mirror of
https://github.com/python/cpython
synced 2024-10-14 16:37:41 +00:00
GH-96177: Move GIL and eval breaker code out of ceval.c into ceval_gil.c. (GH-96204)
This commit is contained in:
parent
4de06e3cc0
commit
a4a9f2e879
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@ -133,6 +133,9 @@ extern struct _PyInterpreterFrame* _PyEval_GetFrame(void);
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extern PyObject* _Py_MakeCoro(PyFunctionObject *func);
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extern int _Py_HandlePending(PyThreadState *tstate);
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#ifdef __cplusplus
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}
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#endif
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@ -85,13 +85,14 @@ _PyThreadState_GET(void)
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return _PyRuntimeState_GetThreadState(&_PyRuntime);
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}
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PyAPI_FUNC(void) _Py_NO_RETURN _Py_FatalError_TstateNULL(const char *func);
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static inline void
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_Py_EnsureFuncTstateNotNULL(const char *func, PyThreadState *tstate)
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{
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if (tstate == NULL) {
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_Py_FatalError_TstateNULL(func);
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_Py_FatalErrorFunc(func,
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"the function must be called with the GIL held, "
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"after Python initialization and before Python finalization, "
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"but the GIL is released (the current Python thread state is NULL)");
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}
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}
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@ -388,6 +388,7 @@ PYTHON_OBJS= \
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Python/getcopyright.o \
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Python/getplatform.o \
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Python/getversion.o \
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Python/ceval_gil.o \
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Python/hamt.o \
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Python/hashtable.o \
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Python/import.o \
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@ -1419,8 +1420,7 @@ regen-opcode-targets:
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$(srcdir)/Python/opcode_targets.h.new
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$(UPDATE_FILE) $(srcdir)/Python/opcode_targets.h $(srcdir)/Python/opcode_targets.h.new
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Python/ceval.o: $(srcdir)/Python/opcode_targets.h $(srcdir)/Python/ceval_gil.h \
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$(srcdir)/Python/condvar.h
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Python/ceval.o: $(srcdir)/Python/opcode_targets.h $(srcdir)/Python/condvar.h
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Python/frozen.o: $(FROZEN_FILES_OUT)
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@ -199,6 +199,7 @@
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<ClCompile Include="..\Python\getopt.c" />
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<ClCompile Include="..\Python\getplatform.c" />
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<ClCompile Include="..\Python\getversion.c" />
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<ClCompile Include="..\Python\ceval_gil.c" />
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<ClCompile Include="..\Python\hamt.c" />
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<ClCompile Include="..\Python\hashtable.c" />
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<ClCompile Include="..\Python\import.c" />
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@ -184,6 +184,9 @@
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<ClCompile Include="..\Python\getversion.c">
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<Filter>Source Files</Filter>
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</ClCompile>
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<ClCompile Include="..\Python\ceval_gil.c">
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<Filter>Source Files</Filter>
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</ClCompile>
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<ClCompile Include="..\Python\hamt.c">
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<Filter>Source Files</Filter>
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</ClCompile>
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@ -327,7 +327,6 @@
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<ClInclude Include="..\Parser\pegen.h" />
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<ClInclude Include="..\PC\errmap.h" />
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<ClInclude Include="..\PC\pyconfig.h" />
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<ClInclude Include="..\Python\ceval_gil.h" />
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<ClInclude Include="..\Python\condvar.h" />
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<ClInclude Include="..\Python\importdl.h" />
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<ClInclude Include="..\Python\stdlib_module_names.h" />
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@ -502,6 +501,7 @@
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<ClCompile Include="..\Python\getopt.c" />
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<ClCompile Include="..\Python\getplatform.c" />
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<ClCompile Include="..\Python\getversion.c" />
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<ClCompile Include="..\Python\ceval_gil.c" />
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<ClCompile Include="..\Python\hamt.c" />
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<ClCompile Include="..\Python\hashtable.c" />
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<ClCompile Include="..\Python\import.c" />
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@ -312,9 +312,6 @@
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<ClInclude Include="..\Python\condvar.h">
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<Filter>Python</Filter>
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</ClInclude>
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<ClInclude Include="..\Python\ceval_gil.h">
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<Filter>Python</Filter>
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</ClInclude>
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<ClInclude Include="..\Include\pyhash.h">
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<Filter>Include</Filter>
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</ClInclude>
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@ -1097,6 +1094,9 @@
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<ClCompile Include="..\Python\getversion.c">
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<Filter>Python</Filter>
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</ClCompile>
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<ClCompile Include="..\Python\ceval_gil.c">
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<Filter>Python</Filter>
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</ClCompile>
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<ClCompile Include="..\Python\hashtable.c">
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<Filter>Modules</Filter>
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</ClCompile>
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642
Python/ceval.c
642
Python/ceval.c
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@ -13,13 +13,11 @@
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#include "pycore_ceval.h" // _PyEval_SignalAsyncExc()
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#include "pycore_code.h"
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#include "pycore_function.h"
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#include "pycore_initconfig.h" // _PyStatus_OK()
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#include "pycore_long.h" // _PyLong_GetZero()
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#include "pycore_object.h" // _PyObject_GC_TRACK()
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#include "pycore_moduleobject.h" // PyModuleObject
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#include "pycore_opcode.h" // EXTRA_CASES
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#include "pycore_pyerrors.h" // _PyErr_Fetch()
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#include "pycore_pylifecycle.h" // _PyErr_Print()
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#include "pycore_pymem.h" // _PyMem_IsPtrFreed()
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#include "pycore_pystate.h" // _PyInterpreterState_GET()
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#include "pycore_range.h" // _PyRangeIterObject
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@ -237,582 +235,9 @@ is_tstate_valid(PyThreadState *tstate)
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#endif
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/* This can set eval_breaker to 0 even though gil_drop_request became
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1. We believe this is all right because the eval loop will release
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the GIL eventually anyway. */
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static inline void
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COMPUTE_EVAL_BREAKER(PyInterpreterState *interp,
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struct _ceval_runtime_state *ceval,
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struct _ceval_state *ceval2)
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{
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_Py_atomic_store_relaxed(&ceval2->eval_breaker,
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_Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)
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| (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)
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&& _Py_ThreadCanHandleSignals(interp))
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| (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)
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&& _Py_ThreadCanHandlePendingCalls())
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| ceval2->pending.async_exc);
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}
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static inline void
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SET_GIL_DROP_REQUEST(PyInterpreterState *interp)
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{
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval2->gil_drop_request, 1);
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_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
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}
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static inline void
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RESET_GIL_DROP_REQUEST(PyInterpreterState *interp)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval2->gil_drop_request, 0);
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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static inline void
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SIGNAL_PENDING_CALLS(PyInterpreterState *interp)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval2->pending.calls_to_do, 1);
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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static inline void
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UNSIGNAL_PENDING_CALLS(PyInterpreterState *interp)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval2->pending.calls_to_do, 0);
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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static inline void
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SIGNAL_PENDING_SIGNALS(PyInterpreterState *interp, int force)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval->signals_pending, 1);
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if (force) {
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_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
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}
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else {
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/* eval_breaker is not set to 1 if thread_can_handle_signals() is false */
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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}
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static inline void
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UNSIGNAL_PENDING_SIGNALS(PyInterpreterState *interp)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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_Py_atomic_store_relaxed(&ceval->signals_pending, 0);
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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static inline void
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SIGNAL_ASYNC_EXC(PyInterpreterState *interp)
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{
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struct _ceval_state *ceval2 = &interp->ceval;
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ceval2->pending.async_exc = 1;
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_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
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}
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static inline void
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UNSIGNAL_ASYNC_EXC(PyInterpreterState *interp)
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{
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struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
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struct _ceval_state *ceval2 = &interp->ceval;
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ceval2->pending.async_exc = 0;
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COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
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}
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include "ceval_gil.h"
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void _Py_NO_RETURN
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_Py_FatalError_TstateNULL(const char *func)
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{
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_Py_FatalErrorFunc(func,
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"the function must be called with the GIL held, "
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"after Python initialization and before Python finalization, "
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"but the GIL is released (the current Python thread state is NULL)");
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}
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int
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_PyEval_ThreadsInitialized(_PyRuntimeState *runtime)
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{
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return gil_created(&runtime->ceval.gil);
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}
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int
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PyEval_ThreadsInitialized(void)
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{
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_PyRuntimeState *runtime = &_PyRuntime;
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return _PyEval_ThreadsInitialized(runtime);
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}
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PyStatus
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_PyEval_InitGIL(PyThreadState *tstate)
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{
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if (!_Py_IsMainInterpreter(tstate->interp)) {
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/* Currently, the GIL is shared by all interpreters,
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and only the main interpreter is responsible to create
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and destroy it. */
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return _PyStatus_OK();
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}
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struct _gil_runtime_state *gil = &tstate->interp->runtime->ceval.gil;
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assert(!gil_created(gil));
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PyThread_init_thread();
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create_gil(gil);
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take_gil(tstate);
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assert(gil_created(gil));
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return _PyStatus_OK();
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}
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void
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_PyEval_FiniGIL(PyInterpreterState *interp)
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{
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if (!_Py_IsMainInterpreter(interp)) {
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/* Currently, the GIL is shared by all interpreters,
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and only the main interpreter is responsible to create
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and destroy it. */
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return;
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}
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struct _gil_runtime_state *gil = &interp->runtime->ceval.gil;
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if (!gil_created(gil)) {
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/* First Py_InitializeFromConfig() call: the GIL doesn't exist
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yet: do nothing. */
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return;
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}
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destroy_gil(gil);
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assert(!gil_created(gil));
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}
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void
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PyEval_InitThreads(void)
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{
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/* Do nothing: kept for backward compatibility */
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}
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void
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_PyEval_Fini(void)
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{
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#ifdef Py_STATS
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_Py_PrintSpecializationStats(1);
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#endif
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}
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void
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PyEval_AcquireLock(void)
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{
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_PyRuntimeState *runtime = &_PyRuntime;
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PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
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_Py_EnsureTstateNotNULL(tstate);
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take_gil(tstate);
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}
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void
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PyEval_ReleaseLock(void)
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{
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_PyRuntimeState *runtime = &_PyRuntime;
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PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
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/* This function must succeed when the current thread state is NULL.
