@@ -0,0 +1,64 @@
+#ifndef Py_INTERNAL_OBJECT_ALLOC_H
+#define Py_INTERNAL_OBJECT_ALLOC_H
+
+#include "pycore_object.h"      // _PyType_HasFeature()
+#include "pycore_pystate.h"     // _PyThreadState_GET()
+#include "pycore_tstate.h"      // _PyThreadStateImpl
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+// Sets the heap used for PyObject_Malloc(), PyObject_Realloc(), etc. calls in
+// Py_GIL_DISABLED builds. We use different heaps depending on if the object
+// supports GC and if it has a pre-header. We smuggle the choice of heap
+// through the _mimalloc_thread_state.
+// This is a no-op outside of Py_GIL_DISABLED builds.
+static inline void *
+_PyObject_MallocWithType(PyTypeObject *tp, size_t size)
+{
+#ifdef Py_GIL_DISABLED
+    _PyThreadStateImpl *tstate = (_PyThreadStateImpl *)_PyThreadState_GET();
+    struct _mimalloc_thread_state *m = &tstate->mimalloc;
+    if (_PyType_HasFeature(tp, Py_TPFLAGS_PREHEADER)) {
+        m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_GC_PRE];
+    }
+    else if (_PyType_IS_GC(tp)) {
+        m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_GC];
+    }
+#endif
+    void *mem = PyObject_Malloc(size);
+#ifdef Py_GIL_DISABLED
+    m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_OBJECT];
+#endif
+    return mem;
+}
+
+static inline void *
+_PyObject_ReallocWithType(PyTypeObject *tp, void *ptr, size_t size)
+{
+#ifdef Py_GIL_DISABLED
+    _PyThreadStateImpl *tstate = (_PyThreadStateImpl *)_PyThreadState_GET();
+    struct _mimalloc_thread_state *m = &tstate->mimalloc;
+    if (_PyType_HasFeature(tp, Py_TPFLAGS_PREHEADER)) {
+        m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_GC_PRE];
+    }
+    else if (_PyType_IS_GC(tp)) {
+        m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_GC];
+    }
+#endif
+    void *mem = PyObject_Realloc(ptr, size);
+#ifdef Py_GIL_DISABLED
+    m->current_object_heap = &m->heaps[_Py_MIMALLOC_HEAP_OBJECT];
+#endif
+    return mem;
+}
+
+#ifdef __cplusplus
+}
+#endif
+#endif  // !Py_INTERNAL_OBJECT_ALLOC_H
@@ -11,6 +11,7 @@
 #include "pycore_modsupport.h"    // _PyArg_NoKwnames()
 #include "pycore_moduleobject.h"  // _PyModule_GetDef()
 #include "pycore_object.h"        // _PyType_HasFeature()
+#include "pycore_object_alloc.h"  // _PyObject_MallocWithType()
 #include "pycore_pyerrors.h"      // _PyErr_Occurred()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_symtable.h"      // _Py_Mangle()
@@ -1729,7 +1730,7 @@ _PyType_AllocNoTrack(PyTypeObject *type, Py_ssize_t nitems)
     const size_t size = _PyObject_VAR_SIZE(type, nitems+1);
 
     const size_t presize = _PyType_PreHeaderSize(type);
-    char *alloc = PyObject_Malloc(size + presize);
+    char *alloc = _PyObject_MallocWithType(type, size + presize);
     if (alloc  == NULL) {
         return PyErr_NoMemory();
     }