All of lore.kernel.org
 help / color / mirror / Atom feed
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 v10 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue
Date: Sat, 16 Nov 2019 12:57:21 +0100	[thread overview]
Message-ID: <157390544128.662247.18090629768427352084.stgit@toke.dk> (raw)
In-Reply-To: <157390543688.662247.3735146484299260207.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..aa145808e57a 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 << 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 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
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 v10 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue
Date: Sat, 16 Nov 2019 12:57:21 +0100	[thread overview]
Message-ID: <157390544128.662247.18090629768427352084.stgit@toke.dk> (raw)
In-Reply-To: <157390543688.662247.3735146484299260207.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..aa145808e57a 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 << 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 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

  parent reply	other threads:[~2019-11-16 11:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-16 11:57 [PATCH v10 0/4] Add Airtime Queue Limits (AQL) to mac80211 Toke Høiland-Jørgensen
2019-11-16 11:57 ` Toke Høiland-Jørgensen
2019-11-16 11:57 ` [PATCH v10 1/4] mac80211: Add new sta_info getter by sta/vif addrs Toke Høiland-Jørgensen
2019-11-16 11:57   ` Toke Høiland-Jørgensen
2019-11-16 11:57 ` [PATCH v10 2/4] mac80211: Import airtime calculation code from mt76 Toke Høiland-Jørgensen
2019-11-16 11:57   ` Toke Høiland-Jørgensen
2019-11-18 21:21   ` Kan Yan
2019-11-18 21:21     ` Kan Yan
2019-11-16 11:57 ` [PATCH v10 3/4] mac80211: Implement Airtime-based Queue Limit (AQL) Toke Høiland-Jørgensen
2019-11-16 11:57   ` Toke Høiland-Jørgensen
2019-11-16 11:57 ` Toke Høiland-Jørgensen [this message]
2019-11-16 11:57   ` [PATCH v10 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Toke Høiland-Jørgensen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=157390544128.662247.18090629768427352084.stgit@toke.dk \
    --to=toke@redhat.com \
    --cc=ath10k@lists.infradead.org \
    --cc=johannes@sipsolutions.net \
    --cc=john@phrozen.org \
    --cc=kevinhayes@google.com \
    --cc=kyan@google.com \
    --cc=linux-wireless@vger.kernel.org \
    --cc=lorenzo@kernel.org \
    --cc=make-wifi-fast@lists.bufferbloat.net \
    --cc=nbd@nbd.name \
    --cc=rmanohar@codeaurora.org \
    --subject='Re: [PATCH v10 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.