From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
The sta_info hash is designed to deal with an AP
with lots of stations associated, or a station interface
connected to a single AP.
However, when you have lots of station VIFs connected
to the same AP, the sta_info hash becomes worthless
as there is a single hash bucket that contains all the
entries in a linked list.
So, have the sdata object cache one of it's station
interfaces. If we are a station VIF with a single
sta_info, then this means we can ignore the sta_info
hash entirely.
On a test case with 128 stations and 50 TCP streams,
tx performance went from around 80Mbps to 124Mbps.
Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
---
:100644 100644 a618bda... 5288a4f... M net/mac80211/cfg.c
:100644 100644 493e2e8... fe5d35b... M net/mac80211/ieee80211_i.h
:100644 100644 415f9c6... 74d58f4... M net/mac80211/sta_info.c
net/mac80211/cfg.c | 5 +++++
net/mac80211/ieee80211_i.h | 6 ++++++
net/mac80211/sta_info.c | 18 +++++++++++++++++-
3 files changed, 28 insertions(+), 1 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index a618bda..5288a4f 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1287,6 +1287,7 @@ static int ieee80211_change_station(struct wiphy *wiphy,
if (params->vlan && params->vlan != sta->sdata->dev) {
bool prev_4addr = false;
bool new_4addr = false;
+ struct sta_info *some_sta;
vlansdata = IEEE80211_DEV_TO_SUB_IF(params->vlan);
@@ -1312,7 +1313,11 @@ static int ieee80211_change_station(struct wiphy *wiphy,
prev_4addr = true;
}
+ some_sta = rcu_dereference(sta->sdata->some_sta);
+ if (some_sta == sta)
+ rcu_assign_pointer(sta->sdata->some_sta, NULL);
sta->sdata = vlansdata;
+ rcu_assign_pointer(sta->sdata->some_sta, sta);
if (sta->sta_state == IEEE80211_STA_AUTHORIZED &&
prev_4addr != new_4addr) {
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 493e2e8..fe5d35b 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -669,6 +669,12 @@ struct ieee80211_sub_if_data {
/* count for keys needing tailroom space allocation */
int crypto_tx_tailroom_needed_cnt;
+ /* A pointer to some station associated with this interface, or
+ * NULL. This aids oportunistic lookup for sta_info objects when
+ * sdata is a station with a single sta_info.
+ */
+ struct sta_info __rcu *some_sta;
+
struct net_device *dev;
struct ieee80211_local *local;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 415f9c6..74d58f4 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -193,7 +193,17 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
const u8 *addr)
{
struct ieee80211_local *local = sdata->local;
- struct sta_info *sta;
+ struct sta_info *sta, *some_sta;
+
+ /* Shortcut for finding station entries when sdata is a station */
+ some_sta = rcu_dereference(sdata->some_sta);
+ if (some_sta) {
+ if (WARN_ON(some_sta->sdata != sdata))
+ rcu_assign_pointer(sdata->some_sta, NULL);
+ else
+ if (ether_addr_equal(some_sta->sta.addr, addr))
+ return some_sta;
+ }
sta = rcu_dereference_check(local->sta_hash[STA_HASH(addr)],
lockdep_is_held(&local->sta_mtx));
@@ -263,10 +273,14 @@ struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
*/
void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
{
+ struct sta_info* some_sta;
if (sta->rate_ctrl)
rate_control_free_sta(sta);
sta_dbg(sta->sdata, "Destroyed STA %pM\n", sta->sta.addr);
+ some_sta = rcu_dereference(sta->sdata->some_sta);
+ if (some_sta == sta)
+ rcu_assign_pointer(sta->sdata->some_sta, NULL);
kfree(sta);
}
@@ -373,6 +387,8 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
for (i = 0; i < NUM_RX_DATA_QUEUES; i++)
sta->last_seq_ctrl[i] = cpu_to_le16(USHRT_MAX);
+ rcu_assign_pointer(sta->sdata->some_sta, sta);
+
sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr);
#ifdef CONFIG_MAC80211_MESH
--
1.7.3.4
--
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