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gh-112075: Make PyDictKeysObject thread-safe #114741

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Merged
DinoV merged 6 commits into from
Feb 21, 2024
Merged

gh-112075: Make PyDictKeysObject thread-safe #114741

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4715734
Make PyDictKeysObject thread-safe
DinoV Jan 22, 2024
18d2916
Fix naming of unsplit -> combined
DinoV Jan 31, 2024
61caf84
Lock less and deal with atomic updates to shared size
DinoV Feb 2, 2024
268c806
Address review feedback
DinoV Feb 8, 2024
7407ce9
Lock in dictresize, not in callers
DinoV Feb 15, 2024
a9d3666
Fixup recursive locking
DinoV Feb 20, 2024
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Lock in dictresize, not in callers
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@DinoV
DinoV committed Feb 20, 2024
commit 7407ce9820a900550bf12655825dc30d2784c823
4 changes: 2 additions & 2 deletions Include/cpython/pyatomic_msc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -945,9 +945,9 @@ _Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value)
#if defined(_M_X64) || defined(_M_IX86)
*(Py_ssize_t volatile *)obj = value;
#elif defined(_M_ARM64)
__stlr64((unsigned __int64 volatile *)obj, (uintptr_t)value);
__stlr64((unsigned __int64 volatile *)obj, (unsigned __int64)value);
#else
# error "no implementation of _Py_atomic_store_int_release"
# error "no implementation of _Py_atomic_store_ssize_release"
#endif
}

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12 changes: 3 additions & 9 deletions Objects/dictobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1350,7 +1350,6 @@ insert_split_dict(PyInterpreterState *interp, PyDictObject *mp,
return -1;
}
assert(!_PyDict_HasSplitTable(mp));
assert(DK_IS_UNICODE(keys));
return insert_combined_dict(interp, mp, hash, key, value);
}

Expand Down Expand Up @@ -1609,7 +1608,7 @@ dictresize(PyInterpreterState *interp, PyDictObject *mp,
Py_ssize_t numentries = mp->ma_used;

if (oldvalues != NULL) {
ASSERT_KEYS_LOCKED(oldkeys);
LOCK_KEYS(oldkeys);
PyDictUnicodeEntry *oldentries = DK_UNICODE_ENTRIES(oldkeys);
/* Convert split table into new combined table.
* We must incref keys; we can transfer values.
Expand Down Expand Up @@ -1640,6 +1639,7 @@ dictresize(PyInterpreterState *interp, PyDictObject *mp,
}
build_indices_unicode(mp->ma_keys, newentries, numentries);
}
UNLOCK_KEYS(oldkeys);
dictkeys_decref(interp, oldkeys);
mp->ma_values = NULL;
free_values(oldvalues);
Expand Down Expand Up @@ -3998,14 +3998,8 @@ dict_popitem_impl(PyDictObject *self)
/* Convert split table to combined table */
if (_PyDict_HasSplitTable(self)) {
PyDictKeysObject *keys = self->ma_keys;
dictkeys_incref(keys);
LOCK_KEYS(keys);

int status = dictresize(interp, self, DK_LOG_SIZE(self->ma_keys), 1);
UNLOCK_KEYS(keys);
dictkeys_decref(interp, keys);

if (status < 0) {
if (dictresize(interp, self, DK_LOG_SIZE(self->ma_keys), 1) < 0) {
Py_DECREF(res);
return NULL;
}
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