Thread (38 messages) 38 messages, 4 authors, 2018-09-13

Re: [PATCH RFC v3 2/4] mac80211: Add airtime accounting and scheduling to TXQs

From: Rajkumar Manoharan <hidden>
Date: 2018-09-12 21:29:06

On 2018-09-12 04:10, Toke Høiland-Jørgensen wrote:
Rajkumar Manoharan [off-list ref] writes:
quoted
On 2018-09-10 04:13, Toke Høiland-Jørgensen wrote:
quoted
Johannes Berg [off-list ref] writes:
quoted
quoted
-			       txqi->flags & (1<<IEEE80211_TXQ_STOP) ? "STOP" : "RUN",
-			       txqi->flags & (1<<IEEE80211_TXQ_AMPDU) ? " AMPDU" : "",
-			       txqi->flags & (1<<IEEE80211_TXQ_NO_AMSDU) ? " NO-AMSDU" 
:
"");
+			       txqi->flags & (1 << IEEE80211_TXQ_STOP) ? "STOP" : 
"RUN",
+			       txqi->flags & (1 << IEEE80211_TXQ_AMPDU) ? " AMPDU" : 
"",
+			       txqi->flags & (1 << IEEE80211_TXQ_NO_AMSDU) ? " 
NO-AMSDU"
: "");
consider BIT() instead as a cleanup? :)

(or maybe this is just a leftover from merging some other patches?)
Yeah, this is a merging artifact; Rajkumar's patch added another 
flag,
that I removed again. Didn't notice that there was still a whitespace
change in this patch...
I added the flag based on our last discussion. The driver needs to 
check
txq status for each tx_dequeue(). One time txq check is not sufficient
as it allows the driver to dequeue all frames from txq.

drv_func() {
       while (ieee80211_airtime_may_transmit(txq) &&
               hw_has_space() &&
              (pkt = ieee80211_tx_dequeue(hw, txq)))
           push_to_hw(pkt);
}
Yeah, but with airtime only being recorded on TX completion, the odds 
of
the value changing within that loop are quite low; so it's not going to
work, which is why I removed it.

However, after reading Kan's patches I get where you're coming from; a
check in tx_dequeue() is needed for the BQL-style queue limiting. Will
try to incorporate a version of that in the next series so you can see
what I mean when I say it should be orthogonal; and I'm still not sure
it needs a flag :)
Got it.. Will wait for next version.. thanks.
quoted
quoted
quoted
quoted
+bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw,
+				struct ieee80211_txq *txq)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct txq_info *txqi = to_txq_info(txq);
+	bool may_tx = false;
+
+	spin_lock_bh(&local->active_txq_lock);
+
+	if (ieee80211_txq_check_deficit(local, txqi)) {
+		may_tx = true;
+		list_del_init(&txqi->schedule_order);
To handle above case, may_transmit should remove the node only
when it is in list.

if (list_empty(&txqi->schedule_order))
        list_del_init(&txqi->schedule_order);
I assume you missed a ! in that if, right? :)
Oops.. yes it should be ! :)

-Rajkumar
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help