[ovs-dev] [PATCH 10/10] ofproto: Use ofproto_flow_mod for learn execution from xlate cache.
Jarno Rajahalme
jarno at ovn.org
Thu Aug 18 22:50:23 UTC 2016
Use ofproto_flow_mod with a reference to an existing or new rule
instead of ofputil_flow_mod for learn action execution from xlate
cache
Typically we would find that when a learn xlate cache entry is
created, a preceding upcall has already created the learned flow. In
this case the xlate cache entry takes a reference to that flow and
keeps refreshing it without needing to perform any flow table lookups.
This is both faster and shrinks the memory cost of each learn cache
entry from ~3.5kb to about 0.3kb.
If the learned rule does not yet exist, it is created and attached to
the ofproto_flow_mod, from which it is then added. If the referred
rule happens to expire and is removed from the classifier tables, we
create a new rule using the old rule as a template, so that we can
avoid storing the ofputil_flow_mod in all cases.
Signed-off-by: Jarno Rajahalme <jarno at ovn.org>
---
ofproto/ofproto-dpif-xlate.c | 61 ++++++-----
ofproto/ofproto-dpif-xlate.h | 4 +-
ofproto/ofproto-dpif.c | 17 ++--
ofproto/ofproto-dpif.h | 5 +-
ofproto/ofproto-provider.h | 6 ++
ofproto/ofproto.c | 233 ++++++++++++++++++++++++++++++++-----------
6 files changed, 233 insertions(+), 93 deletions(-)
diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index 6be78e6..2683464 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -4068,37 +4068,42 @@ xlate_bundle_action(struct xlate_ctx *ctx,
}
static void
-xlate_learn_action__(struct xlate_ctx *ctx, const struct ofpact_learn *learn,
- struct ofputil_flow_mod *fm, struct ofpbuf *ofpacts)
-{
- learn_execute(learn, &ctx->xin->flow, fm, ofpacts);
- if (ctx->xin->may_learn) {
- ofproto_dpif_flow_mod(ctx->xbridge->ofproto, fm);
- }
-}
-
-static void
xlate_learn_action(struct xlate_ctx *ctx, const struct ofpact_learn *learn)
{
learn_mask(learn, ctx->wc);
- if (ctx->xin->xcache) {
- struct xc_entry *entry;
-
- entry = xlate_cache_add_entry(ctx->xin->xcache, XC_LEARN);
- entry->u.learn.ofproto = ctx->xbridge->ofproto;
- entry->u.learn.fm = xmalloc(sizeof *entry->u.learn.fm);
- entry->u.learn.ofpacts = ofpbuf_new(64);
- xlate_learn_action__(ctx, learn, entry->u.learn.fm,
- entry->u.learn.ofpacts);
- } else if (ctx->xin->may_learn) {
+ if (ctx->xin->xcache || ctx->xin->may_learn) {
uint64_t ofpacts_stub[1024 / 8];
struct ofputil_flow_mod fm;
+ struct ofproto_flow_mod ofm__, *ofm;
struct ofpbuf ofpacts;
+ enum ofperr error;
+
+ if (ctx->xin->xcache) {
+ struct xc_entry *entry;
+
+ entry = xlate_cache_add_entry(ctx->xin->xcache, XC_LEARN);
+ entry->u.learn.ofm = xmalloc(sizeof *entry->u.learn.ofm);
+ ofm = entry->u.learn.ofm;
+ } else {
+ ofm = &ofm__;
+ }
ofpbuf_use_stub(&ofpacts, ofpacts_stub, sizeof ofpacts_stub);
- xlate_learn_action__(ctx, learn, &fm, &ofpacts);
+ learn_execute(learn, &ctx->xin->flow, &fm, &ofpacts);
+ error = ofproto_dpif_flow_mod_init_for_learn(ctx->xbridge->ofproto,
+ &fm, ofm);
ofpbuf_uninit(&ofpacts);
+
+ if (!error && ctx->xin->may_learn) {
+ error = ofproto_flow_mod_learn(ofm, ctx->xin->xcache != NULL);
+ }
+
+ if (error) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+ VLOG_WARN_RL(&rl, "%s: LEARN action execution failed.",
+ ctx->xbridge->name);
+ }
}
}
@@ -5779,9 +5784,15 @@ xlate_push_stats_entry(struct xc_entry *entry,
entry->u.mirror.mirrors,
stats->n_packets, stats->n_bytes);
break;
- case XC_LEARN:
- ofproto_dpif_flow_mod(entry->u.learn.ofproto, entry->u.learn.fm);
+ case XC_LEARN: {
+ enum ofperr error;
+ error = ofproto_flow_mod_learn(entry->u.learn.ofm, true);
+ if (error) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+ VLOG_WARN_RL(&rl, "xcache LEARN action execution failed.");
+ }
break;
+ }
case XC_NORMAL:
xlate_cache_normal(entry->u.normal.ofproto, entry->u.normal.flow,
entry->u.normal.vlan);
@@ -5864,8 +5875,8 @@ xlate_cache_clear_entry(struct xc_entry *entry)
mbridge_unref(entry->u.mirror.mbridge);