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We therefore avoid PyThreadState_Get() which dumps a fatal error
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in debug mode. */
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struct _ceval_runtime_state *ceval = &runtime->ceval;
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struct _ceval_state *ceval2 = &tstate->interp->ceval;
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drop_gil(ceval, ceval2, tstate);
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}
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void
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_PyEval_ReleaseLock(PyThreadState *tstate)
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{
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struct _ceval_runtime_state *ceval = &tstate->interp->runtime->ceval;
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struct _ceval_state *ceval2 = &tstate->interp->ceval;
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drop_gil(ceval, ceval2, tstate);
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}
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void
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PyEval_AcquireThread(PyThreadState *tstate)
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{
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_Py_EnsureTstateNotNULL(tstate);
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take_gil(tstate);
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struct _gilstate_runtime_state *gilstate = &tstate->interp->runtime->gilstate;
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if (_PyThreadState_Swap(gilstate, tstate) != NULL) {
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Py_FatalError("non-NULL old thread state");
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}
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}
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void
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PyEval_ReleaseThread(PyThreadState *tstate)
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{
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assert(is_tstate_valid(tstate));
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_PyRuntimeState *runtime = tstate->interp->runtime;
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PyThreadState *new_tstate = _PyThreadState_Swap(&runtime->gilstate, NULL);
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if (new_tstate != tstate) {
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Py_FatalError("wrong thread state");
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}
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struct _ceval_runtime_state *ceval = &runtime->ceval;
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struct _ceval_state *ceval2 = &tstate->interp->ceval;
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drop_gil(ceval, ceval2, tstate);
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}
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#ifdef HAVE_FORK
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/* This function is called from PyOS_AfterFork_Child to destroy all threads
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which are not running in the child process, and clear internal locks
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which might be held by those threads. */
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PyStatus
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_PyEval_ReInitThreads(PyThreadState *tstate)
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{
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_PyRuntimeState *runtime = tstate->interp->runtime;
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struct _gil_runtime_state *gil = &runtime->ceval.gil;
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if (!gil_created(gil)) {
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return _PyStatus_OK();
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}
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recreate_gil(gil);
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take_gil(tstate);
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struct _pending_calls *pending = &tstate->interp->ceval.pending;
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if (_PyThread_at_fork_reinit(&pending->lock) < 0) {
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return _PyStatus_ERR("Can't reinitialize pending calls lock");
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}
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/* Destroy all threads except the current one */
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_PyThreadState_DeleteExcept(runtime, tstate);
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return _PyStatus_OK();
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}
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#endif
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/* This function is used to signal that async exceptions are waiting to be
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raised. */
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void
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_PyEval_SignalAsyncExc(PyInterpreterState *interp)
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{
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SIGNAL_ASYNC_EXC(interp);
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}
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PyThreadState *
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PyEval_SaveThread(void)
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{
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_PyRuntimeState *runtime = &_PyRuntime;
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PyThreadState *tstate = _PyThreadState_Swap(&runtime->gilstate, NULL);
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_Py_EnsureTstateNotNULL(tstate);
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struct _ceval_runtime_state *ceval = &runtime->ceval;
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struct _ceval_state *ceval2 = &tstate->interp->ceval;
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assert(gil_created(&ceval->gil));
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drop_gil(ceval, ceval2, tstate);
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return tstate;
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}
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void
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PyEval_RestoreThread(PyThreadState *tstate)
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{
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_Py_EnsureTstateNotNULL(tstate);
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take_gil(tstate);
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struct _gilstate_runtime_state *gilstate = &tstate->interp->runtime->gilstate;
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_PyThreadState_Swap(gilstate, tstate);
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}
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/* Mechanism whereby asynchronously executing callbacks (e.g. UNIX
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signal handlers or Mac I/O completion routines) can schedule calls
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to a function to be called synchronously.
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The synchronous function is called with one void* argument.
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It should return 0 for success or -1 for failure -- failure should
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be accompanied by an exception.
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If registry succeeds, the registry function returns 0; if it fails
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(e.g. due to too many pending calls) it returns -1 (without setting
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an exception condition).
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Note that because registry may occur from within signal handlers,
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or other asynchronous events, calling malloc() is unsafe!
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Any thread can schedule pending calls, but only the main thread
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will execute them.
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There is no facility to schedule calls to a particular thread, but
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that should be easy to change, should that ever be required. In
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that case, the static variables here should go into the python
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threadstate.
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*/
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void
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_PyEval_SignalReceived(PyInterpreterState *interp)
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{
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#ifdef MS_WINDOWS
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||||
// bpo-42296: On Windows, _PyEval_SignalReceived() is called from a signal
|
||||
// handler which can run in a thread different than the Python thread, in
|
||||
// which case _Py_ThreadCanHandleSignals() is wrong. Ignore
|
||||
// _Py_ThreadCanHandleSignals() and always set eval_breaker to 1.
|
||||
//
|
||||
// The next eval_frame_handle_pending() call will call
|
||||
// _Py_ThreadCanHandleSignals() to recompute eval_breaker.
|
||||
int force = 1;
|
||||
#else
|
||||
int force = 0;
|
||||
#endif
|
||||
/* bpo-30703: Function called when the C signal handler of Python gets a
|
||||
signal. We cannot queue a callback using _PyEval_AddPendingCall() since
|
||||
that function is not async-signal-safe. */
|
||||
SIGNAL_PENDING_SIGNALS(interp, force);
|
||||
}
|
||||
|
||||
/* Push one item onto the queue while holding the lock. */
|
||||
static int
|
||||
_push_pending_call(struct _pending_calls *pending,
|
||||
int (*func)(void *), void *arg)
|
||||
{
|
||||
int i = pending->last;
|
||||
int j = (i + 1) % NPENDINGCALLS;
|
||||
if (j == pending->first) {
|
||||
return -1; /* Queue full */
|
||||
}
|
||||
pending->calls[i].func = func;
|
||||
pending->calls[i].arg = arg;
|
||||
pending->last = j;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Pop one item off the queue while holding the lock. */
|
||||
static void
|
||||
_pop_pending_call(struct _pending_calls *pending,
|
||||
int (**func)(void *), void **arg)
|
||||
{
|
||||
int i = pending->first;
|
||||
if (i == pending->last) {
|
||||
return; /* Queue empty */
|
||||
}
|
||||
|
||||
*func = pending->calls[i].func;
|
||||
*arg = pending->calls[i].arg;
|
||||
pending->first = (i + 1) % NPENDINGCALLS;
|
||||
}
|
||||
|
||||
/* This implementation is thread-safe. It allows
|
||||
scheduling to be made from any thread, and even from an executing
|
||||
callback.
|
||||
*/
|
||||
|
||||
int
|
||||
_PyEval_AddPendingCall(PyInterpreterState *interp,
|
||||
int (*func)(void *), void *arg)
|
||||
{
|
||||
struct _pending_calls *pending = &interp->ceval.pending;
|
||||
|
||||
/* Ensure that _PyEval_InitState() was called
|
||||
and that _PyEval_FiniState() is not called yet. */
|
||||
assert(pending->lock != NULL);
|
||||
|
||||
PyThread_acquire_lock(pending->lock, WAIT_LOCK);
|
||||
int result = _push_pending_call(pending, func, arg);
|
||||
PyThread_release_lock(pending->lock);
|
||||
|
||||
/* signal main loop */
|
||||
SIGNAL_PENDING_CALLS(interp);
|
||||
return result;
|
||||
}
|
||||
|
||||
int
|
||||
Py_AddPendingCall(int (*func)(void *), void *arg)
|
||||
{
|
||||
/* Best-effort to support subinterpreters and calls with the GIL released.
|
||||
|
||||
First attempt _PyThreadState_GET() since it supports subinterpreters.
|
||||
|
||||
If the GIL is released, _PyThreadState_GET() returns NULL . In this
|
||||
case, use PyGILState_GetThisThreadState() which works even if the GIL
|
||||
is released.
|
||||
|
||||
Sadly, PyGILState_GetThisThreadState() doesn't support subinterpreters:
|
||||
see bpo-10915 and bpo-15751.
