From 1c8365272a55301609dc8c46aa49fa0ac048506e Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Fri, 18 May 2018 17:59:33 +0200
Subject: erts: Add system_info(ets_count)

---
 erts/emulator/beam/erl_bif_info.c |  3 +++
 erts/emulator/beam/erl_db.c       | 26 +++++++++++++++++++-------
 erts/emulator/beam/erl_db.h       |  3 ++-
 3 files changed, 24 insertions(+), 8 deletions(-)

(limited to 'erts/emulator/beam')

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;
-- 
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