break;
case XC_LEARN:
- free(entry->u.learn.fm);
- ofpbuf_delete(entry->u.learn.ofpacts);
+ ofproto_flow_mod_uninit(entry->u.learn.ofm);
+ free(entry->u.learn.ofm);
break;
case XC_NORMAL:
free(entry->u.normal.flow);
diff --git a/ofproto/ofproto-dpif-xlate.h b/ofproto/ofproto-dpif-xlate.h
index c21cd7f..7faa199 100644
--- a/ofproto/ofproto-dpif-xlate.h
+++ b/ofproto/ofproto-dpif-xlate.h
@@ -84,9 +84,7 @@ struct xc_entry {
uint16_t vid;
} bond;
struct {
- struct ofproto_dpif *ofproto;
- struct ofputil_flow_mod *fm;
- struct ofpbuf *ofpacts;
+ struct ofproto_flow_mod *ofm;
} learn;
struct {
struct ofproto_dpif *ofproto;
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 77e8277..5a2590a 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -356,13 +356,16 @@ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
/* Initial mappings of port to bridge mappings. */
static struct shash init_ofp_ports = SHASH_INITIALIZER(&init_ofp_ports);
-/* Executes 'fm'. The caller retains ownership of 'fm' and everything in
- * it. */
-void
-ofproto_dpif_flow_mod(struct ofproto_dpif *ofproto,
- const struct ofputil_flow_mod *fm)
-{
- ofproto_flow_mod(&ofproto->up, fm);
+/* Return a reference to a rule according to 'fm'. If the rule already
+ * existed, reference to that rule is returned, otherwise a new rule is created
+ * and returned. */
+enum ofperr
+ofproto_dpif_flow_mod_init_for_learn(struct ofproto_dpif *ofproto,
+ const struct ofputil_flow_mod *fm,
+ struct ofproto_flow_mod *ofm)
+{
+ /* This will not take the global 'ofproto_mutex'. */
+ return ofproto_flow_mod_init_for_learn(&ofproto->up, fm, ofm);
}
/* Appends 'am' to the queue of asynchronous messages to be sent to the
diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
index c156795..54c8703 100644
--- a/ofproto/ofproto-dpif.h
+++ b/ofproto/ofproto-dpif.h
@@ -164,8 +164,9 @@ void ofproto_dpif_send_async_msg(struct ofproto_dpif *,
struct ofproto_async_msg *);
int ofproto_dpif_send_packet(const struct ofport_dpif *, bool oam,
struct dp_packet *);
-void ofproto_dpif_flow_mod(struct ofproto_dpif *,
- const struct ofputil_flow_mod *);
+enum ofperr ofproto_dpif_flow_mod_init_for_learn(struct ofproto_dpif *,
+ const struct ofputil_flow_mod *,
+ struct ofproto_flow_mod *);
struct ofport_dpif *odp_port_to_ofport(const struct dpif_backer *, odp_port_t);
struct ofport_dpif *ofp_port_to_ofport(const struct ofproto_dpif *,
diff --git a/ofproto/ofproto-provider.h b/ofproto/ofproto-provider.h
index d8ef73e..ed76f0a 100644
--- a/ofproto/ofproto-provider.h
+++ b/ofproto/ofproto-provider.h
@@ -1921,6 +1921,12 @@ struct ofproto_group_mod {
enum ofperr ofproto_flow_mod(struct ofproto *, const struct ofputil_flow_mod *)
OVS_EXCLUDED(ofproto_mutex);
+enum ofperr ofproto_flow_mod_init_for_learn(struct ofproto *,
+ const struct ofputil_flow_mod *,
+ struct ofproto_flow_mod *)
+ OVS_EXCLUDED(ofproto_mutex);
+enum ofperr ofproto_flow_mod_learn(struct ofproto_flow_mod *, bool keep_ref)
+ OVS_EXCLUDED(ofproto_mutex);
void ofproto_add_flow(struct ofproto *, const struct match *, int priority,
const struct ofpact *ofpacts, size_t ofpacts_len)
OVS_EXCLUDED(ofproto_mutex);
diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index fd298d6..7912ff6 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -272,7 +272,8 @@ static bool ofproto_group_exists(const struct ofproto *, uint32_t group_id);
static void handle_openflow(struct ofconn *, const struct ofpbuf *);
static enum ofperr ofproto_flow_mod_init(struct ofproto *,
struct ofproto_flow_mod *,
- const struct ofputil_flow_mod *fm)
+ const struct ofputil_flow_mod *fm,
+ struct rule *)
OVS_EXCLUDED(ofproto_mutex);
static enum ofperr ofproto_flow_mod_start(struct ofproto *,
struct ofproto_flow_mod *)
@@ -2153,51 +2154,11 @@ ofproto_add_flow(struct ofproto *ofproto, const struct match *match,
/* Executes the flow modification specified in 'fm'. Returns 0 on success, or
* an OFPERR_* OpenFlow error code on failure.
