+++ /dev/null
-From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
-Date: Mon, 18 Nov 2019 22:06:10 -0800
-Subject: [PATCH] mac80211: Use Airtime-based Queue Limits (AQL) on packet
- dequeue
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-The previous commit added the ability to throttle stations when they queue
-too much airtime in the hardware. This commit enables the functionality by
-calculating the expected airtime usage of each packet that is dequeued from
-the TXQs in mac80211, and accounting that as pending airtime.
-
-The estimated airtime for each skb is stored in the tx_info, so we can
-subtract the same amount from the running total when the skb is freed or
-recycled. The throttling mechanism relies on this accounting to be
-accurate (i.e., that we are not freeing skbs without subtracting any
-airtime they were accounted for), so we put the subtraction into
-ieee80211_report_used_skb(). As an optimisation, we also subtract the
-airtime on regular TX completion, zeroing out the value stored in the
-packet afterwards, to avoid having to do an expensive lookup of the station
-from the packet data on every packet.
-
-This patch does *not* include any mechanism to wake a throttled TXQ again,
-on the assumption that this will happen anyway as a side effect of whatever
-freed the skb (most commonly a TX completion).
-
-Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
-Link: https://lore.kernel.org/r/20191119060610.76681-5-kyan@google.com
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
----
-
---- a/include/net/mac80211.h
-+++ b/include/net/mac80211.h
-@@ -1060,6 +1060,22 @@ struct ieee80211_tx_info {
- };
- };
-
-+static inline u16
-+ieee80211_info_set_tx_time_est(struct ieee80211_tx_info *info, u16 tx_time_est)
-+{
-+ /* We only have 10 bits in tx_time_est, so store airtime
-+ * in increments of 4us and clamp the maximum to 2**12-1
-+ */
-+ info->tx_time_est = min_t(u16, tx_time_est, 4095) >> 2;
-+ return info->tx_time_est << 2;
-+}
-+
-+static inline u16
-+ieee80211_info_get_tx_time_est(struct ieee80211_tx_info *info)
-+{
-+ return info->tx_time_est << 2;
-+}
-+
- /**
- * struct ieee80211_tx_status - extended tx staus info for rate control
- *
---- a/net/mac80211/status.c
-+++ b/net/mac80211/status.c
-@@ -670,12 +670,26 @@ static void ieee80211_report_used_skb(st
- struct sk_buff *skb, bool dropped)
- {
- struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-+ u16 tx_time_est = ieee80211_info_get_tx_time_est(info);
- struct ieee80211_hdr *hdr = (void *)skb->data;
- bool acked = info->flags & IEEE80211_TX_STAT_ACK;
-
- if (dropped)
- acked = false;
-
-+ if (tx_time_est) {
-+ struct sta_info *sta;
-+
-+ rcu_read_lock();
-+
-+ sta = sta_info_get_by_addrs(local, hdr->addr1, hdr->addr2);
-+ ieee80211_sta_update_pending_airtime(local, sta,
-+ skb_get_queue_mapping(skb),
-+ tx_time_est,
-+ true);
-+ rcu_read_unlock();
-+ }
-+
- if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
- struct ieee80211_sub_if_data *sdata;
-
-@@ -885,6 +899,7 @@ static void __ieee80211_tx_status(struct
- struct ieee80211_bar *bar;
- int shift = 0;
- int tid = IEEE80211_NUM_TIDS;
-+ u16 tx_time_est;
-
- rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
-
-@@ -996,6 +1011,17 @@ static void __ieee80211_tx_status(struct
- ieee80211_sta_register_airtime(&sta->sta, tid,
- info->status.tx_time, 0);
-
-+ if ((tx_time_est = ieee80211_info_get_tx_time_est(info)) > 0) {
-+ /* Do this here to avoid the expensive lookup of the sta
-+ * in ieee80211_report_used_skb().
-+ */
-+ ieee80211_sta_update_pending_airtime(local, sta,
-+ skb_get_queue_mapping(skb),
-+ tx_time_est,
-+ true);
-+ ieee80211_info_set_tx_time_est(info, 0);
-+ }
-+
- if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
- if (acked) {
- if (sta->status_stats.lost_packets)
---- a/net/mac80211/tx.c
-+++ b/net/mac80211/tx.c
-@@ -3559,6 +3559,9 @@ struct sk_buff *ieee80211_tx_dequeue(str
-
- WARN_ON_ONCE(softirq_count() == 0);
-
-+ if (!ieee80211_txq_airtime_check(hw, txq))
-+ return NULL;
-+
- begin:
- spin_lock_bh(&fq->lock);
-
-@@ -3687,6 +3690,21 @@ begin:
- }
-
- IEEE80211_SKB_CB(skb)->control.vif = vif;
-+
-+ if (local->airtime_flags & AIRTIME_USE_AQL) {
-+ u32 airtime;
-+
-+ airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
-+ skb->len);
-+ if (airtime) {
-+ airtime = ieee80211_info_set_tx_time_est(info, airtime);
-+ ieee80211_sta_update_pending_airtime(local, tx.sta,
-+ txq->ac,
-+ airtime,
-+ false);
-+ }
-+ }
-+
- return skb;
-
- out:
projects / openwrt / staging / wigyori.git / blobdiff