Fix broken ETS test case

This commit fixes an ETS test case that tests the decentralized memory
counter in tables of type ordered_set with the write_concurrency
option turned on. The test case assumed that the memory consumption of
the table would only grow monotonically when terms are
inserted. However, this was not the case when the emulator was
compiled in debug mode as random splits and joins of CA tree nodes
could happen. This commit fixes the test case by disabling random
splits and joins in the tested table.

6 files changed, 37 insertions, 1 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 7ff345a54b..c3d0ea40f6 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -4693,6 +4693,14 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
                     BIF_RET(am_ok);
             }
         }
+        else if (ERTS_IS_ATOM_STR("ets_debug_random_split_join", BIF_ARG_1)) {
+            if (is_tuple(BIF_ARG_2)) {
+                Eterm* tpl = tuple_val(BIF_ARG_2);
+
+                if (erts_ets_debug_random_split_join(tpl[1], tpl[2] == am_true))
+                    BIF_RET(am_ok);
+            }
+        }
         else if (ERTS_IS_ATOM_STR("mbuf", BIF_ARG_1)) {
             Uint sz = size_object(BIF_ARG_2);
             ErlHeapFragment* frag = new_message_buffer(sz);
diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c
index c0f5c506f4..d24f30f126 100644
--- a/erts/emulator/beam/erl_db.c
+++ b/erts/emulator/beam/erl_db.c
@@ -4573,3 +4573,16 @@ int erts_ets_force_split(Eterm tid, int on)
     db_unlock(tb, LCK_WRITE);
     return 1;
 }
+
+int erts_ets_debug_random_split_join(Eterm tid, int on)
+{
+    DbTable* tb = tid2tab(tid);
+    if (!tb || !IS_CATREE_TABLE(tb->common.type))
+        return 0;
+
+    db_lock(tb, LCK_WRITE);
+    if (!(tb->common.status & DB_DELETE))
+        db_catree_debug_random_split_join(&tb->catree, on);
+    db_unlock(tb, LCK_WRITE);
+    return 1;
+}
diff --git a/erts/emulator/beam/erl_db.h b/erts/emulator/beam/erl_db.h
index b22f35a5ef..b3dc1b9ba3 100644
--- a/erts/emulator/beam/erl_db.h
+++ b/erts/emulator/beam/erl_db.h
@@ -131,6 +131,7 @@ extern erts_atomic_t erts_ets_misc_mem_size;
 
 Eterm erts_ets_colliding_names(Process*, Eterm name, Uint cnt);
 int erts_ets_force_split(Eterm tid, int on);
+int erts_ets_debug_random_split_join(Eterm tid, int on);
 Uint erts_db_get_max_tabs(void);
 Eterm erts_db_make_tid(Process *c_p, DbTableCommon *tb);
 
diff --git a/erts/emulator/beam/erl_db_catree.c b/erts/emulator/beam/erl_db_catree.c
index 962fe4c4f8..e0d5e44f58 100644
--- a/erts/emulator/beam/erl_db_catree.c
+++ b/erts/emulator/beam/erl_db_catree.c
@@ -647,7 +647,8 @@ static int dbg_fastrand(void)
 static void dbg_provoke_random_splitjoin(DbTableCATree* tb,
                                          DbTableCATreeNode* base_node)
 {
-    if (tb->common.status & DB_CATREE_FORCE_SPLIT)
+    if (tb->common.status & DB_CATREE_FORCE_SPLIT ||
+        !(tb->common.status & DB_CATREE_DEBUG_RANDOM_SPLIT_JOIN))
         return;
 
     switch (dbg_fastrand() % 8) {
@@ -1406,6 +1407,9 @@ int db_create_catree(Process *p, DbTable *tbl)
     tb->deletion = 0;
     tb->base_nodes_to_free_list = NULL;
     tb->nr_of_deleted_items = 0;
+#ifdef DEBUG
+    tbl->common.status |= DB_CATREE_DEBUG_RANDOM_SPLIT_JOIN;
+#endif
     erts_atomic_init_relb(&(tb->root), (erts_aint_t)root);
     return DB_ERROR_NONE;
 }
@@ -2257,6 +2261,14 @@ void db_catree_force_split(DbTableCATree* tb, int on)
         tb->common.status &= ~DB_CATREE_FORCE_SPLIT;
 }
 
+void db_catree_debug_random_split_join(DbTableCATree* tb, int on)
+{
+    if (on)
+        tb->common.status |= DB_CATREE_DEBUG_RANDOM_SPLIT_JOIN;
+    else
+        tb->common.status &= ~DB_CATREE_DEBUG_RANDOM_SPLIT_JOIN;
+}
+
 void db_calc_stats_catree(DbTableCATree* tb, DbCATreeStats* stats)
 {
     DbTableCATreeNode* stack[ERL_DB_CATREE_MAX_ROUTE_NODE_LAYER_HEIGHT];
diff --git a/erts/emulator/beam/erl_db_catree.h b/erts/emulator/beam/erl_db_catree.h
index fde442eaf5..cf3498dabb 100644
--- a/erts/emulator/beam/erl_db_catree.h
+++ b/erts/emulator/beam/erl_db_catree.h
@@ -124,6 +124,7 @@ void erts_lcnt_enable_db_catree_lock_count(DbTableCATree *tb, int enable);
 #endif
 
 void db_catree_force_split(DbTableCATree*, int on);
+void db_catree_debug_random_split_join(DbTableCATree*, int on);
 
 typedef struct {
     Uint route_nodes;
diff --git a/erts/emulator/beam/erl_db_util.h b/erts/emulator/beam/erl_db_util.h
index 97f2848679..02d4dd6c9a 100644
--- a/erts/emulator/beam/erl_db_util.h
+++ b/erts/emulator/beam/erl_db_util.h
@@ -326,6 +326,7 @@ typedef struct db_table_common {
 #define DB_BUSY           (1 << 12)
 
 #define DB_CATREE_FORCE_SPLIT (1 << 31)  /* erts_debug */
+#define DB_CATREE_DEBUG_RANDOM_SPLIT_JOIN (1 << 30)  /* erts_debug */
 
 #define IS_HASH_TABLE(Status) (!!((Status) & \
 				  (DB_BAG | DB_SET | DB_DUPLICATE_BAG)))