|
||||
|
||||
Py_AddPendingCall() doesn't require the caller to hold the GIL. */
|
||||
PyThreadState *tstate = _PyThreadState_GET();
|
||||
if (tstate == NULL) {
|
||||
tstate = PyGILState_GetThisThreadState();
|
||||
}
|
||||
|
||||
PyInterpreterState *interp;
|
||||
if (tstate != NULL) {
|
||||
interp = tstate->interp;
|
||||
}
|
||||
else {
|
||||
/* Last resort: use the main interpreter */
|
||||
interp = _PyInterpreterState_Main();
|
||||
}
|
||||
return _PyEval_AddPendingCall(interp, func, arg);
|
||||
}
|
||||
|
||||
static int
|
||||
handle_signals(PyThreadState *tstate)
|
||||
{
|
||||
assert(is_tstate_valid(tstate));
|
||||
if (!_Py_ThreadCanHandleSignals(tstate->interp)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
UNSIGNAL_PENDING_SIGNALS(tstate->interp);
|
||||
if (_PyErr_CheckSignalsTstate(tstate) < 0) {
|
||||
/* On failure, re-schedule a call to handle_signals(). */
|
||||
SIGNAL_PENDING_SIGNALS(tstate->interp, 0);
|
||||
return -1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
make_pending_calls(PyInterpreterState *interp)
|
||||
{
|
||||
/* only execute pending calls on main thread */
|
||||
if (!_Py_ThreadCanHandlePendingCalls()) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* don't perform recursive pending calls */
|
||||
static int busy = 0;
|
||||
if (busy) {
|
||||
return 0;
|
||||
}
|
||||
busy = 1;
|
||||
|
||||
/* unsignal before starting to call callbacks, so that any callback
|
||||
added in-between re-signals */
|
||||
UNSIGNAL_PENDING_CALLS(interp);
|
||||
int res = 0;
|
||||
|
||||
/* perform a bounded number of calls, in case of recursion */
|
||||
struct _pending_calls *pending = &interp->ceval.pending;
|
||||
for (int i=0; i<NPENDINGCALLS; i++) {
|
||||
int (*func)(void *) = NULL;
|
||||
void *arg = NULL;
|
||||
|
||||
/* pop one item off the queue while holding the lock */
|
||||
PyThread_acquire_lock(pending->lock, WAIT_LOCK);
|
||||
_pop_pending_call(pending, &func, &arg);
|
||||
PyThread_release_lock(pending->lock);
|
||||
|
||||
/* having released the lock, perform the callback */
|
||||
if (func == NULL) {
|
||||
break;
|
||||
}
|
||||
res = func(arg);
|
||||
if (res) {
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
|
||||
busy = 0;
|
||||
return res;
|
||||
|
||||
error:
|
||||
busy = 0;
|
||||
SIGNAL_PENDING_CALLS(interp);
|
||||
return res;
|
||||
}
|
||||
|
||||
void
|
||||
_Py_FinishPendingCalls(PyThreadState *tstate)
|
||||
{
|
||||
assert(PyGILState_Check());
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
struct _pending_calls *pending = &tstate->interp->ceval.pending;
|
||||
|
||||
if (!_Py_atomic_load_relaxed_int32(&(pending->calls_to_do))) {
|
||||
return;
|
||||
}
|
||||
|
||||
if (make_pending_calls(tstate->interp) < 0) {
|
||||
PyObject *exc, *val, *tb;
|
||||
_PyErr_Fetch(tstate, &exc, &val, &tb);
|
||||
PyErr_BadInternalCall();
|
||||
_PyErr_ChainExceptions(exc, val, tb);
|
||||
_PyErr_Print(tstate);
|
||||
}
|
||||
}
|
||||
|
||||
/* Py_MakePendingCalls() is a simple wrapper for the sake
|
||||
of backward-compatibility. */
|
||||
int
|
||||
Py_MakePendingCalls(void)
|
||||
{
|
||||
assert(PyGILState_Check());
|
||||
|
||||
PyThreadState *tstate = _PyThreadState_GET();
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
/* Python signal handler doesn't really queue a callback: it only signals
|
||||
that a signal was received, see _PyEval_SignalReceived(). */
|
||||
int res = handle_signals(tstate);
|
||||
if (res != 0) {
|
||||
return res;
|
||||
}
|
||||
|
||||
res = make_pending_calls(tstate->interp);
|
||||
if (res != 0) {
|
||||
return res;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* The interpreter's recursion limit */
|
||||
|
||||
void
|
||||
_PyEval_InitRuntimeState(struct _ceval_runtime_state *ceval)
|
||||
{
|
||||
_gil_initialize(&ceval->gil);
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_InitState(struct _ceval_state *ceval, PyThread_type_lock pending_lock)
|
||||
{
|
||||
struct _pending_calls *pending = &ceval->pending;
|
||||
assert(pending->lock == NULL);
|
||||
|
||||
pending->lock = pending_lock;
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_FiniState(struct _ceval_state *ceval)
|
||||
{
|
||||
struct _pending_calls *pending = &ceval->pending;
|
||||
if (pending->lock != NULL) {
|
||||
PyThread_free_lock(pending->lock);
|
||||
pending->lock = NULL;
|
||||
}
|
||||
}
|
||||
|
||||
int
|
||||
Py_GetRecursionLimit(void)
|
||||
|
@ -1182,71 +607,6 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
|
|||
}
|
||||
|
||||
|
||||
/* Handle signals, pending calls, GIL drop request
|
||||
and asynchronous exception */
|
||||
static int
|
||||
eval_frame_handle_pending(PyThreadState *tstate)
|
||||
{
|
||||
_PyRuntimeState * const runtime = &_PyRuntime;
|
||||
struct _ceval_runtime_state *ceval = &runtime->ceval;
|
||||
|
||||
/* Pending signals */
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)) {
|
||||
if (handle_signals(tstate) != 0) {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/* Pending calls */
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)) {
|
||||
if (make_pending_calls(tstate->interp) != 0) {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/* GIL drop request */
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)) {
|
||||
/* Give another thread a chance */
|
||||
if (_PyThreadState_Swap(&runtime->gilstate, NULL) != tstate) {
|
||||
Py_FatalError("tstate mix-up");
|
||||
}
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
|
||||
/* Other threads may run now */
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
if (_PyThreadState_Swap(&runtime->gilstate, tstate) != NULL) {
|
||||
Py_FatalError("orphan tstate");
|
||||
}
|
||||
}
|
||||
|
||||
/* Check for asynchronous exception. */
|
||||
if (tstate->async_exc != NULL) {
|
||||
PyObject *exc = tstate->async_exc;
|
||||
tstate->async_exc = NULL;
|
||||
UNSIGNAL_ASYNC_EXC(tstate->interp);
|
||||
_PyErr_SetNone(tstate, exc);
|
||||
Py_DECREF(exc);
|
||||
return -1;
|
||||
}
|
||||
|
||||
#ifdef MS_WINDOWS
|
||||
// bpo-42296: On Windows, _PyEval_SignalReceived() can be called in a
|
||||
// different thread than the Python thread, in which case
|
||||
// _Py_ThreadCanHandleSignals() is wrong. Recompute eval_breaker in the
|
||||
// current Python thread with the correct _Py_ThreadCanHandleSignals()
|
||||
// value. It prevents to interrupt the eval loop at every instruction if
|
||||
// the current Python thread cannot handle signals (if
|
||||
// _Py_ThreadCanHandleSignals() is false).
|
||||
COMPUTE_EVAL_BREAKER(tstate->interp, ceval, ceval2);
|
||||
#endif
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
/* Computed GOTOs, or
|
||||
the-optimization-commonly-but-improperly-known-as-"threaded code"
|
||||
using gcc's labels-as-values extension
|
||||
|
@ -1750,7 +1110,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
|
|||
* All loops should include a check of the eval breaker.
|
||||
* We also check on return from any builtin function.
|
||||
*/
|
||||
if (eval_frame_handle_pending(tstate) != 0) {
|
||||
if (_Py_HandlePending(tstate) != 0) {
|
||||
goto error;
|
||||
}
|
||||
DISPATCH();
|
||||
|
|
986
Python/ceval_gil.c
Normal file
986
Python/ceval_gil.c
Normal file
|
@ -0,0 +1,986 @@
|
|||
|
||||
#include "Python.h"
|
||||
#include "pycore_atomic.h" // _Py_atomic_int
|
||||
#include "pycore_ceval.h" // _PyEval_SignalReceived()
|
||||
#include "pycore_pyerrors.h" // _PyErr_Fetch()
|
||||
#include "pycore_pylifecycle.h" // _PyErr_Print()
|
||||
#include "pycore_initconfig.h" // _PyStatus_OK()
|
||||
#include "pycore_pymem.h" // _PyMem_IsPtrFreed()
|
||||
|
||||
/*
|
||||
Notes about the implementation:
|
||||
|
||||
- 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.
|
||||
|
||||
- In the GIL-holding thread, the main loop (PyEval_EvalFrameEx) must be
|
||||
able to release the GIL on demand by another thread. A volatile boolean
|
||||
variable (gil_drop_request) is used for that purpose, which is checked
|
||||
at every turn of the eval loop. That variable is set after a wait of
|
||||
`interval` microseconds on `gil_cond` has timed out.
