gh-112075: Dictionary global version counter should use atomic increments #114568
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colesbury
approved these changes
Jan 25, 2024
| @@ -209,8 +209,14 @@ static inline PyDictUnicodeEntry* DK_UNICODE_ENTRIES(PyDictKeysObject *dk) { | |||
| #define DICT_VERSION_INCREMENT (1 << DICT_MAX_WATCHERS) | |||
| #define DICT_VERSION_MASK (DICT_VERSION_INCREMENT - 1) | |||
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| #ifdef Py_GIL_DISABLED | |||
| #define DICT_NEXT_VERSION(INTERP) \ | |||
| (_Py_atomic_add_uint64(&(INTERP)->dict_state.global_version, DICT_VERSION_INCREMENT) + DICT_VERSION_INCREMENT) | |||
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I think this is fine for now, especially in the interest of getting to the point where we can run the test suite with the GIL disabled, but we will want to avoid contention on the global version counter.
The strategy in nogil and nogil-3.12 was to reserve something like the next 256 versions (atomically) and then serve the next version requests from thread-local state.
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corona10
approved these changes
Jan 26, 2024
aisk
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Feb 11, 2024
…increments (python#114568) Dictionary global version counter should use atomic increments
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Dictionary global version counter should use atomic increments on free-threaded builds
dictobjects thread-safe in--disable-gilbuilds #112075