From: Shaohua Wu <[email protected]>
In scenarios with multiple PMDs, there may be
simultaneous requests for recirc_id from multiple
PMD threads.In recirc_alloc_id_ctx, we first check
if there is a duplicate entry in the metadata_map
for the same frozen_state field. If successful,
we directly retrieve the recirc_id. If unsuccessful,
we create a new recirc_node and insert it into
id_map and metadata_map. There is no locking mechanism
to prevent the possibility of two threads with the same
state simultaneously inserting, meaning their IDs are
different, but their frozen_states are the same.
trace log:
static struct recirc_id_node *
recirc_alloc_id__(const struct frozen_state *state, uint32_t hash)
{
ovs_assert(state->action_set_len <= state->ofpacts_len);
struct recirc_id_node *node = xzalloc(sizeof *node);
node->hash = hash;
ovs_refcount_init(&node->refcount);
node->is_hotupgrade = false;
frozen_state_clone(CONST_CAST(struct frozen_state *, &node->state), state);
struct recirc_id_node *hash_recirc_node = recirc_find_equal(&node->state,
state);
if (hash_recirc_node) {
VLOG_INFO("wsh:hash equal:hash_recirc_node %p id:%u, hash_recirc_node
hash:%u,node %p hash:%u\n",
hash_recirc_nodeļ¼ hash_recirc_node->id,
hash_recirc_node->hash, node, node->hash);
}
ovs_mutex_lock(&mutex);
...
}
Log recording:
2024-04-27T12:28:47.973Z|00006|ofproto_dpif_rid(pmd-c08/id:13)|INFO|wsh:hash
equal:
hash_recirc_node 0x7fb29c0276a0 id:27,hash_recirc_node hash:3224122528,node
0x7fb2900194d0 hash:3224122528
2024-04-27T12:28:47.973Z|00009|ofproto_dpif_rid(pmd-c02/id:15)|INFO|wsh:hash
equal:
hash_recirc_node 0x7fb29c0276a0 id:27,hash_recirc_node hash:3224122528,node
0x7fb288025270 hash:3224122528
2024-04-27T12:28:47.973Z|00006|ofproto_dpif_rid(pmd-c03/id:14)|INFO|wsh:hash
equal:
hash_recirc_node 0x7fb29c0276a0 id:27,hash_recirc_node hash:3224122528,node
0x7fb29401d4e0 hash:3224122528
2024-04-27T12:28:47.973Z|00004|ofproto_dpif_rid(pmd-c09/id:12)|INFO|node->id:28,hash:4019648042,table_id:75
2024-04-27T12:28:47.973Z|00007|ofproto_dpif_rid(pmd-c08/id:13)|INFO|wsh:hash
equal:
hash_recirc_node 0x7fb29c028d40 id:28,hash_recirc_node hash:4019648042,node
0x7fb29001ac30 hash:4019648042
2024-04-27T12:28:48.065Z|00005|ofproto_dpif_rid(pmd-c09/id:12)|INFO|node->id:29,hash:3800776147,table_id:30
2024-04-27T12:28:48.101Z|00007|ofproto_dpif_rid(pmd-c03/id:14)|INFO|node->id:30,hash:1580334976,table_id:75
Signed-off-by: Shaohua Wu <[email protected]>
---
v1->v2:modify log recording , add trace code.
v2->v3:Optimize recirc_alloc_id_ctx. The recirc_alloc_id
interface is used for bond configuration and must
obtain a unique recirc_id.
Signed-off-by: wushaohua <[email protected]>
---
ofproto/ofproto-dpif-rid.c | 37 ++++++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)
diff --git a/ofproto/ofproto-dpif-rid.c b/ofproto/ofproto-dpif-rid.c
index f01468025..eeee81f05 100644
--- a/ofproto/ofproto-dpif-rid.c
+++ b/ofproto/ofproto-dpif-rid.c
@@ -277,11 +277,42 @@ recirc_find_id(const struct frozen_state *target)
uint32_t
recirc_alloc_id_ctx(const struct frozen_state *state)
{
+ ovs_assert(state->action_set_len <= state->ofpacts_len);
+ struct recirc_id_node *node = NULL;
+ struct recirc_id_node *find_node = NULL;
uint32_t hash = frozen_state_hash(state);
- struct recirc_id_node *node = recirc_ref_equal(state, hash);
- if (!node) {
- node = recirc_alloc_id__(state, hash);
+
+ node = xzalloc(sizeof *node);
+ node->hash = hash;
+ ovs_refcount_init(&node->refcount);
+ frozen_state_clone(CONST_CAST(struct frozen_state *, &node->state), state);
+
+ ovs_mutex_lock(&mutex);
+ find_node = recirc_ref_equal(state, hash);
+ if (find_node) {
+ ovs_mutex_unlock(&mutex);
+ recirc_id_node_free(node);
+ return find_node->id;
}
+
+ for (;;) {
+ /* Claim the next ID. The ID space should be sparse enough for the
+ allocation to succeed at the first try. We do skip the first
+ RECIRC_POOL_STATIC_IDS IDs on the later rounds, though, as some of
+ the initial allocations may be for long term uses (like bonds). */
+ node->id = next_id++;
+ if (OVS_UNLIKELY(!node->id)) {
+ next_id = RECIRC_POOL_STATIC_IDS + 1;
+ node->id = next_id++;
+ }
+ /* Find if the id is free. */
+ if (OVS_LIKELY(!recirc_find__(node->id))) {
+ break;
+ }
+ }
+ cmap_insert(&id_map, &node->id_node, node->id);
+ cmap_insert(&metadata_map, &node->metadata_node, node->hash);
+ ovs_mutex_unlock(&mutex);
return node->id;
}
--
2.30.2
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