On Tue, Sep 8, 2020 at 11:30 AM Mark Michelson <[email protected]> wrote:
>
> 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.
>
Exactly :)
> > > > + 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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