mirror of
https://github.com/python/cpython.git
synced 2025-10-09 08:31:26 +00:00
bpo-30860: Consolidate stateful runtime globals. (#3397)
* group the (stateful) runtime globals into various topical structs * consolidate the topical structs under a single top-level _PyRuntimeState struct * add a check-c-globals.py script that helps identify runtime globals Other globals are excluded (see globals.txt and check-c-globals.py).
This commit is contained in:
Eric Snow
GitHub
parent
bab21faded
commit
2ebc5ce42a
72 changed files with 2746 additions and 1312 deletions
|
|
@ -8,20 +8,13 @@
|
|||
|
||||
/* First some general settings */
|
||||
|
||||
/* microseconds (the Python API uses seconds, though) */
|
||||
#define DEFAULT_INTERVAL 5000
|
||||
static unsigned long gil_interval = DEFAULT_INTERVAL;
|
||||
#define INTERVAL (gil_interval >= 1 ? gil_interval : 1)
|
||||
|
||||
/* Enable if you want to force the switching of threads at least every `gil_interval` */
|
||||
#undef FORCE_SWITCHING
|
||||
#define FORCE_SWITCHING
|
||||
#define INTERVAL (_PyRuntime.ceval.gil.interval >= 1 ? _PyRuntime.ceval.gil.interval : 1)
|
||||
|
||||
|
||||
/*
|
||||
Notes about the implementation:
|
||||
|
||||
- The GIL is just a boolean variable (gil_locked) whose access is protected
|
||||
- The GIL is just a boolean variable (locked) whose access is protected
|
||||
by a mutex (gil_mutex), and whose changes are signalled by a condition
|
||||
variable (gil_cond). gil_mutex is taken for short periods of time,
|
||||
and therefore mostly uncontended.
|
||||
|
|
@ -48,7 +41,7 @@ static unsigned long gil_interval = DEFAULT_INTERVAL;
|
|||
- When a thread releases the GIL and gil_drop_request is set, that thread
|
||||
ensures that another GIL-awaiting thread gets scheduled.
|
||||
It does so by waiting on a condition variable (switch_cond) until
|
||||
the value of gil_last_holder is changed to something else than its
|
||||
the value of last_holder is changed to something else than its
|
||||
own thread state pointer, indicating that another thread was able to
|
||||
take the GIL.
|
||||
|
||||
|
|
@ -60,11 +53,7 @@ static unsigned long gil_interval = DEFAULT_INTERVAL;
|
|||
*/
|
||||
|
||||
#include "condvar.h"
|
||||
#ifndef Py_HAVE_CONDVAR
|
||||
#error You need either a POSIX-compatible or a Windows system!
|
||||
#endif
|
||||
|
||||
#define MUTEX_T PyMUTEX_T
|
||||
#define MUTEX_INIT(mut) \
|
||||
if (PyMUTEX_INIT(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_INIT(" #mut ") failed"); };
|
||||
|
|
@ -78,7 +67,6 @@ static unsigned long gil_interval = DEFAULT_INTERVAL;
|
|||
if (PyMUTEX_UNLOCK(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_UNLOCK(" #mut ") failed"); };
|
||||
|
||||
#define COND_T PyCOND_T
|
||||
#define COND_INIT(cond) \
|
||||
if (PyCOND_INIT(&(cond))) { \
|
||||
