[3.9] bpo-40514: Remove --with-experimental-isolated-subinterpreters in 3.9 (GH-20228)

Remove --with-experimental-isolated-subinterpreters configure option
in Python 3.9: the experiment continues in the master branch, but
it's no longer needed in 3.9.

Author: vstinner

Include/internal/pycore_ceval.h

@@ -50,11 +50,7 @@ extern PyObject *_PyEval_EvalCode(
     PyObject *kwdefs, PyObject *closure,
     PyObject *name, PyObject *qualname);
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-extern int _PyEval_ThreadsInitialized(PyInterpreterState *interp);
-#else
 extern int _PyEval_ThreadsInitialized(struct pyruntimestate *runtime);
-#endif
 extern PyStatus _PyEval_InitGIL(PyThreadState *tstate);
 extern void _PyEval_FiniGIL(PyThreadState *tstate);
 

Include/internal/pycore_interp.h

@@ -46,9 +46,6 @@ struct _ceval_state {
     /* Request for dropping the GIL */
     _Py_atomic_int gil_drop_request;
     struct _pending_calls pending;
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    struct _gil_runtime_state gil;
-#endif
 };
 
 /* fs_codec.encoding is initialized to NULL.

Include/internal/pycore_pystate.h

@@ -49,18 +49,10 @@ _Py_ThreadCanHandlePendingCalls(void)
 /* Variable and macro for in-line access to current thread
    and interpreter state */
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-PyAPI_FUNC(PyThreadState*) _PyThreadState_GetTSS(void);
-#endif
-
 static inline PyThreadState*
 _PyRuntimeState_GetThreadState(_PyRuntimeState *runtime)
 {
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    return _PyThreadState_GetTSS();
-#else
     return (PyThreadState*)_Py_atomic_load_relaxed(&runtime->gilstate.tstate_current);
-#endif
 }
 
 /* Get the current Python thread state.
@@ -75,11 +67,7 @@ _PyRuntimeState_GetThreadState(_PyRuntimeState *runtime)
 static inline PyThreadState*
 _PyThreadState_GET(void)
 {
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    return _PyThreadState_GetTSS();
-#else
     return _PyRuntimeState_GetThreadState(&_PyRuntime);
-#endif
 }
 
 /* Redefine PyThreadState_GET() as an alias to _PyThreadState_GET() */

Include/internal/pycore_runtime.h

@@ -19,9 +19,7 @@ struct _ceval_runtime_state {
        the main thread of the main interpreter can handle signals: see
        _Py_ThreadCanHandleSignals(). */
     _Py_atomic_int signals_pending;
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
     struct _gil_runtime_state gil;
-#endif
 };
 
 /* GIL state */

Misc/NEWS.d/next/Build/2020-05-19-17-43-38.bpo-40514.gW-66U.rst

@@ -0,0 +1,3 @@
+Remove ``--with-experimental-isolated-subinterpreters`` configure option in
+Python 3.9: the experiment continues in the master branch, but it's no
+longer needed in 3.9.

Modules/_xxsubinterpretersmodule.c

@@ -1939,20 +1939,6 @@ _run_script_in_interpreter(PyInterpreterState *interp, const char *codestr,
         return -1;
     }
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    // Switch to interpreter.
-    PyThreadState *new_tstate = PyInterpreterState_ThreadHead(interp);
-    PyThreadState *save1 = PyEval_SaveThread();
-
-    (void)PyThreadState_Swap(new_tstate);
-
-    // Run the script.
-    _sharedexception *exc = NULL;
-    int result = _run_script(interp, codestr, shared, &exc);
-
-    // Switch back.
-    PyEval_RestoreThread(save1);
-#else
     // Switch to interpreter.
     PyThreadState *save_tstate = NULL;
     if (interp != PyInterpreterState_Get()) {
@@ -1970,7 +1956,6 @@ _run_script_in_interpreter(PyInterpreterState *interp, const char *codestr,
     if (save_tstate != NULL) {
         PyThreadState_Swap(save_tstate);
     }
-#endif
 
     // Propagate any exception out to the caller.
     if (exc != NULL) {

Modules/gcmodule.c

@@ -1181,14 +1181,6 @@ collect(PyThreadState *tstate, int generation,
     _PyTime_t t1 = 0;   /* initialize to prevent a compiler warning */
     GCState *gcstate = &tstate->interp->gc;
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    if (tstate->interp->config._isolated_interpreter) {
-        // bpo-40533: The garbage collector must not be run on parallel on
-        // Python objects shared by multiple interpreters.
-        return 0;
-    }
-#endif
-
     if (gcstate->debug & DEBUG_STATS) {
         PySys_WriteStderr("gc: collecting generation %d...\n", generation);
         show_stats_each_generations(gcstate);

