On Fri, 2010-04-16 at 10:35 +0300, Juuso Oikarinen wrote:
> The sta_cleanup timer is used to periodically expire buffered frames from the
> tx buf. The timer is executing periodically, regardless of the need for it.
> This is wasting resources.
>
> Fix this simply by not restarting the sta_cleanup timer if the tx buffer was
> empty. Restart the timer when there is some more tx-traffic.
>
> Cc: Janne Ylälehto <janne.ylalehto@xxxxxxxxx>
> Signed-off-by: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx>
> ---
> net/mac80211/sta_info.c | 13 ++++++++++---
> net/mac80211/tx.c | 7 +++++++
> 2 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
> index ff0eb94..3de7a22 100644
> --- a/net/mac80211/sta_info.c
> +++ b/net/mac80211/sta_info.c
> @@ -575,7 +575,7 @@ static int sta_info_buffer_expired(struct sta_info *sta,
> }
>
>
> -static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
> +static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
> struct sta_info *sta)
> {
> unsigned long flags;
> @@ -583,7 +583,7 @@ static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
> struct ieee80211_sub_if_data *sdata;
>
> if (skb_queue_empty(&sta->ps_tx_buf))
> - return;
> + return false;
>
> for (;;) {
> spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
> @@ -608,6 +608,8 @@ static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
> if (skb_queue_empty(&sta->ps_tx_buf))
> sta_info_clear_tim_bit(sta);
> }
> +
> + return true;
> }
>
> static int __must_check __sta_info_destroy(struct sta_info *sta)
> @@ -755,15 +757,20 @@ static void sta_info_cleanup(unsigned long data)
> {
> struct ieee80211_local *local = (struct ieee80211_local *) data;
> struct sta_info *sta;
> + bool timer_needed = false;
>
> rcu_read_lock();
> list_for_each_entry_rcu(sta, &local->sta_list, list)
> - sta_info_cleanup_expire_buffered(local, sta);
> + if (sta_info_cleanup_expire_buffered(local, sta))
> + timer_needed = true;
> rcu_read_unlock();
>
> if (local->quiescing)
> return;
>
> + if (!timer_needed)
> + return;
> +
> local->sta_cleanup.expires =
> round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
> add_timer(&local->sta_cleanup);
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index 2cb7726..e2aa972 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -429,6 +429,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
> struct sta_info *sta = tx->sta;
> struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
> struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
> + struct ieee80211_local *local = tx->local;
> u32 staflags;
>
> if (unlikely(!sta ||
> @@ -476,6 +477,12 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
> info->control.vif = &tx->sdata->vif;
> info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
> skb_queue_tail(&sta->ps_tx_buf, tx->skb);
> +
> + if (!timer_pending(&local->sta_cleanup))
> + mod_timer(&local->sta_cleanup,
> + round_jiffies(jiffies +
> + STA_INFO_CLEANUP_INTERVAL));
> +
Why bother to check !timer_pending?
johannes
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