From: "Toke Høiland-Jørgensen" <toke@redhat.com> To: Johannes Berg <johannes@sipsolutions.net> Cc: linux-wireless@vger.kernel.org, make-wifi-fast@lists.bufferbloat.net, ath10k@lists.infradead.org, John Crispin <john@phrozen.org>, Lorenzo Bianconi <lorenzo@kernel.org>, Felix Fietkau <nbd@nbd.name>, Kan Yan <kyan@google.com>, Rajkumar Manoharan <rmanohar@codeaurora.org>, Kevin Hayes <kevinhayes@google.com> Subject: [PATCH v9 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Date: Fri, 15 Nov 2019 14:20:41 +0100 [thread overview] Message-ID: <157382404118.580235.14216392299709793599.stgit@toke.dk> (raw) In-Reply-To: <157382403672.580235.12525941420808058808.stgit@toke.dk> From: Toke Høiland-Jørgensen <toke@redhat.com> 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> --- include/net/mac80211.h | 16 ++++++++++++++++ net/mac80211/status.c | 26 ++++++++++++++++++++++++++ net/mac80211/tx.c | 18 ++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index ba3f33cc41ea..dcb4a1f19829 100644 --- 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; +} + +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 status info for rate control * diff --git a/net/mac80211/status.c b/net/mac80211/status.c index 0e51def35b8a..39da82b35be9 100644 --- a/net/mac80211/status.c +++ b/net/mac80211/status.c @@ -670,12 +670,26 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local, 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; @@ -877,6 +891,7 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, 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); @@ -986,6 +1001,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, 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 (info->flags & IEEE80211_TX_STAT_ACK) { if (sta->status_stats.lost_packets) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index aafc67b562eb..2fb6571453e7 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3551,6 +3551,9 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, WARN_ON_ONCE(softirq_count() == 0); + if (!ieee80211_txq_airtime_check(hw, txq)) + return NULL; + begin: spin_lock_bh(&fq->lock); @@ -3661,6 +3664,21 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, } 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:
WARNING: multiple messages have this Message-ID (diff)
From: "Toke Høiland-Jørgensen" <toke@redhat.com> To: Johannes Berg <johannes@sipsolutions.net> Cc: Kan Yan <kyan@google.com>, Rajkumar Manoharan <rmanohar@codeaurora.org>, Kevin Hayes <kevinhayes@google.com>, make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org, ath10k@lists.infradead.org, John Crispin <john@phrozen.org>, Lorenzo Bianconi <lorenzo@kernel.org>, Felix Fietkau <nbd@nbd.name> Subject: [PATCH v9 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Date: Fri, 15 Nov 2019 14:20:41 +0100 [thread overview] Message-ID: <157382404118.580235.14216392299709793599.stgit@toke.dk> (raw) In-Reply-To: <157382403672.580235.12525941420808058808.stgit@toke.dk> From: Toke Høiland-Jørgensen <toke@redhat.com> 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> --- include/net/mac80211.h | 16 ++++++++++++++++ net/mac80211/status.c | 26 ++++++++++++++++++++++++++ net/mac80211/tx.c | 18 ++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index ba3f33cc41ea..dcb4a1f19829 100644 --- 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; +} + +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 status info for rate control * diff --git a/net/mac80211/status.c b/net/mac80211/status.c index 0e51def35b8a..39da82b35be9 100644 --- a/net/mac80211/status.c +++ b/net/mac80211/status.c @@ -670,12 +670,26 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local, 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; @@ -877,6 +891,7 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, 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); @@ -986,6 +1001,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, 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 (info->flags & IEEE80211_TX_STAT_ACK) { if (sta->status_stats.lost_packets) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index aafc67b562eb..2fb6571453e7 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3551,6 +3551,9 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, WARN_ON_ONCE(softirq_count() == 0); + if (!ieee80211_txq_airtime_check(hw, txq)) + return NULL; + begin: spin_lock_bh(&fq->lock); @@ -3661,6 +3664,21 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, } 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: _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k
next prev parent reply other threads:[~2019-11-15 13:20 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-15 13:20 [PATCH v9 0/4] Add Airtime Queue Limits (AQL) to mac80211 Toke Høiland-Jørgensen 2019-11-15 13:20 ` Toke Høiland-Jørgensen 2019-11-15 13:20 ` [PATCH v9 1/4] mac80211: Add new sta_info getter by sta/vif addrs Toke Høiland-Jørgensen 2019-11-15 13:20 ` Toke Høiland-Jørgensen 2019-11-15 13:20 ` [PATCH v9 2/4] mac80211: Import airtime calculation code from mt76 Toke Høiland-Jørgensen 2019-11-15 13:20 ` Toke Høiland-Jørgensen 2019-11-15 13:20 ` [PATCH v9 3/4] mac80211: Implement Airtime-based Queue Limit (AQL) Toke Høiland-Jørgensen 2019-11-15 13:20 ` Toke Høiland-Jørgensen 2019-11-18 23:12 ` Kan Yan 2019-11-18 23:12 ` Kan Yan 2019-11-15 13:20 ` Toke Høiland-Jørgensen [this message] 2019-11-15 13:20 ` [PATCH v9 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Toke Høiland-Jørgensen 2019-11-16 2:51 ` Kan Yan 2019-11-16 2:51 ` Kan Yan 2019-11-16 11:55 ` Toke Høiland-Jørgensen 2019-11-16 11:55 ` Toke Høiland-Jørgensen 2019-11-17 20:24 ` Kan Yan 2019-11-17 20:24 ` Kan Yan 2019-11-18 10:10 ` Toke Høiland-Jørgensen 2019-11-18 10:10 ` Toke Høiland-Jørgensen
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