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1b34ec43c9
These macros contain a hidden goto, and are thus extremely error prone and make code hard to audit. Signed-off-by: David S. Miller <davem@davemloft.net>
1140 lines
27 KiB
C
1140 lines
27 KiB
C
/*
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* net/sched/sch_qfq.c Quick Fair Queueing Scheduler.
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*
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* Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/netdevice.h>
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#include <linux/pkt_sched.h>
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#include <net/sch_generic.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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/* Quick Fair Queueing
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===================
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Sources:
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Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient
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Packet Scheduling with Tight Bandwidth Distribution Guarantees."
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See also:
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http://retis.sssup.it/~fabio/linux/qfq/
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*/
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/*
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Virtual time computations.
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S, F and V are all computed in fixed point arithmetic with
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FRAC_BITS decimal bits.
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QFQ_MAX_INDEX is the maximum index allowed for a group. We need
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one bit per index.
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QFQ_MAX_WSHIFT is the maximum power of two supported as a weight.
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The layout of the bits is as below:
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[ MTU_SHIFT ][ FRAC_BITS ]
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[ MAX_INDEX ][ MIN_SLOT_SHIFT ]
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^.__grp->index = 0
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*.__grp->slot_shift
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where MIN_SLOT_SHIFT is derived by difference from the others.
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The max group index corresponds to Lmax/w_min, where
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Lmax=1<<MTU_SHIFT, w_min = 1 .
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From this, and knowing how many groups (MAX_INDEX) we want,
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we can derive the shift corresponding to each group.
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Because we often need to compute
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F = S + len/w_i and V = V + len/wsum
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instead of storing w_i store the value
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inv_w = (1<<FRAC_BITS)/w_i
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so we can do F = S + len * inv_w * wsum.
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We use W_TOT in the formulas so we can easily move between
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static and adaptive weight sum.
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The per-scheduler-instance data contain all the data structures
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for the scheduler: bitmaps and bucket lists.
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*/
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/*
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* Maximum number of consecutive slots occupied by backlogged classes
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* inside a group.
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*/
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#define QFQ_MAX_SLOTS 32
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/*
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* Shifts used for class<->group mapping. We allow class weights that are
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* in the range [1, 2^MAX_WSHIFT], and we try to map each class i to the
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* group with the smallest index that can support the L_i / r_i configured
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* for the class.
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*
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* grp->index is the index of the group; and grp->slot_shift
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* is the shift for the corresponding (scaled) sigma_i.
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*/
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#define QFQ_MAX_INDEX 19
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#define QFQ_MAX_WSHIFT 16
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#define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT)
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#define QFQ_MAX_WSUM (2*QFQ_MAX_WEIGHT)
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#define FRAC_BITS 30 /* fixed point arithmetic */
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#define ONE_FP (1UL << FRAC_BITS)
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#define IWSUM (ONE_FP/QFQ_MAX_WSUM)
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#define QFQ_MTU_SHIFT 11
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#define QFQ_MIN_SLOT_SHIFT (FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX)
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/*
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* Possible group states. These values are used as indexes for the bitmaps
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* array of struct qfq_queue.
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*/
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enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE };
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struct qfq_group;
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struct qfq_class {
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struct Qdisc_class_common common;
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unsigned int refcnt;
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unsigned int filter_cnt;
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struct gnet_stats_basic_packed bstats;
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struct gnet_stats_queue qstats;
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struct gnet_stats_rate_est rate_est;
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struct Qdisc *qdisc;
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struct hlist_node next; /* Link for the slot list. */
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u64 S, F; /* flow timestamps (exact) */
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/* group we belong to. In principle we would need the index,
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* which is log_2(lmax/weight), but we never reference it
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* directly, only the group.
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*/
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struct qfq_group *grp;
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/* these are copied from the flowset. */
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u32 inv_w; /* ONE_FP/weight */
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u32 lmax; /* Max packet size for this flow. */
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};
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struct qfq_group {
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u64 S, F; /* group timestamps (approx). */
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unsigned int slot_shift; /* Slot shift. */
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unsigned int index; /* Group index. */
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unsigned int front; /* Index of the front slot. */
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unsigned long full_slots; /* non-empty slots */
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/* Array of RR lists of active classes. */
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struct hlist_head slots[QFQ_MAX_SLOTS];
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};
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struct qfq_sched {
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struct tcf_proto *filter_list;
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struct Qdisc_class_hash clhash;
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u64 V; /* Precise virtual time. */
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u32 wsum; /* weight sum */
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unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */
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struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */
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};
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static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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struct Qdisc_class_common *clc;
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clc = qdisc_class_find(&q->clhash, classid);
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if (clc == NULL)
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return NULL;
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return container_of(clc, struct qfq_class, common);
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}
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static void qfq_purge_queue(struct qfq_class *cl)
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{
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unsigned int len = cl->qdisc->q.qlen;
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qdisc_reset(cl->qdisc);
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qdisc_tree_decrease_qlen(cl->qdisc, len);
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}
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static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = {
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[TCA_QFQ_WEIGHT] = { .type = NLA_U32 },
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[TCA_QFQ_LMAX] = { .type = NLA_U32 },
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};
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/*
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* Calculate a flow index, given its weight and maximum packet length.