|
||||
|
||||
[Actually, another volatile boolean variable (eval_breaker) is used
|
||||
which ORs several conditions into one. Volatile booleans are
|
||||
sufficient as inter-thread signalling means since Python is run
|
||||
on cache-coherent architectures only.]
|
||||
|
||||
- A thread wanting to take the GIL will first let pass a given amount of
|
||||
time (`interval` microseconds) before setting gil_drop_request. This
|
||||
encourages a defined switching period, but doesn't enforce it since
|
||||
opcodes can take an arbitrary time to execute.
|
||||
|
||||
The `interval` value is available for the user to read and modify
|
||||
using the Python API `sys.{get,set}switchinterval()`.
|
||||
|
||||
- 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 last_holder is changed to something else than its
|
||||
own thread state pointer, indicating that another thread was able to
|
||||
take the GIL.
|
||||
|
||||
This is meant to prohibit the latency-adverse behaviour on multi-core
|
||||
machines where one thread would speculatively release the GIL, but still
|
||||
run and end up being the first to re-acquire it, making the "timeslices"
|
||||
much longer than expected.
|
||||
(Note: this mechanism is enabled with FORCE_SWITCHING above)
|
||||
*/
|
||||
|
||||
// GH-89279: Force inlining by using a macro.
|
||||
#if defined(_MSC_VER) && SIZEOF_INT == 4
|
||||
#define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) (assert(sizeof((ATOMIC_VAL)->_value) == 4), *((volatile int*)&((ATOMIC_VAL)->_value)))
|
||||
#else
|
||||
#define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) _Py_atomic_load_relaxed(ATOMIC_VAL)
|
||||
#endif
|
||||
|
||||
/* This can set eval_breaker to 0 even though gil_drop_request became
|
||||
1. We believe this is all right because the eval loop will release
|
||||
the GIL eventually anyway. */
|
||||
static inline void
|
||||
COMPUTE_EVAL_BREAKER(PyInterpreterState *interp,
|
||||
struct _ceval_runtime_state *ceval,
|
||||
struct _ceval_state *ceval2)
|
||||
{
|
||||
_Py_atomic_store_relaxed(&ceval2->eval_breaker,
|
||||
_Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)
|
||||
| (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)
|
||||
&& _Py_ThreadCanHandleSignals(interp))
|
||||
| (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)
|
||||
&& _Py_ThreadCanHandlePendingCalls())
|
||||
| ceval2->pending.async_exc);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
SET_GIL_DROP_REQUEST(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval2->gil_drop_request, 1);
|
||||
_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
RESET_GIL_DROP_REQUEST(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval2->gil_drop_request, 0);
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
SIGNAL_PENDING_CALLS(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval2->pending.calls_to_do, 1);
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
UNSIGNAL_PENDING_CALLS(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval2->pending.calls_to_do, 0);
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
SIGNAL_PENDING_SIGNALS(PyInterpreterState *interp, int force)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval->signals_pending, 1);
|
||||
if (force) {
|
||||
_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
|
||||
}
|
||||
else {
|
||||
/* eval_breaker is not set to 1 if thread_can_handle_signals() is false */
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
UNSIGNAL_PENDING_SIGNALS(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
_Py_atomic_store_relaxed(&ceval->signals_pending, 0);
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
SIGNAL_ASYNC_EXC(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
ceval2->pending.async_exc = 1;
|
||||
_Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
|
||||
}
|
||||
|
||||
|
||||
static inline void
|
||||
UNSIGNAL_ASYNC_EXC(PyInterpreterState *interp)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
ceval2->pending.async_exc = 0;
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
#ifndef NDEBUG
|
||||
/* Ensure that tstate is valid */
|
||||
static int
|
||||
is_tstate_valid(PyThreadState *tstate)
|
||||
{
|
||||
assert(!_PyMem_IsPtrFreed(tstate));
|
||||
assert(!_PyMem_IsPtrFreed(tstate->interp));
|
||||
return 1;
|
||||
}
|
||||
#endif
|
||||
|
||||
/*
|
||||
* Implementation of the Global Interpreter Lock (GIL).
|
||||
*/
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <errno.h>
|
||||
|
||||
#include "pycore_atomic.h"
|
||||
|
||||
|
||||
#include "condvar.h"
|
||||
|
||||
#define MUTEX_INIT(mut) \
|
||||
if (PyMUTEX_INIT(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_INIT(" #mut ") failed"); };
|
||||
#define MUTEX_FINI(mut) \
|
||||
if (PyMUTEX_FINI(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_FINI(" #mut ") failed"); };
|
||||
#define MUTEX_LOCK(mut) \
|
||||
if (PyMUTEX_LOCK(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_LOCK(" #mut ") failed"); };
|
||||
#define MUTEX_UNLOCK(mut) \
|
||||
if (PyMUTEX_UNLOCK(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_UNLOCK(" #mut ") failed"); };
|
||||
|
||||
#define COND_INIT(cond) \
|
||||
if (PyCOND_INIT(&(cond))) { \
|
||||
Py_FatalError("PyCOND_INIT(" #cond ") failed"); };
|
||||
#define COND_FINI(cond) \
|
||||
if (PyCOND_FINI(&(cond))) { \
|
||||
Py_FatalError("PyCOND_FINI(" #cond ") failed"); };
|
||||
#define COND_SIGNAL(cond) \
|
||||
if (PyCOND_SIGNAL(&(cond))) { \
|
||||
Py_FatalError("PyCOND_SIGNAL(" #cond ") failed"); };
|
||||
#define COND_WAIT(cond, mut) \
|
||||
if (PyCOND_WAIT(&(cond), &(mut))) { \
|
||||
Py_FatalError("PyCOND_WAIT(" #cond ") failed"); };
|
||||
#define COND_TIMED_WAIT(cond, mut, microseconds, timeout_result) \
|
||||
{ \
|
||||
int r = PyCOND_TIMEDWAIT(&(cond), &(mut), (microseconds)); \
|
||||
if (r < 0) \
|
||||
Py_FatalError("PyCOND_WAIT(" #cond ") failed"); \
|
||||
if (r) /* 1 == timeout, 2 == impl. can't say, so assume timeout */ \
|
||||
timeout_result = 1; \
|
||||
else \
|
||||
timeout_result = 0; \
|
||||
} \
|
||||
|
||||
|
||||
#define DEFAULT_INTERVAL 5000
|
||||
|
||||
static void _gil_initialize(struct _gil_runtime_state *gil)
|
||||
{
|
||||
_Py_atomic_int uninitialized = {-1};
|
||||
gil->locked = uninitialized;
|
||||
gil->interval = DEFAULT_INTERVAL;
|
||||
}
|
||||
|
||||
static int gil_created(struct _gil_runtime_state *gil)
|
||||
{
|
||||
return (_Py_atomic_load_explicit(&gil->locked, _Py_memory_order_acquire) >= 0);
|
||||
}
|
||||
|
||||
static void create_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
MUTEX_INIT(gil->mutex);
|
||||
#ifdef FORCE_SWITCHING
|
||||
MUTEX_INIT(gil->switch_mutex);
|
||||
#endif
|
||||
COND_INIT(gil->cond);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_INIT(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);
|
||||
}
|
||||
|
||||
static void destroy_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
/* 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);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_FINI(gil->switch_cond);
|
||||
MUTEX_FINI(gil->switch_mutex);
|
||||
#endif
|
||||
_Py_atomic_store_explicit(&gil->locked, -1,
|
||||
_Py_memory_order_release);
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
|
||||
}
|
||||
|
||||
#ifdef HAVE_FORK
|
||||
static void recreate_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
|
||||
/* XXX should we destroy the old OS resources here? */
|
||||
create_gil(gil);
|
||||
}
|
||||
#endif
|
||||
|
||||
static void
|
||||
drop_gil(struct _ceval_runtime_state *ceval, struct _ceval_state *ceval2,
|
||||
PyThreadState *tstate)
|
||||
{
|
||||
struct _gil_runtime_state *gil = &ceval->gil;
|
||||
if (!_Py_atomic_load_relaxed(&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);
|
||||
}
|
||||
|
||||
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);
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
if (_Py_atomic_load_relaxed(&ceval2->gil_drop_request) && tstate != NULL) {
|
||||
MUTEX_LOCK(gil->switch_mutex);
|
||||
/* Not switched yet => wait */
|
||||
if (((PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) == tstate)
|
||||
{
|
||||
assert(is_tstate_valid(tstate));
|
||||
RESET_GIL_DROP_REQUEST(tstate->interp);
|
||||
/* 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(gil->switch_cond, gil->switch_mutex);
|
||||
}
|
||||
MUTEX_UNLOCK(gil->switch_mutex);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
/* Check if a Python thread must exit immediately, rather than taking the GIL
|
||||
if Py_Finalize() has been called.
|
||||
|
||||
When this function is called by a daemon thread after Py_Finalize() has been
|
||||
called, the GIL does no longer exist.
