Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Strip down gil.h to the simple version only. #4218

Closed
wants to merge 8 commits into from
Closed

Strip down gil.h to the simple version only. #4218

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
7bbc06e
Strip down gil.h to the simple version only.
rwgk Oct 6, 2022
e70b38b
Explicit `py::gil_scoped_release()` in test_interpreter.cpp `TEST_CAS…
rwgk Oct 6, 2022
7115159
clang-tidy fix
rwgk Oct 6, 2022
7fc5df8
Delete copy ctor, assignment operator also in `!defined(WITH_THREAD)`…
rwgk Oct 6, 2022
f12f194
Use the simplified gil.h from detail/internals.h (to replace gil_scop…
rwgk Oct 6, 2022
ad126f5
Remove explicit `get_internals()` from `TEST_CASE("Threads")` and `RE…
rwgk Oct 6, 2022
be83638
@jbms wrote: We can leave internals.tstate present (depending on ABI …
rwgk Oct 6, 2022
b6b3ad1
Correct silly mistake in previous commit. More version guards are nee…
rwgk Oct 6, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
21 changes: 12 additions & 9 deletions include/pybind11/detail/internals.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@

#pragma once

#include "../gil.h"
#include "../pytypes.h"

#include <exception>
Expand Down Expand Up @@ -169,16 +170,21 @@ struct internals {
PyTypeObject *default_metaclass;
PyObject *instance_base;
#if defined(WITH_THREAD)
# if PYBIND11_INTERNALS_VERSION < 6
PYBIND11_TLS_KEY_INIT(tstate)
# endif // PYBIND11_INTERNALS_VERSION < 6
# if PYBIND11_INTERNALS_VERSION > 4
PYBIND11_TLS_KEY_INIT(loader_life_support_tls_key)
# endif // PYBIND11_INTERNALS_VERSION > 4
# if PYBIND11_INTERNALS_VERSION < 6
PyInterpreterState *istate = nullptr;
# endif // PYBIND11_INTERNALS_VERSION < 6
~internals() {
# if PYBIND11_INTERNALS_VERSION > 4
PYBIND11_TLS_FREE(loader_life_support_tls_key);
# endif // PYBIND11_INTERNALS_VERSION > 4

# if PYBIND11_INTERNALS_VERSION < 6
// This destructor is called *after* Py_Finalize() in finalize_interpreter().
// That *SHOULD BE* fine. The following details what happens when PyThread_tss_free is
// called. PYBIND11_TLS_FREE is PyThread_tss_free on python 3.7+. On older python, it does
Expand All @@ -187,6 +193,7 @@ struct internals {
// Neither of those have anything to do with CPython internals. PyMem_RawFree *requires*
// that the `tstate` be allocated with the CPython allocator.
PYBIND11_TLS_FREE(tstate);
# endif // PYBIND11_INTERNALS_VERSION < 6
}
#endif
};
Expand Down Expand Up @@ -408,15 +415,7 @@ PYBIND11_NOINLINE internals &get_internals() {
return **internals_pp;
}

// Ensure that the GIL is held since we will need to make Python calls.
// Cannot use py::gil_scoped_acquire here since that constructor calls get_internals.
struct gil_scoped_acquire_local {
gil_scoped_acquire_local() : state(PyGILState_Ensure()) {}
gil_scoped_acquire_local(const gil_scoped_acquire_local &) = delete;
gil_scoped_acquire_local &operator=(const gil_scoped_acquire_local &) = delete;
~gil_scoped_acquire_local() { PyGILState_Release(state); }
const PyGILState_STATE state;
} gil;
gil_scoped_acquire gil;
error_scope err_scope;

PYBIND11_STR_TYPE id(PYBIND11_INTERNALS_ID);
Expand Down Expand Up @@ -445,19 +444,23 @@ PYBIND11_NOINLINE internals &get_internals() {
# if PY_VERSION_HEX < 0x03090000
PyEval_InitThreads();
# endif
# if PYBIND11_INTERNALS_VERSION < 6
PyThreadState *tstate = PyThreadState_Get();
if (!PYBIND11_TLS_KEY_CREATE(internals_ptr->tstate)) {
pybind11_fail("get_internals: could not successfully initialize the tstate TSS key!");
}
PYBIND11_TLS_REPLACE_VALUE(internals_ptr->tstate, tstate);
# endif