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* index = log_2(maxlen/weight) but we need to apply the scaling.
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* This is used only once at flow creation.
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*/
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static int qfq_calc_index(u32 inv_w, unsigned int maxlen)
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{
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u64 slot_size = (u64)maxlen * inv_w;
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unsigned long size_map;
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int index = 0;
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size_map = slot_size >> QFQ_MIN_SLOT_SHIFT;
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if (!size_map)
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goto out;
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index = __fls(size_map) + 1; /* basically a log_2 */
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index -= !(slot_size - (1ULL << (index + QFQ_MIN_SLOT_SHIFT - 1)));
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if (index < 0)
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index = 0;
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out:
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pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n",
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(unsigned long) ONE_FP/inv_w, maxlen, index);
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return index;
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}
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static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
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struct nlattr **tca, unsigned long *arg)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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struct qfq_class *cl = (struct qfq_class *)*arg;
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struct nlattr *tb[TCA_QFQ_MAX + 1];
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u32 weight, lmax, inv_w;
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int i, err;
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int delta_w;
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if (tca[TCA_OPTIONS] == NULL) {
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pr_notice("qfq: no options\n");
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return -EINVAL;
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}
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err = nla_parse_nested(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], qfq_policy);
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if (err < 0)
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return err;
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if (tb[TCA_QFQ_WEIGHT]) {
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weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]);
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if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) {
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pr_notice("qfq: invalid weight %u\n", weight);
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return -EINVAL;
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}
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} else
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weight = 1;
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inv_w = ONE_FP / weight;
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weight = ONE_FP / inv_w;
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delta_w = weight - (cl ? ONE_FP / cl->inv_w : 0);
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if (q->wsum + delta_w > QFQ_MAX_WSUM) {
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pr_notice("qfq: total weight out of range (%u + %u)\n",
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delta_w, q->wsum);
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return -EINVAL;
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}
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if (tb[TCA_QFQ_LMAX]) {
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lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
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if (!lmax || lmax > (1UL << QFQ_MTU_SHIFT)) {
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pr_notice("qfq: invalid max length %u\n", lmax);
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return -EINVAL;
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}
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} else
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lmax = 1UL << QFQ_MTU_SHIFT;
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if (cl != NULL) {
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if (tca[TCA_RATE]) {
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err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
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qdisc_root_sleeping_lock(sch),
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tca[TCA_RATE]);
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if (err)
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return err;
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}
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if (inv_w != cl->inv_w) {
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sch_tree_lock(sch);
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q->wsum += delta_w;
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cl->inv_w = inv_w;
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sch_tree_unlock(sch);
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}
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return 0;
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}
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cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL);
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if (cl == NULL)
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return -ENOBUFS;
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cl->refcnt = 1;
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cl->common.classid = classid;
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cl->lmax = lmax;
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cl->inv_w = inv_w;
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i = qfq_calc_index(cl->inv_w, cl->lmax);
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cl->grp = &q->groups[i];
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cl->qdisc = qdisc_create_dflt(sch->dev_queue,
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&pfifo_qdisc_ops, classid);
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if (cl->qdisc == NULL)
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cl->qdisc = &noop_qdisc;
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if (tca[TCA_RATE]) {
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err = gen_new_estimator(&cl->bstats, &cl->rate_est,
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qdisc_root_sleeping_lock(sch),
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tca[TCA_RATE]);
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if (err) {
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qdisc_destroy(cl->qdisc);
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kfree(cl);
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return err;
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}
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}
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q->wsum += weight;
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sch_tree_lock(sch);
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qdisc_class_hash_insert(&q->clhash, &cl->common);
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sch_tree_unlock(sch);
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qdisc_class_hash_grow(sch, &q->clhash);
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*arg = (unsigned long)cl;
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return 0;
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}
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static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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if (cl->inv_w) {
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q->wsum -= ONE_FP / cl->inv_w;
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cl->inv_w = 0;
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}
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gen_kill_estimator(&cl->bstats, &cl->rate_est);
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qdisc_destroy(cl->qdisc);
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kfree(cl);
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}
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static int qfq_delete_class(struct Qdisc *sch, unsigned long arg)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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struct qfq_class *cl = (struct qfq_class *)arg;
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if (cl->filter_cnt > 0)
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return -EBUSY;
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sch_tree_lock(sch);
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qfq_purge_queue(cl);
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qdisc_class_hash_remove(&q->clhash, &cl->common);
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BUG_ON(--cl->refcnt == 0);
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/*
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* This shouldn't happen: we "hold" one cops->get() when called
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* from tc_ctl_tclass; the destroy method is done from cops->put().
