mac80211: implement codel on fair queuing flows
There is no other limit other than a global
packet count limit when using software queuing.
This means a single flow queue can grow insanely
long. This is particularly bad for TCP congestion
algorithms which requires a little more
sophisticated frame dropping scheme than a mere
headdrop on limit overflow.
Hence apply (a slighly modified, to fit the knobs)
CoDel5 on flow queues. This improves TCP
convergence and stability when combined with
wireless driver which keeps its own tx queue/fifo
at a minimum fill level for given link conditions.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index a8683ae..a52009f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -21,6 +21,7 @@
#include <linux/skbuff.h>
#include <linux/ieee80211.h>
#include <net/cfg80211.h>
+#include <net/codel.h>
#include <asm/unaligned.h>
/**
@@ -895,7 +896,18 @@
unsigned long jiffies;
};
/* NB: vif can be NULL for injected frames */
- struct ieee80211_vif *vif;
+ union {
+ /* NB: vif can be NULL for injected frames */
+ struct ieee80211_vif *vif;
+
+ /* When packets are enqueued on txq it's easy
+ * to re-construct the vif pointer. There's no
+ * more space in tx_info so it can be used to
+ * store the necessary enqueue time for packet
+ * sojourn time computation.
+ */
+ codel_time_t enqueue_time;
+ };
struct ieee80211_key_conf *hw_key;
u32 flags;
/* 4 bytes free */