*
- * This is a helper function for in-band control and fail-open and the "learn"
- * action. */
+ * This is a helper function for in-band control and fail-open. */
enum ofperr
ofproto_flow_mod(struct ofproto *ofproto, const struct ofputil_flow_mod *fm)
OVS_EXCLUDED(ofproto_mutex)
{
- /* Optimize for the most common case of a repeated learn action.
- * If an identical flow already exists we only need to update its
- * 'modified' time. */
- if (fm->command == OFPFC_MODIFY_STRICT && fm->table_id != OFPTT_ALL
- && !(fm->flags & OFPUTIL_FF_RESET_COUNTS)) {
- struct oftable *table = &ofproto->tables[fm->table_id];
- struct rule *rule;
- bool done = false;
-
- rule = rule_from_cls_rule(classifier_find_match_exactly(
- &table->cls, &fm->match, fm->priority,
- OVS_VERSION_MAX));
- if (rule) {
- /* Reading many of the rule fields and writing on 'modified'
- * requires the rule->mutex. */
- const struct rule_actions *actions;
-
- ovs_mutex_lock(&rule->mutex);
- actions = rule_get_actions(rule);
- if (rule->idle_timeout == fm->idle_timeout
- && rule->hard_timeout == fm->hard_timeout
- && rule->importance == fm->importance
- && rule->flags == (fm->flags & OFPUTIL_FF_STATE)
- && (!fm->modify_cookie || (fm->new_cookie == rule->flow_cookie))
- && ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
- actions->ofpacts, actions->ofpacts_len)) {
- /* Rule already exists and need not change, only update the
- modified timestamp. */
- rule->modified = time_msec();
- done = true;
- }
- ovs_mutex_unlock(&rule->mutex);
- }
-
- if (done) {
- return 0;
- }
- }
-
return handle_flow_mod__(ofproto, fm, NULL);
}
@@ -2861,8 +2822,10 @@ ofproto_rule_try_ref(struct rule *rule)
* stay around accross the RCU quiescent periods. */
void
ofproto_rule_unref(struct rule *rule)
+ OVS_NO_THREAD_SAFETY_ANALYSIS
{
if (rule && ovs_refcount_unref_relaxed(&rule->ref_count) == 1) {
+ ovs_assert(rule->state != RULE_INSERTED);
ovsrcu_postpone(rule_destroy_cb, rule);
}
}
@@ -4701,18 +4664,21 @@ add_flow_init(struct ofproto *ofproto, struct ofproto_flow_mod *ofm,
return OFPERR_OFPBRC_EPERM;
}
- cls_rule_init(&cr, &fm->match, fm->priority);
+ if (!ofm->temp_rule) {
+ cls_rule_init(&cr, &fm->match, fm->priority);
- /* Allocate new rule. Destroys 'cr'. */
- error = ofproto_rule_create(ofproto, &cr, table - ofproto->tables,
- fm->new_cookie, fm->idle_timeout,
- fm->hard_timeout, fm->flags, fm->importance,
- fm->ofpacts, fm->ofpacts_len, &ofm->temp_rule);
- if (error) {
- return error;
- }
+ /* Allocate new rule. Destroys 'cr'. */
+ error = ofproto_rule_create(ofproto, &cr, table - ofproto->tables,
+ fm->new_cookie, fm->idle_timeout,
+ fm->hard_timeout, fm->flags,
+ fm->importance, fm->ofpacts,
+ fm->ofpacts_len, &ofm->temp_rule);
+ if (error) {
+ return error;
+ }
- get_conjunctions(fm, &ofm->conjs, &ofm->n_conjs);
+ get_conjunctions(fm, &ofm->conjs, &ofm->n_conjs);
+ }
return 0;
}
@@ -4876,6 +4842,161 @@ ofproto_rule_create(struct ofproto *ofproto, struct cls_rule *cr,
return 0;
}
+/* Create a rule based on 'fm', but do not insert it anywhere yet. This is a
+ * helper for learn action, so the flow may not have conjunctions.