Py_FatalError("PyCOND_INIT(" #cond ") failed"); };
|
||||
|
|
@ -103,48 +91,36 @@ static unsigned long gil_interval = DEFAULT_INTERVAL;
|
|||
} \
|
||||
|
||||
|
||||
#define DEFAULT_INTERVAL 5000
|
||||
|
||||
/* Whether the GIL is already taken (-1 if uninitialized). This is atomic
|
||||
because it can be read without any lock taken in ceval.c. */
|
||||
static _Py_atomic_int gil_locked = {-1};
|
||||
/* Number of GIL switches since the beginning. */
|
||||
static unsigned long gil_switch_number = 0;
|
||||
/* Last PyThreadState holding / having held the GIL. This helps us know
|
||||
whether anyone else was scheduled after we dropped the GIL. */
|
||||
static _Py_atomic_address gil_last_holder = {0};
|
||||
|
||||
/* This condition variable allows one or several threads to wait until
|
||||
the GIL is released. In addition, the mutex also protects the above
|
||||
variables. */
|
||||
static COND_T gil_cond;
|
||||
static MUTEX_T gil_mutex;
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
/* This condition variable helps the GIL-releasing thread wait for
|
||||
a GIL-awaiting thread to be scheduled and take the GIL. */
|
||||
static COND_T switch_cond;
|
||||
static MUTEX_T switch_mutex;
|
||||
#endif
|
||||
|
||||
static void _gil_initialize(struct _gil_runtime_state *state)
|
||||
{
|
||||
_Py_atomic_int uninitialized = {-1};
|
||||
state->locked = uninitialized;
|
||||
state->interval = DEFAULT_INTERVAL;
|
||||
}
|
||||
|
||||
static int gil_created(void)
|
||||
{
|
||||
return _Py_atomic_load_explicit(&gil_locked, _Py_memory_order_acquire) >= 0;
|
||||
return (_Py_atomic_load_explicit(&_PyRuntime.ceval.gil.locked,
|
||||
_Py_memory_order_acquire)
|
||||
) >= 0;
|
||||
}
|
||||
|
||||
static void create_gil(void)
|
||||
{
|
||||
MUTEX_INIT(gil_mutex);
|
||||
MUTEX_INIT(_PyRuntime.ceval.gil.mutex);
|
||||
#ifdef FORCE_SWITCHING
|
||||
MUTEX_INIT(switch_mutex);
|
||||
MUTEX_INIT(_PyRuntime.ceval.gil.switch_mutex);
|
||||
#endif
|
||||
COND_INIT(gil_cond);
|
||||
COND_INIT(_PyRuntime.ceval.gil.cond);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_INIT(switch_cond);
|
||||
COND_INIT(_PyRuntime.ceval.gil.switch_cond);
|
||||
#endif
|
||||
_Py_atomic_store_relaxed(&gil_last_holder, 0);
|
||||
_Py_ANNOTATE_RWLOCK_CREATE(&gil_locked);
|
||||
_Py_atomic_store_explicit(&gil_locked, 0, _Py_memory_order_release);
|
||||
_Py_atomic_store_relaxed(&_PyRuntime.ceval.gil.last_holder, 0);
|
||||
_Py_ANNOTATE_RWLOCK_CREATE(&_PyRuntime.ceval.gil.locked);
|
||||
_Py_atomic_store_explicit(&_PyRuntime.ceval.gil.locked, 0,
|
||||
_Py_memory_order_release);
|
||||
}
|
||||
|
||||
static void destroy_gil(void)
|
||||
|
|
@ -152,54 +128,62 @@ static void destroy_gil(void)
|
|||
/* some pthread-like implementations tie the mutex to the cond
|
||||
* and must have the cond destroyed first.