|
||||
|
||||
tstate must be non-NULL. */
|
||||
static inline int
|
||||
tstate_must_exit(PyThreadState *tstate)
|
||||
{
|
||||
/* bpo-39877: Access _PyRuntime directly rather than using
|
||||
tstate->interp->runtime to support calls from Python daemon threads.
|
||||
After Py_Finalize() has been called, tstate can be a dangling pointer:
|
||||
point to PyThreadState freed memory. */
|
||||
PyThreadState *finalizing = _PyRuntimeState_GetFinalizing(&_PyRuntime);
|
||||
return (finalizing != NULL && finalizing != tstate);
|
||||
}
|
||||
|
||||
|
||||
/* Take the GIL.
|
||||
|
||||
The function saves errno at entry and restores its value at exit.
|
||||
|
||||
tstate must be non-NULL. */
|
||||
static void
|
||||
take_gil(PyThreadState *tstate)
|
||||
{
|
||||
int err = errno;
|
||||
|
||||
assert(tstate != NULL);
|
||||
|
||||
if (tstate_must_exit(tstate)) {
|
||||
/* bpo-39877: If Py_Finalize() has been called and tstate is not the
|
||||
thread which called Py_Finalize(), exit immediately the thread.
|
||||
|
||||
This code path can be reached by a daemon thread after Py_Finalize()
|
||||
completes. In this case, tstate is a dangling pointer: points to
|
||||
PyThreadState freed memory. */
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
|
||||
assert(is_tstate_valid(tstate));
|
||||
PyInterpreterState *interp = tstate->interp;
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
struct _gil_runtime_state *gil = &ceval->gil;
|
||||
|
||||
/* Check that _PyEval_InitThreads() was called to create the lock */
|
||||
assert(gil_created(gil));
|
||||
|
||||
MUTEX_LOCK(gil->mutex);
|
||||
|
||||
if (!_Py_atomic_load_relaxed(&gil->locked)) {
|
||||
goto _ready;
|
||||
}
|
||||
|
||||
while (_Py_atomic_load_relaxed(&gil->locked)) {
|
||||
unsigned long saved_switchnum = gil->switch_number;
|
||||
|
||||
unsigned long interval = (gil->interval >= 1 ? gil->interval : 1);
|
||||
int timed_out = 0;
|
||||
COND_TIMED_WAIT(gil->cond, 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)
|
||||
{
|
||||
if (tstate_must_exit(tstate)) {
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
SET_GIL_DROP_REQUEST(interp);
|
||||
}
|
||||
}
|
||||
|
||||
_ready:
|
||||
#ifdef FORCE_SWITCHING
|
||||
/* This mutex must be taken before modifying gil->last_holder:
|
||||
see drop_gil(). */
|
||||
MUTEX_LOCK(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);
|
||||
|
||||
if (tstate != (PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) {
|
||||
_Py_atomic_store_relaxed(&gil->last_holder, (uintptr_t)tstate);
|
||||
++gil->switch_number;
|
||||
}
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_SIGNAL(gil->switch_cond);
|
||||
MUTEX_UNLOCK(gil->switch_mutex);
|
||||
#endif
|
||||
|
||||
if (tstate_must_exit(tstate)) {
|
||||
/* bpo-36475: If Py_Finalize() has been called and tstate is not
|
||||
the thread which called Py_Finalize(), exit immediately the
|
||||
thread.
|
||||
|
||||
This code path can be reached by a daemon thread which was waiting
|
||||
in take_gil() while the main thread called
|
||||
wait_for_thread_shutdown() from Py_Finalize(). */
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
if (_Py_atomic_load_relaxed(&ceval2->gil_drop_request)) {
|
||||
RESET_GIL_DROP_REQUEST(interp);
|
||||
}
|
||||
else {
|
||||
/* bpo-40010: eval_breaker should be recomputed to be set to 1 if there
|
||||
is a pending signal: signal received by another thread which cannot
|
||||
handle signals.
|
||||
|
||||
Note: RESET_GIL_DROP_REQUEST() calls COMPUTE_EVAL_BREAKER(). */
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
/* Don't access tstate if the thread must exit */
|
||||
if (tstate->async_exc != NULL) {
|
||||
_PyEval_SignalAsyncExc(tstate->interp);
|
||||
}
|
||||
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
|
||||
errno = err;
|
||||
}
|
||||
|
||||
void _PyEval_SetSwitchInterval(unsigned long microseconds)
|
||||
{
|
||||
struct _gil_runtime_state *gil = &_PyRuntime.ceval.gil;
|
||||
gil->interval = microseconds;
|
||||
}
|
||||
|
||||
unsigned long _PyEval_GetSwitchInterval()
|
||||
{
|
||||
struct _gil_runtime_state *gil = &_PyRuntime.ceval.gil;
|
||||
return gil->interval;
|
||||
}
|
||||
|
||||
|
||||
int
|
||||
_PyEval_ThreadsInitialized(_PyRuntimeState *runtime)
|
||||
{
|
||||
return gil_created(&runtime->ceval.gil);
|
||||
}
|
||||
|
||||
int
|
||||
PyEval_ThreadsInitialized(void)
|
||||
{
|
||||
_PyRuntimeState *runtime = &_PyRuntime;
|
||||
return _PyEval_ThreadsInitialized(runtime);
|
||||
}
|
||||
|
||||
PyStatus
|
||||
_PyEval_InitGIL(PyThreadState *tstate)
|
||||
{
|
||||
if (!_Py_IsMainInterpreter(tstate->interp)) {
|
||||
/* Currently, the GIL is shared by all interpreters,
|
||||
and only the main interpreter is responsible to create
|
||||
and destroy it. */
|
||||
return _PyStatus_OK();
|
||||
}
|
||||
|
||||
struct _gil_runtime_state *gil = &tstate->interp->runtime->ceval.gil;
|
||||
assert(!gil_created(gil));
|
||||
|
||||
PyThread_init_thread();
|
||||
create_gil(gil);
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
assert(gil_created(gil));
|
||||
return _PyStatus_OK();
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_FiniGIL(PyInterpreterState *interp)
|
||||
{
|
||||
if (!_Py_IsMainInterpreter(interp)) {
|
||||
/* Currently, the GIL is shared by all interpreters,
|
||||
and only the main interpreter is responsible to create
|
||||
and destroy it. */
|
||||
return;
|
||||
}
|
||||
|
||||
struct _gil_runtime_state *gil = &interp->runtime->ceval.gil;
|
||||
if (!gil_created(gil)) {
|
||||
/* First Py_InitializeFromConfig() call: the GIL doesn't exist
|
||||
yet: do nothing. */
|
||||
return;
|
||||
}
|
||||
|
||||
destroy_gil(gil);
|
||||
assert(!gil_created(gil));
|
||||
}
|
||||
|
||||
void
|
||||
PyEval_InitThreads(void)
|
||||
{
|
||||
/* Do nothing: kept for backward compatibility */
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_Fini(void)
|
||||
{
|
||||
#ifdef Py_STATS
|
||||
_Py_PrintSpecializationStats(1);
|
||||
#endif
|
||||
}
|
||||
void
|
||||
PyEval_AcquireLock(void)
|
||||
{
|
||||
_PyRuntimeState *runtime = &_PyRuntime;
|
||||
PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
|
||||
_Py_EnsureTstateNotNULL(tstate);
|
||||
|
||||
take_gil(tstate);
|
||||
}
|
||||
|
||||
void
|
||||
PyEval_ReleaseLock(void)
|
||||
{
|
||||
_PyRuntimeState *runtime = &_PyRuntime;
|
||||
PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
|
||||
/* This function must succeed when the current thread state is NULL.