Objects/dictobject.c

@@ -251,12 +251,6 @@ static uint64_t pydict_global_version = 0;
 #define PyDict_MAXFREELIST 80
 #endif
 
-/* bpo-40521: dict free lists are shared by all interpreters. */
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  undef PyDict_MAXFREELIST
-#  define PyDict_MAXFREELIST 0
-#endif
-
 #if PyDict_MAXFREELIST > 0
 static PyDictObject *free_list[PyDict_MAXFREELIST];
 static int numfree = 0;

Objects/frameobject.c

@@ -559,12 +559,6 @@ static PyGetSetDef frame_getsetlist[] = {
 /* max value for numfree */
 #define PyFrame_MAXFREELIST 200
 
-/* bpo-40521: frame free lists are shared by all interpreters. */
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  undef PyFrame_MAXFREELIST
-#  define PyFrame_MAXFREELIST 0
-#endif
-
 #if PyFrame_MAXFREELIST > 0
 static PyFrameObject *free_list = NULL;
 static int numfree = 0;         /* number of frames currently in free_list */

Objects/listobject.c

@@ -101,12 +101,6 @@ list_preallocate_exact(PyListObject *self, Py_ssize_t size)
 #  define PyList_MAXFREELIST 80
 #endif
 
-/* bpo-40521: list free lists are shared by all interpreters. */
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  undef PyList_MAXFREELIST
-#  define PyList_MAXFREELIST 0
-#endif
-
 static PyListObject *free_list[PyList_MAXFREELIST];
 static int numfree = 0;
 

Objects/tupleobject.c

@@ -22,12 +22,6 @@ class tuple "PyTupleObject *" "&PyTuple_Type"
 #define PyTuple_MAXFREELIST  2000  /* Maximum number of tuples of each size to save */
 #endif
 
-/* bpo-40521: tuple free lists are shared by all interpreters. */
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  undef PyTuple_MAXSAVESIZE
-#  define PyTuple_MAXSAVESIZE 0
-#endif
-
 #if PyTuple_MAXSAVESIZE > 0
 /* Entries 1 up to PyTuple_MAXSAVESIZE are free lists, entry 0 is the empty
    tuple () of which at most one instance will be allocated.

Objects/typeobject.c

@@ -19,10 +19,7 @@ class object "PyObject *" "&PyBaseObject_Type"
 
 #include "clinic/typeobject.c.h"
 
-/* bpo-40521: Type method cache is shared by all subinterpreters */
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  define MCACHE
-#endif
+#define MCACHE
 
 #ifdef MCACHE
 /* Support type attribute cache */
@@ -63,10 +60,7 @@ static size_t method_cache_misses = 0;
 static size_t method_cache_collisions = 0;
 #endif
 
-/* bpo-40521: Interned strings are shared by all subinterpreters */
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  define INTERN_NAME_STRINGS
-#endif
+#define INTERN_NAME_STRINGS
 
 /* alphabetical order */
 _Py_IDENTIFIER(__abstractmethods__);

Objects/unicodeobject.c

@@ -198,10 +198,7 @@ extern "C" {
 #  define OVERALLOCATE_FACTOR 4
 #endif
 
-/* bpo-40521: Interned strings are shared by all interpreters. */
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  define INTERNED_STRINGS
-#endif
+#define INTERNED_STRINGS
 
 /* This dictionary holds all interned unicode strings.  Note that references
    to strings in this dictionary are *not* counted in the string's ob_refcnt.
@@ -288,10 +285,7 @@ unicode_decode_utf8(const char *s, Py_ssize_t size,
 /* List of static strings. */
 static _Py_Identifier *static_strings = NULL;
 
-/* bpo-40521: Latin1 singletons are shared by all interpreters. */
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-#  define LATIN1_SINGLETONS
-#endif
+#define LATIN1_SINGLETONS
 
 #ifdef LATIN1_SINGLETONS
 /* Single character Unicode strings in the Latin-1 range are being

Python/ceval.c

@@ -250,21 +250,6 @@ ensure_tstate_not_null(const char *func, PyThreadState *tstate)
 }
 