# if PYBIND11_INTERNALS_VERSION > 4
if (!PYBIND11_TLS_KEY_CREATE(internals_ptr->loader_life_support_tls_key)) {
pybind11_fail("get_internals: could not successfully initialize the "
"loader_life_support TSS key!");
}
# endif
# if PYBIND11_INTERNALS_VERSION < 6
internals_ptr->istate = tstate->interp;
# endif
#endif
builtins[id] = capsule(internals_pp);
internals_ptr->registered_exception_translators.push_front(&translate_exception);
Expand Down
178 changes: 11 additions & 167 deletions include/pybind11/gil.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,180 +10,16 @@
#pragma once

#include "detail/common.h"
#include "detail/internals.h"

PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)

PYBIND11_NAMESPACE_BEGIN(detail)
#if defined(WITH_THREAD)

// forward declarations
PyThreadState *get_thread_state_unchecked();

PYBIND11_NAMESPACE_END(detail)

#if defined(WITH_THREAD) && !defined(PYPY_VERSION)

/* The functions below essentially reproduce the PyGILState_* API using a RAII
* pattern, but there are a few important differences:
*
* 1. When acquiring the GIL from an non-main thread during the finalization
* phase, the GILState API blindly terminates the calling thread, which
* is often not what is wanted. This API does not do this.
*
* 2. The gil_scoped_release function can optionally cut the relationship
* of a PyThreadState and its associated thread, which allows moving it to
* another thread (this is a fairly rare/advanced use case).
*
* 3. The reference count of an acquired thread state can be controlled. This
* can be handy to prevent cases where callbacks issued from an external
* thread would otherwise constantly construct and destroy thread state data
* structures.
*
* See the Python bindings of NanoGUI (http://github.com/wjakob/nanogui) for an
* example which uses features 2 and 3 to migrate the Python thread of
* execution to another thread (to run the event loop on the original thread,
* in this case).
*/

class gil_scoped_acquire {
public:
PYBIND11_NOINLINE gil_scoped_acquire() {
auto &internals = detail::get_internals();
tstate = (PyThreadState *) PYBIND11_TLS_GET_VALUE(internals.tstate);

if (!tstate) {
/* Check if the GIL was acquired using the PyGILState_* API instead (e.g. if
calling from a Python thread). Since we use a different key, this ensures
we don't create a new thread state and deadlock in PyEval_AcquireThread
below. Note we don't save this state with internals.tstate, since we don't
create it we would fail to clear it (its reference count should be > 0). */
tstate = PyGILState_GetThisThreadState();
}

if (!tstate) {
tstate = PyThreadState_New(internals.istate);
# if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
if (!tstate) {
pybind11_fail("scoped_acquire: could not create thread state!");
}
# endif
tstate->gilstate_counter = 0;
PYBIND11_TLS_REPLACE_VALUE(internals.tstate, tstate);
} else {
release = detail::get_thread_state_unchecked() != tstate;
}

if (release) {
PyEval_AcquireThread(tstate);
}

inc_ref();
}

gil_scoped_acquire(const gil_scoped_acquire &) = delete;
gil_scoped_acquire &operator=(const gil_scoped_acquire &) = delete;

void inc_ref() { ++tstate->gilstate_counter; }

PYBIND11_NOINLINE void dec_ref() {
--tstate->gilstate_counter;
# if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
if (detail::get_thread_state_unchecked() != tstate) {
pybind11_fail("scoped_acquire::dec_ref(): thread state must be current!");
}
if (tstate->gilstate_counter < 0) {
pybind11_fail("scoped_acquire::dec_ref(): reference count underflow!");
}
# endif
if (tstate->gilstate_counter == 0) {
# if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
if (!release) {
pybind11_fail("scoped_acquire::dec_ref(): internal error!");
}
# endif
PyThreadState_Clear(tstate);
if (active) {
PyThreadState_DeleteCurrent();
}
PYBIND11_TLS_DELETE_VALUE(detail::get_internals().tstate);
release = false;
}
}

