mirror of https://github.com/python/cpython
67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
#ifndef Py_INTERNAL_GIL_H
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#define Py_INTERNAL_GIL_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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#include "pycore_condvar.h" // PyCOND_T
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#ifndef Py_HAVE_CONDVAR
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# error You need either a POSIX-compatible or a Windows system!
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#endif
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/* Enable if you want to force the switching of threads at least
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every `interval`. */
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#undef FORCE_SWITCHING
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#define FORCE_SWITCHING
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struct _gil_runtime_state {
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#ifdef Py_GIL_DISABLED
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/* If this GIL is disabled, enabled == 0.
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If this GIL is enabled transiently (most likely to initialize a module
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of unknown safety), enabled indicates the number of active transient
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requests.
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If this GIL is enabled permanently, enabled == INT_MAX.
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It must not be modified directly; use _PyEval_EnableGILTransiently(),
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_PyEval_EnableGILPermanently(), and _PyEval_DisableGIL()
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It is always read and written atomically, but a thread can assume its
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value will be stable as long as that thread is attached or knows that no
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other threads are attached (e.g., during a stop-the-world.). */
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int enabled;
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#endif
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/* microseconds (the Python API uses seconds, though) */
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unsigned long interval;
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/* Last PyThreadState holding / having held the GIL. This helps us
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know whether anyone else was scheduled after we dropped the GIL. */
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PyThreadState* last_holder;
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/* Whether the GIL is already taken (-1 if uninitialized). This is
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atomic because it can be read without any lock taken in ceval.c. */
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int locked;
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/* Number of GIL switches since the beginning. */
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unsigned long switch_number;
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/* This condition variable allows one or several threads to wait
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until the GIL is released. In addition, the mutex also protects
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the above variables. */
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PyCOND_T cond;
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PyMUTEX_T mutex;
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#ifdef FORCE_SWITCHING
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/* This condition variable helps the GIL-releasing thread wait for
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a GIL-awaiting thread to be scheduled and take the GIL. */
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PyCOND_T switch_cond;
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PyMUTEX_T switch_mutex;
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#endif
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};
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_GIL_H */
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