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authorJiri Pirko <jiri@mellanox.com>2017-11-03 11:46:25 +0100
committerDavid S. Miller <davem@davemloft.net>2017-11-03 21:57:24 +0900
commit46209401f8f6116bd0b2c2d14a63958e83ffca0b (patch)
tree54915d3a3f2af715f1681da274e3a98f6198e71b /net/sched/sch_generic.c
parentc7eb7d7230509ec862d4144f7a831f995bc5d028 (diff)
net: core: introduce mini_Qdisc and eliminate usage of tp->q for clsact fastpath
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. Also, introduce a helper to swap the mini_Qdisc structures in case filter list head changes. This removes need for tp->q usage without added overhead. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_generic.c')
-rw-r--r--net/sched/sch_generic.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index aa74aa42b5d7..3839cbbdc32b 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1024,3 +1024,49 @@ void psched_ratecfg_precompute(struct psched_ratecfg *r,
}
}
EXPORT_SYMBOL(psched_ratecfg_precompute);
+
+static void mini_qdisc_rcu_func(struct rcu_head *head)
+{
+}
+
+void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
+ struct tcf_proto *tp_head)
+{
+ struct mini_Qdisc *miniq_old = rtnl_dereference(*miniqp->p_miniq);
+ struct mini_Qdisc *miniq;
+
+ if (!tp_head) {
+ RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
+ return;
+ }
+
+ miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
+ &miniqp->miniq1 : &miniqp->miniq2;
+
+ /* We need to make sure that readers won't see the miniq
+ * we are about to modify. So wait until previous call_rcu_bh callback
+ * is done.
+ */
+ rcu_barrier_bh();
+ miniq->filter_list = tp_head;
+ rcu_assign_pointer(*miniqp->p_miniq, miniq);
+
+ if (miniq_old)
+ /* This is counterpart of the rcu barrier above. We need to
+ * block potential new user of miniq_old until all readers
+ * are not seeing it.
+ */
+ call_rcu_bh(&miniq_old->rcu, mini_qdisc_rcu_func);
+}
+EXPORT_SYMBOL(mini_qdisc_pair_swap);
+
+void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
+ struct mini_Qdisc __rcu **p_miniq)
+{
+ miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
+ miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
+ miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
+ miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
+ miniqp->p_miniq = p_miniq;
+}
+EXPORT_SYMBOL(mini_qdisc_pair_init);