group was surely ineligible, remove */
__clear_bit(grp->index, &q->bitmaps[IR]);
__clear_bit(grp->index, &q->bitmaps[IB]);
} else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V))
q->V = roundedS;
grp->S = roundedS;
grp->F = roundedS + (2ULL << grp->slot_shift);
s = qfq_calc_state(q, grp);
__set_bit(grp->index, &q->bitmaps[s]);
pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n",
s, q->bitmaps[s],
(unsigned long long) cl->S,
(unsigned long long) cl->F,
(unsigned long long) q->V);
skip_update:
qfq_slot_insert(grp, cl, roundedS);
return err;
}
static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp,
struct qfq_class *cl)
{
unsigned int i, offset;
u64 roundedS;
roundedS = qfq_round_down(cl->S, grp->slot_shift);
offset = (roundedS - grp->S) >> grp->slot_shift;
i = (grp->front + offset) % QFQ_MAX_SLOTS;
hlist_del(&cl->next);
if (hlist_empty(&grp->slots[i]))
__clear_bit(offset, &grp->full_slots);
}
/*
* called to forcibly destroy a queue.
* If the queue is not in the front bucket, or if it has
* other queues in the front bucket, we can simply remove
* the queue with no other side effects.
* Otherwise we must propagate the event up.
*/
static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl)
{
struct qfq_group *grp = cl->grp;
unsigned long mask;
u64 roundedS;
int s;
cl->F = cl->S;
qfq_slot_remove(q, grp, cl);
if (!grp->full_slots) {
__clear_bit(grp->index, &q->bitmaps[IR]);
__clear_bit(grp->index, &q->bitmaps[EB]);
__clear_bit(grp->index, &q->bitmaps[IB]);
if (test_bit(grp->index, &q->bitmaps[ER]) &&
!(q->bitmaps[ER] & ~((1UL << grp->index) - 1))) {
mask = q->bitmaps[ER] & ((1UL << grp->index) - 1);
if (mask)
mask = ~((1UL << __fls(mask)) - 1);
else
mask = ~0UL;
qfq_move_groups(q, mask, EB, ER);
qfq_move_groups(q, mask, IB, IR);
}
__clear_bit(grp->index, &q->bitmaps[ER]);
} else if (hlist_empty(&grp->slots[grp->front])) {
cl = qfq_slot_scan(grp);
roundedS = qfq_round_down(cl->S, grp->slot_shift);
if (grp->S != roundedS) {
__clear_bit(grp->index, &q->bitmaps[ER]);
__clear_bit(grp->index, &q->bitmaps[IR]);
__clear_bit(grp->index, &q->bitmaps[EB]);
__clear_bit(grp->index, &q->bitmaps[IB]);
grp->S = roundedS;
grp->F = roundedS + (2ULL << grp->slot_shift);
s = qfq_calc_state(q, grp);
__set_bit(grp->index, &q->bitmaps[s]);
}
}
qfq_update_eligible(q, q->V);
}
static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl = (struct qfq_class *)arg;
if (cl->qdisc->q.qlen == 0)
qfq_deactivate_class(q, cl);
}
static unsigned int qfq_drop(struct Qdisc *sch)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
unsigned int i, j, len;
for (i = 0; i <= QFQ_MAX_INDEX; i++) {
grp = &q->groups[i];
for (j = 0; j < QFQ_MAX_SLOTS; j++) {
struct qfq_class *cl;
struct hlist_node *n;
hlist_for_each_entry(cl, n, &grp->slots[j], next) {
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;
}
static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
int i, j, err;
err = qdisc_class_hash_init(&q->clhash);
if (err < 0)
return err;
for (i = 0; i <= QFQ_MAX_INDEX; i++) {
grp = &q->groups[i];
grp->index = i;
grp->slot_shift = QFQ_MTU_SHIFT + FRAC_BITS
- (QFQ_MAX_INDEX - i);
for (j = 0; j < QFQ_MAX_SLOTS; j++)
INIT_HLIST_HEAD(&grp->slots[j]);
}
return 0;
}
static void qfq_reset_qdisc(struct Qdisc *sch)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_group *grp;
struct qfq_class *cl;
struct hlist_node *n, *tmp;
unsigned int i, j;
for (i = 0; i <= QFQ_MAX_INDEX; i++) {
grp = &q->groups[i];
for (j = 0; j < QFQ_MAX_SLOTS; j++) {
hlist_for_each_entry_safe(cl, n, tmp,
&grp->slots[j], next) {
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);
}
sch->q.qlen = 0;
}
static void qfq_destroy_qdisc(struct Qdisc *sch)
{
struct qfq_sched *q = qdisc_priv(sch);
struct qfq_class *cl;
struct hlist_node *n, *next;
unsigned int i;
tcf_destroy_chain(&q->filter_list);
for (i = 0; i < q->clhash.hashsize; i++) {
hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
common.hnode) {
qfq_destroy_class(sch, cl);
}
}
qdisc_class_hash_destroy(&q->clhash);
}
static const struct Qdisc_class_ops qfq_class_ops = {
.change = qfq_change_class,
.delete = qfq_delete_class,
.get = qfq_get_class,
.put = qfq_put_class,
.tcf_chain = qfq_tcf_chain,
.bind_tcf = qfq_bind_tcf,
.unbind_tcf = qfq_unbind_tcf,
.graft = qfq_graft_class,
.leaf = qfq_class_leaf,
.qlen_notify = qfq_qlen_notify,
.dump = qfq_dump_class,
.dump_stats = qfq_dump_class_stats,
.walk = qfq_walk,
};
static struct Qdisc_ops qfq_qdisc_ops __read_mostly = {
.cl_ops = &qfq_class_ops,
.id = "qfq",
.priv_size = sizeof(struct qfq_sched),
.enqueue = qfq_enqueue,
.dequeue = qfq_dequeue,
.peek = qdisc_peek_dequeued,
.drop = qfq_drop,
.init = qfq_init_qdisc,
.reset = qfq_reset_qdisc,
.destroy = qfq_destroy_qdisc,
.owner = THIS_MODULE,
};
static int __init qfq_init(void)
{
return register_qdisc(&qfq_qdisc_ops);
}
static void __exit qfq_exit(void)
{
unregister_qdisc(&qfq_qdisc_ops);
}
module_init(qfq_init);
module_exit(qfq_exit);
MODULE_LICENSE("GPL");