|
||||
*/
|
||||
COND_FINI(gil_cond);
|
||||
MUTEX_FINI(gil_mutex);
|
||||
COND_FINI(_PyRuntime.ceval.gil.cond);
|
||||
MUTEX_FINI(_PyRuntime.ceval.gil.mutex);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_FINI(switch_cond);
|
||||
MUTEX_FINI(switch_mutex);
|
||||
COND_FINI(_PyRuntime.ceval.gil.switch_cond);
|
||||
MUTEX_FINI(_PyRuntime.ceval.gil.switch_mutex);
|
||||
#endif
|
||||
_Py_atomic_store_explicit(&gil_locked, -1, _Py_memory_order_release);
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil_locked);
|
||||
_Py_atomic_store_explicit(&_PyRuntime.ceval.gil.locked, -1,
|
||||
_Py_memory_order_release);
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&_PyRuntime.ceval.gil.locked);
|
||||
}
|
||||
|
||||
static void recreate_gil(void)
|
||||
{
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil_locked);
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&_PyRuntime.ceval.gil.locked);
|
||||
/* XXX should we destroy the old OS resources here? */
|
||||
create_gil();
|
||||
}
|
||||
|
||||
static void drop_gil(PyThreadState *tstate)
|
||||
{
|
||||
if (!_Py_atomic_load_relaxed(&gil_locked))
|
||||
if (!_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil.locked))
|
||||
Py_FatalError("drop_gil: GIL is not locked");
|
||||
/* tstate is allowed to be NULL (early interpreter init) */
|
||||
if (tstate != NULL) {
|
||||
/* Sub-interpreter support: threads might have been switched
|
||||
under our feet using PyThreadState_Swap(). Fix the GIL last
|
||||
holder variable so that our heuristics work. */
|
||||
_Py_atomic_store_relaxed(&gil_last_holder, (uintptr_t)tstate);
|
||||
_Py_atomic_store_relaxed(&_PyRuntime.ceval.gil.last_holder,
|
||||
(uintptr_t)tstate);
|
||||
}
|
||||
|
||||
MUTEX_LOCK(gil_mutex);
|
||||
_Py_ANNOTATE_RWLOCK_RELEASED(&gil_locked, /*is_write=*/1);
|
||||
_Py_atomic_store_relaxed(&gil_locked, 0);
|
||||
COND_SIGNAL(gil_cond);
|
||||
MUTEX_UNLOCK(gil_mutex);
|
||||
MUTEX_LOCK(_PyRuntime.ceval.gil.mutex);
|
||||
_Py_ANNOTATE_RWLOCK_RELEASED(&_PyRuntime.ceval.gil.locked, /*is_write=*/1);
|
||||
_Py_atomic_store_relaxed(&_PyRuntime.ceval.gil.locked, 0);
|
||||
COND_SIGNAL(_PyRuntime.ceval.gil.cond);
|
||||
MUTEX_UNLOCK(_PyRuntime.ceval.gil.mutex);
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
if (_Py_atomic_load_relaxed(&gil_drop_request) && tstate != NULL) {
|
||||
MUTEX_LOCK(switch_mutex);
|
||||
if (_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil_drop_request) &&
|
||||
tstate != NULL)
|
||||
{
|
||||
MUTEX_LOCK(_PyRuntime.ceval.gil.switch_mutex);
|
||||
/* Not switched yet => wait */
|
||||
if ((PyThreadState*)_Py_atomic_load_relaxed(&gil_last_holder) == tstate) {
|
||||
if (((PyThreadState*)_Py_atomic_load_relaxed(
|
||||
&_PyRuntime.ceval.gil.last_holder)
|
||||
) == tstate)
|
||||
{
|
||||
RESET_GIL_DROP_REQUEST();
|
||||
/* NOTE: if COND_WAIT does not atomically start waiting when
|
||||
releasing the mutex, another thread can run through, take
|
||||
the GIL and drop it again, and reset the condition
|
||||
before we even had a chance to wait for it. */
|
||||
COND_WAIT(switch_cond, switch_mutex);
|
||||
COND_WAIT(_PyRuntime.ceval.gil.switch_cond,
|
||||
_PyRuntime.ceval.gil.switch_mutex);
|
||||
}
|
||||
MUTEX_UNLOCK(switch_mutex);
|
||||
MUTEX_UNLOCK(_PyRuntime.ceval.gil.switch_mutex);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
|
