package/kernel/mac80211/patches/subsys/336-mac80211-only-accumulate-airtime-deficit-for-active-.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 25 Jun 2022 23:10:19 +0200
   3 Subject: [PATCH] mac80211: only accumulate airtime deficit for active
   4  clients
   5
   6 When a client does not generate any local tx activity, accumulating airtime
   7 deficit for the round-robin scheduler can be harmful. If this goes on for too
   8 long, the deficit could grow quite large, which might cause unreasonable
   9 initial latency once the client becomes active
  10
  11 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  12 ---
  13
  14 --- a/net/mac80211/sta_info.c
  15 +++ b/net/mac80211/sta_info.c
  16 @@ -1900,6 +1900,7 @@ void ieee80211_sta_register_airtime(stru
  17         struct ieee80211_local *local = sta->sdata->local;
  18         u8 ac = ieee80211_ac_from_tid(tid);
  19         u32 airtime = 0;
  20 +       u32 diff;
  21
  22         if (sta->local->airtime_flags & AIRTIME_USE_TX)
  23                 airtime += tx_airtime;
  24 @@ -1909,7 +1910,11 @@ void ieee80211_sta_register_airtime(stru
  25         spin_lock_bh(&local->active_txq_lock[ac]);
  26         sta->airtime[ac].tx_airtime += tx_airtime;
  27         sta->airtime[ac].rx_airtime += rx_airtime;
  28 -       sta->airtime[ac].deficit -= airtime;
  29 +
  30 +       diff = (u32)jiffies - sta->airtime[ac].last_active;
  31 +       if (diff <= AIRTIME_ACTIVE_DURATION)
  32 +               sta->airtime[ac].deficit -= airtime;
  33 +
  34         spin_unlock_bh(&local->active_txq_lock[ac]);
  35  }
  36  EXPORT_SYMBOL(ieee80211_sta_register_airtime);