mac80211: enable collecting station statistics per-CPU

If the driver advertises the new HW flag USE_RSS, make the
station statistics on the fast-rx path per-CPU. This will
enable calling the RX in parallel, only hitting locking or
shared cachelines when the fast-RX path isn't available.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 92 insertions, 16 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index a0ce7e4..cf2aca0 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -254,6 +254,7 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 #ifdef CONFIG_MAC80211_MESH
 	kfree(sta->mesh);
 #endif
+	free_percpu(sta->pcpu_rx_stats);
 	kfree(sta);
 }
 
@@ -311,6 +312,13 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 	if (!sta)
 		return NULL;
 
+	if (ieee80211_hw_check(hw, USES_RSS)) {
+		sta->pcpu_rx_stats =
+			alloc_percpu(struct ieee80211_sta_rx_stats);
+		if (!sta->pcpu_rx_stats)
+			goto free;
+	}
+
 	spin_lock_init(&sta->lock);
 	spin_lock_init(&sta->ps_lock);
 	INIT_WORK(&sta->drv_deliver_wk, sta_deliver_ps_frames);
@@ -1932,6 +1940,28 @@ u8 sta_info_tx_streams(struct sta_info *sta)
 			>> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
 }
 
+static struct ieee80211_sta_rx_stats *
+sta_get_last_rx_stats(struct sta_info *sta)
+{
+	struct ieee80211_sta_rx_stats *stats = &sta->rx_stats;
+	struct ieee80211_local *local = sta->local;
+	int cpu;
+
+	if (!ieee80211_hw_check(&local->hw, USES_RSS))
+		return stats;
+
+	for_each_possible_cpu(cpu) {
+		struct ieee80211_sta_rx_stats *cpustats;
+
+		cpustats = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+
+		if (time_after(cpustats->last_rx, stats->last_rx))
+			stats = cpustats;
+	}
+
+	return stats;
+}
+
 static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
 				  struct rate_info *rinfo)
 {
@@ -1967,7 +1997,7 @@ static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
 
 static void sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
 {
-	u16 rate = ACCESS_ONCE(sta->rx_stats.last_rate);
+	u16 rate = ACCESS_ONCE(sta_get_last_rx_stats(sta)->last_rate);
 
 	if (rate == STA_STATS_RATE_INVALID)
 		rinfo->flags = 0;
@@ -2010,13 +2040,29 @@ static void sta_set_tidstats(struct sta_info *sta,
 	}
 }
 
+static inline u64 sta_get_stats_bytes(struct ieee80211_sta_rx_stats *rxstats)
+{
+	unsigned int start;
+	u64 value;
+
+	do {
+		start = u64_stats_fetch_begin(&rxstats->syncp);
+		value = rxstats->bytes;
+	} while (u64_stats_fetch_retry(&rxstats->syncp, start));
+
+	return value;
+}
+
 void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	struct ieee80211_local *local = sdata->local;
 	struct rate_control_ref *ref = NULL;
 	u32 thr = 0;
-	int i, ac;
+	int i, ac, cpu;
+	struct ieee80211_sta_rx_stats *last_rxstats;
+
+	last_rxstats = sta_get_last_rx_stats(sta);
 
 	if (test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
 		ref = local->rate_ctrl;
@@ -2064,17 +2110,30 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 
 	if (!(sinfo->filled & (BIT(NL80211_STA_INFO_RX_BYTES64) |
 			       BIT(NL80211_STA_INFO_RX_BYTES)))) {
-		unsigned int start;
+		sinfo->rx_bytes += sta_get_stats_bytes(&sta->rx_stats);
+
+		if (sta->pcpu_rx_stats) {
+			for_each_possible_cpu(cpu) {
+				struct ieee80211_sta_rx_stats *cpurxs;
+
+				cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+				sinfo->rx_bytes += sta_get_stats_bytes(cpurxs);
+			}
+		}
 
