cpython/Python/critical_section.c at 3.13 · python/cpython · GitHub

Name: cpython/Python/critical_section.c at 3.13 · python/cpython · GitHub
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#include"Python.h"

#include"pycore_lock.h"
#include"pycore_critical_section.h"

#ifdefPy_GIL_DISABLED
static_assert(_Alignof(PyCriticalSection) >= 4,
"critical section must be aligned to at least 4 bytes");
#endif

void
_PyCriticalSection_BeginSlow(PyCriticalSection*c, PyMutex*m)
{
#ifdefPy_GIL_DISABLED
PyThreadState*tstate=_PyThreadState_GET();
c->_cs_mutex=NULL;
c->_cs_prev= (uintptr_t)tstate->critical_section;
tstate->critical_section= (uintptr_t)c;

PyMutex_Lock(m);
c->_cs_mutex=m;
#endif
}

void
_PyCriticalSection2_BeginSlow(PyCriticalSection2*c, PyMutex*m1, PyMutex*m2,
intis_m1_locked)
{
#ifdefPy_GIL_DISABLED
PyThreadState*tstate=_PyThreadState_GET();
c->_cs_base._cs_mutex=NULL;
c->_cs_mutex2=NULL;
c->_cs_base._cs_prev=tstate->critical_section;
tstate->critical_section= (uintptr_t)c | _Py_CRITICAL_SECTION_TWO_MUTEXES;

if (!is_m1_locked) {
PyMutex_Lock(m1);
 }
PyMutex_Lock(m2);
c->_cs_base._cs_mutex=m1;
c->_cs_mutex2=m2;
#endif
}

#ifdefPy_GIL_DISABLED
staticPyCriticalSection*
untag_critical_section(uintptr_ttag)
{
return (PyCriticalSection*)(tag& ~_Py_CRITICAL_SECTION_MASK);
}
#endif

// Release all locks held by critical sections. This is called by
// _PyThreadState_Detach.
void
_PyCriticalSection_SuspendAll(PyThreadState*tstate)
{
#ifdefPy_GIL_DISABLED
uintptr_t*tagptr=&tstate->critical_section;
while (_PyCriticalSection_IsActive(*tagptr)) {
PyCriticalSection*c=untag_critical_section(*tagptr);

if (c->_cs_mutex) {
PyMutex_Unlock(c->_cs_mutex);
if ((*tagptr&_Py_CRITICAL_SECTION_TWO_MUTEXES)) {
PyCriticalSection2*c2= (PyCriticalSection2*)c;
if (c2->_cs_mutex2) {
PyMutex_Unlock(c2->_cs_mutex2);
 }
 }
 }

*tagptr |= _Py_CRITICAL_SECTION_INACTIVE;
tagptr=&c->_cs_prev;
 }
#endif
}

void
_PyCriticalSection_Resume(PyThreadState*tstate)
{
#ifdefPy_GIL_DISABLED
uintptr_tp=tstate->critical_section;
PyCriticalSection*c=untag_critical_section(p);
assert(!_PyCriticalSection_IsActive(p));

PyMutex*m1=c->_cs_mutex;
c->_cs_mutex=NULL;

PyMutex*m2=NULL;
PyCriticalSection2*c2=NULL;
if ((p&_Py_CRITICAL_SECTION_TWO_MUTEXES)) {
c2= (PyCriticalSection2*)c;
m2=c2->_cs_mutex2;
c2->_cs_mutex2=NULL;
 }

if (m1) {
PyMutex_Lock(m1);
 }
if (m2) {
PyMutex_Lock(m2);
 }

c->_cs_mutex=m1;
if (m2) {
c2->_cs_mutex2=m2;
 }

tstate->critical_section &= ~_Py_CRITICAL_SECTION_INACTIVE;
#endif
}

#undef PyCriticalSection_Begin
void
PyCriticalSection_Begin(PyCriticalSection*c, PyObject*op)
{
#ifdefPy_GIL_DISABLED
_PyCriticalSection_Begin(c, op);
#endif
}

#undef PyCriticalSection_End
void
PyCriticalSection_End(PyCriticalSection*c)
{
#ifdefPy_GIL_DISABLED
_PyCriticalSection_End(c);
#endif
}

#undef PyCriticalSection2_Begin
void
PyCriticalSection2_Begin(PyCriticalSection2*c, PyObject*a, PyObject*b)
{
#ifdefPy_GIL_DISABLED
_PyCriticalSection2_Begin(c, a, b);
#endif
}

#undef PyCriticalSection2_End
void
PyCriticalSection2_End(PyCriticalSection2*c)
{
#ifdefPy_GIL_DISABLED
_PyCriticalSection2_End(c);
#endif
}