On Thu, Oct 26, 2017 at 11:41:03AM +0200, Jiri Pirko wrote: > From: Jiri Pirko <[email protected]> > > In sch_handle_egress and sch_handle_ingress tp->q is used only in order > to update stats. So stats and filter list are the only things that are > needed in clsact qdisc fastpath processing. Introduce new mini_Qdisc > struct to hold those items. This removes need for tp->q usage without > added overhead.
that is false claim. The patch adds run-time overhead instead. > Signed-off-by: Jiri Pirko <[email protected]> > --- > v1->v2: > - Use dev instead of skb->dev in sch_handle_egress as pointed out by Daniel > - Fixed synchronize_rcu_bh() in mini_qdisc_disable and commented ... > diff --git a/net/core/dev.c b/net/core/dev.c > index 24ac908..44ea1c3 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -3274,14 +3274,16 @@ EXPORT_SYMBOL(dev_loopback_xmit); > static struct sk_buff * > sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev) > { > - struct tcf_proto *cl = rcu_dereference_bh(dev->egress_cl_list); > + struct mini_Qdisc *miniq = rcu_dereference_bh(dev->miniq_egress); > struct tcf_result cl_res; > + struct tcf_proto *cl; > > - if (!cl) > + if (!miniq) > return skb; > + cl = rcu_dereference_bh(miniq->filter_list); Just like Daniel pointed out in the earlier version of the patch it adds another rcu dereference to critical path of execution for every packet... > @@ -4189,16 +4191,19 @@ sch_handle_ingress(struct sk_buff *skb, struct > packet_type **pt_prev, int *ret, > struct net_device *orig_dev) > { > #ifdef CONFIG_NET_CLS_ACT > - struct tcf_proto *cl = rcu_dereference_bh(skb->dev->ingress_cl_list); > + struct mini_Qdisc *miniq = rcu_dereference_bh(skb->dev->miniq_ingress); > struct tcf_result cl_res; > + struct tcf_proto *cl; > > /* If there's at least one ingress present somewhere (so > * we get here via enabled static key), remaining devices > * that are not configured with an ingress qdisc will bail > * out here. > */ > - if (!cl) > + if (!miniq) > return skb; > + cl = rcu_dereference_bh(miniq->filter_list); ... both ingress and egress paths. There gotta be very strong reasons to penalize all users for this and I don't see them in commit log.
