target/linux/mediatek/patches-4.9/0048-net-core-add-RPS-balancer.patch

   1 From 3e969c9695b45e1a052d43b367096ec99f2f0aac Mon Sep 17 00:00:00 2001
   2 From: John Crispin <john@phrozen.org>
   3 Date: Thu, 10 Aug 2017 15:58:29 +0200
   4 Subject: [PATCH 48/57] net: core: add RPS balancer
   5
   6 Signed-off-by: John Crispin <john@phrozen.org>
   7 ---
   8  net/core/dev.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
   9  1 file changed, 56 insertions(+), 1 deletion(-)
  10
  11 --- a/net/core/dev.c
  12 +++ b/net/core/dev.c
  13 @@ -3547,6 +3547,58 @@ set_rps_cpu(struct net_device *dev, stru
  14         return rflow;
  15  }
  16
  17 +#define RPS_TBL_SIZE_SHIFT     10
  18 +#define RPS_TBL_SIZE           (1 << RPS_TBL_SIZE_SHIFT)
  19 +struct rps_table {
  20 +       int                     core;
  21 +       struct timer_list       expire;
  22 +};
  23 +static struct rps_table rps_table[RPS_TBL_SIZE];
  24 +static int rps_table_last_core;
  25 +
  26 +static void rps_table_expire(unsigned long data)
  27 +{
  28 +       struct rps_table *entry = (struct rps_table *) data;
  29 +
  30 +       entry->core = -1;
  31 +}
  32 +
  33 +static int rps_table_core(struct rps_map *map)
  34 +{
  35 +       int i;
  36 +
  37 +       for (i = 0; i < map->len; i++) {
  38 +               int cpu = map->cpus[(rps_table_last_core + i + 1) % map->len];
  39 +               if (cpu_online(cpu)) {
  40 +                       rps_table_last_core = cpu;
  41 +                       return cpu;
  42 +               }
  43 +       }
  44 +       return map->cpus[0];
  45 +}
  46 +
  47 +static int rps_table_lookup(struct rps_map *map, u32 hash)
  48 +{
  49 +       int bucket = hash & 0x3ff;
  50 +
  51 +       if (rps_table[bucket].core < 0)
  52 +               rps_table[bucket].core = rps_table_core(map);
  53 +       mod_timer(&rps_table[bucket].expire, jiffies + HZ);
  54 +
  55 +       return rps_table[bucket].core;
  56 +}
  57 +
  58 +static void rps_table_init(void)
  59 +{
  60 +       int i;
  61 +
  62 +       for (i = 0; i < RPS_TBL_SIZE; i++) {
  63 +               rps_table[i].core = -1;
  64 +               setup_timer(&rps_table[i].expire, rps_table_expire,
  65 +                           (unsigned long) &rps_table[i]);
  66 +       }
  67 +}
  68 +
  69  /*
  70   * get_rps_cpu is called from netif_receive_skb and returns the target
  71   * CPU from the RPS map of the receiving queue for a given skb.
  72 @@ -3636,7 +3688,7 @@ static int get_rps_cpu(struct net_device
  73  try_rps:
  74
  75         if (map) {
  76 -               tcpu = map->cpus[reciprocal_scale(hash, map->len)];
  77 +               tcpu = rps_table_lookup(map, hash);
  78                 if (cpu_online(tcpu)) {
  79                         cpu = tcpu;
  80                         goto done;
  81 @@ -8426,6 +8478,9 @@ static int __init net_dev_init(void)
  82                 sd->backlog.weight = weight_p;
  83         }
  84
  85 +       if (IS_ENABLED(CONFIG_RPS))
  86 +               rps_table_init();
  87 +
  88         dev_boot_phase = 0;
  89
  90         /* The loopback device is special if any other network devices