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gh-99113: Add PyInterpreterConfig.own_gil (gh-104204)
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We also add PyInterpreterState.ceval.own_gil to record if the interpreter actually has its own GIL.

Note that for now we don't actually respect own_gil; all interpreters still share the one GIL.  However, PyInterpreterState.ceval.own_gil does reflect PyInterpreterConfig.own_gil.  That lie is a temporary one that we will fix when the GIL really becomes per-interpreter.
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ericsnowcurrently authored May 5, 2023

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1 parent 66558d2 commit f3e7eb4
Showing 11 changed files with 80 additions and 19 deletions.
3 changes: 3 additions & 0 deletions Include/cpython/initconfig.h
Original file line number Diff line number Diff line change
@@ -252,6 +252,7 @@ typedef struct {
int allow_threads;
int allow_daemon_threads;
int check_multi_interp_extensions;
int own_gil;
} PyInterpreterConfig;

#define _PyInterpreterConfig_INIT \
@@ -262,6 +263,7 @@ typedef struct {
.allow_threads = 1, \
.allow_daemon_threads = 0, \
.check_multi_interp_extensions = 1, \
.own_gil = 1, \
}

#define _PyInterpreterConfig_LEGACY_INIT \
@@ -272,6 +274,7 @@ typedef struct {
.allow_threads = 1, \
.allow_daemon_threads = 1, \
.check_multi_interp_extensions = 0, \
.own_gil = 0, \
}

/* --- Helper functions --------------------------------------- */
2 changes: 1 addition & 1 deletion Include/internal/pycore_ceval.h
Original file line number Diff line number Diff line change
@@ -97,7 +97,7 @@ _PyEval_Vector(PyThreadState *tstate,
PyObject *kwnames);

extern int _PyEval_ThreadsInitialized(void);
extern PyStatus _PyEval_InitGIL(PyThreadState *tstate);
extern PyStatus _PyEval_InitGIL(PyThreadState *tstate, int own_gil);
extern void _PyEval_FiniGIL(PyInterpreterState *interp);

extern void _PyEval_ReleaseLock(PyThreadState *tstate);
1 change: 1 addition & 0 deletions Include/internal/pycore_ceval_state.h
Original file line number Diff line number Diff line change
@@ -86,6 +86,7 @@ struct _pending_calls {
struct _ceval_state {
int recursion_limit;
struct _gil_runtime_state *gil;
int own_gil;
/* This single variable consolidates all requests to break out of
the fast path in the eval loop. */
_Py_atomic_int eval_breaker;
36 changes: 26 additions & 10 deletions Lib/test/test_capi/test_misc.py
Original file line number Diff line number Diff line change
@@ -1401,23 +1401,37 @@ def test_configured_settings(self):
DAEMON_THREADS = 1<<11
FORK = 1<<15
EXEC = 1<<16

features = ['obmalloc', 'fork', 'exec', 'threads', 'daemon_threads',
'extensions']
ALL_FLAGS = (OBMALLOC | FORK | EXEC | THREADS | DAEMON_THREADS
| EXTENSIONS);

features = [
'obmalloc',
'fork',
'exec',
'threads',
'daemon_threads',
'extensions',
'own_gil',
]
kwlist = [f'allow_{n}' for n in features]
kwlist[0] = 'use_main_obmalloc'
kwlist[-1] = 'check_multi_interp_extensions'
kwlist[-2] = 'check_multi_interp_extensions'
kwlist[-1] = 'own_gil'

# expected to work
for config, expected in {
(True, True, True, True, True, True):
OBMALLOC | FORK | EXEC | THREADS | DAEMON_THREADS | EXTENSIONS,
(True, False, False, False, False, False): OBMALLOC,
(False, False, False, True, False, True): THREADS | EXTENSIONS,
(True, True, True, True, True, True, True):
(ALL_FLAGS, True),
(True, False, False, False, False, False, False):
(OBMALLOC, False),
(False, False, False, True, False, True, False):
(THREADS | EXTENSIONS, False),
}.items():
kwargs = dict(zip(kwlist, config))
exp_flags, exp_gil = expected
expected = {
'feature_flags': expected,
'feature_flags': exp_flags,
'own_gil': exp_gil,
}
with self.subTest(config):
r, w = os.pipe()
@@ -1437,7 +1451,7 @@ def test_configured_settings(self):

