gh-113055: Use pointer for interp->obmalloc state (gh-113412)

For interpreters that share state with the main interpreter, this points
to the same static memory structure.  For interpreters with their own
obmalloc state, it is heap allocated.  Add free_obmalloc_arenas() which
will free the obmalloc arenas and radix tree structures for interpreters
with their own obmalloc state.

Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>

2 files changed, 22 insertions, 8 deletions

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 261622a..fff64dd 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -32,6 +32,7 @@
 #include "pycore_typevarobject.h" // _Py_clear_generic_types()
 #include "pycore_unicodeobject.h" // _PyUnicode_InitTypes()
 #include "pycore_weakref.h"       // _PyWeakref_GET_REF()
+#include "pycore_obmalloc.h"      // _PyMem_init_obmalloc()
 
 #include "opcode.h"
 
@@ -645,6 +646,13 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
         return status;
     }
 
+    // initialize the interp->obmalloc state.  This must be done after
+    // the settings are loaded (so that feature_flags are set) but before
+    // any calls are made to obmalloc functions.
+    if (_PyMem_init_obmalloc(interp) < 0) {
+        return  _PyStatus_NO_MEMORY();
+    }
+
     PyThreadState *tstate = _PyThreadState_New(interp,
                                                _PyThreadState_WHENCE_INTERP);
     if (tstate == NULL) {
@@ -2144,6 +2152,14 @@ new_interpreter(PyThreadState **tstate_p, const PyInterpreterConfig *config)
         goto error;
     }
 
+    // initialize the interp->obmalloc state.  This must be done after
+    // the settings are loaded (so that feature_flags are set) but before
+    // any calls are made to obmalloc functions.
+    if (_PyMem_init_obmalloc(interp) < 0) {
+        status = _PyStatus_NO_MEMORY();
+        goto error;
+    }
+
     tstate = _PyThreadState_New(interp, _PyThreadState_WHENCE_INTERP);
     if (tstate == NULL) {
         status = _PyStatus_NO_MEMORY();
diff --git a/Python/pystate.c b/Python/pystate.c
index 5ad5b6f..8e097c8 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -18,6 +18,7 @@
 #include "pycore_pystate.h"
 #include "pycore_runtime_init.h"  // _PyRuntimeState_INIT
 #include "pycore_sysmodule.h"     // _PySys_Audit()
+#include "pycore_obmalloc.h"      // _PyMem_obmalloc_state_on_heap()
 
 /* --------------------------------------------------------------------------
 CAUTION
@@ -553,6 +554,11 @@ free_interpreter(PyInterpreterState *interp)
     // The main interpreter is statically allocated so
     // should not be freed.
     if (interp != &_PyRuntime._main_interpreter) {
+        if (_PyMem_obmalloc_state_on_heap(interp)) {
+            // interpreter has its own obmalloc state, free it
+            PyMem_RawFree(interp->obmalloc);
+            interp->obmalloc = NULL;
+        }
         PyMem_RawFree(interp);
     }
 }
@@ -595,14 +601,6 @@ init_interpreter(PyInterpreterState *interp,
     assert(next != NULL || (interp == runtime->interpreters.main));
     interp->next = next;
 
-    /* Initialize obmalloc, but only for subinterpreters,
-       since the main interpreter is initialized statically. */
-    if (interp != &runtime->_main_interpreter) {
-        poolp temp[OBMALLOC_USED_POOLS_SIZE] = \
-                _obmalloc_pools_INIT(interp->obmalloc.pools);
-        memcpy(&interp->obmalloc.pools.used, temp, sizeof(temp));
-    }
-
     PyStatus status = _PyObject_InitState(interp);
     if (_PyStatus_EXCEPTION(status)) {
         return status;