target/linux/layerscape/patches-5.4/701-net-0043-sdk_dpaa-ceetm-stop-transmitting-frames-when-the-CQ-.patch

   1 From 3aa939c73c176690a9ebe646612cd097f281efe5 Mon Sep 17 00:00:00 2001
   2 From: Camelia Groza <camelia.groza@nxp.com>
   3 Date: Fri, 24 Nov 2017 10:48:31 +0200
   4 Subject: [PATCH] sdk_dpaa: ceetm: stop transmitting frames when the CQ is
   5  congested
   6
   7 When the egress CQ is congested, drop the frames instead of enqueueing
   8 them. This is more efficient than enqueueing and receiving them back on
   9 the ERN queue.
  10
  11 We also can't stop the netdev queues because that would affect all the CQs
  12 and would hinder prioritization.
  13
  14 Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
  15 ---
  16  .../ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c   | 22 ++++++++++++++++------
  17  .../ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.h   |  1 +
  18  2 files changed, 17 insertions(+), 6 deletions(-)
  19
  20 --- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
  21 +++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
  22 @@ -125,16 +125,16 @@ static void ceetm_cscn(struct qm_ceetm_c
  23                 break;
  24         }
  25
  26 +       ceetm_fq->congested = congested;
  27 +
  28         if (congested) {
  29                 dpa_priv->cgr_data.congestion_start_jiffies = jiffies;
  30 -               netif_tx_stop_all_queues(dpa_priv->net_dev);
  31                 dpa_priv->cgr_data.cgr_congested_count++;
  32                 if (cstats)
  33                         cstats->congested_count++;
  34         } else {
  35                 dpa_priv->cgr_data.congested_jiffies +=
  36                         (jiffies - dpa_priv->cgr_data.congestion_start_jiffies);
  37 -               netif_tx_wake_all_queues(dpa_priv->net_dev);
  38         }
  39  }
  40
  41 @@ -148,6 +148,7 @@ static int ceetm_alloc_fq(struct ceetm_f
  42
  43         (*fq)->net_dev = dev;
  44         (*fq)->ceetm_cls = cls;
  45 +       (*fq)->congested = 0;
  46         return 0;
  47  }
  48
  49 @@ -1913,7 +1914,8 @@ int __hot ceetm_tx(struct sk_buff *skb,
  50         struct Qdisc *sch = net_dev->qdisc;
  51         struct ceetm_class *cl;
  52         struct dpa_priv_s *priv_dpa;
  53 -       struct qman_fq *egress_fq, *conf_fq;
  54 +       struct ceetm_fq *ceetm_fq;
  55 +       struct qman_fq *conf_fq;
  56         struct ceetm_qdisc *priv = qdisc_priv(sch);
  57         struct ceetm_qdisc_stats *qstats = this_cpu_ptr(priv->root.qstats);
  58         struct ceetm_class_stats *cstats;
  59 @@ -1945,11 +1947,11 @@ int __hot ceetm_tx(struct sk_buff *skb,
  60          */
  61         switch (cl->type) {
  62         case CEETM_PRIO:
  63 -               egress_fq = &cl->prio.fq->fq;
  64 +               ceetm_fq = cl->prio.fq;
  65                 cstats = this_cpu_ptr(cl->prio.cstats);
  66                 break;
  67         case CEETM_WBFS:
  68 -               egress_fq = &cl->wbfs.fq->fq;
  69 +               ceetm_fq = cl->wbfs.fq;
  70                 cstats = this_cpu_ptr(cl->wbfs.cstats);
  71                 break;
  72         default:
  73 @@ -1957,8 +1959,16 @@ int __hot ceetm_tx(struct sk_buff *skb,
  74                 goto drop;
  75         }
  76
  77 +       /* If the FQ is congested, avoid enqueuing the frame and dropping it
  78 +        * when it returns on the ERN path. Drop it here directly instead.
  79 +        */
  80 +       if (unlikely(ceetm_fq->congested)) {
  81 +               qstats->drops++;
  82 +               goto drop;
  83 +       }
  84 +
  85         bstats_update(&cstats->bstats, skb);
  86 -       return dpa_tx_extended(skb, net_dev, egress_fq, conf_fq);
  87 +       return dpa_tx_extended(skb, net_dev, &ceetm_fq->fq, conf_fq);
  88
  89  drop:
  90         dev_kfree_skb_any(skb);
  91 --- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.h
  92 +++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.h
  93 @@ -105,6 +105,7 @@ struct ceetm_fq {
  94         struct qman_fq fq;
  95         struct net_device *net_dev;
  96         struct ceetm_class *ceetm_cls;
  97 +       int congested; /* Congestion status */
  98  };
  99
 100  struct root_q {