# expected to fail
for config in [
(False, False, False, False, False, False),
(False, False, False, False, False, False, False),
]:
kwargs = dict(zip(kwlist, config))
with self.subTest(config):
@@ -1473,6 +1487,7 @@ def test_overridden_setting_extensions_subinterp_check(self):
'allow_exec': True,
'allow_threads': True,
'allow_daemon_threads': True,
'own_gil': False,
}

def check(enabled, override):
@@ -1483,6 +1498,7 @@ def check(enabled, override):
flags = BASE_FLAGS | EXTENSIONS if enabled else BASE_FLAGS
settings = {
'feature_flags': flags,
'own_gil': False,
}

expected = {
1 change: 1 addition & 0 deletions Lib/test/test_embed.py
Original file line number Diff line number Diff line change
@@ -1666,6 +1666,7 @@ def test_init_main_interpreter_settings(self):
# All optional features should be enabled.
'feature_flags':
OBMALLOC | FORK | EXEC | THREADS | DAEMON_THREADS,
'own_gil': True,
}
out, err = self.run_embedded_interpreter(
'test_init_main_interpreter_settings',
1 change: 1 addition & 0 deletions Lib/test/test_import/__init__.py
Original file line number Diff line number Diff line change
@@ -1640,6 +1640,7 @@ class SubinterpImportTests(unittest.TestCase):
)
ISOLATED = dict(
use_main_obmalloc=False,
own_gil=True,
)
NOT_ISOLATED = {k: not v for k, v in ISOLATED.items()}

1 change: 1 addition & 0 deletions Lib/test/test_threading.py
Original file line number Diff line number Diff line change
@@ -1349,6 +1349,7 @@ def func():
allow_threads={allowed},
allow_daemon_threads={daemon_allowed},
check_multi_interp_extensions=False,
own_gil=False,
)
""")
with test.support.SuppressCrashReport():
12 changes: 10 additions & 2 deletions Modules/_testcapimodule.c
Original file line number Diff line number Diff line change
@@ -1488,6 +1488,7 @@ run_in_subinterp_with_config(PyObject *self, PyObject *args, PyObject *kwargs)
int allow_threads = -1;
int allow_daemon_threads = -1;
int check_multi_interp_extensions = -1;
int own_gil = -1;
int r;
PyThreadState *substate, *mainstate;
/* only initialise 'cflags.cf_flags' to test backwards compatibility */
@@ -1500,13 +1501,15 @@ run_in_subinterp_with_config(PyObject *self, PyObject *args, PyObject *kwargs)
"allow_threads",
"allow_daemon_threads",
"check_multi_interp_extensions",
"own_gil",
NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwargs,
"s$pppppp:run_in_subinterp_with_config", kwlist,
"s$ppppppp:run_in_subinterp_with_config", kwlist,
&code, &use_main_obmalloc,
&allow_fork, &allow_exec,
&allow_threads, &allow_daemon_threads,
&check_multi_interp_extensions)) {
&check_multi_interp_extensions,
&own_gil)) {
return NULL;
}
if (use_main_obmalloc < 0) {
@@ -1525,6 +1528,10 @@ run_in_subinterp_with_config(PyObject *self, PyObject *args, PyObject *kwargs)
PyErr_SetString(PyExc_ValueError, "missing allow_threads");
return NULL;
}
if (own_gil < 0) {
PyErr_SetString(PyExc_ValueError, "missing own_gil");
return NULL;
}
if (allow_daemon_threads < 0) {
PyErr_SetString(PyExc_ValueError, "missing allow_daemon_threads");
return NULL;
@@ -1545,6 +1552,7 @@ run_in_subinterp_with_config(PyObject *self, PyObject *args, PyObject *kwargs)
.allow_threads = allow_threads,
.allow_daemon_threads = allow_daemon_threads,
.check_multi_interp_extensions = check_multi_interp_extensions,
.own_gil = own_gil,
};
PyStatus status = Py_NewInterpreterFromConfig(&substate, &config);
if (PyStatus_Exception(status)) {
7 changes: 7 additions & 0 deletions Modules/_testinternalcapi.c
Original file line number Diff line number Diff line change
@@ -729,6 +729,13 @@ get_interp_settings(PyObject *self, PyObject *args)
return NULL;
}

