bpo-24165: Add a freelist for long objects by methane · Pull Request #22884 · python/cpython

Expand Up @@ -67,6 +67,11 @@ maybe_small_long(PyLongObject *v) #define maybe_small_long(val) (val) #endif
/* Speed optimization to avoid frequent malloc/free of small ints */ #ifndef PyLong_MAXFREELIST # define PyLong_MAXFREELIST 100 #endif
/* If a freshly-allocated int is already shared, it must be a small integer, so negating it must go to PyLong_FromLong */ Py_LOCAL_INLINE(void) Expand Down Expand Up @@ -130,22 +135,34 @@ long_normalize(PyLongObject *v) PyLongObject * _PyLong_New(Py_ssize_t size) { struct _Py_long_state *state = &_PyInterpreterState_GET()->long_state; #ifdef Py_DEBUG // _PyLong_New() must not be called after _PyLong_Fini() assert(state->numfree != -1); #endif
PyLongObject *result; /* Number of bytes needed is: offsetof(PyLongObject, ob_digit) + sizeof(digit)*size. Previous incarnations of this code used sizeof(PyVarObject) instead of the offsetof, but this risks being incorrect in the presence of padding between the PyVarObject header and the digits. */ if (size > (Py_ssize_t)MAX_LONG_DIGITS) { PyErr_SetString(PyExc_OverflowError, "too many digits in integer"); return NULL; if (size == 1 && (result = (PyLongObject*)state->free_list) != NULL) { state->free_list = (PyLongObject *)Py_TYPE(result); state->numfree--; } result = PyObject_MALLOC(offsetof(PyLongObject, ob_digit) + size*sizeof(digit)); if (!result) { PyErr_NoMemory(); return NULL; else { /* Number of bytes needed is: offsetof(PyLongObject, ob_digit) + sizeof(digit)*size. Previous incarnations of this code used sizeof(PyVarObject) instead of the offsetof, but this risks being incorrect in the presence of padding between the PyVarObject header and the digits. */ if (size > (Py_ssize_t)MAX_LONG_DIGITS) { PyErr_SetString(PyExc_OverflowError, "too many digits in integer"); return NULL; } result = PyObject_MALLOC(offsetof(PyLongObject, ob_digit) + size*sizeof(digit)); if (!result) { PyErr_NoMemory(); return NULL; } } _PyObject_InitVar((PyVarObject*)result, &PyLong_Type, size); return result; Expand Down Expand Up @@ -204,7 +221,7 @@ PyLong_FromLong(long ival) }
/* Fast path for single-digit ints */ if (!(abs_ival >> PyLong_SHIFT)) { if (abs_ival < (1UL << PyLong_SHIFT)) { v = _PyLong_New(1); if (v) { Py_SET_SIZE(v, sign); Expand All @@ -214,9 +231,9 @@ PyLong_FromLong(long ival) return (PyObject*)v; }
#if PyLong_SHIFT==15 #if 2*PyLong_SHIFT < 8*PY_LONG_SIZE /* 2 digits */ if (!(abs_ival >> 2*PyLong_SHIFT)) { if (abs_ival < (1UL << 2*PyLong_SHIFT)) { v = _PyLong_New(2); if (v) { Py_SET_SIZE(v, 2 * sign); Expand Down Expand Up @@ -2885,6 +2902,27 @@ PyLong_AsDouble(PyObject *v) return ldexp(x, (int)exponent); }
static void long_dealloc(PyObject *v) { if (PyLong_CheckExact(v)) { struct _Py_long_state *state = &_PyInterpreterState_GET()->long_state; #ifdef Py_DEBUG // long_dealloc() must not be called after _PyLong_Fini() assert(state->numfree != -1); #endif Py_ssize_t size = Py_SIZE(v); if ((size == 1 || size == -1) && state->numfree < PyLong_MAXFREELIST) { Py_SET_TYPE(v, (PyTypeObject *)state->free_list); state->free_list = (PyLongObject *)v; state->numfree++; return; } } Py_TYPE(v)->tp_free(v); }
/* Methods */
/* if a < b, return a negative number Expand Down Expand Up @@ -5631,7 +5669,7 @@ PyTypeObject PyLong_Type = { "int", /* tp_name */ offsetof(PyLongObject, ob_digit), /* tp_basicsize */ sizeof(digit), /* tp_itemsize */ 0, /* tp_dealloc */ long_dealloc, /* tp_dealloc */ 0, /* tp_vectorcall_offset */ 0, /* tp_getattr */ 0, /* tp_setattr */ Expand Down Expand Up @@ -5751,6 +5789,20 @@ _PyLong_Init(PyThreadState *tstate) return 1; }
void _PyLong_ClearFreeList(PyThreadState *tstate) { struct _Py_long_state *state = &tstate->interp->long_state; PyLongObject *f = state->free_list; while (f != NULL) { PyLongObject *next = (PyLongObject*) Py_TYPE(f); PyObject_FREE(f); f = next; } state->free_list = NULL; state->numfree = 0; }
void _PyLong_Fini(PyThreadState *tstate) { Expand All @@ -5764,4 +5816,10 @@ _PyLong_Fini(PyThreadState *tstate) Py_CLEAR(tstate->interp->small_ints[i]); } #endif
_PyLong_ClearFreeList(tstate); #ifdef Py_DEBUG struct _Py_long_state *state = &tstate->interp->long_state; state->numfree = -1; #endif }