+ * This does not take the global 'ofproto_mutex'. */
+enum ofperr
+ofproto_flow_mod_init_for_learn(struct ofproto *ofproto,
+ const struct ofputil_flow_mod *fm,
+ struct ofproto_flow_mod *ofm)
+ OVS_EXCLUDED(ofproto_mutex)
+{
+ enum ofperr error;
+
+ /* Reject flow mods that do not look like they were generated by a learn
+ * action. */
+ if (fm->command != OFPFC_MODIFY_STRICT || fm->table_id == OFPTT_ALL
+ || fm->flags & OFPUTIL_FF_RESET_COUNTS
+ || fm->buffer_id != UINT32_MAX) {
+ return OFPERR_OFPFMFC_UNKNOWN;
+ }
+
+ /* Check if the rule already exists, and we can get a reference to it. */
+ struct oftable *table = &ofproto->tables[fm->table_id];
+ struct rule *rule;
+
+ rule = rule_from_cls_rule(classifier_find_match_exactly(
+ &table->cls, &fm->match, fm->priority,
+ OVS_VERSION_MAX));
+ if (rule) {
+ /* Check if the rule's attributes match as well. */
+ const struct rule_actions *actions;
+
+ ovs_mutex_lock(&rule->mutex);
+ actions = rule_get_actions(rule);
+ if (rule->idle_timeout == fm->idle_timeout
+ && rule->hard_timeout == fm->hard_timeout
+ && rule->importance == fm->importance
+ && rule->flags == (fm->flags & OFPUTIL_FF_STATE)
+ && (!fm->modify_cookie || (fm->new_cookie == rule->flow_cookie))
+ && ofpacts_equal(fm->ofpacts, fm->ofpacts_len,
+ actions->ofpacts, actions->ofpacts_len)) {
+ /* Rule already exists and need not change, except for the modified
+ * timestamp. Get a reference to the existing rule. */
+ ovs_mutex_unlock(&rule->mutex);
+ if (!ofproto_rule_try_ref(rule)) {
+ rule = NULL; /* Pretend it did not exist. */
+ }
+ } else {
+ ovs_mutex_unlock(&rule->mutex);
+ rule = NULL;
+ }
+ }
+
+ /* Initialize ofproto_flow_mod for future use. */
+ error = ofproto_flow_mod_init(ofproto, ofm, fm, rule);
+ if (error) {
+ ofproto_rule_unref(rule);
+ return error;
+ }
+ return 0;
+}
+
+/* Refresh 'ofm->temp_rule', for which the caller holds a reference, if already
+ * in the classifier, insert it otherwise. If the rule has already been
+ * removed from the classifier, a new rule is created using 'ofm->temp_rule' as
+ * a template and the reference to the old 'ofm->temp_rule' is freed. If
+ * 'keep_ref' is true, then a reference to the current rule is held, otherwise
+ * it is released and 'ofm->temp_rule' is set to NULL.