/* "own GIL" */
PyObject *own_gil = interp->ceval.own_gil ? Py_True : Py_False;
if (PyDict_SetItemString(settings, "own_gil", own_gil) != 0) {
Py_DECREF(settings);
return NULL;
}

return settings;
}

23 changes: 22 additions & 1 deletion Python/ceval_gil.c
Original file line number Diff line number Diff line change
@@ -500,9 +500,18 @@ PyEval_ThreadsInitialized(void)
}

PyStatus
_PyEval_InitGIL(PyThreadState *tstate)
_PyEval_InitGIL(PyThreadState *tstate, int own_gil)
{
assert(tstate->interp->ceval.gil == NULL);
if (!own_gil) {
PyInterpreterState *main_interp = _PyInterpreterState_Main();
assert(tstate->interp != main_interp);
struct _gil_runtime_state *gil = main_interp->ceval.gil;
assert(gil_created(gil));
tstate->interp->ceval.gil = gil;
tstate->interp->ceval.own_gil = 0;
return _PyStatus_OK();
}

/* XXX per-interpreter GIL */
struct _gil_runtime_state *gil = &tstate->interp->runtime->ceval.gil;
@@ -512,15 +521,19 @@ _PyEval_InitGIL(PyThreadState *tstate)
and destroy it. */
assert(gil_created(gil));
tstate->interp->ceval.gil = gil;
// XXX For now we lie.
tstate->interp->ceval.own_gil = 1;
return _PyStatus_OK();
}
assert(own_gil);

assert(!gil_created(gil));

PyThread_init_thread();
create_gil(gil);
assert(gil_created(gil));
tstate->interp->ceval.gil = gil;
tstate->interp->ceval.own_gil = 1;
take_gil(tstate);
return _PyStatus_OK();
}
@@ -530,6 +543,14 @@ _PyEval_FiniGIL(PyInterpreterState *interp)
{
if (interp->ceval.gil == NULL) {
/* It was already finalized (or hasn't been initialized yet). */
assert(!interp->ceval.own_gil);
return;
}
else if (!interp->ceval.own_gil) {
PyInterpreterState *main_interp = _PyInterpreterState_Main();
assert(interp != main_interp);
assert(interp->ceval.gil == main_interp->ceval.gil);
interp->ceval.gil = NULL;
return;
}

12 changes: 7 additions & 5 deletions Python/pylifecycle.c
Original file line number Diff line number Diff line change
@@ -585,7 +585,7 @@ init_interp_settings(PyInterpreterState *interp,


static PyStatus
init_interp_create_gil(PyThreadState *tstate)
init_interp_create_gil(PyThreadState *tstate, int own_gil)
{
PyStatus status;

@@ -600,7 +600,7 @@ init_interp_create_gil(PyThreadState *tstate)
}

/* Create the GIL and take it */
status = _PyEval_InitGIL(tstate);
status = _PyEval_InitGIL(tstate, own_gil);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
@@ -632,7 +632,9 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
return status;
}

const PyInterpreterConfig config = _PyInterpreterConfig_LEGACY_INIT;
PyInterpreterConfig config = _PyInterpreterConfig_LEGACY_INIT;
// The main interpreter always has its own GIL.
config.own_gil = 1;
status = init_interp_settings(interp, &config);
if (_PyStatus_EXCEPTION(status)) {
return status;
@@ -645,7 +647,7 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
_PyThreadState_Bind(tstate);
(void) PyThreadState_Swap(tstate);

status = init_interp_create_gil(tstate);
status = init_interp_create_gil(tstate, config.own_gil);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
@@ -2047,7 +2049,7 @@ new_interpreter(PyThreadState **tstate_p, const PyInterpreterConfig *config)
goto error;
}

status = init_interp_create_gil(tstate);
status = init_interp_create_gil(tstate, config->own_gil);
if (_PyStatus_EXCEPTION(status)) {
goto error;
}

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