|
||||
We therefore avoid PyThreadState_Get() which dumps a fatal error
|
||||
in debug mode. */
|
||||
struct _ceval_runtime_state *ceval = &runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_ReleaseLock(PyThreadState *tstate)
|
||||
{
|
||||
struct _ceval_runtime_state *ceval = &tstate->interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
}
|
||||
|
||||
void
|
||||
PyEval_AcquireThread(PyThreadState *tstate)
|
||||
{
|
||||
_Py_EnsureTstateNotNULL(tstate);
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
struct _gilstate_runtime_state *gilstate = &tstate->interp->runtime->gilstate;
|
||||
if (_PyThreadState_Swap(gilstate, tstate) != NULL) {
|
||||
Py_FatalError("non-NULL old thread state");
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
PyEval_ReleaseThread(PyThreadState *tstate)
|
||||
{
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
_PyRuntimeState *runtime = tstate->interp->runtime;
|
||||
PyThreadState *new_tstate = _PyThreadState_Swap(&runtime->gilstate, NULL);
|
||||
if (new_tstate != tstate) {
|
||||
Py_FatalError("wrong thread state");
|
||||
}
|
||||
struct _ceval_runtime_state *ceval = &runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
}
|
||||
|
||||
#ifdef HAVE_FORK
|
||||
/* This function is called from PyOS_AfterFork_Child to destroy all threads
|
||||
which are not running in the child process, and clear internal locks
|
||||
which might be held by those threads. */
|
||||
PyStatus
|
||||
_PyEval_ReInitThreads(PyThreadState *tstate)
|
||||
{
|
||||
_PyRuntimeState *runtime = tstate->interp->runtime;
|
||||
|
||||
struct _gil_runtime_state *gil = &runtime->ceval.gil;
|
||||
if (!gil_created(gil)) {
|
||||
return _PyStatus_OK();
|
||||
}
|
||||
recreate_gil(gil);
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
struct _pending_calls *pending = &tstate->interp->ceval.pending;
|
||||
if (_PyThread_at_fork_reinit(&pending->lock) < 0) {
|
||||
return _PyStatus_ERR("Can't reinitialize pending calls lock");
|
||||
}
|
||||
|
||||
/* Destroy all threads except the current one */
|
||||
_PyThreadState_DeleteExcept(runtime, tstate);
|
||||
return _PyStatus_OK();
|
||||
}
|
||||
#endif
|
||||
|
||||
/* This function is used to signal that async exceptions are waiting to be
|
||||
raised. */
|
||||
|
||||
void
|
||||
_PyEval_SignalAsyncExc(PyInterpreterState *interp)
|
||||
{
|
||||
SIGNAL_ASYNC_EXC(interp);
|
||||
}
|
||||
|
||||
PyThreadState *
|
||||
PyEval_SaveThread(void)
|
||||
{
|
||||
_PyRuntimeState *runtime = &_PyRuntime;
|
||||
PyThreadState *tstate = _PyThreadState_Swap(&runtime->gilstate, NULL);
|
||||
_Py_EnsureTstateNotNULL(tstate);
|
||||
|
||||
struct _ceval_runtime_state *ceval = &runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
assert(gil_created(&ceval->gil));
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
return tstate;
|
||||
}
|
||||
|
||||
void
|
||||
PyEval_RestoreThread(PyThreadState *tstate)
|
||||
{
|
||||
_Py_EnsureTstateNotNULL(tstate);
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
struct _gilstate_runtime_state *gilstate = &tstate->interp->runtime->gilstate;
|
||||
_PyThreadState_Swap(gilstate, tstate);
|
||||
}
|
||||
|
||||
|
||||
/* Mechanism whereby asynchronously executing callbacks (e.g. UNIX
|
||||
signal handlers or Mac I/O completion routines) can schedule calls
|
||||
to a function to be called synchronously.
|
||||
The synchronous function is called with one void* argument.
|
||||
It should return 0 for success or -1 for failure -- failure should
|
||||
be accompanied by an exception.
|
||||
|
||||
If registry succeeds, the registry function returns 0; if it fails
|
||||
(e.g. due to too many pending calls) it returns -1 (without setting
|
||||
an exception condition).
|
||||
|
||||
Note that because registry may occur from within signal handlers,
|
||||
or other asynchronous events, calling malloc() is unsafe!
|
||||
|
||||
Any thread can schedule pending calls, but only the main thread
|
||||
will execute them.
|
||||
There is no facility to schedule calls to a particular thread, but
|
||||
that should be easy to change, should that ever be required. In
|
||||
that case, the static variables here should go into the python
|
||||
threadstate.
|
||||
*/
|
||||
|
||||
void
|
||||
_PyEval_SignalReceived(PyInterpreterState *interp)
|
||||
{
|
||||
#ifdef MS_WINDOWS
|
||||
// bpo-42296: On Windows, _PyEval_SignalReceived() is called from a signal
|
||||
// handler which can run in a thread different than the Python thread, in
|
||||
// which case _Py_ThreadCanHandleSignals() is wrong. Ignore
|
||||
// _Py_ThreadCanHandleSignals() and always set eval_breaker to 1.
|
||||
//
|
||||
// The next eval_frame_handle_pending() call will call
|
||||
// _Py_ThreadCanHandleSignals() to recompute eval_breaker.
|
||||
int force = 1;
|
||||
#else
|
||||
int force = 0;
|
||||
#endif
|
||||
/* bpo-30703: Function called when the C signal handler of Python gets a
|
||||
signal. We cannot queue a callback using _PyEval_AddPendingCall() since
|
||||
that function is not async-signal-safe. */
|
||||
SIGNAL_PENDING_SIGNALS(interp, force);
|
||||
}
|
||||
|
||||
/* Push one item onto the queue while holding the lock. */
|
||||
static int
|
||||
_push_pending_call(struct _pending_calls *pending,
|
||||
int (*func)(void *), void *arg)
|
||||
{
|
||||
int i = pending->last;
|
||||
int j = (i + 1) % NPENDINGCALLS;
|
||||
if (j == pending->first) {
|
||||
return -1; /* Queue full */
|
||||
}
|
||||
pending->calls[i].func = func;
|
||||
pending->calls[i].arg = arg;
|
||||
pending->last = j;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Pop one item off the queue while holding the lock. */
|
||||
static void
|
||||
_pop_pending_call(struct _pending_calls *pending,
|
||||
int (**func)(void *), void **arg)
|
||||
{
|
||||
int i = pending->first;
|
||||
if (i == pending->last) {
|
||||
return; /* Queue empty */
|
||||
}
|
||||
|
||||
*func = pending->calls[i].func;
|
||||
*arg = pending->calls[i].arg;
|
||||
pending->first = (i + 1) % NPENDINGCALLS;
|
||||
}
|
||||
|
||||
/* This implementation is thread-safe. It allows
|
||||
scheduling to be made from any thread, and even from an executing
|
||||
callback.
|
||||
*/
|
||||
|
||||
int
|
||||
_PyEval_AddPendingCall(PyInterpreterState *interp,
|
||||
int (*func)(void *), void *arg)
|
||||
{
|
||||
struct _pending_calls *pending = &interp->ceval.pending;
|
||||
/* Ensure that _PyEval_InitState() was called
|
||||
and that _PyEval_FiniState() is not called yet. */
|
||||
assert(pending->lock != NULL);
|
||||
|
||||
PyThread_acquire_lock(pending->lock, WAIT_LOCK);
|
||||
int result = _push_pending_call(pending, func, arg);
|
||||
PyThread_release_lock(pending->lock);
|
||||
|
||||
/* signal main loop */
|
||||
SIGNAL_PENDING_CALLS(interp);
|
||||
return result;
|
||||
}
|
||||
|
||||
int
|
||||
Py_AddPendingCall(int (*func)(void *), void *arg)
|
||||
{
|
||||
/* Best-effort to support subinterpreters and calls with the GIL released.
|
||||
|
||||
First attempt _PyThreadState_GET() since it supports subinterpreters.
|
||||
|
||||
If the GIL is released, _PyThreadState_GET() returns NULL . In this
|
||||
case, use PyGILState_GetThisThreadState() which works even if the GIL
|
||||
is released.
|
||||
|
||||
Sadly, PyGILState_GetThisThreadState() doesn't support subinterpreters:
|
||||
see bpo-10915 and bpo-15751.
