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[ovs-dev,v2,4/6] conntrack: Turn zl local limit into atomic.

Message ID 20240930205034.65484-4-pvalerio@redhat.com
State Accepted
Commit 41f3f5b902cb3dc1e0df5ffb65595ce45a6eae34
Delegated to: aaron conole
Headers show
Series [ovs-dev,v2,1/6] conntrack: Correctly annotate conntrack member. | expand

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Commit Message

Paolo Valerio Sept. 30, 2024, 8:50 p.m. UTC 
while at it, changes struct zone_limit initialization in
zone_limit_create() in order to use atomic init operations instead of
relying on memset() which, although correctly initializes the struct,
is semantically not aware of atomics.

Signed-off-by: Paolo Valerio <pvalerio@redhat.com>

---
v2:
- Fixed typo s/semantially/semantically (Aaron)
---
 lib/conntrack-private.h |  2 +-
 lib/conntrack.c         | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 8 deletions(-)
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Patch

diff --git a/lib/conntrack-private.h b/lib/conntrack-private.h
index 2c625d710..2770470d1 100644
--- a/lib/conntrack-private.h
+++ b/lib/conntrack-private.h
@@ -201,7 +201,7 @@  enum ct_ephemeral_range {
 
 struct conntrack_zone_limit {
     int32_t zone;
-    uint32_t limit;
+    atomic_uint32_t limit;
     atomic_count count;
     uint32_t zone_limit_seq; /* Used to disambiguate zone limit counts. */
 };
diff --git a/lib/conntrack.c b/lib/conntrack.c
index 112d43216..3d19d37df 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -341,7 +341,7 @@  zone_limit_get(struct conntrack *ct, int32_t zone)
     struct zone_limit *zl = zone_limit_lookup_or_default(ct, zone);
     if (zl) {
         czl.zone = zl->czl.zone;
-        czl.limit = zl->czl.limit;
+        atomic_read_relaxed(&zl->czl.limit, &czl.limit);
         czl.count = atomic_count_get(&zl->czl.count);
     }
     return czl;
@@ -358,8 +358,9 @@  zone_limit_create(struct conntrack *ct, int32_t zone, uint32_t limit)
     }
 
     if (zone >= DEFAULT_ZONE && zone <= MAX_ZONE) {
-        zl = xzalloc(sizeof *zl);
-        zl->czl.limit = limit;
+        zl = xmalloc(sizeof *zl);
+        atomic_init(&zl->czl.limit, limit);
+        atomic_count_init(&zl->czl.count, 0);
         zl->czl.zone = zone;
         zl->czl.zone_limit_seq = ct->zone_limit_seq++;
         uint32_t hash = zone_key_hash(zone, ct->hash_basis);
@@ -376,7 +377,7 @@  zone_limit_update(struct conntrack *ct, int32_t zone, uint32_t limit)
     int err = 0;
     struct zone_limit *zl = zone_limit_lookup(ct, zone);
     if (zl) {
-        zl->czl.limit = limit;
+        atomic_store_relaxed(&zl->czl.limit, limit);
         VLOG_INFO("Changed zone limit of %u for zone %d", limit, zone);
     } else {
         ovs_mutex_lock(&ct->ct_lock);
@@ -916,12 +917,16 @@  conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
     }
 
     if (commit) {
+        uint32_t czl_limit;
         struct conn_key_node *fwd_key_node, *rev_key_node;
         struct zone_limit *zl = zone_limit_lookup_or_default(ct,
                                                              ctx->key.zone);
-        if (zl && atomic_count_get(&zl->czl.count) >= zl->czl.limit) {
-            COVERAGE_INC(conntrack_zone_full);
-            return nc;
+        if (zl) {
+            atomic_read_relaxed(&zl->czl.limit, &czl_limit);
+            if (atomic_count_get(&zl->czl.count) >= czl_limit) {
+                COVERAGE_INC(conntrack_zone_full);
+                return nc;
+            }
         }
 
         unsigned int n_conn_limit;