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1528 lines
42 KiB
1528 lines
42 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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|
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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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|
|
|
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/* Quick Fair Queueing Plus |
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======================== |
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|
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Sources: |
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|
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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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|
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Sources for QFQ: |
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|
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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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|
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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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/* |
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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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|
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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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|
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Virtual time computations. |
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|
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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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|
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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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|
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The layout of the bits is as below: |
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|
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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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|
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where MIN_SLOT_SHIFT is derived by difference from the others. |
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|
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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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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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#define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */ |
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|
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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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|
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struct qfq_group; |
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|
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struct qfq_aggregate; |
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|
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struct qfq_class { |
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struct Qdisc_class_common common; |
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|
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unsigned int filter_cnt; |
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|
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struct gnet_stats_basic_packed bstats; |
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struct gnet_stats_queue qstats; |
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struct net_rate_estimator __rcu *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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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struct hlist_node nonfull_next; /* See nonfull_aggs in qfq_sched. */ |
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}; |
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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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|
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struct qfq_sched { |
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struct tcf_proto __rcu *filter_list; |
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struct tcf_block *block; |
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struct Qdisc_class_hash clhash; |
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|
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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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|
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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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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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return index; |
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} |
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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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|
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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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|
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agg->lmax = lmax; |
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agg->class_weight = weight; |
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} |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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agg->num_classes = new_num_classes; |
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} |
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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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|
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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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|
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static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *); |
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|
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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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|
|
|
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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; |
|
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, |
|
struct netlink_ext_ack *extack) |
