mac80211: add a few performance improvement patches
authorFelix Fietkau <nbd@nbd.name>
Sat, 16 Mar 2019 18:50:44 +0000 (19:50 +0100)
committerFelix Fietkau <nbd@nbd.name>
Sat, 16 Mar 2019 18:59:02 +0000 (19:59 +0100)
Signed-off-by: Felix Fietkau <nbd@nbd.name>
package/kernel/mac80211/patches/subsys/353-mac80211-mesh-drop-redundant-rcu_read_lock-unlock-ca.patch [new file with mode: 0644]
package/kernel/mac80211/patches/subsys/354-mac80211-calculate-hash-for-fq-without-holding-fq-lo.patch [new file with mode: 0644]
package/kernel/mac80211/patches/subsys/355-mac80211-run-late-dequeue-late-tx-handlers-without-h.patch [new file with mode: 0644]
package/kernel/mac80211/patches/subsys/356-mac80211-set-NETIF_F_LLTX-when-using-intermediate-tx.patch [new file with mode: 0644]

diff --git a/package/kernel/mac80211/patches/subsys/353-mac80211-mesh-drop-redundant-rcu_read_lock-unlock-ca.patch b/package/kernel/mac80211/patches/subsys/353-mac80211-mesh-drop-redundant-rcu_read_lock-unlock-ca.patch
new file mode 100644 (file)
index 0000000..ae5be18
--- /dev/null
@@ -0,0 +1,96 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 16 Mar 2019 17:43:58 +0100
+Subject: [PATCH] mac80211: mesh: drop redundant rcu_read_lock/unlock calls
+
+The callers of these functions are all within RCU locked sections
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/mesh_hwmp.c
++++ b/net/mac80211/mesh_hwmp.c
+@@ -1112,16 +1112,13 @@ int mesh_nexthop_resolve(struct ieee8021
+       struct mesh_path *mpath;
+       struct sk_buff *skb_to_free = NULL;
+       u8 *target_addr = hdr->addr3;
+-      int err = 0;
+       /* Nulls are only sent to peers for PS and should be pre-addressed */
+       if (ieee80211_is_qos_nullfunc(hdr->frame_control))
+               return 0;
+-      rcu_read_lock();
+-      err = mesh_nexthop_lookup(sdata, skb);
+-      if (!err)
+-              goto endlookup;
++      if (!mesh_nexthop_lookup(sdata, skb))
++              return 0;
+       /* no nexthop found, start resolving */
+       mpath = mesh_path_lookup(sdata, target_addr);
+@@ -1129,8 +1126,7 @@ int mesh_nexthop_resolve(struct ieee8021
+               mpath = mesh_path_add(sdata, target_addr);
+               if (IS_ERR(mpath)) {
+                       mesh_path_discard_frame(sdata, skb);
+-                      err = PTR_ERR(mpath);
+-                      goto endlookup;
++                      return PTR_ERR(mpath);
+               }
+       }
+@@ -1143,13 +1139,10 @@ int mesh_nexthop_resolve(struct ieee8021
+       info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
+       ieee80211_set_qos_hdr(sdata, skb);
+       skb_queue_tail(&mpath->frame_queue, skb);
+-      err = -ENOENT;
+       if (skb_to_free)
+               mesh_path_discard_frame(sdata, skb_to_free);
+-endlookup:
+-      rcu_read_unlock();
+-      return err;
++      return -ENOENT;
+ }
+ /**
+@@ -1169,13 +1162,10 @@ int mesh_nexthop_lookup(struct ieee80211
+       struct sta_info *next_hop;
+       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+       u8 *target_addr = hdr->addr3;
+-      int err = -ENOENT;
+-      rcu_read_lock();
+       mpath = mesh_path_lookup(sdata, target_addr);
+-
+       if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
+-              goto endlookup;
++              return -ENOENT;
+       if (time_after(jiffies,
+                      mpath->exp_time -
+@@ -1190,12 +1180,10 @@ int mesh_nexthop_lookup(struct ieee80211
+               memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
+               memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
+               ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
+-              err = 0;
++              return 0;
+       }
+-endlookup:
+-      rcu_read_unlock();
+-      return err;
++      return -ENOENT;
+ }
+ void mesh_path_timer(struct timer_list *t)
