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References: <20220823075717.28072-1-shaozhengchao@huawei.com>
In-Reply-To: <20220823075717.28072-1-shaozhengchao@huawei.com>
From:   Eric Dumazet <edumazet@google.com>
Date:   Tue, 23 Aug 2022 09:29:06 -0700
Message-ID: <CANn89iKta=-C43_jQpVVra_v3HxfCjvx+pJFj6NfLoa_GTXfAQ@mail.gmail.com>
Subject: Re: [PATCH net-next] net: sched: delete duplicate cleanup of backlog
 and qlen
To:     Zhengchao Shao <shaozhengchao@huawei.com>
Cc:     netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        David Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Vinicius Gomes <vinicius.gomes@intel.com>,
        weiyongjun1@huawei.com, YueHaibing <yuehaibing@huawei.com>
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Precedence: bulk

On Tue, Aug 23, 2022 at 12:54 AM Zhengchao Shao
<shaozhengchao@huawei.com> wrote:
>
> The qdisc_reset function has cleared the backlog and qlen of the qdisc.
> There is no need to clear them again in the specific reset function.

changelog is slightly inaccurate.

qdisc_reset() is clearing qdisc->q.qlen and qdisc->qstats.backlog
_after_ calling qdisc->ops->reset,
not before.

>
> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
> ---
>  include/net/sch_generic.h | 1 -
>  net/sched/sch_atm.c       | 1 -
>  net/sched/sch_cbq.c       | 1 -
>  net/sched/sch_choke.c     | 2 --
>  net/sched/sch_drr.c       | 2 --
>  net/sched/sch_dsmark.c    | 2 --
>  net/sched/sch_etf.c       | 3 ---
>  net/sched/sch_ets.c       | 2 --
>  net/sched/sch_fq_codel.c  | 2 --
>  net/sched/sch_fq_pie.c    | 3 ---
>  net/sched/sch_hfsc.c      | 2 --
>  net/sched/sch_htb.c       | 2 --
>  net/sched/sch_multiq.c    | 1 -
>  net/sched/sch_prio.c      | 2 --
>  net/sched/sch_qfq.c       | 2 --
>  net/sched/sch_red.c       | 2 --
>  net/sched/sch_sfb.c       | 2 --
>  net/sched/sch_skbprio.c   | 3 ---
>  net/sched/sch_taprio.c    | 2 --
>  net/sched/sch_tbf.c       | 2 --
>  net/sched/sch_teql.c      | 1 -
>  21 files changed, 40 deletions(-)
>
> diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
> index ec693fe7c553..f2958fb5ae08 100644
> --- a/include/net/sch_generic.h
> +++ b/include/net/sch_generic.h
> @@ -1137,7 +1137,6 @@ static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
>  static inline void qdisc_reset_queue(struct Qdisc *sch)
>  {
>         __qdisc_reset_queue(&sch->q);
> -       sch->qstats.backlog = 0;
>  }
>
>  static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
> diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
> index 4c8e994cf0a5..816fd0d7ba38 100644
> --- a/net/sched/sch_atm.c
> +++ b/net/sched/sch_atm.c
> @@ -577,7 +577,6 @@ static void atm_tc_reset(struct Qdisc *sch)
>         pr_debug("atm_tc_reset(sch %p,[qdisc %p])\n", sch, p);
>         list_for_each_entry(flow, &p->flows, list)
>                 qdisc_reset(flow->q);
> -       sch->q.qlen = 0;
>  }
>
>  static void atm_tc_destroy(struct Qdisc *sch)
> diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
> index af126eb3e431..b026daca160e 100644
> --- a/net/sched/sch_cbq.c
> +++ b/net/sched/sch_cbq.c
> @@ -975,7 +975,6 @@ cbq_reset(struct Qdisc *sch)
>                         cl->cpriority = cl->priority;
>                 }
>         }
> -       sch->q.qlen = 0;
>  }
>
>
> diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
> index 2adbd945bf15..25d2daaa8122 100644
> --- a/net/sched/sch_choke.c
> +++ b/net/sched/sch_choke.c
> @@ -315,8 +315,6 @@ static void choke_reset(struct Qdisc *sch)
>                 rtnl_qdisc_drop(skb, sch);
>         }
>
> -       sch->q.qlen = 0;
> -       sch->qstats.backlog = 0;
>         if (q->tab)
