ofp-flow: Reduce memory consumption for ofputil_flow_mod, using minimatch.

Until now, struct ofputil_flow_mod, which represents an OpenFlow flow table
modification request, has incorporated a struct match, which made the
overall ofputil_flow_mod about 2.5 kB.  This is OK for a small number of
flows, but absurdly inflates memory requirements when there are hundreds of
thousands of flows.  This commit fixes the problem by changing struct match
to struct minimatch inside ofputil_flow_mod, which reduces its size to
about 100 bytes plus the actual size of the flow match (usually a few dozen
bytes).

This affects memory usage of ovs-ofctl (when it adds a large number of
flows) more than ovs-vswitchd.

Reported-by: Michael Ben-Ami <mbenami@digitalocean.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Reviewed-by: Armando Migliaccio <armamig@gmail.com>
Tested-by: Armando Migliaccio <armamig@gmail.com>
Reviewed-by: Jan Scheurich <jan.scheurich@ericsson.com>
Tested-by: Jan Scheurich <jan.scheurich@ericsson.com>
Tested-by: Yifeng Sun <pkusunyifeng@gmail.com>
Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com>

1 files changed, 12 insertions, 10 deletions

diff --git a/ovn/controller/ofctrl.c b/ovn/controller/ofctrl.c
index 8d6d1b6ae..83340bbf2 100644
--- a/ovn/controller/ofctrl.c
+++ b/ovn/controller/ofctrl.c
@@ -58,7 +58,7 @@ struct ovn_flow {
     /* Key. */
     uint8_t table_id;
     uint16_t priority;
-    struct match match;
+    struct minimatch match;
 
     /* Data. */
     struct ofpact *ofpacts;
@@ -373,14 +373,16 @@ error:
 static void
 run_S_CLEAR_FLOWS(void)
 {
+    VLOG_DBG("clearing all flows");
+
     /* Send a flow_mod to delete all flows. */
     struct ofputil_flow_mod fm = {
-        .match = MATCH_CATCHALL_INITIALIZER,
         .table_id = OFPTT_ALL,
         .command = OFPFC_DELETE,
     };
+    minimatch_init_catchall(&fm.match);
     queue_msg(encode_flow_mod(&fm));
-    VLOG_DBG("clearing all flows");
+    minimatch_destroy(&fm.match);
 
     /* Clear installed_flows, to match the state of the switch. */
     ovn_flow_table_clear(&installed_flows);
@@ -630,13 +632,12 @@ ofctrl_recv(const struct ofp_header *oh, enum ofptype type)
 void
 ofctrl_add_flow(struct hmap *desired_flows,
                 uint8_t table_id, uint16_t priority, uint64_t cookie,
-                const struct match *match,
-                const struct ofpbuf *actions)
+                const struct match *match, const struct ofpbuf *actions)
 {
     struct ovn_flow *f = xmalloc(sizeof *f);
     f->table_id = table_id;
     f->priority = priority;
-    f->match = *match;
+    minimatch_init(&f->match, match);
     f->ofpacts = xmemdup(actions->data, actions->size);
     f->ofpacts_len = actions->size;
     f->hmap_node.hash = ovn_flow_hash(f);
@@ -665,7 +666,7 @@ static uint32_t
 ovn_flow_hash(const struct ovn_flow *f)
 {
     return hash_2words((f->table_id << 16) | f->priority,
-                       match_hash(&f->match, 0));
+                       minimatch_hash(&f->match, 0));
 
 }
 
@@ -676,7 +677,7 @@ ofctrl_dup_flow(struct ovn_flow *src)
     struct ovn_flow *dst = xmalloc(sizeof *dst);
     dst->table_id = src->table_id;
     dst->priority = src->priority;
-    dst->match = src->match;
+    minimatch_clone(&dst->match, &src->match);
     dst->ofpacts = xmemdup(src->ofpacts, src->ofpacts_len);
     dst->ofpacts_len = src->ofpacts_len;
     dst->hmap_node.hash = ovn_flow_hash(dst);
@@ -694,7 +695,7 @@ ovn_flow_lookup(struct hmap *flow_table, const struct ovn_flow *target)
                              flow_table) {
         if (f->table_id == target->table_id
             && f->priority == target->priority
-            && match_equal(&f->match, &target->match)) {
+            && minimatch_equal(&f->match, &target->match)) {
             return f;
         }
     }
@@ -707,7 +708,7 @@ ovn_flow_to_string(const struct ovn_flow *f)
     struct ds s = DS_EMPTY_INITIALIZER;
     ds_put_format(&s, "table_id=%"PRIu8", ", f->table_id);
     ds_put_format(&s, "priority=%"PRIu16", ", f->priority);
-    match_format(&f->match, NULL, &s, OFP_DEFAULT_PRIORITY);
+    minimatch_format(&f->match, NULL, NULL, &s, OFP_DEFAULT_PRIORITY);
     ds_put_cstr(&s, ", actions=");
     struct ofpact_format_params fp = { .s = &s };
     ofpacts_format(f->ofpacts, f->ofpacts_len, &fp);
@@ -728,6 +729,7 @@ static void
 ovn_flow_destroy(struct ovn_flow *f)
 {
     if (f) {
+        minimatch_destroy(&f->match);
         free(f->ofpacts);
         free(f);
     }