On 07/06/16 16:05, Kevin Darbyshire-Bryant wrote:
On 07/06/16 15:50, Jonathan Morton wrote:
On 7 Jun, 2016, at 14:20, Kevin Darbyshire-Bryant
<ke...@darbyshire-bryant.me.uk> wrote:
I had a nose at CAKE but couldn't quit work out if a similar issue
is present but I suspect it is. Certainly if Eric can't get it right
"My prior attempt to fix the backlogs of parents failed." then it's
not an 'obvious to solve' problem :-)
It appears my code already handles it correctly. This is most likely
because it inherited the analogous handling from the old function
called here.
I was intrigued by how in the case of XMIT_CN he reports the backlog
without the packet just dropped 'cos the parent qdisc won't include
that length in its calculations because we reported we dropped the
packet. Preventing double accounting.
+ /* As we dropped packet(s), better let upper stack know this.
+ * If we dropped a packet for this flow, return NET_XMIT_CN,
+ * but in this case, our parents wont increase their backlogs.
+ */
+ prev_qlen -= sch->q.qlen;
+ prev_backlog -= sch->qstats.backlog;
+ if (ret == idx) {
+ qdisc_tree_reduce_backlog(sch, prev_qlen - 1,
+ prev_backlog - qdisc_pkt_len(skb)); <<<<here
+ return NET_XMIT_CN;
+ }
+ qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog);
+ return NET_XMIT_SUCCESS;
And now there's a version 2 of Eric's fix:
http://marc.info/?l=linux-netdev&m=146507012302643&w=2
Does this change apply to cake?
Cheers,
Kevin
_______________________________________________
Cake mailing list
Cake@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cake
