From: Samuel Just <sjust@redhat.com>
Date: Fri, 7 Nov 2025 23:56:14 +0000 (+0000)
Subject: mgr: add mgr_subinterpreter_modules config
X-Git-Tag: testing/wip-pdonnell-testing-20260128.205435-debug~3^2~2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=239b0dc8a9c42449ee1faa1bf78bdcc380345ae2;p=ceph-ci.git

mgr: add mgr_subinterpreter_modules config

This commit adds a mgr_subinterpreter_modules config to cause specified
modules (or all if * is specified) to be loaded in individual
subinterpreters.

This changes the default behavior of ceph-mgr from running each module
in a distinct subinterpreter to running them all in the same main
interpreter.  We can reintroduce subinterpreter support over time by
adding modules to the list as we test them.

Fixes: https://tracker.ceph.com/issues/73857
Fixes: https://tracker.ceph.com/issues/73859
Signed-off-by: Samuel Just <sjust@redhat.com>
---

diff --git a/src/common/options/CMakeLists.txt b/src/common/options/CMakeLists.txt
index 60cdbc3f224..916f55dcfbd 100644
--- a/src/common/options/CMakeLists.txt
+++ b/src/common/options/CMakeLists.txt
@@ -82,6 +82,8 @@ if(WITH_MGR)
   endif()
 endif()
 
+set(mgr_subinterpreter_modules "")
+
 add_options(global)
 add_options(cephfs-mirror)
 add_options(crimson)
diff --git a/src/common/options/mgr.yaml.in b/src/common/options/mgr.yaml.in
index c6bdee1d156..aaddf7cb2d1 100644
--- a/src/common/options/mgr.yaml.in
+++ b/src/common/options/mgr.yaml.in
@@ -145,6 +145,19 @@ options:
   - mgr_module_path
   flags:
   - startup
+- name: mgr_subinterpreter_modules
+  type: str
+  level: advanced
+  desc: List of manager modules to load in independent subinterpreters
+  long_desc: A comma delimited list of module names. This list is read by manager
+    when it starts. By default, manager loads each module into the main interpreter.
+    Modules in this list will instead be loaded into independent subinterpreters.
+    Specifying '*' will cause all modules to be run in independent subinterpreters.
+  default: @mgr_subinterpreter_modules@
+  services:
+  - mgr
+  flags:
+  - startup
 - name: mgr_initial_modules
   type: str
   level: basic
diff --git a/src/mgr/PyModule.cc b/src/mgr/PyModule.cc
index e412713e210..1c75d70f466 100644
--- a/src/mgr/PyModule.cc
+++ b/src/mgr/PyModule.cc
@@ -23,6 +23,7 @@
 #include "include/stringify.h"
 #include "common/BackTrace.h"
 #include "common/JSONFormatter.h"
+#include "common/split.h"
 #include "global/signal_handler.h"
 
 #include "common/debug.h"
@@ -335,8 +336,23 @@ int PyModule::load(PyThreadState *pMainThreadState)
 {
   ceph_assert(pMainThreadState != nullptr);
 
-  // Configure sub-interpreter
-  {
+  const auto subinterpreter_modules_opt = g_conf().get_val<std::string>(
+    "mgr_subinterpreter_modules"
+  );
+  auto subinterpreter_modules = ceph::split(subinterpreter_modules_opt);
+  use_main_interpreter = std::count(
+    subinterpreter_modules.begin(), subinterpreter_modules.end(), "*"
+  ) == 0 && std::count(
+    subinterpreter_modules.begin(), subinterpreter_modules.end(), module_name
+  ) == 0;
+
+  if (use_main_interpreter) {
+    // Use main interpreter
+    derr << "Loading module " << module_name << " in main interpreter" << dendl;
+    pMyThreadState.set(pMainThreadState);
+  } else {
+    // Configure sub-interpreter
+    derr << "Loading module " << module_name << " in sub-interpreter" << dendl;
     SafeThreadState sts(pMainThreadState);
     Gil gil(sts);
 
@@ -348,6 +364,7 @@ int PyModule::load(PyThreadState *pMainThreadState)
       pMyThreadState.set(thread_state);
     }
   }
+
   // Environment is all good, import the external module
   {
     Gil gil(pMyThreadState);
@@ -768,7 +785,9 @@ PyModule::~PyModule()
     Py_XDECREF(pClass);
     Py_XDECREF(pStandbyClass);
     Py_XDECREF(pPickleModule);
-    Py_EndInterpreter(pMyThreadState.ts);
+    if (use_main_interpreter) {
+      Py_EndInterpreter(pMyThreadState.ts);
+    }
     pMyThreadState.ts = nullptr;
   }
 }
diff --git a/src/mgr/PyModule.h b/src/mgr/PyModule.h
index c67dfc9a5e5..01cca1d8e27 100644
--- a/src/mgr/PyModule.h
+++ b/src/mgr/PyModule.h
@@ -105,6 +105,9 @@ public:
   PyObject *pStandbyClass = nullptr;
   PyObject *pPickleModule = nullptr;
 
+  // true unless module in mgr_subinterpreter_modules
+  bool use_main_interpreter = true;
+
   explicit PyModule(const std::string &module_name_)
     : module_name(module_name_)
   {