erts: Add system_info(ets_count)

5 files changed, 47 insertions, 8 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index cff56b9cb8..5e0d30ebb7 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -8166,6 +8166,12 @@ ok
             <c>erl(1)</c>.
             </p>
           </item>
+	  <tag><marker id="system_info_ets_count"/>
+            <c>ets_count</c></tag>
+          <item>
+            <p>Returns the number of ETS tables currently existing at the
+            local node.</p>
+          </item>
           <tag><marker id="system_info_ets_limit"/>
             <c>ets_limit</c></tag>
           <item>
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 8b2b1a58c7..5789fa8e71 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3129,6 +3129,9 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
     else if (ERTS_IS_ATOM_STR("ets_limit",BIF_ARG_1)) {
         BIF_RET(make_small(erts_db_get_max_tabs()));
     }
+    else if (ERTS_IS_ATOM_STR("ets_count",BIF_ARG_1)) {
+        BIF_RET(make_small(erts_ets_table_count()));
+    }
     else if (ERTS_IS_ATOM_STR("atom_limit",BIF_ARG_1)) {
         BIF_RET(make_small(erts_get_atom_limit()));
     }
diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c
index c1eaaeee06..c9ab75fc88 100644
--- a/erts/emulator/beam/erl_db.c
+++ b/erts/emulator/beam/erl_db.c
@@ -450,7 +450,7 @@ save_sched_table(Process *c_p, DbTable *tb)
     DbTable *first;
 
     ASSERT(esdp);
-    esdp->ets_tables.count++;
+    erts_atomic_inc_nob(&esdp->ets_tables.count);
     erts_refc_inc(&tb->common.refc, 1);
 
     first = esdp->ets_tables.clist;
@@ -474,8 +474,8 @@ remove_sched_table(ErtsSchedulerData *esdp, DbTable *tb)
     ASSERT(erts_get_ref_numbers_thr_id(ERTS_MAGIC_BIN_REFN(tb->common.btid))
            == (Uint32) esdp->no);
 
-    ASSERT(esdp->ets_tables.count > 0);
-    esdp->ets_tables.count--;
+    ASSERT(erts_atomic_read_nob(&esdp->ets_tables.count) > 0);
+    erts_atomic_dec_nob(&esdp->ets_tables.count);
 
     eaydp = ERTS_SCHED_AUX_YIELD_DATA(esdp, ets_all);
     if (eaydp->ongoing) {
@@ -2446,7 +2446,7 @@ ets_all_reply(ErtsSchedulerData *esdp, ErtsEtsAllReq **reqpp,
         ASSERT(!*tablepp);
 
         /* Max heap size needed... */
-        sz = esdp->ets_tables.count;
+        sz = erts_atomic_read_nob(&esdp->ets_tables.count);
         sz *= ERTS_MAGIC_REF_THING_SIZE + 2;
         sz += 3 + ERTS_REF_THING_SIZE;
         hfragp = new_message_buffer(sz);
@@ -2530,7 +2530,8 @@ erts_handle_yielded_ets_all_request(ErtsSchedulerData *esdp,
             if (!eaydp->queue)
                 return 0; /* All work completed! */
 
-            if (yc < ERTS_ETS_ALL_TB_YCNT_START && yc > esdp->ets_tables.count)
+            if (yc < ERTS_ETS_ALL_TB_YCNT_START &&
+                yc > erts_atomic_read_nob(&esdp->ets_tables.count))
                 return 1; /* Yield! */
 
             eaydp->ongoing = ongoing = eaydp->queue;
@@ -2609,7 +2610,6 @@ BIF_RETTYPE ets_internal_request_all_0(BIF_ALIST_0)
     BIF_RET(ref);
 }
 
-
 /*
 ** db_slot(Db, Slot) -> [Items].
 */
@@ -3539,7 +3539,7 @@ erts_ets_sched_spec_data_init(ErtsSchedulerData *esdp)
     eaydp->tab = NULL;
     eaydp->queue = NULL;
     esdp->ets_tables.clist = NULL;
-    esdp->ets_tables.count = 0;
+    erts_atomic_init_nob(&esdp->ets_tables.count, 0);
 }
 
 
@@ -4347,6 +4347,18 @@ erts_db_get_max_tabs()
     return db_max_tabs;
 }
 
+Uint erts_ets_table_count(void)
+{
+    Uint tb_count = 0;
+    Uint six;
+
+    for (six = 0; six < erts_no_schedulers; six++) {
+        ErtsSchedulerData *esdp = &erts_aligned_scheduler_data[six].esd;
+        tb_count += erts_atomic_read_nob(&esdp->ets_tables.count);
+    }
+    return tb_count;
+}
+
 /*
  * For testing of meta tables only.
  *
diff --git a/erts/emulator/beam/erl_db.h b/erts/emulator/beam/erl_db.h
index db86c81914..1664db9a41 100644
--- a/erts/emulator/beam/erl_db.h
+++ b/erts/emulator/beam/erl_db.h
@@ -45,7 +45,7 @@ typedef struct {
 } ErtsEtsAllYieldData;
 
 typedef struct {
-    Uint count;
+    erts_atomic_t count;
     DbTable *clist;
 } ErtsEtsTables;
 
@@ -69,6 +69,7 @@ typedef struct {
 /*TT*/
 
 Uint erts_get_ets_misc_mem_size(void);
+Uint erts_ets_table_count(void);
 
 typedef struct {
     DbTableCommon common;
diff --git a/erts/emulator/test/system_info_SUITE.erl b/erts/emulator/test/system_info_SUITE.erl
index fdf4aab24d..7309908337 100644
--- a/erts/emulator/test/system_info_SUITE.erl
+++ b/erts/emulator/test/system_info_SUITE.erl
@@ -37,6 +37,7 @@
 
 -export([process_count/1, system_version/1, misc_smoke_tests/1,
          heap_size/1, wordsize/1, memory/1, ets_limit/1, atom_limit/1,
+         ets_count/1,
          atom_count/1]).
 
 suite() ->
@@ -45,6 +46,7 @@ suite() ->
 
 all() -> 
     [process_count, system_version, misc_smoke_tests,
+     ets_count,
      heap_size, wordsize, memory, ets_limit, atom_limit, atom_count].
 
 %%%
@@ -478,6 +480,21 @@ get_node_name(Config) ->
 		 ++ "-"
 		 ++ integer_to_list(erlang:unique_integer([positive]))).
 
+ets_count(Config) when is_list(Config) ->
+    [ets_count_do([Type | Named])
+     || Type <- [set, bag, duplicate_bag, ordered_set],
+        Named <- [[named_table], []]
+    ],
+    ok.
+
+ets_count_do(Opts) ->
+    Before = erlang:system_info(ets_count),
+    T = ets:new(?MODULE, Opts),
+    After = erlang:system_info(ets_count),
+    After = Before + 1,
+    ets:delete(T),
+    Before = erlang:system_info(ets_count).
+
 
 %% Verify system_info(ets_limit) reflects max ETS table settings.
 ets_limit(Config0) when is_list(Config0) ->