+ *
+ * Caller needs to be the exclusive owner of 'ofm' as it is being manipulated
+ * during the call. */
+enum ofperr
+ofproto_flow_mod_learn(struct ofproto_flow_mod *ofm, bool keep_ref)
+ OVS_EXCLUDED(ofproto_mutex)
+{
+ enum ofperr error = 0;
+
+ /* ofm->temp_rule is our reference to the learned rule. We have a
+ * reference to an existing rule, if it already was in the classifier,
+ * otherwise we may have a fresh rule that we need to insert. */
+ struct rule *rule = ofm->temp_rule;
+ if (!rule) {
+ return OFPERR_OFPFMFC_UNKNOWN;
+ }
+ struct ofproto *ofproto = rule->ofproto;
+
+ ovs_mutex_lock(&rule->mutex);
+ enum rule_state state = rule->state;
+
+ /* Create a new rule if the current one has been removed from the
+ * classifier. We need to do this since RCU does not allow a current rule
+ * to be reinserted before all threads have quiesced. */
+ if (state == RULE_REMOVED) {
+ struct cls_rule cr;
+
+ cls_rule_clone(&cr, &rule->cr);
+ error = ofproto_rule_create(ofproto, &cr, rule->table_id,
+ rule->flow_cookie,
+ rule->idle_timeout,
+ rule->hard_timeout, rule->flags,
+ rule->importance,
+ rule->actions->ofpacts,
+ rule->actions->ofpacts_len,
+ &ofm->temp_rule);
+ ovs_mutex_unlock(&rule->mutex);
+ if (error) {
+ goto error;
+ }
+ ofproto_rule_unref(rule);
+ rule = ofm->temp_rule;
+ state = RULE_INITIALIZED; /* We know this. */
+ } else {
+ /* Refresh the existing rule while we still have the lock. */
+ rule->modified = time_msec();
+ ovs_mutex_unlock(&rule->mutex);
+ }
+
+ /* Do we need to insert the rule? In this case no-one else has the
+ * reference to this rule yet, but multiple threads may compete inserting
+ * duplicate rules. This race is resolved by holding the ofproto_mutex and
+ * any possible old rule we don't know of yet being removed by the flow
+ * add. */
+ if (state == RULE_INITIALIZED) {
+ bool old_modify_cookie = ofm->modify_cookie;
+ enum ofperr error;
+
+ ovs_mutex_lock(&ofproto_mutex);
+ if (keep_ref) {
+ /* flow mod processing either takes ownership or releases the
+ * reference, so we need to take a new one if needed. */
+ ofproto_rule_ref(rule);
+ }
+ ofm->version = ofproto->tables_version + 1;
+ error = ofproto_flow_mod_start(ofproto, ofm);
+ if (!error) {
+ ofproto_bump_tables_version(ofproto);
+ ofproto_flow_mod_finish(ofproto, ofm, NULL);
+ }
+ ofmonitor_flush(ofproto->connmgr);
+ ovs_mutex_unlock(&ofproto_mutex);
+
+ /* Restore state that may have been modified by flow mod processing so
+ * that we may use the same ofproto_flow_mod again later. */
+ if (keep_ref) {
+ ofm->temp_rule = rule;
+ }
+ ofm->modify_cookie = old_modify_cookie;
+ return 0;
+ }
+error:
+ if (!keep_ref) {
+ ofproto_rule_unref(ofm->temp_rule);
+ ofm->temp_rule = NULL;
+ }
+ return error;
+}
+
static void
replace_rule_start(struct ofproto *ofproto, struct ofproto_flow_mod *ofm,
struct rule *old_rule, struct rule *new_rule)
@@ -5503,7 +5624,7 @@ handle_flow_mod__(struct ofproto *ofproto, const struct ofputil_flow_mod *fm,
struct ofproto_flow_mod ofm;
enum ofperr error;
- error = ofproto_flow_mod_init(ofproto, &ofm, fm);
+ error = ofproto_flow_mod_init(ofproto, &ofm, fm, NULL);
if (error) {
return error;
}
@@ -7101,7 +7222,7 @@ ofproto_flow_mod_uninit(struct ofproto_flow_mod *ofm)
static enum ofperr
ofproto_flow_mod_init(struct ofproto *ofproto, struct ofproto_flow_mod *ofm,
- const struct ofputil_flow_mod *fm)
+ const struct ofputil_flow_mod *fm, struct rule *rule)
OVS_EXCLUDED(ofproto_mutex)
{
enum ofperr error;
@@ -7115,7 +7236,7 @@ ofproto_flow_mod_init(struct ofproto *ofproto, struct ofproto_flow_mod *ofm,
&& fm->cookie_mask == htonll(0));
/* Initialize state needed by ofproto_flow_mod_uninit(). */
- ofm->temp_rule = NULL;
+ ofm->temp_rule = rule;
ofm->criteria.version = OVS_VERSION_NOT_REMOVED;
ofm->conjs = NULL;
ofm->n_conjs = 0;
@@ -7477,7 +7598,7 @@ handle_bundle_add(struct ofconn *ofconn, const struct ofp_header *oh)
u16_to_ofp(ofproto->max_ports),
ofproto->n_tables);
if (!error) {
- error = ofproto_flow_mod_init(ofproto, &bmsg->ofm, &fm);
+ error = ofproto_flow_mod_init(ofproto, &bmsg->ofm, &fm, NULL);
}
ofpbuf_uninit(&ofpacts);
} else if (type == OFPTYPE_GROUP_MOD) {
--
2.1.4
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