On 9/8/20 2:07 PM, Han Zhou wrote:
On Tue, Sep 8, 2020 at 8:55 AM Mark Michelson <[email protected]
<mailto:[email protected]>> wrote:
>
> On 9/7/20 2:45 AM, Han Zhou wrote:
> > This patch optimizes the previous patch that incrementally processes
> > flow installation by merging the "add-after-delete" flow changes as
> > much as possible to avoid unnecessary OpenFlow updates.
> >
> > Signed-off-by: Han Zhou <[email protected] <mailto:[email protected]>>
> > ---
> > controller/ofctrl.c | 74
+++++++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 74 insertions(+)
> >
> > diff --git a/controller/ofctrl.c b/controller/ofctrl.c
> > index a2aa45d..81a00c8 100644
> > --- a/controller/ofctrl.c
> > +++ b/controller/ofctrl.c
> > @@ -1692,10 +1692,84 @@ update_installed_flows_by_compare(struct
ovn_desired_flow_table *flow_table,
> > }
> > }
> >
> > +/* Finds and returns a desired_flow in 'deleted_flows' that is
exactly the
> > + * same as 'target', including cookie and actions.
> > + */
> > +static struct desired_flow *
> > +deleted_flow_lookup(struct hmap *deleted_flows, struct ovn_flow
*target)
> > +{
> > + struct desired_flow *d;
> > + HMAP_FOR_EACH_WITH_HASH (d, match_hmap_node, target->hash,
> > + deleted_flows) {
> > + struct ovn_flow *f = &d->flow;
> > + if (f->table_id == target->table_id
> > + && f->priority == target->priority
> > + && minimatch_equal(&f->match, &target->match)
> > + && f->cookie == target->cookie
> > + && ofpacts_equal(f->ofpacts, f->ofpacts_len,
target->ofpacts,
> > + target->ofpacts_len)) {
> > + return d;
> > + }
> > + }
> > + return NULL;
> > +}
> > +
> > +/* This function scans the tracked flow changes in the order and
merges "add"
> > + * or "update" after "deleted" operations for exactly same flow
(priority,
> > + * table, match, action and cookie), to avoid unnecessary OF
messages being
> > + * sent to OVS. */
> > +static void
> > +merge_tracked_flows(struct ovn_desired_flow_table *flow_table)
> > +{
> > + struct hmap deleted_flows = HMAP_INITIALIZER(&deleted_flows);
> > + struct desired_flow *f, *next;
> > + LIST_FOR_EACH_SAFE (f, next, track_list_node,
> > + &flow_table->tracked_flows) {
> > + if (f->is_deleted) {
> > + /* reuse f->match_hmap_node field since it is already
removed from
> > + * the desired flow table's match index. */
> > + hmap_insert(&deleted_flows, &f->match_hmap_node,
> > + f->flow.hash);
> > + } else {
> > + struct desired_flow *del_f =
deleted_flow_lookup(&deleted_flows,
> > +
&f->flow);
> > + if (!del_f) {
> > + continue;
> > + }
> > +
> > + /* del_f must have been installed, otherwise it should
have been
> > + * removed during track_flow_add_or_modify. */
> > + ovs_assert(del_f->installed_flow);
> > + if (!f->installed_flow) {
> > + /* f is not installed yet. */
> > + struct installed_flow *i = del_f->installed_flow;
> > + unlink_installed_to_desired(i, del_f);
> > + link_installed_to_desired(i, f);
> > + } else {
> > + /* f has been installed before, and now was
updated to exact
> > + * the same flow as del_f. */
> > + ovs_assert(f->installed_flow ==
del_f->installed_flow);
> > + unlink_installed_to_desired(del_f->installed_flow,
del_f);
> > + }
> > + hmap_remove(&deleted_flows, &del_f->match_hmap_node);
> > + ovs_list_remove(&del_f->track_list_node);
> > + desired_flow_destroy(del_f);
> > +
> > + ovs_list_remove(&f->track_list_node);
> > + ovs_list_init(&f->track_list_node);
> > + }
> > + }
>
> What happens here if the deleted flow comes later in the list than the
> added/modified flows? Can that happen? If so, then this needs to be
> separated into two separate list traversals. The first adds all
> f->is_deleted flows to deleted_flows, and the second modifies the links
> on all !f->is_deleted flows that are found in deleted_flows.
>
Hi Mark, "delete-after-add/modify" is handled on-the-fly when the flows
add/modify & delete are tracked, in track_flow_del(). Here the function
merge_tracked_flows() is to handle the "add-after-delete" only. The
"add-after-delete" is handled separately here because a deleted flow is
removed from the desired flow table already and the following add
operation is operating on a new desired_flow instance instead of the
deleted one. Maybe I should add this in comments.
Got it. So the list's order is important here. So if the delete comes
before the add/modify, that indicates the overall intention is to really
just modify, whereas add/modify before delete means the overall
intention is to just delete.
> > + HMAP_FOR_EACH_SAFE (f, next, match_hmap_node, &deleted_flows) {
> > + hmap_remove(&deleted_flows, &f->match_hmap_node);
> > + }
> > + hmap_destroy(&deleted_flows);
> > +}
> > +
> > static void
> > update_installed_flows_by_track(struct ovn_desired_flow_table
*flow_table,
> > struct ovs_list *msgs)
> > {
> > + merge_tracked_flows(flow_table);
> > struct desired_flow *f, *f_next;
> > LIST_FOR_EACH_SAFE (f, f_next, track_list_node,
> > &flow_table->tracked_flows) {
> >
>
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