-		do {
-			start = u64_stats_fetch_begin(&sta->rx_stats.syncp);
-			sinfo->rx_bytes = sta->rx_stats.bytes;
-		} while (u64_stats_fetch_retry(&sta->rx_stats.syncp, start));
 		sinfo->filled |= BIT(NL80211_STA_INFO_RX_BYTES64);
 	}
 
 	if (!(sinfo->filled & BIT(NL80211_STA_INFO_RX_PACKETS))) {
 		sinfo->rx_packets = sta->rx_stats.packets;
+		if (sta->pcpu_rx_stats) {
+			for_each_possible_cpu(cpu) {
+				struct ieee80211_sta_rx_stats *cpurxs;
+
+				cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+				sinfo->rx_packets += cpurxs->packets;
+			}
+		}
 		sinfo->filled |= BIT(NL80211_STA_INFO_RX_PACKETS);
 	}
 
@@ -2089,6 +2148,14 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 	}
 
 	sinfo->rx_dropped_misc = sta->rx_stats.dropped;
+	if (sta->pcpu_rx_stats) {
+		for_each_possible_cpu(cpu) {
+			struct ieee80211_sta_rx_stats *cpurxs;
+
+			cpurxs = per_cpu_ptr(sta->pcpu_rx_stats, cpu);
+			sinfo->rx_packets += cpurxs->dropped;
+		}
+	}
 
 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 	    !(sdata->vif.driver_flags & IEEE80211_VIF_BEACON_FILTER)) {
@@ -2100,27 +2167,34 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 	if (ieee80211_hw_check(&sta->local->hw, SIGNAL_DBM) ||
 	    ieee80211_hw_check(&sta->local->hw, SIGNAL_UNSPEC)) {
 		if (!(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL))) {
-			sinfo->signal = (s8)sta->rx_stats.last_signal;
+			sinfo->signal = (s8)last_rxstats->last_signal;
 			sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL);
 		}
 
-		if (!(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL_AVG))) {
+		if (!sta->pcpu_rx_stats &&
+		    !(sinfo->filled & BIT(NL80211_STA_INFO_SIGNAL_AVG))) {
 			sinfo->signal_avg =
 				-ewma_signal_read(&sta->rx_stats_avg.signal);
 			sinfo->filled |= BIT(NL80211_STA_INFO_SIGNAL_AVG);
 		}
 	}
 
-	if (sta->rx_stats.chains &&
+	/* for the average - if pcpu_rx_stats isn't set - rxstats must point to
+	 * the sta->rx_stats struct, so the check here is fine with and without
+	 * pcpu statistics
+	 */
+	if (last_rxstats->chains &&
 	    !(sinfo->filled & (BIT(NL80211_STA_INFO_CHAIN_SIGNAL) |
 			       BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG)))) {
-		sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL) |
-				 BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG);
+		sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL);
+		if (!sta->pcpu_rx_stats)
+			sinfo->filled |= BIT(NL80211_STA_INFO_CHAIN_SIGNAL_AVG);
+
+		sinfo->chains = last_rxstats->chains;
 
-		sinfo->chains = sta->rx_stats.chains;
 		for (i = 0; i < ARRAY_SIZE(sinfo->chain_signal); i++) {
 			sinfo->chain_signal[i] =
-				sta->rx_stats.chain_signal_last[i];
+				last_rxstats->chain_signal_last[i];
 			sinfo->chain_signal_avg[i] =
 				-ewma_signal_read(&sta->rx_stats_avg.chain_signal[i]);
 		}
@@ -2213,7 +2287,9 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 
 unsigned long ieee80211_sta_last_active(struct sta_info *sta)
 {
-	if (time_after(sta->rx_stats.last_rx, sta->status_stats.last_ack))
-		return sta->rx_stats.last_rx;
+	struct ieee80211_sta_rx_stats *stats = sta_get_last_rx_stats(sta);
+
+	if (time_after(stats->last_rx, sta->status_stats.last_ack))
+		return stats->last_rx;
 	return sta->status_stats.last_ack;
 }