>                 memset(q->tab, 0, (q->tab_mask + 1) * sizeof(struct sk_buff *));
>         q->head = q->tail = 0;
> diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
> index 18e4f7a0b291..4e5b1cf11b85 100644
> --- a/net/sched/sch_drr.c
> +++ b/net/sched/sch_drr.c
> @@ -441,8 +441,6 @@ static void drr_reset_qdisc(struct Qdisc *sch)
>                         qdisc_reset(cl->qdisc);
>                 }
>         }
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void drr_destroy_qdisc(struct Qdisc *sch)
> diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
> index 4c100d105269..7da6dc38a382 100644
> --- a/net/sched/sch_dsmark.c
> +++ b/net/sched/sch_dsmark.c
> @@ -409,8 +409,6 @@ static void dsmark_reset(struct Qdisc *sch)
>         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
>         if (p->q)
>                 qdisc_reset(p->q);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void dsmark_destroy(struct Qdisc *sch)
> diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
> index c48f91075b5c..d96103b0e2bf 100644
> --- a/net/sched/sch_etf.c
> +++ b/net/sched/sch_etf.c
> @@ -445,9 +445,6 @@ static void etf_reset(struct Qdisc *sch)
>         timesortedlist_clear(sch);
>         __qdisc_reset_queue(&sch->q);
>
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
> -
>         q->last = 0;
>  }
>
> diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c
> index d73393493553..8de4365886e8 100644
> --- a/net/sched/sch_ets.c
> +++ b/net/sched/sch_ets.c
> @@ -727,8 +727,6 @@ static void ets_qdisc_reset(struct Qdisc *sch)
>         }
>         for (band = 0; band < q->nbands; band++)
>                 qdisc_reset(q->classes[band].qdisc);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void ets_qdisc_destroy(struct Qdisc *sch)
> diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
> index 839e1235db05..23a042adb74d 100644
> --- a/net/sched/sch_fq_codel.c
> +++ b/net/sched/sch_fq_codel.c
> @@ -347,8 +347,6 @@ static void fq_codel_reset(struct Qdisc *sch)
>                 codel_vars_init(&flow->cvars);
>         }
>         memset(q->backlogs, 0, q->flows_cnt * sizeof(u32));
> -       sch->q.qlen = 0;
> -       sch->qstats.backlog = 0;
>         q->memory_usage = 0;
>  }
>
> diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
> index d6aba6edd16e..35c35465226b 100644
> --- a/net/sched/sch_fq_pie.c
> +++ b/net/sched/sch_fq_pie.c
> @@ -521,9 +521,6 @@ static void fq_pie_reset(struct Qdisc *sch)
>                 INIT_LIST_HEAD(&flow->flowchain);
>                 pie_vars_init(&flow->vars);
>         }
> -
> -       sch->q.qlen = 0;
> -       sch->qstats.backlog = 0;
>  }
>
>  static void fq_pie_destroy(struct Qdisc *sch)
> diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
> index d3979a6000e7..03efc40e42fc 100644
> --- a/net/sched/sch_hfsc.c
> +++ b/net/sched/sch_hfsc.c
> @@ -1484,8 +1484,6 @@ hfsc_reset_qdisc(struct Qdisc *sch)
>         }
>         q->eligible = RB_ROOT;
>         qdisc_watchdog_cancel(&q->watchdog);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void
> diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
> index 23a9d6242429..cb5872d22ecf 100644
> --- a/net/sched/sch_htb.c
> +++ b/net/sched/sch_htb.c
> @@ -1008,8 +1008,6 @@ static void htb_reset(struct Qdisc *sch)
>         }
>         qdisc_watchdog_cancel(&q->watchdog);
>         __qdisc_reset_queue(&q->direct_queue);
> -       sch->q.qlen = 0;
> -       sch->qstats.backlog = 0;
>         memset(q->hlevel, 0, sizeof(q->hlevel));
>         memset(q->row_mask, 0, sizeof(q->row_mask));
>  }
> diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
> index cd8ab90c4765..f28050c7f12d 100644
