![WANG Cong](/assets/img/avatar_default.png)
Reported-by: Stas Nichiporovich <stasn77@gmail.com>
Fixes: 2ccccf5fb4
("net_sched: update hierarchical backlog too")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1545 lines
42 KiB
C
1545 lines
42 KiB
C
/*
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* net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler.
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*
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* Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
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* Copyright (c) 2012 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 Plus
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========================
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Sources:
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[1] Paolo Valente,
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"Reducing the Execution Time of Fair-Queueing Schedulers."
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http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf
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Sources for QFQ:
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[2] 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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QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES
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classes. Each aggregate is timestamped with a virtual start time S
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and a virtual finish time F, and scheduled according to its
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timestamps. S and F are computed as a function of a system virtual
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time function V. The classes within each aggregate are instead
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scheduled with DRR.
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To speed up operations, QFQ+ divides also aggregates into a limited
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number of groups. Which group a class belongs to depends on the
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ratio between the maximum packet length for the class and the weight
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of the class. Groups have their own S and F. In the end, QFQ+
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schedules groups, then aggregates within groups, then classes within
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aggregates. See [1] and [2] for a full description.
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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 aggregate<->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 aggregate 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 classes in the aggregate.
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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 24
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#define QFQ_MAX_WSHIFT 10
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#define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */
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#define QFQ_MAX_WSUM (64*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 QFQ_MTU_SHIFT 16 /* to support TSO/GSO */
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#define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */
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#define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */
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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_aggregate;
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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_est64 rate_est;
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struct Qdisc *qdisc;
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struct list_head alist; /* Link for active-classes list. */
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struct qfq_aggregate *agg; /* Parent aggregate. */
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int deficit; /* DRR deficit counter. */
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};
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struct qfq_aggregate {
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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 class_weight; /* Weight of each class in this aggregate. */
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/* Max pkt size for the classes in this aggregate, DRR quantum. */
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int lmax;
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u32 inv_w; /* ONE_FP/(sum of weights of classes in aggr.). */
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u32 budgetmax; /* Max budget for this aggregate. */
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u32 initial_budget, budget; /* Initial and current budget. */
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int num_classes; /* Number of classes in this aggr. */
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struct list_head active; /* DRR queue of active classes. */
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struct hlist_node nonfull_next; /* See nonfull_aggs in qfq_sched. */
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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 aggregates. */
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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 __rcu *filter_list;
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struct Qdisc_class_hash clhash;
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u64 oldV, V; /* Precise virtual times. */
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struct qfq_aggregate *in_serv_agg; /* Aggregate being served. */
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u32 wsum; /* weight sum */
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u32 iwsum; /* inverse 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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u32 min_slot_shift; /* Index of the group-0 bit in the bitmaps. */
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u32 max_agg_classes; /* Max number of classes per aggr. */
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struct hlist_head nonfull_aggs; /* Aggs with room for more classes. */
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};
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/*
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* Possible reasons why the timestamps of an aggregate are updated
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* enqueue: the aggregate switches from idle to active and must scheduled
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* for service
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* requeue: the aggregate finishes its budget, so it stops being served and
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* must be rescheduled for service
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*/
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enum update_reason {enqueue, requeue};
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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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unsigned int backlog = cl->qdisc->qstats.backlog;
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qdisc_reset(cl->qdisc);
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qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
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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, u32 min_slot_shift)
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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 >> 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 + 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 void qfq_deactivate_agg(struct qfq_sched *, struct qfq_aggregate *);
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static void qfq_activate_agg(struct qfq_sched *, struct qfq_aggregate *,
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enum update_reason);
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static void qfq_init_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
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u32 lmax, u32 weight)
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{
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INIT_LIST_HEAD(&agg->active);
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hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs);
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agg->lmax = lmax;
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agg->class_weight = weight;
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}
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static struct qfq_aggregate *qfq_find_agg(struct qfq_sched *q,
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u32 lmax, u32 weight)
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{
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struct qfq_aggregate *agg;
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hlist_for_each_entry(agg, &q->nonfull_aggs, nonfull_next)
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if (agg->lmax == lmax && agg->class_weight == weight)
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return agg;
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return NULL;
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}
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/* Update aggregate as a function of the new number of classes. */
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static void qfq_update_agg(struct qfq_sched *q, struct qfq_aggregate *agg,
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int new_num_classes)
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{
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u32 new_agg_weight;
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if (new_num_classes == q->max_agg_classes)
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hlist_del_init(&agg->nonfull_next);
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if (agg->num_classes > new_num_classes &&
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new_num_classes == q->max_agg_classes - 1) /* agg no more full */
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hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs);
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/* The next assignment may let
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* agg->initial_budget > agg->budgetmax
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* hold, we will take it into account in charge_actual_service().