+--- a/net/mac80211/mesh_pathtbl.c
++++ b/net/mac80211/mesh_pathtbl.c
+@@ -217,7 +217,7 @@ static struct mesh_path *mpath_lookup(st
+ {
+       struct mesh_path *mpath;
+-      mpath = rhashtable_lookup_fast(&tbl->rhead, dst, mesh_rht_params);
++      mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
+       if (mpath && mpath_expired(mpath)) {
+               spin_lock_bh(&mpath->state_lock);
diff --git a/package/kernel/mac80211/patches/subsys/354-mac80211-calculate-hash-for-fq-without-holding-fq-lo.patch b/package/kernel/mac80211/patches/subsys/354-mac80211-calculate-hash-for-fq-without-holding-fq-lo.patch
new file mode 100644 (file)
index 0000000..2b6d8ab
--- /dev/null
@@ -0,0 +1,124 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 16 Mar 2019 17:57:38 +0100
+Subject: [PATCH] mac80211: calculate hash for fq without holding fq->lock
+ in itxq enqueue
+
+Reduces lock contention on enqueue/dequeue of iTXQ packets
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/fq_impl.h
++++ b/include/net/fq_impl.h
+@@ -107,21 +107,23 @@ begin:
+       return skb;
+ }
++static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
++{
++      u32 hash = skb_get_hash_perturb(skb, fq->perturbation);
++
++      return reciprocal_scale(hash, fq->flows_cnt);
++}
++
+ static struct fq_flow *fq_flow_classify(struct fq *fq,
+-                                      struct fq_tin *tin,
++                                      struct fq_tin *tin, u32 idx,
+                                       struct sk_buff *skb,
+                                       fq_flow_get_default_t get_default_func)
+ {
+       struct fq_flow *flow;
+-      u32 hash;
+-      u32 idx;
+       lockdep_assert_held(&fq->lock);
+-      hash = skb_get_hash_perturb(skb, fq->perturbation);
+-      idx = reciprocal_scale(hash, fq->flows_cnt);
+       flow = &fq->flows[idx];
+-
+       if (flow->tin && flow->tin != tin) {
+               flow = get_default_func(fq, tin, idx, skb);
+               tin->collisions++;
+@@ -153,7 +155,7 @@ static void fq_recalc_backlog(struct fq
+ }
+ static void fq_tin_enqueue(struct fq *fq,
+-                         struct fq_tin *tin,
++                         struct fq_tin *tin, u32 idx,
+                          struct sk_buff *skb,
+                          fq_skb_free_t free_func,
+                          fq_flow_get_default_t get_default_func)
+@@ -163,7 +165,7 @@ static void fq_tin_enqueue(struct fq *fq
+       lockdep_assert_held(&fq->lock);
+-      flow = fq_flow_classify(fq, tin, skb, get_default_func);
++      flow = fq_flow_classify(fq, tin, idx, skb, get_default_func);
+       flow->tin = tin;
+       flow->backlog += skb->len;
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -1390,11 +1390,15 @@ static void ieee80211_txq_enqueue(struct
+ {
+       struct fq *fq = &local->fq;
+       struct fq_tin *tin = &txqi->tin;
++      u32 flow_idx = fq_flow_idx(fq, skb);
+       ieee80211_set_skb_enqueue_time(skb);
+-      fq_tin_enqueue(fq, tin, skb,
++
++      spin_lock_bh(&fq->lock);
++      fq_tin_enqueue(fq, tin, flow_idx, skb,
+                      fq_skb_free_func,
+                      fq_flow_get_default_func);
++      spin_unlock_bh(&fq->lock);
+ }
+ static bool fq_vlan_filter_func(struct fq *fq, struct fq_tin *tin,
+@@ -1564,7 +1568,6 @@ static bool ieee80211_queue_skb(struct i
+                               struct sta_info *sta,
+                               struct sk_buff *skb)
+ {
+-      struct fq *fq = &local->fq;
+       struct ieee80211_vif *vif;
+       struct txq_info *txqi;
+@@ -1582,9 +1585,7 @@ static bool ieee80211_queue_skb(struct i
+       if (!txqi)
+               return false;
+-      spin_lock_bh(&fq->lock);
+       ieee80211_txq_enqueue(local, txqi, skb);
+-      spin_unlock_bh(&fq->lock);
+       schedule_and_wake_txq(local, txqi);
+@@ -3198,6 +3199,7 @@ static bool ieee80211_amsdu_aggregate(st
+       u8 max_subframes = sta->sta.max_amsdu_subframes;
+       int max_frags = local->hw.max_tx_fragments;
+       int max_amsdu_len = sta->sta.max_amsdu_len;
++      u32 flow_idx;
+       int orig_truesize;
+       __be16 len;
+       void *data;
+@@ -3220,6 +3222,8 @@ static bool ieee80211_amsdu_aggregate(st
+               max_amsdu_len = min_t(int, max_amsdu_len,
+                                     sta->sta.max_rc_amsdu_len);
++      flow_idx = fq_flow_idx(fq, skb);
++
+       spin_lock_bh(&fq->lock);
+       /* TODO: Ideally aggregation should be done on dequeue to remain
+@@ -3227,7 +3231,8 @@ static bool ieee80211_amsdu_aggregate(st
+        */
+       tin = &txqi->tin;
+-      flow = fq_flow_classify(fq, tin, skb, fq_flow_get_default_func);
++      flow = fq_flow_classify(fq, tin, flow_idx, skb,
++                              fq_flow_get_default_func);
+       head = skb_peek_tail(&flow->queue);
+       if (!head)
+               goto unlock;
diff --git a/package/kernel/mac80211/patches/subsys/355-mac80211-run-late-dequeue-late-tx-handlers-without-h.patch b/package/kernel/mac80211/patches/subsys/355-mac80211-run-late-dequeue-late-tx-handlers-without-h.patch
new file mode 100644 (file)
index 0000000..3127c86
--- /dev/null
@@ -0,0 +1,55 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 16 Mar 2019 18:00:12 +0100
+Subject: [PATCH] mac80211: run late dequeue late tx handlers without
+ holding fq->lock
+
+Reduces lock contention on enqueue/dequeue of iTXQ packets
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3507,6 +3507,7 @@ struct sk_buff *ieee80211_tx_dequeue(str
+       ieee80211_tx_result r;
+       struct ieee80211_vif *vif = txq->vif;
++begin:
+       spin_lock_bh(&fq->lock);
+       if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags) ||
+@@ -3523,11 +3524,12 @@ struct sk_buff *ieee80211_tx_dequeue(str
+       if (skb)
+               goto out;
+-begin:
+       skb = fq_tin_dequeue(fq, tin, fq_tin_dequeue_func);
+       if (!skb)
+               goto out;
++      spin_unlock_bh(&fq->lock);
++
+       hdr = (struct ieee80211_hdr *)skb->data;
+       info = IEEE80211_SKB_CB(skb);
+@@ -3573,8 +3575,11 @@ begin:
+               skb = __skb_dequeue(&tx.skbs);
+-              if (!skb_queue_empty(&tx.skbs))
++              if (!skb_queue_empty(&tx.skbs)) {
++                      spin_lock_bh(&fq->lock);
+                       skb_queue_splice_tail(&tx.skbs, &txqi->frags);
++                      spin_unlock_bh(&fq->lock);
++              }
+       }
+       if (skb && skb_has_frag_list(skb) &&
+@@ -3613,6 +3618,7 @@ begin:
+       }
+       IEEE80211_SKB_CB(skb)->control.vif = vif;
++      return skb;
+ out:
+       spin_unlock_bh(&fq->lock);
diff --git a/package/kernel/mac80211/patches/subsys/356-mac80211-set-NETIF_F_LLTX-when-using-intermediate-tx.patch b/package/kernel/mac80211/patches/subsys/356-mac80211-set-NETIF_F_LLTX-when-using-intermediate-tx.patch
new file mode 100644 (file)
index 0000000..95ab3ab
--- /dev/null
@@ -0,0 +1,22 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 16 Mar 2019 18:01:53 +0100
+Subject: [PATCH] mac80211: set NETIF_F_LLTX when using intermediate tx
+ queues
+
+When using iTXQ, tx sequence number allocation and statistics are run at
+dequeue time. Because of that, it is safe to enable NETIF_F_LLTX, which
+allows tx handlers to run on multiple CPUs in parallel.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/iface.c
++++ b/net/mac80211/iface.c
+@@ -1301,6 +1301,7 @@ static void ieee80211_if_setup(struct ne
+ static void ieee80211_if_setup_no_queue(struct net_device *dev)
+ {
+       ieee80211_if_setup(dev);
++      dev->features |= NETIF_F_LLTX;
+ #if LINUX_VERSION_IS_GEQ(4,3,0)
+       dev->priv_flags |= IFF_NO_QUEUE;
+ #else