On 2019-09-18 05:24, Toke Høiland-Jørgensen wrote:
Yibo Zhao <yiboz@xxxxxxxxxxxxxx> writes:
Global airtime weight sum is updated only when txq is added/removed
from rbtree. If upper layer configures sta weight during high load,
airtime weight sum will not be updated since txq is most likely on the
tree. It could a little late for upper layer to reconfigure sta weight
when txq is already in the rbtree. And thus, incorrect airtime weight
sum
will lead to incorrect global virtual time calculation as well as
global
airtime weight sum overflow of airtime weight sum during txq removed.
Hence, need to update airtime weight sum upon receiving event for
configuring sta weight once sta's txq is on the rbtree.
Besides, if airtime weight sum of ACs and sta weight is synced under
the
same per AC lock protection, there can be a very short window causing
incorrct airtime weight sum calculation as below:
active_txq_lock_VO .
VO weight sum is syncd .
sta airtime weight sum is synced .
active_txq_unlock_VO .
. .
active_txq_lock_VI .
VI weight sum is syncd .
sta airtime weight sum active_txq_lock_BE
active_txq_unlock_VI Remove txq and thus sum
. is calculated with synced
. sta airtime weight
. active_txq_unlock_BE
So introduce a per ac synced station airtime weight synced with per
AC synced weight sum together. And the per-AC station airtime weight
is used to calculate weight sum.
Signed-off-by: Yibo Zhao <yiboz@xxxxxxxxxxxxxx>
---
net/mac80211/cfg.c | 27 +++++++++++++++++++++++++--
net/mac80211/sta_info.c | 6 ++++--
net/mac80211/sta_info.h | 3 +++
net/mac80211/tx.c | 4 ++--
4 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index d65aa01..4b420bb 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1284,7 +1284,8 @@ static int sta_apply_parameters(struct
ieee80211_local *local,
int ret = 0;
struct ieee80211_supported_band *sband;
struct ieee80211_sub_if_data *sdata = sta->sdata;
- u32 mask, set;
+ u32 mask, set, tid, ac;
+ struct txq_info *txqi;
sband = ieee80211_get_sband(sdata);
if (!sband)
@@ -1452,8 +1453,30 @@ static int sta_apply_parameters(struct
ieee80211_local *local,
if (ieee80211_vif_is_mesh(&sdata->vif))
sta_apply_mesh_params(local, sta, params);
- if (params->airtime_weight)
+ if (params->airtime_weight &&
+ params->airtime_weight != sta->airtime_weight) {
+ for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
+ spin_lock_bh(&local->active_txq_lock[ac]);
+ for (tid = 0; tid < IEEE80211_NUM_TIDS + 1; tid++) {
+ if (!sta->sta.txq[tid] ||
+ ac != ieee80211_ac_from_tid(tid))
+ continue;
+
+ sta->airtime_weight_synced[ac] =
+ params->airtime_weight;
+
+ txqi = to_txq_info(sta->sta.txq[tid]);
+ if (RB_EMPTY_NODE(&txqi->schedule_order))
+ continue;
+
+ local->airtime_weight_sum[ac] = local->airtime_weight_sum[ac] +
+ params->airtime_weight -
+ sta->airtime_weight;
+ }
+ spin_unlock_bh(&local->active_txq_lock[ac]);
+ }
sta->airtime_weight = params->airtime_weight;
With this, airtime_weight is basically only used to return to and from
userspace, right? I.e., after the above loop has run, it will match the
contents of airtime_weight_synced; so why not just turn airtime_weight
into a per-ac array? You could just use airtime_weight[0] as the value
to return to userspace...
Yes, I also feel it is a little weird to keep both of them. I am fine
with suggestion.
-Toke
--
Yibo