> --- a/net/sched/sch_multiq.c
> +++ b/net/sched/sch_multiq.c
> @@ -152,7 +152,6 @@ multiq_reset(struct Qdisc *sch)
>
>         for (band = 0; band < q->bands; band++)
>                 qdisc_reset(q->queues[band]);
> -       sch->q.qlen = 0;
>         q->curband = 0;
>  }
>
> diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
> index 3b8d7197c06b..c03a11dd990f 100644
> --- a/net/sched/sch_prio.c
> +++ b/net/sched/sch_prio.c
> @@ -135,8 +135,6 @@ prio_reset(struct Qdisc *sch)
>
>         for (prio = 0; prio < q->bands; prio++)
>                 qdisc_reset(q->queues[prio]);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
> diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
> index d4ce58c90f9f..13246a9dc5c1 100644
> --- a/net/sched/sch_qfq.c
> +++ b/net/sched/sch_qfq.c
> @@ -1458,8 +1458,6 @@ static void qfq_reset_qdisc(struct Qdisc *sch)
>                         qdisc_reset(cl->qdisc);
>                 }
>         }
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void qfq_destroy_qdisc(struct Qdisc *sch)
> diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
> index 40adf1f07a82..f1e013e3f04a 100644
> --- a/net/sched/sch_red.c
> +++ b/net/sched/sch_red.c
> @@ -176,8 +176,6 @@ static void red_reset(struct Qdisc *sch)
>         struct red_sched_data *q = qdisc_priv(sch);
>
>         qdisc_reset(q->qdisc);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>         red_restart(&q->vars);
>  }
>
> diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c
> index 3d061a13d7ed..31717fa45a4f 100644
> --- a/net/sched/sch_sfb.c
> +++ b/net/sched/sch_sfb.c
> @@ -453,8 +453,6 @@ static void sfb_reset(struct Qdisc *sch)
>         struct sfb_sched_data *q = qdisc_priv(sch);
>
>         qdisc_reset(q->qdisc);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>         q->slot = 0;
>         q->double_buffering = false;
>         sfb_zero_all_buckets(q);
> diff --git a/net/sched/sch_skbprio.c b/net/sched/sch_skbprio.c
> index 7a5e4c454715..df72fb83d9c7 100644
> --- a/net/sched/sch_skbprio.c
> +++ b/net/sched/sch_skbprio.c
> @@ -213,9 +213,6 @@ static void skbprio_reset(struct Qdisc *sch)
>         struct skbprio_sched_data *q = qdisc_priv(sch);
>         int prio;
>
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
> -
>         for (prio = 0; prio < SKBPRIO_MAX_PRIORITY; prio++)
>                 __skb_queue_purge(&q->qdiscs[prio]);
>
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 0b941dd63d26..db88a692ef81 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -1636,8 +1636,6 @@ static void taprio_reset(struct Qdisc *sch)
>                         if (q->qdiscs[i])
>                                 qdisc_reset(q->qdiscs[i]);
>         }
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>  }
>
>  static void taprio_destroy(struct Qdisc *sch)
> diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
> index 72102277449e..d0288e223542 100644
> --- a/net/sched/sch_tbf.c
> +++ b/net/sched/sch_tbf.c
> @@ -330,8 +330,6 @@ static void tbf_reset(struct Qdisc *sch)
>         struct tbf_sched_data *q = qdisc_priv(sch);
>
>         qdisc_reset(q->qdisc);
> -       sch->qstats.backlog = 0;
> -       sch->q.qlen = 0;
>         q->t_c = ktime_get_ns();
>         q->tokens = q->buffer;
>         q->ptokens = q->mtu;
> diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
> index 6af6b95bdb67..79aaab51cbf5 100644
> --- a/net/sched/sch_teql.c
> +++ b/net/sched/sch_teql.c
> @@ -124,7 +124,6 @@ teql_reset(struct Qdisc *sch)
>         struct teql_sched_data *dat = qdisc_priv(sch);
>
>         skb_queue_purge(&dat->q);
> -       sch->q.qlen = 0;
>  }
>
>  static void
> --
> 2.17.1
>