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{ |
|
struct qfq_sched *q = qdisc_priv(sch); |
|
struct qfq_class *cl = (struct qfq_class *)*arg; |
|
bool existing = false; |
|
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; |
|
int err; |
|
int delta_w; |
|
|
|
if (tca[TCA_OPTIONS] == NULL) { |
|
pr_notice("qfq: no options\n"); |
|
return -EINVAL; |
|
} |
|
|
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err = nla_parse_nested_deprecated(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], |
|
qfq_policy, NULL); |
|
if (err < 0) |
|
return err; |
|
|
|
if (tb[TCA_QFQ_WEIGHT]) { |
|
weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]); |
|
if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) { |
|
pr_notice("qfq: invalid weight %u\n", weight); |
|
return -EINVAL; |
|
} |
|
} else |
|
weight = 1; |
|
|
|
if (tb[TCA_QFQ_LMAX]) { |
|
lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); |
|
if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) { |
|
pr_notice("qfq: invalid max length %u\n", lmax); |
|
return -EINVAL; |
|
} |
|
} else |
|
lmax = psched_mtu(qdisc_dev(sch)); |
|
|
|
inv_w = ONE_FP / weight; |
|
weight = ONE_FP / inv_w; |
|
|
|
if (cl != NULL && |
|
lmax == cl->agg->lmax && |
|
weight == cl->agg->class_weight) |
|
return 0; /* nothing to change */ |
|
|
|
delta_w = weight - (cl ? cl->agg->class_weight : 0); |
|
|
|
if (q->wsum + delta_w > QFQ_MAX_WSUM) { |
|
pr_notice("qfq: total weight out of range (%d + %u)\n", |
|
delta_w, q->wsum); |
|
return -EINVAL; |
|
} |
|
|
|
if (cl != NULL) { /* modify existing class */ |
|
if (tca[TCA_RATE]) { |
|
err = gen_replace_estimator(&cl->bstats, NULL, |
|
&cl->rate_est, |
|
NULL, |
|
qdisc_root_sleeping_running(sch), |
|
tca[TCA_RATE]); |
|
if (err) |
|
return err; |
|
} |
|
existing = true; |
|
goto set_change_agg; |
|
} |
|
|
|
/* create and init new class */ |
|
cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL); |
|
if (cl == NULL) |
|
return -ENOBUFS; |
|
|
|
cl->common.classid = classid; |
|
cl->deficit = lmax; |
|
|
|
cl->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, |
|
classid, NULL); |
|
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; |
|
} |
|
|
|
if (cl->qdisc != &noop_qdisc) |
|
qdisc_hash_add(cl->qdisc, true); |
|
sch_tree_lock(sch); |
|
qdisc_class_hash_insert(&q->clhash, &cl->common); |
|
sch_tree_unlock(sch); |
|
|
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qdisc_class_hash_grow(sch, &q->clhash); |
|
|
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set_change_agg: |
|
sch_tree_lock(sch); |
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new_agg = qfq_find_agg(q, lmax, weight); |
|
if (new_agg == NULL) { /* create new aggregate */ |
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sch_tree_unlock(sch); |
|
new_agg = kzalloc(sizeof(*new_agg), GFP_KERNEL); |
|
if (new_agg == NULL) { |
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err = -ENOBUFS; |
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gen_kill_estimator(&cl->rate_est); |
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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_put(cl->qdisc); |
|
kfree(cl); |
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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->rate_est); |
|
qdisc_put(cl->qdisc); |
|
kfree(cl); |
|
} |
|
|
|
static int qfq_delete_class(struct Qdisc *sch, unsigned long arg, |
|
struct netlink_ext_ack *extack) |
|
{ |
|
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); |
|
|
|
qdisc_purge_queue(cl->qdisc); |
|
qdisc_class_hash_remove(&q->clhash, &cl->common); |
|
|
|
sch_tree_unlock(sch); |
|
|
|
qfq_destroy_class(sch, cl); |
|
return 0; |
|
} |
|
|
|
static unsigned long qfq_search_class(struct Qdisc *sch, u32 classid) |
|
{ |
|
return (unsigned long)qfq_find_class(sch, classid); |
|
} |
|
|
|
static struct tcf_block *qfq_tcf_block(struct Qdisc *sch, unsigned long cl, |
|
struct netlink_ext_ack *extack) |
|
{ |
|
struct qfq_sched *q = qdisc_priv(sch); |
|
|
|
if (cl) |
|
return NULL; |
|
|
|
return q->block; |
|
} |
|
|
|
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 netlink_ext_ack *extack) |
|
{ |
|
struct qfq_class *cl = (struct qfq_class *)arg; |
|
|
|
if (new == NULL) { |
|
new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, |
|
cl->common.classid, NULL); |
|
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_noflag(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->rate_est) < 0 || |
|
qdisc_qstats_copy(d, cl->qdisc) < 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 = tcf_classify(skb, fl, &res, false); |
|
if (result >= 0) { |
|
#ifdef CONFIG_NET_CLS_ACT |
|
switch (result) { |
|
case TC_ACT_QUEUED: |
|
case TC_ACT_STOLEN: |
|
case TC_ACT_TRAP: |
|
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; |
|
fallthrough; |
|
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) |
|
{ |
|
unsigned int len = qdisc_pkt_len(skb), gso_segs; |
|
struct qfq_sched *q = qdisc_priv(sch); |
|
struct qfq_class *cl; |
|
struct qfq_aggregate *agg; |
|
int err = 0; |
|
bool first; |
|
|
|
cl = qfq_classify(skb, sch, &err); |
|
if (cl == NULL) { |
|
if (err & __NET_XMIT_BYPASS) |
|
qdisc_qstats_drop(sch); |
|
__qdisc_drop(skb, to_free); |
|
return err; |
|
} |
|
pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); |
|
|
|
if (unlikely(cl->agg->lmax < len)) { |
|
pr_debug("qfq: increasing maxpkt from %u to %u for class %u", |
|
cl->agg->lmax, len, cl->common.classid); |
|
err = qfq_change_agg(sch, cl, cl->agg->class_weight, len); |
|
if (err) { |
|
cl->qstats.drops++; |
|
return qdisc_drop(skb, sch, to_free); |
|
} |
|
} |
|
|
|
gso_segs = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1; |
|
first = !cl->qdisc->q.qlen; |
|
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; |
|
} |
|
|
|
cl->bstats.bytes += len; |
|
cl->bstats.packets += gso_segs; |
|
sch->qstats.backlog += len; |
|
++sch->q.qlen; |
|
|
|
agg = cl->agg; |
|
/* if the queue was not empty, then done here */ |
|
if (!first) { |
|
if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) && |
|
list_first_entry(&agg->active, struct qfq_class, alist) |
|
== cl && cl->deficit < len) |
|
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; |
|
|
|
qfq_deactivate_class(q, cl); |
|
} |
|
|
|
static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt, |
|
struct netlink_ext_ack *extack) |
|
{ |
|
struct qfq_sched *q = qdisc_priv(sch); |
|
struct qfq_group *grp; |
|
int i, j, err; |
|
u32 max_cl_shift, maxbudg_shift, max_classes; |
|
|
|
err = tcf_block_get(&q->block, &q->filter_list, sch, extack); |
|
if (err) |
|
return err; |
|
|
|
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_block_put(q->block); |
|
|
|
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, |
|
.find = qfq_search_class, |
|
.tcf_block = qfq_tcf_block, |
|
.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");
|
|
|