[ovs-dev] [urcu v2 15/15] dpif-netdev: Use RCU to protect data.
Ben Pfaff
blp at nicira.com
Tue Mar 11 20:56:17 UTC 2014
Signed-off-by: Ben Pfaff <blp at nicira.com>
---
lib/dpif-netdev.c | 148 ++++++++++++++++-------------------------------------
1 file changed, 43 insertions(+), 105 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index d9e7a1a..eb437d1 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -49,6 +49,7 @@
#include "odp-util.h"
#include "ofp-print.h"
#include "ofpbuf.h"
+#include "ovs-rcu.h"
#include "packets.h"
#include "poll-loop.h"
#include "random.h"
@@ -245,12 +246,6 @@ struct dp_netdev_flow {
const struct hmap_node node; /* In owning dp_netdev's 'flow_table'. */
const struct flow flow; /* The flow that created this entry. */
- /* Number of references.
- * The classifier owns one reference.
- * Any thread trying to keep a rule from being freed should hold its own
- * reference. */
- struct ovs_refcount ref_cnt;
-
/* Protects members marked OVS_GUARDED.
*
* Acquire after datapath's flow_mutex. */
@@ -266,12 +261,10 @@ struct dp_netdev_flow {
* Reading 'actions' requires 'mutex'.
* Writing 'actions' requires 'mutex' and (to allow for transactions) the
* datapath's flow_mutex. */
- struct dp_netdev_actions *actions OVS_GUARDED;
+ OVSRCU_TYPE(struct dp_netdev_actions *) actions;
};
-static struct dp_netdev_flow *dp_netdev_flow_ref(
- const struct dp_netdev_flow *);
-static void dp_netdev_flow_unref(struct dp_netdev_flow *);
+static void dp_netdev_flow_free(struct dp_netdev_flow *);
/* Contained by struct dp_netdev_flow's 'stats' member. */
struct dp_netdev_flow_stats {
@@ -294,8 +287,6 @@ struct dp_netdev_flow_stats {
* 'flow' is the dp_netdev_flow for which 'flow->actions == actions') or that
* owns a reference to 'actions->ref_cnt' (or both). */
struct dp_netdev_actions {
- struct ovs_refcount ref_cnt;
-
/* These members are immutable: they do not change during the struct's
* lifetime. */
struct nlattr *actions; /* Sequence of OVS_ACTION_ATTR_* attributes. */
@@ -304,9 +295,9 @@ struct dp_netdev_actions {
struct dp_netdev_actions *dp_netdev_actions_create(const struct nlattr *,
size_t);
-struct dp_netdev_actions *dp_netdev_actions_ref(
- const struct dp_netdev_actions *);
-void dp_netdev_actions_unref(struct dp_netdev_actions *);
+struct dp_netdev_actions *dp_netdev_flow_get_actions(
+ const struct dp_netdev_flow *);
+static void dp_netdev_actions_free(struct dp_netdev_actions *);
/* A thread that receives packets from some ports, looks them up in the flow
* table, and executes the actions it finds. */
@@ -870,6 +861,24 @@ dpif_netdev_port_query_by_name(const struct dpif *dpif, const char *devname,
}
static void
+dp_netdev_flow_free(struct dp_netdev_flow *flow)
+{
+ struct dp_netdev_flow_stats *bucket;
+ size_t i;
+
+ OVSTHREAD_STATS_FOR_EACH_BUCKET (bucket, i, &flow->stats) {
+ ovs_mutex_destroy(&bucket->mutex);
+ free_cacheline(bucket);
+ }
+ ovsthread_stats_destroy(&flow->stats);
+
+ cls_rule_destroy(CONST_CAST(struct cls_rule *, &flow->cr));
+ dp_netdev_actions_free(dp_netdev_flow_get_actions(flow));
+ ovs_mutex_destroy(&flow->mutex);
+ free(flow);
+}
+
+static void
dp_netdev_remove_flow(struct dp_netdev *dp, struct dp_netdev_flow *flow)
OVS_REQ_WRLOCK(dp->cls.rwlock)
OVS_REQUIRES(dp->flow_mutex)
@@ -879,39 +888,7 @@ dp_netdev_remove_flow(struct dp_netdev *dp, struct dp_netdev_flow *flow)
classifier_remove(&dp->cls, cr);
hmap_remove(&dp->flow_table, node);
- dp_netdev_flow_unref(flow);
-}
-
-static struct dp_netdev_flow *
-dp_netdev_flow_ref(const struct dp_netdev_flow *flow_)
-{
- struct dp_netdev_flow *flow = CONST_CAST(struct dp_netdev_flow *, flow_);
- if (flow) {
- ovs_refcount_ref(&flow->ref_cnt);
- }
- return flow;
-}
-
-static void
-dp_netdev_flow_unref(struct dp_netdev_flow *flow)
-{
- if (flow && ovs_refcount_unref(&flow->ref_cnt) == 1) {
- struct dp_netdev_flow_stats *bucket;
- size_t i;
-
- OVSTHREAD_STATS_FOR_EACH_BUCKET (bucket, i, &flow->stats) {
- ovs_mutex_destroy(&bucket->mutex);
- free_cacheline(bucket);
- }
- ovsthread_stats_destroy(&flow->stats);
-
- cls_rule_destroy(CONST_CAST(struct cls_rule *, &flow->cr));
- ovs_mutex_lock(&flow->mutex);
- dp_netdev_actions_unref(flow->actions);
- ovs_mutex_unlock(&flow->mutex);
- ovs_mutex_destroy(&flow->mutex);
- free(flow);
- }
+ ovsrcu_postpone(dp_netdev_flow_free, flow);
}
static void
@@ -1030,7 +1007,6 @@ dp_netdev_lookup_flow(const struct dp_netdev *dp, const struct flow *flow)
fat_rwlock_rdlock(&dp->cls.rwlock);
netdev_flow = dp_netdev_flow_cast(classifier_lookup(&dp->cls, flow, NULL));
- dp_netdev_flow_ref(netdev_flow);
fat_rwlock_unlock(&dp->cls.rwlock);
return netdev_flow;
@@ -1045,7 +1021,7 @@ dp_netdev_find_flow(const struct dp_netdev *dp, const struct flow *flow)
HMAP_FOR_EACH_WITH_HASH (netdev_flow, node, flow_hash(flow, 0),
&dp->flow_table) {
if (flow_equal(&netdev_flow->flow, flow)) {
- return dp_netdev_flow_ref(netdev_flow);
+ return netdev_flow;
}
}
@@ -1176,25 +1152,17 @@ dpif_netdev_flow_get(const struct dpif *dpif,
fat_rwlock_unlock(&dp->cls.rwlock);
if (netdev_flow) {
- struct dp_netdev_actions *actions = NULL;
-
if (stats) {
get_dpif_flow_stats(netdev_flow, stats);
}
- ovs_mutex_lock(&netdev_flow->mutex);
if (actionsp) {
- actions = dp_netdev_actions_ref(netdev_flow->actions);
- }
- ovs_mutex_unlock(&netdev_flow->mutex);
-
- dp_netdev_flow_unref(netdev_flow);
+ struct dp_netdev_actions *actions;
- if (actionsp) {
+ actions = dp_netdev_flow_get_actions(netdev_flow);
*actionsp = ofpbuf_clone_data(actions->actions, actions->size);
- dp_netdev_actions_unref(actions);
}
- } else {
+ } else {
error = ENOENT;
}
@@ -1213,14 +1181,13 @@ dp_netdev_flow_add(struct dp_netdev *dp, const struct flow *flow,
netdev_flow = xzalloc(sizeof *netdev_flow);
*CONST_CAST(struct flow *, &netdev_flow->flow) = *flow;
- ovs_refcount_init(&netdev_flow->ref_cnt);
ovs_mutex_init(&netdev_flow->mutex);
- ovs_mutex_lock(&netdev_flow->mutex);
ovsthread_stats_init(&netdev_flow->stats);
- netdev_flow->actions = dp_netdev_actions_create(actions, actions_len);
+ ovsrcu_set(&netdev_flow->actions,
+ dp_netdev_actions_create(actions, actions_len));
match_init(&match, flow, wc);
cls_rule_init(CONST_CAST(struct cls_rule *, &netdev_flow->cr),
@@ -1233,8 +1200,6 @@ dp_netdev_flow_add(struct dp_netdev *dp, const struct flow *flow,
flow_hash(flow, 0));
fat_rwlock_unlock(&dp->cls.rwlock);
- ovs_mutex_unlock(&netdev_flow->mutex);
-
return 0;
}
@@ -1299,10 +1264,8 @@ dpif_netdev_flow_put(struct dpif *dpif, const struct dpif_flow_put *put)
new_actions = dp_netdev_actions_create(put->actions,
put->actions_len);
- ovs_mutex_lock(&netdev_flow->mutex);
- old_actions = netdev_flow->actions;
- netdev_flow->actions = new_actions;
- ovs_mutex_unlock(&netdev_flow->mutex);
+ old_actions = dp_netdev_flow_get_actions(netdev_flow);
+ ovsrcu_set(&netdev_flow->actions, new_actions);
if (put->stats) {
get_dpif_flow_stats(netdev_flow, put->stats);
@@ -1311,14 +1274,13 @@ dpif_netdev_flow_put(struct dpif *dpif, const struct dpif_flow_put *put)
clear_stats(netdev_flow);
}
- dp_netdev_actions_unref(old_actions);
+ ovsrcu_postpone(dp_netdev_actions_free, old_actions);
} else if (put->flags & DPIF_FP_CREATE) {
error = EEXIST;
} else {
/* Overlapping flow. */
error = EINVAL;
}
- dp_netdev_flow_unref(netdev_flow);
}
ovs_mutex_unlock(&dp->flow_mutex);
@@ -1346,7 +1308,6 @@ dpif_netdev_flow_del(struct dpif *dpif, const struct dpif_flow_del *del)
get_dpif_flow_stats(netdev_flow, del->stats);
}
dp_netdev_remove_flow(dp, netdev_flow);
- dp_netdev_flow_unref(netdev_flow);
} else {
error = ENOENT;
}
@@ -1384,7 +1345,6 @@ dpif_netdev_flow_dump_state_uninit(void *state_)
{
struct dp_netdev_flow_state *state = state_;
- dp_netdev_actions_unref(state->actions);
free(state);
}
@@ -1401,6 +1361,7 @@ dpif_netdev_flow_dump_start(const struct dpif *dpif OVS_UNUSED, void **iterp)
return 0;
}
+/* XXX the caller must use 'actions' without quiescing */
static int
dpif_netdev_flow_dump_next(const struct dpif *dpif, void *iter_, void *state_,
const struct nlattr **key, size_t *key_len,
@@ -1423,7 +1384,6 @@ dpif_netdev_flow_dump_next(const struct dpif *dpif, void *iter_, void *state_,
node = hmap_at_position(&dp->flow_table, &iter->bucket, &iter->offset);
if (node) {
netdev_flow = CONTAINER_OF(node, struct dp_netdev_flow, node);
- dp_netdev_flow_ref(netdev_flow);
}
fat_rwlock_unlock(&dp->cls.rwlock);
if (!node) {
@@ -1461,16 +1421,13 @@ dpif_netdev_flow_dump_next(const struct dpif *dpif, void *iter_, void *state_,
}
if (actions || stats) {
- dp_netdev_actions_unref(state->actions);
state->actions = NULL;
- ovs_mutex_lock(&netdev_flow->mutex);
if (actions) {
- state->actions = dp_netdev_actions_ref(netdev_flow->actions);
+ state->actions = dp_netdev_flow_get_actions(netdev_flow);
*actions = state->actions->actions;
*actions_len = state->actions->size;
}
- ovs_mutex_unlock(&netdev_flow->mutex);
if (stats) {
get_dpif_flow_stats(netdev_flow, &state->stats);
@@ -1478,8 +1435,6 @@ dpif_netdev_flow_dump_next(const struct dpif *dpif, void *iter_, void *state_,
}
}
- dp_netdev_flow_unref(netdev_flow);
-
return 0;
}
@@ -1605,35 +1560,23 @@ dp_netdev_actions_create(const struct nlattr *actions, size_t size)
struct dp_netdev_actions *netdev_actions;
netdev_actions = xmalloc(sizeof *netdev_actions);
- ovs_refcount_init(&netdev_actions->ref_cnt);
netdev_actions->actions = xmemdup(actions, size);
netdev_actions->size = size;
return netdev_actions;
}
-/* Increments 'actions''s refcount. */
struct dp_netdev_actions *
-dp_netdev_actions_ref(const struct dp_netdev_actions *actions_)
+dp_netdev_flow_get_actions(const struct dp_netdev_flow *flow)
{
- struct dp_netdev_actions *actions;
-
- actions = CONST_CAST(struct dp_netdev_actions *, actions_);
- if (actions) {
- ovs_refcount_ref(&actions->ref_cnt);
- }
- return actions;
+ return ovsrcu_get(struct dp_netdev_actions *, &flow->actions);
}
-/* Decrements 'actions''s refcount and frees 'actions' if the refcount reaches
- * 0. */
-void
-dp_netdev_actions_unref(struct dp_netdev_actions *actions)
+static void
+dp_netdev_actions_free(struct dp_netdev_actions *actions)
{
- if (actions && ovs_refcount_unref(&actions->ref_cnt) == 1) {
- free(actions->actions);
- free(actions);
- }
+ free(actions->actions);
+ free(actions);
}
static void *
@@ -1820,14 +1763,9 @@ dp_netdev_port_input(struct dp_netdev *dp, struct ofpbuf *packet,
dp_netdev_flow_used(netdev_flow, packet);
- ovs_mutex_lock(&netdev_flow->mutex);
- actions = dp_netdev_actions_ref(netdev_flow->actions);
- ovs_mutex_unlock(&netdev_flow->mutex);
-
+ actions = dp_netdev_flow_get_actions(netdev_flow);
dp_netdev_execute_actions(dp, &key, packet, md,
actions->actions, actions->size);
- dp_netdev_actions_unref(actions);
- dp_netdev_flow_unref(netdev_flow);
dp_netdev_count_packet(dp, DP_STAT_HIT);
} else {
dp_netdev_count_packet(dp, DP_STAT_MISS);
--
1.7.10.4
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