|
||||
|
||||
Py_AddPendingCall() doesn't require the caller to hold the GIL. */
|
||||
PyThreadState *tstate = _PyThreadState_GET();
|
||||
if (tstate == NULL) {
|
||||
tstate = PyGILState_GetThisThreadState();
|
||||
}
|
||||
|
||||
PyInterpreterState *interp;
|
||||
if (tstate != NULL) {
|
||||
interp = tstate->interp;
|
||||
}
|
||||
else {
|
||||
/* Last resort: use the main interpreter */
|
||||
interp = _PyInterpreterState_Main();
|
||||
}
|
||||
return _PyEval_AddPendingCall(interp, func, arg);
|
||||
}
|
||||
|
||||
static int
|
||||
handle_signals(PyThreadState *tstate)
|
||||
{
|
||||
assert(is_tstate_valid(tstate));
|
||||
if (!_Py_ThreadCanHandleSignals(tstate->interp)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
UNSIGNAL_PENDING_SIGNALS(tstate->interp);
|
||||
if (_PyErr_CheckSignalsTstate(tstate) < 0) {
|
||||
/* On failure, re-schedule a call to handle_signals(). */
|
||||
SIGNAL_PENDING_SIGNALS(tstate->interp, 0);
|
||||
return -1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
make_pending_calls(PyInterpreterState *interp)
|
||||
{
|
||||
/* only execute pending calls on main thread */
|
||||
if (!_Py_ThreadCanHandlePendingCalls()) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* don't perform recursive pending calls */
|
||||
static int busy = 0;
|
||||
if (busy) {
|
||||
return 0;
|
||||
}
|
||||
busy = 1;
|
||||
|
||||
/* unsignal before starting to call callbacks, so that any callback
|
||||
added in-between re-signals */
|
||||
UNSIGNAL_PENDING_CALLS(interp);
|
||||
int res = 0;
|
||||
|
||||
/* perform a bounded number of calls, in case of recursion */
|
||||
struct _pending_calls *pending = &interp->ceval.pending;
|
||||
for (int i=0; i<NPENDINGCALLS; i++) {
|
||||
int (*func)(void *) = NULL;
|
||||
void *arg = NULL;
|
||||
|
||||
/* pop one item off the queue while holding the lock */
|
||||
PyThread_acquire_lock(pending->lock, WAIT_LOCK);
|
||||
_pop_pending_call(pending, &func, &arg);
|
||||
PyThread_release_lock(pending->lock);
|
||||
|
||||
/* having released the lock, perform the callback */
|
||||
if (func == NULL) {
|
||||
break;
|
||||
}
|
||||
res = func(arg);
|
||||
if (res) {
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
|
||||
busy = 0;
|
||||
return res;
|
||||
|
||||
error:
|
||||
busy = 0;
|
||||
SIGNAL_PENDING_CALLS(interp);
|
||||
return res;
|
||||
}
|
||||
|
||||
void
|
||||
_Py_FinishPendingCalls(PyThreadState *tstate)
|
||||
{
|
||||
assert(PyGILState_Check());
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
struct _pending_calls *pending = &tstate->interp->ceval.pending;
|
||||
|
||||
if (!_Py_atomic_load_relaxed_int32(&(pending->calls_to_do))) {
|
||||
return;
|
||||
}
|
||||
|
||||
if (make_pending_calls(tstate->interp) < 0) {
|
||||
PyObject *exc, *val, *tb;
|
||||
_PyErr_Fetch(tstate, &exc, &val, &tb);
|
||||
PyErr_BadInternalCall();
|
||||
_PyErr_ChainExceptions(exc, val, tb);
|
||||
_PyErr_Print(tstate);
|
||||
}
|
||||
}
|
||||
|
||||
/* Py_MakePendingCalls() is a simple wrapper for the sake
|
||||
of backward-compatibility. */
|
||||
int
|
||||
Py_MakePendingCalls(void)
|
||||
{
|
||||
assert(PyGILState_Check());
|
||||
|
||||
PyThreadState *tstate = _PyThreadState_GET();
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
/* Python signal handler doesn't really queue a callback: it only signals
|
||||
that a signal was received, see _PyEval_SignalReceived(). */
|
||||
int res = handle_signals(tstate);
|
||||
if (res != 0) {
|
||||
return res;
|
||||
}
|
||||
|
||||
res = make_pending_calls(tstate->interp);
|
||||
if (res != 0) {
|
||||
return res;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* The interpreter's recursion limit */
|
||||
|
||||
void
|
||||
_PyEval_InitRuntimeState(struct _ceval_runtime_state *ceval)
|
||||
{
|
||||
_gil_initialize(&ceval->gil);
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_InitState(struct _ceval_state *ceval, PyThread_type_lock pending_lock)
|
||||
{
|
||||
struct _pending_calls *pending = &ceval->pending;
|
||||
assert(pending->lock == NULL);
|
||||
|
||||
pending->lock = pending_lock;
|
||||
}
|
||||
|
||||
void
|
||||
_PyEval_FiniState(struct _ceval_state *ceval)
|
||||
{
|
||||
struct _pending_calls *pending = &ceval->pending;
|
||||
if (pending->lock != NULL) {
|
||||
PyThread_free_lock(pending->lock);
|
||||
pending->lock = NULL;
|
||||
}
|
||||
}
|
||||
|
||||
/* Handle signals, pending calls, GIL drop request
|
||||
and asynchronous exception */
|
||||
int
|
||||
_Py_HandlePending(PyThreadState *tstate)
|
||||
{
|
||||
_PyRuntimeState * const runtime = &_PyRuntime;
|
||||
struct _ceval_runtime_state *ceval = &runtime->ceval;
|
||||
|
||||
/* Pending signals */
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)) {
|
||||
if (handle_signals(tstate) != 0) {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/* Pending calls */
|
||||
struct _ceval_state *ceval2 = &tstate->interp->ceval;
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)) {
|
||||
if (make_pending_calls(tstate->interp) != 0) {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/* GIL drop request */
|
||||
if (_Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)) {
|
||||
/* Give another thread a chance */
|
||||
if (_PyThreadState_Swap(&runtime->gilstate, NULL) != tstate) {
|
||||
Py_FatalError("tstate mix-up");
|
||||
}
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
|
||||
/* Other threads may run now */
|
||||
|
||||
take_gil(tstate);
|
||||
|
||||
if (_PyThreadState_Swap(&runtime->gilstate, tstate) != NULL) {
|
||||
Py_FatalError("orphan tstate");
|
||||
}
|
||||
}
|
||||
|
||||
/* Check for asynchronous exception. */
|
||||
if (tstate->async_exc != NULL) {
|
||||
PyObject *exc = tstate->async_exc;
|
||||
tstate->async_exc = NULL;
|
||||
UNSIGNAL_ASYNC_EXC(tstate->interp);
|
||||
_PyErr_SetNone(tstate, exc);
|
||||
Py_DECREF(exc);
|
||||
return -1;
|
||||
}
|
||||
|
||||
#ifdef MS_WINDOWS
|
||||
// bpo-42296: On Windows, _PyEval_SignalReceived() can be called in a
|
||||
// different thread than the Python thread, in which case
|
||||
// _Py_ThreadCanHandleSignals() is wrong. Recompute eval_breaker in the
|
||||
// current Python thread with the correct _Py_ThreadCanHandleSignals()
|
||||
// value. It prevents to interrupt the eval loop at every instruction if
|
||||
// the current Python thread cannot handle signals (if
|
||||
// _Py_ThreadCanHandleSignals() is false).
|
||||
COMPUTE_EVAL_BREAKER(tstate->interp, ceval, ceval2);
|
||||
#endif
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -1,333 +0,0 @@
|
|||
/*
|
||||
* Implementation of the Global Interpreter Lock (GIL).
|
||||
*/
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <errno.h>
|
||||
|
||||
#include "pycore_atomic.h"
|
||||
|
||||
|
||||
/*
|
||||
Notes about the implementation:
|
||||
|
||||
- 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.
|
||||
|
||||
- In the GIL-holding thread, the main loop (PyEval_EvalFrameEx) must be
|
||||
able to release the GIL on demand by another thread. A volatile boolean
|
||||
variable (gil_drop_request) is used for that purpose, which is checked
|
||||
at every turn of the eval loop. That variable is set after a wait of
|
||||
`interval` microseconds on `gil_cond` has timed out.
|
||||
|
||||
[Actually, another volatile boolean variable (eval_breaker) is used
|
||||
which ORs several conditions into one. Volatile booleans are
|
||||
sufficient as inter-thread signalling means since Python is run
|
||||
on cache-coherent architectures only.]
|
||||
|
||||
- A thread wanting to take the GIL will first let pass a given amount of
|
||||
time (`interval` microseconds) before setting gil_drop_request. This
|
||||
encourages a defined switching period, but doesn't enforce it since
|
||||
opcodes can take an arbitrary time to execute.
|
||||
|
||||
The `interval` value is available for the user to read and modify
|
||||
using the Python API `sys.{get,set}switchinterval()`.
|
||||
|
||||
- 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 last_holder is changed to something else than its
|
||||
own thread state pointer, indicating that another thread was able to
|
||||
take the GIL.
|
||||
|
||||
This is meant to prohibit the latency-adverse behaviour on multi-core
|
||||
machines where one thread would speculatively release the GIL, but still
|
||||
run and end up being the first to re-acquire it, making the "timeslices"
|
||||
much longer than expected.
