work in progress

[nbds] / txn / txn.c

diff --git a/txn/txn.c b/txn/txn.c
index a932f66a3d9f79b05121a3da9f776c55397c4ea4..b3aadfd14b38d76a9295dbc355f840b850d61e91 100644 (file)
--- a/txn/txn.c
+++ b/txn/txn.c
@@ -36,19 +36,15 @@ struct txn {
     write_rec_t *writes;
     size_t writes_size;
     size_t writes_count;
-    size_t writes_scan;
+    size_t validate_scan;
     txn_state_e state;
 };
 
 static txn_state_e txn_validate (txn_t *txn);
 
-static version_t version_ = 1;
-
 static skiplist_t *active_ = NULL;
 
-__attribute__ ((constructor)) void txn_init (void) {
-    active_ = sl_alloc(NULL);
-}
+static version_t version_ = 1;
 
 // Validate the updates for <key>. Validation fails if there is a write-write conflict. That is if after our
 // read version another transaction committed a change to an entry we are also trying to change.
@@ -118,16 +114,15 @@ static txn_state_e validate_key (txn_t *txn, map_key_t key) {
 
 static txn_state_e txn_validate (txn_t *txn) {
     assert(txn->state != TXN_RUNNING);
-    int i;
     switch (txn->state) {
 
         case TXN_VALIDATING:
             if (txn->wv == UNDETERMINED_VERSION) {
                 version_t wv = SYNC_ADD(&version_, 1);
-                SYNC_CAS(&txn->wv, UNDETERMINED_VERSION, wv);
+                (void)SYNC_CAS(&txn->wv, UNDETERMINED_VERSION, wv);
             }
 
-            for (i = 0; i < txn->writes_count; ++i) {
+            for (int i = 0; i < txn->writes_count; ++i) {
                 txn_state_e s = validate_key(txn, txn->writes[i].key);
                 if (s == TXN_ABORTED) {
                     txn->state = TXN_ABORTED;
@@ -168,6 +163,12 @@ txn_t *txn_begin (map_t *map) {
     txn->map = map;
     txn->writes = nbd_malloc(sizeof(*txn->writes) * INITIAL_WRITES_SIZE);
     txn->writes_size = INITIAL_WRITES_SIZE;
+    if (EXPECT_FALSE(active_ == NULL)) {
+        skiplist_t *a = sl_alloc(NULL);
+        if (SYNC_CAS(&active_, NULL, a) != NULL) {
+            sl_free(a);
+        }
+    }
 
     // acquire the read version for txn. must be careful to avoid a race
     do {
@@ -327,7 +328,6 @@ map_val_t txn_map_get (txn_t *txn, map_key_t key) {
     map_val_t value = update->value;
     TRACE("x1", "txn_map_get: key found returning value %p", value, 0);
 
-    return value;
     // collect some garbage
     version_t min_active_version = UNDETERMINED_VERSION;
     update_t *next_update = NULL;