@ -211,60 +195,65 @@ static void take_gil(PyThreadState *tstate)
|
|||
Py_FatalError("take_gil: NULL tstate");
|
||||
|
||||
err = errno;
|
||||
MUTEX_LOCK(gil_mutex);
|
||||
MUTEX_LOCK(_PyRuntime.ceval.gil.mutex);
|
||||
|
||||
if (!_Py_atomic_load_relaxed(&gil_locked))
|
||||
if (!_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil.locked))
|
||||
goto _ready;
|
||||
|
||||
while (_Py_atomic_load_relaxed(&gil_locked)) {
|
||||
while (_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil.locked)) {
|
||||
int timed_out = 0;
|
||||
unsigned long saved_switchnum;
|
||||
|
||||
saved_switchnum = gil_switch_number;
|
||||
COND_TIMED_WAIT(gil_cond, gil_mutex, INTERVAL, timed_out);
|
||||
saved_switchnum = _PyRuntime.ceval.gil.switch_number;
|
||||
COND_TIMED_WAIT(_PyRuntime.ceval.gil.cond, _PyRuntime.ceval.gil.mutex,
|
||||
INTERVAL, timed_out);
|
||||
/* If we timed out and no switch occurred in the meantime, it is time
|
||||
to ask the GIL-holding thread to drop it. */
|
||||
if (timed_out &&
|
||||
_Py_atomic_load_relaxed(&gil_locked) &&
|
||||
gil_switch_number == saved_switchnum) {
|
||||
_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil.locked) &&
|
||||
_PyRuntime.ceval.gil.switch_number == saved_switchnum) {
|
||||
SET_GIL_DROP_REQUEST();
|
||||
}
|
||||
}
|
||||
_ready:
|
||||
#ifdef FORCE_SWITCHING
|
||||
/* This mutex must be taken before modifying gil_last_holder (see drop_gil()). */
|
||||
MUTEX_LOCK(switch_mutex);
|
||||
/* This mutex must be taken before modifying
|
||||
_PyRuntime.ceval.gil.last_holder (see drop_gil()). */
|
||||
MUTEX_LOCK(_PyRuntime.ceval.gil.switch_mutex);
|
||||
#endif
|
||||
/* We now hold the GIL */
|
||||
_Py_atomic_store_relaxed(&gil_locked, 1);
|
||||
_Py_ANNOTATE_RWLOCK_ACQUIRED(&gil_locked, /*is_write=*/1);
|
||||
_Py_atomic_store_relaxed(&_PyRuntime.ceval.gil.locked, 1);
|
||||
_Py_ANNOTATE_RWLOCK_ACQUIRED(&_PyRuntime.ceval.gil.locked, /*is_write=*/1);
|
||||
|
||||
if (tstate != (PyThreadState*)_Py_atomic_load_relaxed(&gil_last_holder)) {
|
||||
_Py_atomic_store_relaxed(&gil_last_holder, (uintptr_t)tstate);
|
||||
++gil_switch_number;
|
||||
if (tstate != (PyThreadState*)_Py_atomic_load_relaxed(
|
||||
&_PyRuntime.ceval.gil.last_holder))
|
||||
{
|
||||
_Py_atomic_store_relaxed(&_PyRuntime.ceval.gil.last_holder,
|
||||
(uintptr_t)tstate);
|
||||
++_PyRuntime.ceval.gil.switch_number;
|
||||
}
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_SIGNAL(switch_cond);
|
||||
MUTEX_UNLOCK(switch_mutex);
|
||||
COND_SIGNAL(_PyRuntime.ceval.gil.switch_cond);
|
||||
MUTEX_UNLOCK(_PyRuntime.ceval.gil.switch_mutex);
|
||||
#endif
|
||||
if (_Py_atomic_load_relaxed(&gil_drop_request)) {
|
||||
if (_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil_drop_request)) {
|
||||
RESET_GIL_DROP_REQUEST();
|
||||
}
|
||||
if (tstate->async_exc != NULL) {
|
||||
_PyEval_SignalAsyncExc();
|
||||
}
|
||||
|
||||
MUTEX_UNLOCK(gil_mutex);
|
||||
MUTEX_UNLOCK(_PyRuntime.ceval.gil.mutex);
|
||||
errno = err;
|
||||
}
|
||||
|
||||
void _PyEval_SetSwitchInterval(unsigned long microseconds)
|
||||
{
|
||||
gil_interval = microseconds;
|
||||
_PyRuntime.ceval.gil.interval = microseconds;
|
||||
}
|
||||
|
||||
unsigned long _PyEval_GetSwitchInterval()
|
||||
{
|
||||
return gil_interval;
|
||||
return _PyRuntime.ceval.gil.interval;
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue