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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
@@ -107,29 +107,31 @@ begin:
return skb;
}
-static struct fq_flow *fq_flow_classify(struct fq *fq,
- struct fq_tin *tin,
- struct sk_buff *skb,
- fq_flow_get_default_t get_default_func)
+static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
{
- struct fq_flow *flow;
- u32 hash;
- u32 idx;
-
- lockdep_assert_held(&fq->lock);
-
#if LINUX_VERSION_IS_GEQ(5,3,10) || \
LINUX_VERSION_IN_RANGE(4,19,83, 4,20,0) || \
LINUX_VERSION_IN_RANGE(4,14,153, 4,15,0) || \
LINUX_VERSION_IN_RANGE(4,9,200, 4,10,0) || \
LINUX_VERSION_IN_RANGE(4,4,200, 4,5,0)
- hash = skb_get_hash_perturb(skb, &fq->perturbation);
+ u32 hash = skb_get_hash_perturb(skb, &fq->perturbation);
#else
- hash = skb_get_hash_perturb(skb, fq->perturbation);
+ u32 hash = skb_get_hash_perturb(skb, fq->perturbation);
#endif
- idx = reciprocal_scale(hash, fq->flows_cnt);
- flow = &fq->flows[idx];
+ return reciprocal_scale(hash, fq->flows_cnt);
+}
+
+static struct fq_flow *fq_flow_classify(struct fq *fq,
+ struct fq_tin *tin, u32 idx,
+ struct sk_buff *skb,
+ fq_flow_get_default_t get_default_func)
+{
+ struct fq_flow *flow;
+
+ lockdep_assert_held(&fq->lock);
+
+ flow = &fq->flows[idx];
if (flow->tin && flow->tin != tin) {
flow = get_default_func(fq, tin, idx, skb);
tin->collisions++;
@@ -161,7 +163,7 @@ 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)
@@ -171,7 +173,7 @@ 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);
@@ -3211,6 +3212,7 @@ 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;
@@ -3233,6 +3235,8 @@ 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
@@ -3240,7 +3244,8 @@ 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 out;
|