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-int
-_PyEval_ThreadsInitialized(PyInterpreterState *interp)
-{
-    return gil_created(&interp->ceval.gil);
-}
-
-int
-PyEval_ThreadsInitialized(void)
-{
-    // Fatal error if there is no current interpreter
-    PyInterpreterState *interp = PyInterpreterState_Get();
-    return _PyEval_ThreadsInitialized(interp);
-}
-#else
 int
 _PyEval_ThreadsInitialized(_PyRuntimeState *runtime)
 {
@@ -277,25 +262,18 @@ PyEval_ThreadsInitialized(void)
     _PyRuntimeState *runtime = &_PyRuntime;
     return _PyEval_ThreadsInitialized(runtime);
 }
-#endif
 
 PyStatus
 _PyEval_InitGIL(PyThreadState *tstate)
 {
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
     if (!_Py_IsMainInterpreter(tstate)) {
         /* Currently, the GIL is shared by all interpreters,
            and only the main interpreter is responsible to create
            and destroy it. */
         return _PyStatus_OK();
     }
-#endif
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    struct _gil_runtime_state *gil = &tstate->interp->ceval.gil;
-#else
     struct _gil_runtime_state *gil = &tstate->interp->runtime->ceval.gil;
-#endif
     assert(!gil_created(gil));
 
     PyThread_init_thread();
@@ -310,20 +288,14 @@ _PyEval_InitGIL(PyThreadState *tstate)
 void
 _PyEval_FiniGIL(PyThreadState *tstate)
 {
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
     if (!_Py_IsMainInterpreter(tstate)) {
         /* Currently, the GIL is shared by all interpreters,
            and only the main interpreter is responsible to create
            and destroy it. */
         return;
     }
-#endif
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    struct _gil_runtime_state *gil = &tstate->interp->ceval.gil;
-#else
     struct _gil_runtime_state *gil = &tstate->interp->runtime->ceval.gil;
-#endif
     if (!gil_created(gil)) {
         /* First Py_InitializeFromConfig() call: the GIL doesn't exist
            yet: do nothing. */
@@ -408,13 +380,9 @@ PyEval_AcquireThread(PyThreadState *tstate)
     take_gil(tstate);
 
     struct _gilstate_runtime_state *gilstate = &tstate->interp->runtime->gilstate;
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    (void)_PyThreadState_Swap(gilstate, tstate);
-#else
     if (_PyThreadState_Swap(gilstate, tstate) != NULL) {
         Py_FatalError("non-NULL old thread state");
     }
-#endif
 }
 
 void
@@ -444,11 +412,7 @@ _PyEval_ReInitThreads(_PyRuntimeState *runtime)
     PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
     ensure_tstate_not_null(__func__, tstate);
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    struct _gil_runtime_state *gil = &tstate->interp->ceval.gil;
-#else
     struct _gil_runtime_state *gil = &runtime->ceval.gil;
-#endif
     if (!gil_created(gil)) {
         return;
     }
@@ -480,21 +444,12 @@ PyThreadState *
 PyEval_SaveThread(void)
 {
     _PyRuntimeState *runtime = &_PyRuntime;
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    PyThreadState *old_tstate = _PyThreadState_GET();
-    PyThreadState *tstate = _PyThreadState_Swap(&runtime->gilstate, old_tstate);
-#else
     PyThreadState *tstate = _PyThreadState_Swap(&runtime->gilstate, NULL);
-#endif
     ensure_tstate_not_null(__func__, tstate);
 
     struct _ceval_runtime_state *ceval = &runtime->ceval;
     struct _ceval_state *ceval2 = &tstate->interp->ceval;
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    assert(gil_created(&ceval2->gil));
-#else
     assert(gil_created(&ceval->gil));
-#endif
     drop_gil(ceval, ceval2, tstate);
     return tstate;
 }
@@ -753,9 +708,7 @@ void
 _PyEval_InitRuntimeState(struct _ceval_runtime_state *ceval)
 {
     _Py_CheckRecursionLimit = Py_DEFAULT_RECURSION_LIMIT;
-#ifndef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
     _gil_initialize(&ceval->gil);
-#endif
 }
 
 int
@@ -771,10 +724,6 @@ _PyEval_InitState(struct _ceval_state *ceval)
         return -1;
     }
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-    _gil_initialize(&ceval->gil);
-#endif
-
     return 0;
 }
 
@@ -919,13 +868,9 @@ eval_frame_handle_pending(PyThreadState *tstate)
 
         take_gil(tstate);
 
-#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS
-        (void)_PyThreadState_Swap(&runtime->gilstate, tstate);
-#else
         if (_PyThreadState_Swap(&runtime->gilstate, tstate) != NULL) {
             Py_FatalError("orphan tstate");
         }
-#endif
     }
 
     /* Check for asynchronous exception. */