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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 v2 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue
Date: Tue, 15 Oct 2019 19:19:01 +0200	[thread overview]
Message-ID: <157115994190.2500430.14955682016008497593.stgit@toke.dk> (raw)
In-Reply-To: <157115993755.2500430.12214017471129215800.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>
---
 net/mac80211/status.c |   38 ++++++++++++++++++++++++++++++++++++++
 net/mac80211/tx.c     |   16 ++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index ab8ba5835ca0..ce990a1e9043 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -676,6 +676,33 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
 	if (dropped)
 		acked = false;
 
+	if (info->status.tx_time_est) {
+		struct ieee80211_sub_if_data *sdata;
+		struct sta_info *sta = NULL;
+		u8 *qc, ac;
+		int tid;
+
+		rcu_read_lock();
+
+		sdata = ieee80211_sdata_from_skb(local, skb);
+		if (sdata)
+			sta = sta_info_get_bss(sdata, skb_mac_header(skb));
+
+		if (ieee80211_is_data_qos(hdr->frame_control)) {
+			qc = ieee80211_get_qos_ctl(hdr);
+			tid = qc[0] & 0xf;
+			ac = ieee80211_ac_from_tid(tid);
+		} else {
+			ac = IEEE80211_AC_BE;
+		}
+
+		ieee80211_sta_update_pending_airtime(local, sta, ac,
+						     info->status.tx_time_est,
+						     true);
+		rcu_read_unlock();
+
+	}
+
 	if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
 		struct ieee80211_sub_if_data *sdata;
 
@@ -930,6 +957,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw,
 			tid = qc[0] & 0xf;
 		}
 
+		if (info->status.tx_time_est) {
+			/* Do this here to avoid the expensive lookup of the sta
+			 * in ieee80211_report_used_skb().
+			 */
+			ieee80211_sta_update_pending_airtime(local, sta,
+							     ieee80211_ac_from_tid(tid),
+							     info->status.tx_time_est,
+							     true);
+			info->status.tx_time_est = 0;
+		}
+
 		if (!acked && ieee80211_is_back_req(fc)) {
 			u16 control;
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 405f622b3fe0..b6b47171b340 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3539,9 +3539,14 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 	struct ieee80211_tx_data tx;
 	ieee80211_tx_result r;
 	struct ieee80211_vif *vif = txq->vif;
+	u8 ac = txq->ac;
+	u32 airtime;
 
 	WARN_ON_ONCE(softirq_count() == 0);
 
+	if (!ieee80211_txq_airtime_check(hw, txq))
+		return NULL;
+
 begin:
 	spin_lock_bh(&fq->lock);
 
@@ -3652,6 +3657,17 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 	}
 
 	IEEE80211_SKB_CB(skb)->control.vif = vif;
+
+	if (local->airtime_flags & AIRTIME_USE_AQL) {
+		airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
+							     skb->len + 38);
+		if (airtime) {
+			info->control.tx_time_est = airtime;
+			ieee80211_sta_update_pending_airtime(local, tx.sta, ac,
+							     airtime, false);
+		}
+	}
+
 	return skb;
 
 out:


WARNING: multiple messages have this Message-ID
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 v2 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue
Date: Tue, 15 Oct 2019 19:19:01 +0200	[thread overview]
Message-ID: <157115994190.2500430.14955682016008497593.stgit@toke.dk> (raw)
In-Reply-To: <157115993755.2500430.12214017471129215800.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>
---
 net/mac80211/status.c |   38 ++++++++++++++++++++++++++++++++++++++
 net/mac80211/tx.c     |   16 ++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index ab8ba5835ca0..ce990a1e9043 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -676,6 +676,33 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
 	if (dropped)
 		acked = false;
 
+	if (info->status.tx_time_est) {
+		struct ieee80211_sub_if_data *sdata;
+		struct sta_info *sta = NULL;
+		u8 *qc, ac;
+		int tid;
+
+		rcu_read_lock();
+
+		sdata = ieee80211_sdata_from_skb(local, skb);
+		if (sdata)
+			sta = sta_info_get_bss(sdata, skb_mac_header(skb));
+
+		if (ieee80211_is_data_qos(hdr->frame_control)) {
+			qc = ieee80211_get_qos_ctl(hdr);
+			tid = qc[0] & 0xf;
+			ac = ieee80211_ac_from_tid(tid);
+		} else {
+			ac = IEEE80211_AC_BE;
+		}
+
+		ieee80211_sta_update_pending_airtime(local, sta, ac,
+						     info->status.tx_time_est,
+						     true);
+		rcu_read_unlock();
+
+	}
+
 	if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
 		struct ieee80211_sub_if_data *sdata;
 
@@ -930,6 +957,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw,
 			tid = qc[0] & 0xf;
 		}
 
