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authorFelix Fietkau <nbd@openwrt.org>2012-03-19 01:58:06 +0400
committerJohn W. Linville <linville@tuxdriver.com>2012-04-10 00:09:36 +0400
commit12d3952fc4a1cd96234bc7023bf7eefeb0bb6355 (patch)
tree5c3437e1f996a5c772b286530a3fce547a7d40f2 /net/mac80211/agg-rx.c
parentfcb2c9e1025cd529890303ffbde813a98cdffed4 (diff)
downloadlinux-12d3952fc4a1cd96234bc7023bf7eefeb0bb6355.tar.xz
mac80211: optimize aggregation session timeout handling
Calling mod_timer from the rx/tx hotpath is somewhat expensive, and the timeout doesn't need to be so precise. Switch to a different strategy: Schedule the timer initially, store jiffies of all last rx/tx activity which would previously modify the timer, and let the timer re-arm itself after checking the last rx/tx timestamp. Make the session timers deferrable to avoid causing extra wakeups on systems running on battery. This visibly reduces CPU load under high network load on small embedded systems. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/mac80211/agg-rx.c')
-rw-r--r--net/mac80211/agg-rx.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 64d3ce5ea1a0..a070d4f460ea 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -142,6 +142,18 @@ static void sta_rx_agg_session_timer_expired(unsigned long data)
u8 *timer_to_id = ptid - *ptid;
struct sta_info *sta = container_of(timer_to_id, struct sta_info,
timer_to_tid[0]);
+ struct tid_ampdu_rx *tid_rx;
+ unsigned long timeout;
+
+ tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[*ptid]);
+ if (!tid_rx)
+ return;
+
+ timeout = tid_rx->last_rx + TU_TO_JIFFIES(tid_rx->timeout);
+ if (time_is_after_jiffies(timeout)) {
+ mod_timer(&tid_rx->session_timer, timeout);
+ return;
+ }
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
@@ -291,7 +303,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
/* rx timer */
tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
- init_timer(&tid_agg_rx->session_timer);
+ init_timer_deferrable(&tid_agg_rx->session_timer);
/* rx reorder timer */
tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
@@ -335,8 +347,10 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
/* activate it for RX */
rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
- if (timeout)
+ if (timeout) {
mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
+ tid_agg_rx->last_rx = jiffies;
+ }
end:
mutex_unlock(&sta->ampdu_mlme.mtx);