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bpo-30040: new empty dict uses key-sharing dict (GH-1080)

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Sizeof new empty dict becomes 72 bytes from 240 bytes (amd64).
It is same size to empty dict created by dict.clear().
This commit is contained in:
Inada Naoki 2019-03-12 17:25:44 +09:00 • committed by GitHub
parent fc06a192fd
commit f2a186712b
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4 changed files with 13 additions and 8 deletions
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Objects/dictobject.c
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@ -691,10 +691,8 @@ clone_combined_dict(PyDictObject *orig)
PyObject *
PyDict_New(void)
{
PyDictKeysObject *keys = new_keys_object(PyDict_MINSIZE);
if (keys == NULL)
return NULL;
return new_dict(keys, NULL);
dictkeys_incref(Py_EMPTY_KEYS);
return new_dict(Py_EMPTY_KEYS, empty_values);
}
/* Search index of hash table from offset of entry table */
@ -1276,6 +1274,9 @@ _PyDict_NewPresized(Py_ssize_t minused)
Py_ssize_t newsize;
PyDictKeysObject *new_keys;
if (minused == 0) {
return PyDict_New();
}
/* There are no strict guarantee that returned dict can contain minused
* items without resize. So we create medium size dict instead of very
* large dict or MemoryError.