+		if (info->status.tx_time_est) {
+			/* Do this here to avoid the expensive lookup of the sta
+			 * in ieee80211_report_used_skb().
+			 */
+			ieee80211_sta_update_pending_airtime(local, sta,
+							     ieee80211_ac_from_tid(tid),
+							     info->status.tx_time_est,
+							     true);
+			info->status.tx_time_est = 0;
+		}
+
 		if (!acked && ieee80211_is_back_req(fc)) {
 			u16 control;
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 405f622b3fe0..b6b47171b340 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3539,9 +3539,14 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 	struct ieee80211_tx_data tx;
 	ieee80211_tx_result r;
 	struct ieee80211_vif *vif = txq->vif;
+	u8 ac = txq->ac;
+	u32 airtime;
 
 	WARN_ON_ONCE(softirq_count() == 0);
 
+	if (!ieee80211_txq_airtime_check(hw, txq))
+		return NULL;
+
 begin:
 	spin_lock_bh(&fq->lock);
 
@@ -3652,6 +3657,17 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 	}
 
 	IEEE80211_SKB_CB(skb)->control.vif = vif;
+
+	if (local->airtime_flags & AIRTIME_USE_AQL) {
+		airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
+							     skb->len + 38);
+		if (airtime) {
+			info->control.tx_time_est = airtime;
+			ieee80211_sta_update_pending_airtime(local, tx.sta, ac,
+							     airtime, false);
+		}
+	}
+
 	return skb;
 
 out:


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  parent reply	other threads:[~2019-10-15 17:19 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-15 17:18 [PATCH v2 0/4] Add Airtime Queue Limits (AQL) to mac80211 Toke Høiland-Jørgensen
2019-10-15 17:18 ` Toke Høiland-Jørgensen
2019-10-15 17:18 ` [PATCH v2 1/4] mac80211: Rearrange ieee80211_tx_info to make room for tx_time_est Toke Høiland-Jørgensen
2019-10-15 17:18   ` Toke Høiland-Jørgensen
2019-10-18  0:50   ` Kan Yan
2019-10-18  0:50     ` Kan Yan
2019-10-18 10:15     ` Toke Høiland-Jørgensen
2019-10-18 10:15       ` Toke Høiland-Jørgensen
2019-10-18 12:21       ` Johannes Berg
2019-10-18 12:21         ` Johannes Berg
2019-10-18 13:31         ` Toke Høiland-Jørgensen
2019-10-18 13:31           ` Toke Høiland-Jørgensen
2019-10-18 13:48           ` Johannes Berg
2019-10-18 13:48             ` Johannes Berg
2019-10-18 14:01             ` Toke Høiland-Jørgensen
2019-10-18 14:01               ` Toke Høiland-Jørgensen
2019-10-18 14:07               ` Johannes Berg
2019-10-18 14:07                 ` Johannes Berg
2019-10-18 14:22                 ` Toke Høiland-Jørgensen
2019-10-18 14:22                   ` Toke Høiland-Jørgensen
2019-10-18 14:14               ` Johannes Berg
2019-10-18 14:14                 ` Johannes Berg
2019-10-18 14:30                 ` Toke Høiland-Jørgensen
2019-10-18 14:30                   ` Toke Høiland-Jørgensen
2019-10-18 12:35       ` Johannes Berg
2019-10-18 12:35         ` Johannes Berg
2019-10-18 13:01         ` Ben Greear
2019-10-18 13:01           ` Ben Greear
2019-10-15 17:18 ` [PATCH v2 2/4] mac80211: Import airtime calculation code from mt76 Toke Høiland-Jørgensen
2019-10-15 17:18   ` Toke Høiland-Jørgensen
2019-10-15 17:19 ` [PATCH v2 3/4] mac80211: Implement Airtime-based Queue Limit (AQL) Toke Høiland-Jørgensen
2019-10-15 17:19   ` Toke Høiland-Jørgensen
2019-10-15 17:19 ` Toke Høiland-Jørgensen [this message]
2019-10-15 17:19   ` [PATCH v2 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Toke Høiland-Jørgensen
2019-10-17  0:33   ` Kan Yan
2019-10-17  0:33     ` Kan Yan
2019-10-17  9:44     ` Toke Høiland-Jørgensen
2019-10-17  9:44       ` Toke Høiland-Jørgensen
2019-10-17  9:57       ` [Make-wifi-fast] " Sebastian Moeller
2019-10-17  9:57         ` Sebastian Moeller
2019-10-17 10:24         ` Toke Høiland-Jørgensen
2019-10-17 10:24           ` Toke Høiland-Jørgensen
2019-10-17 10:25           ` Sebastian Moeller
2019-10-17 10:25             ` Sebastian Moeller
2019-10-18  1:11             ` Kan Yan
2019-10-18  1:11               ` Kan Yan
2019-10-18 14:15               ` Johannes Berg
2019-10-18 14:15                 ` Johannes Berg

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