Make sure that "Other ETS" and "Other system" memory metrics are never negative

michaelklishin · michaelklishin · commit 6e7bf23ac022 · 2026-01-16T19:29:28.000-08:00
They can become negative due to ETS tables being concurrently
added, removed and updated.

So simply report 0 in such cases.
diff --git a/deps/rabbit/src/rabbit_vm.erl b/deps/rabbit/src/rabbit_vm.erl
@@ -117,7 +117,7 @@ memory() ->
     [
      {mnesia,               MnesiaETS},
      {metadata_store_ets,   MetadataStoreETS},
-     {other_ets,            ETS - MnesiaETS - MetricsETS - MgmtDbETS - MsgIndexETS  - MetadataStoreETS - lists:sum(QueuesEtsStats)},
+     {other_ets,            max(0, ETS - MnesiaETS - MetricsETS - MgmtDbETS - MsgIndexETS - MetadataStoreETS - lists:sum(QueuesEtsStats))},
 
      %% Messages (mostly, some binaries are not messages)
      {binary,               Bin},
@@ -126,7 +126,7 @@ memory() ->
      %% System
      {code,                 Code},
      {atom,                 Atom},
-     {other_system,         System - ETS - Bin - Code - Atom},
+     {other_system,         max(0, System - ETS - Bin - Code - Atom)},
      {allocated_unused,     AllocatedUnused},
      {reserved_unallocated, OSReserved},
      {strategy,             Strategy},
diff --git a/deps/rabbit/test/unit_rabbit_vm_SUITE.erl b/deps/rabbit/test/unit_rabbit_vm_SUITE.erl
@@ -0,0 +1,74 @@
+%% This Source Code Form is subject to the terms of the Mozilla Public
+%% License, v. 2.0. If a copy of the MPL was not distributed with this
+%% file, You can obtain one at https://mozilla.org/MPL/2.0/.
+%%
+%% Copyright (c) 2007-2026 Broadcom. All Rights Reserved. The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries. All rights reserved.
+%%
+
+-module(unit_rabbit_vm_SUITE).
+
+-include_lib("eunit/include/eunit.hrl").
+
+-compile(export_all).
+
+all() ->
+    [
+      {group, sequential_tests}
+    ].
+
+groups() ->
+    [
+      {sequential_tests, [], [
+          memory_breakdown_non_negative
+        ]}
+    ].
+
+%% -------------------------------------------------------------------
+%% Test suite setup/teardown
+%% -------------------------------------------------------------------
+
+init_per_suite(Config) ->
+    rabbit_ct_helpers:log_environment(),
+    rabbit_ct_helpers:run_setup_steps(Config).
+
+end_per_suite(Config) ->
+    rabbit_ct_helpers:run_teardown_steps(Config).
+
+init_per_group(Group, Config) ->
+    Config1 = rabbit_ct_helpers:set_config(Config, [
+        {rmq_nodename_suffix, Group},
+        {rmq_nodes_count, 1}
+      ]),
+    rabbit_ct_helpers:run_steps(Config1,
+      rabbit_ct_broker_helpers:setup_steps() ++
+      rabbit_ct_client_helpers:setup_steps()).
+
+end_per_group(_Group, Config) ->
+    rabbit_ct_helpers:run_steps(Config,
+      rabbit_ct_client_helpers:teardown_steps() ++
+      rabbit_ct_broker_helpers:teardown_steps()).
+
+init_per_testcase(Testcase, Config) ->
+    rabbit_ct_helpers:testcase_started(Config, Testcase).
+
+end_per_testcase(Testcase, Config) ->
+    rabbit_ct_helpers:testcase_finished(Config, Testcase).
+
+%% -------------------------------------------------------------------
+%% Test cases
+%% -------------------------------------------------------------------
+
+memory_breakdown_non_negative(Config) ->
+    ok = rabbit_ct_broker_helpers:rpc(Config, 0,
+      ?MODULE, memory_breakdown_non_negative1, []).
+
+memory_breakdown_non_negative1() ->
+    Memory = rabbit_vm:memory(),
+    Keys = [other_proc, other_ets, other_system],
+    lists:foreach(
+      fun(Key) ->
+              Value = proplists:get_value(Key, Memory),
+              ?assert(is_integer(Value)),
+              ?assert(Value >= 0)
+      end, Keys),
+    ok.