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*/
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sch_tree_unlock(sch);
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return 0;
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}
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static unsigned long qfq_get_class(struct Qdisc *sch, u32 classid)
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{
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struct qfq_class *cl = qfq_find_class(sch, classid);
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if (cl != NULL)
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cl->refcnt++;
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return (unsigned long)cl;
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}
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static void qfq_put_class(struct Qdisc *sch, unsigned long arg)
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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if (--cl->refcnt == 0)
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qfq_destroy_class(sch, cl);
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}
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static struct tcf_proto **qfq_tcf_chain(struct Qdisc *sch, unsigned long cl)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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if (cl)
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return NULL;
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return &q->filter_list;
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}
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static unsigned long qfq_bind_tcf(struct Qdisc *sch, unsigned long parent,
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u32 classid)
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{
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struct qfq_class *cl = qfq_find_class(sch, classid);
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if (cl != NULL)
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cl->filter_cnt++;
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return (unsigned long)cl;
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}
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static void qfq_unbind_tcf(struct Qdisc *sch, unsigned long arg)
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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cl->filter_cnt--;
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}
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static int qfq_graft_class(struct Qdisc *sch, unsigned long arg,
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struct Qdisc *new, struct Qdisc **old)
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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if (new == NULL) {
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new = qdisc_create_dflt(sch->dev_queue,
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&pfifo_qdisc_ops, cl->common.classid);
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if (new == NULL)
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new = &noop_qdisc;
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}
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sch_tree_lock(sch);
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qfq_purge_queue(cl);
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*old = cl->qdisc;
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cl->qdisc = new;
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sch_tree_unlock(sch);
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return 0;
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}
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static struct Qdisc *qfq_class_leaf(struct Qdisc *sch, unsigned long arg)
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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return cl->qdisc;
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}
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static int qfq_dump_class(struct Qdisc *sch, unsigned long arg,
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struct sk_buff *skb, struct tcmsg *tcm)
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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struct nlattr *nest;
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tcm->tcm_parent = TC_H_ROOT;
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tcm->tcm_handle = cl->common.classid;
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tcm->tcm_info = cl->qdisc->handle;
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nest = nla_nest_start(skb, TCA_OPTIONS);
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if (nest == NULL)
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goto nla_put_failure;
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if (nla_put_u32(skb, TCA_QFQ_WEIGHT, ONE_FP/cl->inv_w) ||
|
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nla_put_u32(skb, TCA_QFQ_LMAX, cl->lmax))
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goto nla_put_failure;
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return nla_nest_end(skb, nest);
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|
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nla_put_failure:
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nla_nest_cancel(skb, nest);
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return -EMSGSIZE;
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}
|
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|
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static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
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struct gnet_dump *d)
|
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{
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struct qfq_class *cl = (struct qfq_class *)arg;
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struct tc_qfq_stats xstats;
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|
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memset(&xstats, 0, sizeof(xstats));
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cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
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|
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xstats.weight = ONE_FP/cl->inv_w;
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xstats.lmax = cl->lmax;
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|
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if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
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gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
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gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
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return -1;
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return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
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}
|
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|
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static void qfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
|
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{
|
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struct qfq_sched *q = qdisc_priv(sch);
|
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struct qfq_class *cl;
|
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struct hlist_node *n;
|
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unsigned int i;
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|
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if (arg->stop)
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return;
|
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|
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for (i = 0; i < q->clhash.hashsize; i++) {
|
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hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
|
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if (arg->count < arg->skip) {
|
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arg->count++;
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continue;
|
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}
|
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if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
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arg->stop = 1;
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return;
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}
|
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arg->count++;
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}
|
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}
|
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}
|
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|
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static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
|
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int *qerr)
|
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{
|
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struct qfq_sched *q = qdisc_priv(sch);
|
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struct qfq_class *cl;
|
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struct tcf_result res;
|
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int result;
|
|
|
|
if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
|
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pr_debug("qfq_classify: found %d\n", skb->priority);
|
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cl = qfq_find_class(sch, skb->priority);
|
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if (cl != NULL)
|
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return cl;
|
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}
|
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|
|
*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)) {
|
|
cl->S = next->F;
|
|
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");
|