|
||||
(Note: this mechanism is enabled with FORCE_SWITCHING above)
|
||||
*/
|
||||
|
||||
#include "condvar.h"
|
||||
|
||||
#define MUTEX_INIT(mut) \
|
||||
if (PyMUTEX_INIT(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_INIT(" #mut ") failed"); };
|
||||
#define MUTEX_FINI(mut) \
|
||||
if (PyMUTEX_FINI(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_FINI(" #mut ") failed"); };
|
||||
#define MUTEX_LOCK(mut) \
|
||||
if (PyMUTEX_LOCK(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_LOCK(" #mut ") failed"); };
|
||||
#define MUTEX_UNLOCK(mut) \
|
||||
if (PyMUTEX_UNLOCK(&(mut))) { \
|
||||
Py_FatalError("PyMUTEX_UNLOCK(" #mut ") failed"); };
|
||||
|
||||
#define COND_INIT(cond) \
|
||||
if (PyCOND_INIT(&(cond))) { \
|
||||
Py_FatalError("PyCOND_INIT(" #cond ") failed"); };
|
||||
#define COND_FINI(cond) \
|
||||
if (PyCOND_FINI(&(cond))) { \
|
||||
Py_FatalError("PyCOND_FINI(" #cond ") failed"); };
|
||||
#define COND_SIGNAL(cond) \
|
||||
if (PyCOND_SIGNAL(&(cond))) { \
|
||||
Py_FatalError("PyCOND_SIGNAL(" #cond ") failed"); };
|
||||
#define COND_WAIT(cond, mut) \
|
||||
if (PyCOND_WAIT(&(cond), &(mut))) { \
|
||||
Py_FatalError("PyCOND_WAIT(" #cond ") failed"); };
|
||||
#define COND_TIMED_WAIT(cond, mut, microseconds, timeout_result) \
|
||||
{ \
|
||||
int r = PyCOND_TIMEDWAIT(&(cond), &(mut), (microseconds)); \
|
||||
if (r < 0) \
|
||||
Py_FatalError("PyCOND_WAIT(" #cond ") failed"); \
|
||||
if (r) /* 1 == timeout, 2 == impl. can't say, so assume timeout */ \
|
||||
timeout_result = 1; \
|
||||
else \
|
||||
timeout_result = 0; \
|
||||
} \
|
||||
|
||||
|
||||
#define DEFAULT_INTERVAL 5000
|
||||
|
||||
static void _gil_initialize(struct _gil_runtime_state *gil)
|
||||
{
|
||||
_Py_atomic_int uninitialized = {-1};
|
||||
gil->locked = uninitialized;
|
||||
gil->interval = DEFAULT_INTERVAL;
|
||||
}
|
||||
|
||||
static int gil_created(struct _gil_runtime_state *gil)
|
||||
{
|
||||
return (_Py_atomic_load_explicit(&gil->locked, _Py_memory_order_acquire) >= 0);
|
||||
}
|
||||
|
||||
static void create_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
MUTEX_INIT(gil->mutex);
|
||||
#ifdef FORCE_SWITCHING
|
||||
MUTEX_INIT(gil->switch_mutex);
|
||||
#endif
|
||||
COND_INIT(gil->cond);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_INIT(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);
|
||||
}
|
||||
|
||||
static void destroy_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
/* 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);
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_FINI(gil->switch_cond);
|
||||
MUTEX_FINI(gil->switch_mutex);
|
||||
#endif
|
||||
_Py_atomic_store_explicit(&gil->locked, -1,
|
||||
_Py_memory_order_release);
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
|
||||
}
|
||||
|
||||
#ifdef HAVE_FORK
|
||||
static void recreate_gil(struct _gil_runtime_state *gil)
|
||||
{
|
||||
_Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
|
||||
/* XXX should we destroy the old OS resources here? */
|
||||
create_gil(gil);
|
||||
}
|
||||
#endif
|
||||
|
||||
static void
|
||||
drop_gil(struct _ceval_runtime_state *ceval, struct _ceval_state *ceval2,
|
||||
PyThreadState *tstate)
|
||||
{
|
||||
struct _gil_runtime_state *gil = &ceval->gil;
|
||||
if (!_Py_atomic_load_relaxed(&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);
|
||||
}
|
||||
|
||||
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);
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
if (_Py_atomic_load_relaxed(&ceval2->gil_drop_request) && tstate != NULL) {
|
||||
MUTEX_LOCK(gil->switch_mutex);
|
||||
/* Not switched yet => wait */
|
||||
if (((PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) == tstate)
|
||||
{
|
||||
assert(is_tstate_valid(tstate));
|
||||
RESET_GIL_DROP_REQUEST(tstate->interp);
|
||||
/* 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(gil->switch_cond, gil->switch_mutex);
|
||||
}
|
||||
MUTEX_UNLOCK(gil->switch_mutex);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
/* Check if a Python thread must exit immediately, rather than taking the GIL
|
||||
if Py_Finalize() has been called.
|
||||
|
||||
When this function is called by a daemon thread after Py_Finalize() has been
|
||||
called, the GIL does no longer exist.
|
||||
|
||||
tstate must be non-NULL. */
|
||||
static inline int
|
||||
tstate_must_exit(PyThreadState *tstate)
|
||||
{
|
||||
/* bpo-39877: Access _PyRuntime directly rather than using
|
||||
tstate->interp->runtime to support calls from Python daemon threads.
|
||||
After Py_Finalize() has been called, tstate can be a dangling pointer:
|
||||
point to PyThreadState freed memory. */
|
||||
PyThreadState *finalizing = _PyRuntimeState_GetFinalizing(&_PyRuntime);
|
||||
return (finalizing != NULL && finalizing != tstate);
|
||||
}
|
||||
|
||||
|
||||
/* Take the GIL.
|
||||
|
||||
The function saves errno at entry and restores its value at exit.
|
||||
|
||||
tstate must be non-NULL. */
|
||||
static void
|
||||
take_gil(PyThreadState *tstate)
|
||||
{
|
||||
int err = errno;
|
||||
|
||||
assert(tstate != NULL);
|
||||
|
||||
if (tstate_must_exit(tstate)) {
|
||||
/* bpo-39877: If Py_Finalize() has been called and tstate is not the
|
||||
thread which called Py_Finalize(), exit immediately the thread.
|
||||
|
||||
This code path can be reached by a daemon thread after Py_Finalize()
|
||||
completes. In this case, tstate is a dangling pointer: points to
|
||||
PyThreadState freed memory. */
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
|
||||
assert(is_tstate_valid(tstate));
|
||||
PyInterpreterState *interp = tstate->interp;
|
||||
struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
|
||||
struct _ceval_state *ceval2 = &interp->ceval;
|
||||
struct _gil_runtime_state *gil = &ceval->gil;
|
||||
|
||||
/* Check that _PyEval_InitThreads() was called to create the lock */
|
||||
assert(gil_created(gil));
|
||||
|
||||
MUTEX_LOCK(gil->mutex);
|
||||
|
||||
if (!_Py_atomic_load_relaxed(&gil->locked)) {
|
||||
goto _ready;
|
||||
}
|
||||
|
||||
while (_Py_atomic_load_relaxed(&gil->locked)) {
|
||||
unsigned long saved_switchnum = gil->switch_number;
|
||||
|
||||
unsigned long interval = (gil->interval >= 1 ? gil->interval : 1);
|
||||
int timed_out = 0;
|
||||
COND_TIMED_WAIT(gil->cond, 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)
|
||||
{
|
||||
if (tstate_must_exit(tstate)) {
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
SET_GIL_DROP_REQUEST(interp);
|
||||
}
|
||||
}
|
||||
|
||||
_ready:
|
||||
#ifdef FORCE_SWITCHING
|
||||
/* This mutex must be taken before modifying gil->last_holder:
|
||||
see drop_gil(). */
|
||||
MUTEX_LOCK(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);
|
||||
|
||||
if (tstate != (PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) {
|
||||
_Py_atomic_store_relaxed(&gil->last_holder, (uintptr_t)tstate);
|
||||
++gil->switch_number;
|
||||
}
|
||||
|
||||
#ifdef FORCE_SWITCHING
|
||||
COND_SIGNAL(gil->switch_cond);
|
||||
MUTEX_UNLOCK(gil->switch_mutex);
|
||||
#endif
|
||||
|
||||
if (tstate_must_exit(tstate)) {
|
||||
/* bpo-36475: If Py_Finalize() has been called and tstate is not
|
||||
the thread which called Py_Finalize(), exit immediately the
|
||||
thread.
|
||||
|
||||
This code path can be reached by a daemon thread which was waiting
|
||||
in take_gil() while the main thread called
|
||||
wait_for_thread_shutdown() from Py_Finalize(). */
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
drop_gil(ceval, ceval2, tstate);
|
||||
PyThread_exit_thread();
|
||||
}
|
||||
assert(is_tstate_valid(tstate));
|
||||
|
||||
if (_Py_atomic_load_relaxed(&ceval2->gil_drop_request)) {
|
||||
RESET_GIL_DROP_REQUEST(interp);
|
||||
}
|
||||
else {
|
||||
/* bpo-40010: eval_breaker should be recomputed to be set to 1 if there
|
||||
is a pending signal: signal received by another thread which cannot
|
||||
handle signals.
|
||||
|
||||
Note: RESET_GIL_DROP_REQUEST() calls COMPUTE_EVAL_BREAKER(). */
|
||||
COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
|
||||
}
|
||||
|
||||
/* Don't access tstate if the thread must exit */
|
||||
if (tstate->async_exc != NULL) {
|
||||
_PyEval_SignalAsyncExc(tstate->interp);
|
||||
}
|
||||
|
||||
MUTEX_UNLOCK(gil->mutex);
|
||||
|
||||
errno = err;
|
||||
}
|
||||
|
||||
void _PyEval_SetSwitchInterval(unsigned long microseconds)
|
||||
{
|
||||
struct _gil_runtime_state *gil = &_PyRuntime.ceval.gil;
|
||||
gil->interval = microseconds;
|
||||
}
|
||||
|
||||
unsigned long _PyEval_GetSwitchInterval()
|
||||
{
|
||||
struct _gil_runtime_state *gil = &_PyRuntime.ceval.gil;
|
||||
return gil->interval;
|
||||
}
|
|
@ -174,7 +174,6 @@ def clean_lines(text):
|
|||
Objects/stringlib/unicode_format.h Py_BUILD_CORE 1
|
||||
Parser/string_parser.h Py_BUILD_CORE 1
|
||||
Parser/pegen.h Py_BUILD_CORE 1
|
||||
Python/ceval_gil.h Py_BUILD_CORE 1
|
||||
Python/condvar.h Py_BUILD_CORE 1
|
||||
|
||||
Modules/_json.c Py_BUILD_CORE_BUILTIN 1
|
||||
|
|
|
@ -1752,7 +1752,7 @@ def is_other_python_frame(self):
|
|||
|
||||
def is_waiting_for_gil(self):
|
||||
'''Is this frame waiting on the GIL?'''
|
||||
# This assumes the _POSIX_THREADS version of Python/ceval_gil.h:
|
||||
# This assumes the _POSIX_THREADS version of Python/ceval_gil.c:
|
||||
name = self._gdbframe.name()
|
||||
if name:
|
||||
return (name == 'take_gil')
|
||||
|
|
Loading…
Reference in a new issue