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*/
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agg->budgetmax = new_num_classes * agg->lmax;
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new_agg_weight = agg->class_weight * new_num_classes;
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agg->inv_w = ONE_FP/new_agg_weight;
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if (agg->grp == NULL) {
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int i = qfq_calc_index(agg->inv_w, agg->budgetmax,
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q->min_slot_shift);
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agg->grp = &q->groups[i];
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}
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q->wsum +=
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(int) agg->class_weight * (new_num_classes - agg->num_classes);
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q->iwsum = ONE_FP / q->wsum;
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agg->num_classes = new_num_classes;
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}
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/* Add class to aggregate. */
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static void qfq_add_to_agg(struct qfq_sched *q,
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struct qfq_aggregate *agg,
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struct qfq_class *cl)
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{
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cl->agg = agg;
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qfq_update_agg(q, agg, agg->num_classes+1);
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if (cl->qdisc->q.qlen > 0) { /* adding an active class */
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list_add_tail(&cl->alist, &agg->active);
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if (list_first_entry(&agg->active, struct qfq_class, alist) ==
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cl && q->in_serv_agg != agg) /* agg was inactive */
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qfq_activate_agg(q, agg, enqueue); /* schedule agg */
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}
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}
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static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *);
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static void qfq_destroy_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
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{
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hlist_del_init(&agg->nonfull_next);
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q->wsum -= agg->class_weight;
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if (q->wsum != 0)
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q->iwsum = ONE_FP / q->wsum;
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if (q->in_serv_agg == agg)
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q->in_serv_agg = qfq_choose_next_agg(q);
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kfree(agg);
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}
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/* Deschedule class from within its parent aggregate. */
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static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl)
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{
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struct qfq_aggregate *agg = cl->agg;
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list_del(&cl->alist); /* remove from RR queue of the aggregate */
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if (list_empty(&agg->active)) /* agg is now inactive */
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qfq_deactivate_agg(q, agg);
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}
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/* Remove class from its parent aggregate. */
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static void qfq_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl)
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{
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struct qfq_aggregate *agg = cl->agg;
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cl->agg = NULL;
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if (agg->num_classes == 1) { /* agg being emptied, destroy it */
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qfq_destroy_agg(q, agg);
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return;
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}
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qfq_update_agg(q, agg, agg->num_classes-1);
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}
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/* Deschedule class and remove it from its parent aggregate. */
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static void qfq_deact_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl)
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{
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if (cl->qdisc->q.qlen > 0) /* class is active */
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qfq_deactivate_class(q, cl);
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qfq_rm_from_agg(q, cl);
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}
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/* Move class to a new aggregate, matching the new class weight and/or lmax */
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static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight,
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u32 lmax)
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{
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struct qfq_sched *q = qdisc_priv(sch);
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struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight);
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if (new_agg == NULL) { /* create new aggregate */
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new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC);
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if (new_agg == NULL)
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return -ENOBUFS;
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qfq_init_agg(q, new_agg, lmax, weight);
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}
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qfq_deact_rm_from_agg(q, cl);
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qfq_add_to_agg(q, new_agg, cl);
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return 0;
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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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bool existing = false;
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struct nlattr *tb[TCA_QFQ_MAX + 1];
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struct qfq_aggregate *new_agg = NULL;
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u32 weight, lmax, inv_w;
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int 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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if (tb[TCA_QFQ_LMAX]) {
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lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
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if (lmax < QFQ_MIN_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 = psched_mtu(qdisc_dev(sch));
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inv_w = ONE_FP / weight;
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weight = ONE_FP / inv_w;
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if (cl != NULL &&
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lmax == cl->agg->lmax &&
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weight == cl->agg->class_weight)
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return 0; /* nothing to change */
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delta_w = weight - (cl ? cl->agg->class_weight : 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 (%d + %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 (cl != NULL) { /* modify existing class */
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if (tca[TCA_RATE]) {
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err = gen_replace_estimator(&cl->bstats, NULL,
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&cl->rate_est,
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NULL,
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qdisc_root_sleeping_running(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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existing = true;
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goto set_change_agg;
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}
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/* create and init new class */
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cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL);
|
|
if (cl == NULL)
|
|
return -ENOBUFS;
|
|
|
|
cl->refcnt = 1;
|
|
cl->common.classid = classid;
|
|
cl->deficit = lmax;
|
|
|
|
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, NULL,
|
|
&cl->rate_est,
|
|
NULL,
|
|
qdisc_root_sleeping_running(sch),
|
|
tca[TCA_RATE]);
|
|
if (err)
|
|
goto destroy_class;
|
|
}
|
|
|
|
sch_tree_lock(sch);
|
|
qdisc_class_hash_insert(&q->clhash, &cl->common);
|
|
sch_tree_unlock(sch);
|
|
|
|
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;
|
|
return 0;
|
|
|
|
destroy_class:
|
|
qdisc_destroy(cl->qdisc);
|
|
kfree(cl);
|
|
return err;
|
|
}
|
|
|
|
static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl)
|
|
{
|
|
struct qfq_sched *q = qdisc_priv(sch);
|
|
|
|
qfq_rm_from_agg(q, cl);
|
|
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 __rcu **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;
|
|
}
|
|
|
|
*old = qdisc_replace(sch, new, &cl->qdisc);
|
|
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;
|
|
if (nla_put_u32(skb, TCA_QFQ_WEIGHT, cl->agg->class_weight) ||
|
|
nla_put_u32(skb, TCA_QFQ_LMAX, cl->agg->lmax))
|
|
goto nla_put_failure;
|
|
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));
|
|
|
|
xstats.weight = cl->agg->class_weight;
|
|
xstats.lmax = cl->agg->lmax;
|
|
|
|
if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
|
|
d, NULL, &cl->bstats) < 0 ||
|
|
gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
|
|
gnet_stats_copy_queue(d, NULL,
|
|
&cl->qdisc->qstats, cl->qdisc->q.qlen) < 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;
|
|
unsigned int i;
|
|
|
|
if (arg->stop)
|
|
return;
|
|
|
|
for (i = 0; i < q->clhash.hashsize; i++) {
|
|
hlist_for_each_entry(cl, &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;
|
|
struct tcf_proto *fl;
|
|
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;
|
|
fl = rcu_dereference_bh(q->filter_list);
|
|
result = tc_classify(skb, fl, &res, false);
|
|
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 >>= q->min_slot_shift;
|
|
if (old_V) {
|
|
...
|
|
}
|
|
*
|
|
*/
|
|
static void qfq_make_eligible(struct qfq_sched *q)
|
|
{
|
|
unsigned long vslot = q->V >> q->min_slot_shift;
|
|
unsigned long old_vslot = q->oldV >> q->min_slot_shift;
|
|
|
|
if (vslot != old_vslot) {
|
|
unsigned long mask;
|
|
int last_flip_pos = fls(vslot ^ old_vslot);
|
|
|
|
if (last_flip_pos > 31) /* higher than the number of groups */
|
|
mask = ~0UL; /* make all groups eligible */
|
|
else
|
|
mask = (1UL << last_flip_pos) - 1;
|
|
|
|
qfq_move_groups(q, mask, IR, ER);
|
|
qfq_move_groups(q, mask, IB, EB);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The index of the slot in which the input aggregate agg is to be
|
|
* inserted must not be higher than QFQ_MAX_SLOTS-2. There is a '-2'
|
|
* and not a '-1' 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.
|
|
*
|
|
* QFQ+ fully satisfies this bound to the slot index if the parameters
|
|
* of the classes are not changed dynamically, and if QFQ+ never
|
|
* happens to postpone the service of agg unjustly, i.e., it never
|
|
* happens that the aggregate becomes backlogged and eligible, or just
|
|
* eligible, while an aggregate with a higher approximated finish time
|
|
* is being served. In particular, in this case QFQ+ guarantees that
|
|
* the timestamps of agg are low enough that the slot index is never
|
|
* higher than 2. Unfortunately, QFQ+ cannot provide the same
|
|
* guarantee if it happens to unjustly postpone the service of agg, or
|
|
* if the parameters of some class are changed.
|
|
*
|
|
* As for the first event, i.e., an out-of-order service, the
|
|
* upper bound to the slot index guaranteed by QFQ+ grows to
|
|
* 2 +
|
|
* QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) *
|
|
* (current_max_weight/current_wsum) <= 2 + 8 * 128 * 1.
|
|
*
|
|
* The following function deals with this problem by backward-shifting
|
|
* the timestamps of agg, if needed, so as to guarantee that the slot
|
|
* index is never higher than QFQ_MAX_SLOTS-2. This backward-shift may
|
|
* cause the service of other aggregates to be postponed, yet the
|
|
* worst-case guarantees of these aggregates are not violated. In
|
|
* fact, in case of no out-of-order service, the timestamps of agg
|
|
* would have been even lower than they are after the backward shift,
|
|
* because QFQ+ would have guaranteed a maximum value equal to 2 for
|
|
* the slot index, and 2 < QFQ_MAX_SLOTS-2. Hence the aggregates whose
|
|
* service is postponed because of the backward-shift would have
|
|
* however waited for the service of agg before being served.
|
|
*
|
|
* The other event that may cause the slot index to be higher than 2
|
|
* for agg is a recent change of the parameters of some class. If the
|
|
* weight of a class is increased or the lmax (max_pkt_size) of the
|
|
* class is decreased, then a new aggregate with smaller slot size
|
|
* than the original parent aggregate of the class may happen to be
|
|
* activated. The activation of this aggregate should be properly
|
|
* delayed to when the service of the class has finished in the ideal
|
|
* system tracked by QFQ+. If the activation of the aggregate is not
|
|
* delayed to this reference time instant, then this aggregate may be
|
|
* unjustly served before other aggregates waiting for service. This
|
|
* may cause the above bound to the slot index to be violated for some
|
|
* of these unlucky aggregates.
|
|
*
|
|
* Instead of delaying the activation of the new aggregate, which is
|
|
* quite complex, the above-discussed capping of the slot index is
|
|
* used to handle also the consequences of a change of the parameters
|
|
* of a class.
|
|
*/
|
|
static void qfq_slot_insert(struct qfq_group *grp, struct qfq_aggregate *agg,
|
|
u64 roundedS)
|
|
{
|
|
u64 slot = (roundedS - grp->S) >> grp->slot_shift;
|
|
unsigned int i; /* slot index in the bucket list */
|
|
|
|
if (unlikely(slot > QFQ_MAX_SLOTS - 2)) {
|
|
u64 deltaS = roundedS - grp->S -
|
|
((u64)(QFQ_MAX_SLOTS - 2)<<grp->slot_shift);
|
|
agg->S -= deltaS;
|
|
agg->F -= deltaS;
|
|
slot = QFQ_MAX_SLOTS - 2;
|
|
}
|
|
|
|
i = (grp->front + slot) % QFQ_MAX_SLOTS;
|
|
|
|
hlist_add_head(&agg->next, &grp->slots[i]);
|
|
__set_bit(slot, &grp->full_slots);
|
|
}
|
|
|
|
/* Maybe introduce hlist_first_entry?? */
|
|
static struct qfq_aggregate *qfq_slot_head(struct qfq_group *grp)
|
|
{
|
|
return hlist_entry(grp->slots[grp->front].first,
|
|
struct qfq_aggregate, next);
|
|
}
|
|
|
|
/*
|
|
* remove the entry from the slot
|
|
*/
|
|
static void qfq_front_slot_remove(struct qfq_group *grp)
|
|
{
|
|
struct qfq_aggregate *agg = qfq_slot_head(grp);
|
|
|
|
BUG_ON(!agg);
|
|
hlist_del(&agg->next);
|
|
if (hlist_empty(&grp->slots[grp->front]))
|
|
__clear_bit(0, &grp->full_slots);
|
|
}
|
|
|
|
/*
|
|
* Returns the first aggregate in the first non-empty bucket of the
|
|
* group. As a side effect, adjusts the bucket list so the first
|
|
* non-empty bucket is at position 0 in full_slots.
|
|
*/
|
|
static struct qfq_aggregate *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)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
|
|
/* Dequeue head packet of the head class in the DRR queue of the aggregate. */
|
|
static void agg_dequeue(struct qfq_aggregate *agg,
|
|
struct qfq_class *cl, unsigned int len)
|
|
{
|
|
qdisc_dequeue_peeked(cl->qdisc);
|
|
|
|
cl->deficit -= (int) len;
|
|
|
|
if (cl->qdisc->q.qlen == 0) /* no more packets, remove from list */
|
|
list_del(&cl->alist);
|
|
else if (cl->deficit < qdisc_pkt_len(cl->qdisc->ops->peek(cl->qdisc))) {
|
|
cl->deficit += agg->lmax;
|
|
list_move_tail(&cl->alist, &agg->active);
|
|
}
|
|
}
|
|
|
|
static inline struct sk_buff *qfq_peek_skb(struct qfq_aggregate *agg,
|
|
struct qfq_class **cl,
|
|
unsigned int *len)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
*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, taking into
|
|
* account that, after decreasing the number of classes in
|
|
* agg, it may happen that
|
|
* agg->initial_budget - agg->budget > agg->bugdetmax
|
|
*/
|
|
u32 service_received = min(agg->budgetmax,
|
|
agg->initial_budget - agg->budget);
|
|
|
|
agg->F = agg->S + (u64)service_received * agg->inv_w;
|
|
}
|
|
|
|
/* Assign a reasonable start time for a new aggregate 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 EB (see [2]). 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_aggregate *agg)
|
|
{
|
|
unsigned long mask;
|
|
u64 limit, roundedF;
|
|
int slot_shift = agg->grp->slot_shift;
|
|
|
|
roundedF = qfq_round_down(agg->F, slot_shift);
|
|
limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift);
|
|
|
|
if (!qfq_gt(agg->F, q->V) || qfq_gt(roundedF, limit)) {
|
|
/* timestamp was stale */
|
|
mask = mask_from(q->bitmaps[ER], agg->grp->index);
|
|
if (mask) {
|
|
struct qfq_group *next = qfq_ffs(q, mask);
|
|
if (qfq_gt(roundedF, next->F)) {
|
|
if (qfq_gt(limit, next->F))
|
|
agg->S = next->F;
|
|
else /* preserve timestamp correctness */
|
|
agg->S = limit;
|
|
return;
|
|
}
|
|
}
|
|
agg->S = q->V;
|
|
} else /* timestamp is not stale */
|
|
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 *q, struct qfq_aggregate *agg);
|
|
|
|
static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
|
|
{
|
|
struct qfq_sched *q = qdisc_priv(sch);
|
|
struct qfq_aggregate *in_serv_agg = q->in_serv_agg;
|
|
struct qfq_class *cl;
|
|
struct sk_buff *skb = NULL;
|
|
/* next-packet len, 0 means no more active classes in in-service agg */
|
|
unsigned int len = 0;
|
|
|
|
if (in_serv_agg == NULL)
|
|
return NULL;
|
|
|
|
if (!list_empty(&in_serv_agg->active))
|
|
skb = qfq_peek_skb(in_serv_agg, &cl, &len);
|
|
|
|
/*
|
|
* If there are no active classes in the in-service aggregate,
|
|
* or if the aggregate has not enough budget to serve its next
|
|
* class, then choose the next aggregate to serve.
|
|
*/
|
|
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_update_agg_ts(q, in_serv_agg, requeue);
|
|
qfq_schedule_agg(q, in_serv_agg);
|
|
} 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;
|
|
|
|
qdisc_qstats_backlog_dec(sch, skb);
|
|
sch->q.qlen--;
|
|
qdisc_bstats_update(sch, skb);
|
|
|
|
agg_dequeue(in_serv_agg, cl, len);
|
|
/* If lmax is lowered, through qfq_change_class, for a class
|
|
* owning pending packets with larger size than the new value
|
|
* of lmax, then the following condition may hold.
|
|
*/
|
|
if (unlikely(in_serv_agg->budget < len))
|
|
in_serv_agg->budget = 0;
|
|
else
|
|
in_serv_agg->budget -= len;
|
|
|
|
q->V += (u64)len * q->iwsum;
|
|
pr_debug("qfq dequeue: len %u F %lld now %lld\n",
|
|
len, (unsigned long long) in_serv_agg->F,
|
|
(unsigned long long) q->V);
|
|
|
|
return skb;
|
|
}
|
|
|
|
static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *q)
|
|
{
|
|
struct qfq_group *grp;
|
|
struct qfq_aggregate *agg, *new_front_agg;
|
|
u64 old_F;
|
|
|
|
qfq_update_eligible(q);
|
|
q->oldV = q->V;
|
|
|
|
if (!q->bitmaps[ER])
|
|
return NULL;
|
|
|
|
grp = qfq_ffs(q, q->bitmaps[ER]);
|
|
old_F = grp->F;
|
|
|
|
agg = qfq_slot_head(grp);
|
|
|
|
/* 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]);
|
|
}
|
|
|
|
qfq_unblock_groups(q, grp->index, old_F);
|
|
|
|
return agg;
|
|
}
|
|
|
|
static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
|
|
struct sk_buff **to_free)
|
|
{
|
|
struct qfq_sched *q = qdisc_priv(sch);
|
|
struct qfq_class *cl;
|
|
struct qfq_aggregate *agg;
|
|
int err = 0;
|
|
|
|
cl = qfq_classify(skb, sch, &err);
|
|
if (cl == NULL) {
|
|
if (err & __NET_XMIT_BYPASS)
|
|
qdisc_qstats_drop(sch);
|
|
kfree_skb(skb);
|
|
return err;
|
|
}
|
|
pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid);
|
|
|
|
if (unlikely(cl->agg->lmax < qdisc_pkt_len(skb))) {
|
|
pr_debug("qfq: increasing maxpkt from %u to %u for class %u",
|
|
cl->agg->lmax, qdisc_pkt_len(skb), cl->common.classid);
|
|
err = qfq_change_agg(sch, cl, cl->agg->class_weight,
|
|
qdisc_pkt_len(skb));
|
|
if (err) {
|
|
cl->qstats.drops++;
|
|
return qdisc_drop(skb, sch, to_free);
|
|
}
|
|
}
|
|
|
|
err = qdisc_enqueue(skb, cl->qdisc, to_free);
|
|
if (unlikely(err != NET_XMIT_SUCCESS)) {
|
|
pr_debug("qfq_enqueue: enqueue failed %d\n", err);
|
|
if (net_xmit_drop_count(err)) {
|
|
cl->qstats.drops++;
|
|
qdisc_qstats_drop(sch);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
bstats_update(&cl->bstats, skb);
|
|
qdisc_qstats_backlog_inc(sch, skb);
|
|
++sch->q.qlen;
|
|
|
|
agg = cl->agg;
|
|
/* 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;
|
|
}
|
|
|
|
/* schedule class for service within the aggregate */
|
|
cl->deficit = agg->lmax;
|
|
list_add_tail(&cl->alist, &agg->active);
|
|
|
|
if (list_first_entry(&agg->active, struct qfq_class, alist) != cl ||
|
|
q->in_serv_agg == agg)
|
|
return err; /* non-empty or in service, nothing else to do */
|
|
|
|
qfq_activate_agg(q, agg, enqueue);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Schedule aggregate according to its timestamps.