/// This method will disable the PyThreadState_DeleteCurrent call and the
/// GIL won't be acquired. This method should be used if the interpreter
/// could be shutting down when this is called, as thread deletion is not
/// allowed during shutdown. Check _Py_IsFinalizing() on Python 3.7+, and
/// protect subsequent code.
PYBIND11_NOINLINE void disarm() { active = false; }

PYBIND11_NOINLINE ~gil_scoped_acquire() {
dec_ref();
if (release) {
PyEval_SaveThread();
}
}

private:
PyThreadState *tstate = nullptr;
bool release = true;
bool active = true;
};

class gil_scoped_release {
public:
explicit gil_scoped_release(bool disassoc = false) : disassoc(disassoc) {
// `get_internals()` must be called here unconditionally in order to initialize
// `internals.tstate` for subsequent `gil_scoped_acquire` calls. Otherwise, an
// initialization race could occur as multiple threads try `gil_scoped_acquire`.
auto &internals = detail::get_internals();
// NOLINTNEXTLINE(cppcoreguidelines-prefer-member-initializer)
tstate = PyEval_SaveThread();
if (disassoc) {
// Python >= 3.7 can remove this, it's an int before 3.7
// NOLINTNEXTLINE(readability-qualified-auto)
auto key = internals.tstate;
PYBIND11_TLS_DELETE_VALUE(key);
}
}

gil_scoped_release(const gil_scoped_acquire &) = delete;
gil_scoped_release &operator=(const gil_scoped_acquire &) = delete;

/// This method will disable the PyThreadState_DeleteCurrent call and the
/// GIL won't be acquired. This method should be used if the interpreter
/// could be shutting down when this is called, as thread deletion is not
/// allowed during shutdown. Check _Py_IsFinalizing() on Python 3.7+, and
/// protect subsequent code.
PYBIND11_NOINLINE void disarm() { active = false; }

~gil_scoped_release() {
if (!tstate) {
return;
}
// `PyEval_RestoreThread()` should not be called if runtime is finalizing
if (active) {
PyEval_RestoreThread(tstate);
}
if (disassoc) {
// Python >= 3.7 can remove this, it's an int before 3.7
// NOLINTNEXTLINE(readability-qualified-auto)
auto key = detail::get_internals().tstate;
PYBIND11_TLS_REPLACE_VALUE(key, tstate);
}
}

private:
PyThreadState *tstate;
bool disassoc;
bool active = true;
};
#elif defined(PYPY_VERSION)
class gil_scoped_acquire {
PyGILState_STATE state;

public:
gil_scoped_acquire() { state = PyGILState_Ensure(); }
gil_scoped_acquire() : state{PyGILState_Ensure()} {}
gil_scoped_acquire(const gil_scoped_acquire &) = delete;
gil_scoped_acquire &operator=(const gil_scoped_acquire &) = delete;
~gil_scoped_acquire() { PyGILState_Release(state); }
Expand All @@ -194,19 +30,27 @@ class gil_scoped_release {
PyThreadState *state;

public:
gil_scoped_release() { state = PyEval_SaveThread(); }
gil_scoped_release() : state{PyEval_SaveThread()} {}
gil_scoped_release(const gil_scoped_release &) = delete;
gil_scoped_release &operator=(const gil_scoped_acquire &) = delete;
~gil_scoped_release() { PyEval_RestoreThread(state); }
void disarm() {}
};

#else

class gil_scoped_acquire {
gil_scoped_acquire(const gil_scoped_acquire &) = delete;
gil_scoped_acquire &operator=(const gil_scoped_acquire &) = delete;
void disarm() {}
};

class gil_scoped_release {
gil_scoped_release(const gil_scoped_release &) = delete;
gil_scoped_release &operator=(const gil_scoped_acquire &) = delete;
void disarm() {}
};

#endif

PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
1 change: 0 additions & 1 deletion tests/test_embed/test_interpreter.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -293,7 +293,6 @@ TEST_CASE("Threads") {

{
py::gil_scoped_release gil_release{};
REQUIRE(has_pybind11_internals_static());

auto threads = std::vector<std::thread>();
for (auto i = 0; i < num_threads; ++i) {
Expand Down