|
|
*/
|
|
static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
|
|
{
|
|
struct qfq_group *grp = agg->grp;
|
|
u64 roundedS;
|
|
int s;
|
|
|
|
roundedS = qfq_round_down(agg->S, grp->slot_shift);
|
|
|
|
/*
|
|
* Insert agg in the correct bucket.
|
|
* If agg->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, agg->S))
|
|
goto skip_update;
|
|
|
|
/* create a slot for this agg->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->in_serv_agg == NULL)
|
|
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) agg->S,
|
|
(unsigned long long) agg->F,
|
|
(unsigned long long) q->V);
|
|
|
|
skip_update:
|
|
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)
|
|
{
|
|
agg->initial_budget = agg->budget = agg->budgetmax; /* recharge budg. */
|
|
|
|
qfq_update_agg_ts(q, agg, reason);
|
|
if (q->in_serv_agg == NULL) { /* no aggr. in service or scheduled */
|
|
q->in_serv_agg = agg; /* start serving this aggregate */
|
|
/* update V: to be in service, agg must be eligible */
|
|
q->oldV = q->V = agg->S;
|
|
} else if (agg != q->in_serv_agg)
|
|
qfq_schedule_agg(q, agg);
|
|
}
|
|
|
|
static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp,
|
|
struct qfq_aggregate *agg)
|
|
{
|
|
unsigned int i, offset;
|
|
u64 roundedS;
|
|
|
|
roundedS = qfq_round_down(agg->S, grp->slot_shift);
|
|
offset = (roundedS - grp->S) >> grp->slot_shift;
|
|
|
|
i = (grp->front + offset) % QFQ_MAX_SLOTS;
|
|
|
|
hlist_del(&agg->next);
|
|
if (hlist_empty(&grp->slots[i]))
|
|
__clear_bit(offset, &grp->full_slots);
|
|
}
|
|
|
|
/*
|
|
* Called to forcibly deschedule an aggregate. If the aggregate is
|
|
* not in the front bucket, or if the latter has other aggregates in
|
|
* the front bucket, we can simply remove the aggregate with no other
|
|
* side effects.
|
|
* Otherwise we must propagate the event up.
|
|
*/
|
|
static void qfq_deactivate_agg(struct qfq_sched *q, struct qfq_aggregate *agg)
|
|
{
|
|
struct qfq_group *grp = agg->grp;
|
|
unsigned long mask;
|
|
u64 roundedS;
|
|
int s;
|
|
|
|
if (agg == q->in_serv_agg) {
|
|
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) {
|
|
__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])) {
|
|
agg = qfq_slot_scan(grp);
|
|
roundedS = qfq_round_down(agg->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]);
|
|
}
|
|
}
|
|
}
|
|
|
|
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 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;
|
|
u32 max_cl_shift, maxbudg_shift, max_classes;
|
|
|
|
err = qdisc_class_hash_init(&q->clhash);
|
|
if (err < 0)
|
|
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++) {
|
|
grp = &q->groups[i];
|
|
grp->index = i;
|
|
grp->slot_shift = q->min_slot_shift + i;
|
|
for (j = 0; j < QFQ_MAX_SLOTS; j++)
|
|
INIT_HLIST_HEAD(&grp->slots[j]);
|
|
}
|
|
|
|
INIT_HLIST_HEAD(&q->nonfull_aggs);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void qfq_reset_qdisc(struct Qdisc *sch)
|
|
{
|
|
struct qfq_sched *q = qdisc_priv(sch);
|
|
struct qfq_class *cl;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < q->clhash.hashsize; i++) {
|
|
hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
|
|
if (cl->qdisc->q.qlen > 0)
|
|
qfq_deactivate_class(q, cl);
|
|
|
|
qdisc_reset(cl->qdisc);
|
|
}
|
|
}
|
|
sch->qstats.backlog = 0;
|
|
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 *next;
|
|
unsigned int i;
|
|
|
|
tcf_destroy_chain(&q->filter_list);
|
|
|
|
for (i = 0; i < q->clhash.hashsize; i++) {
|
|
hlist_for_each_entry_safe(cl, 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,
|
|
.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");
|