bpo-38858: Small integer per interpreter (GH-17315)
Each Python subinterpreter now has its own "small integer
singletons": numbers in [-5; 257] range.
It is no longer possible to change the number of small integers at
build time by overriding NSMALLNEGINTS and NSMALLPOSINTS macros:
macros should now be modified manually in pycore_pystate.h header
file.
For now, continue to share _PyLong_Zero and _PyLong_One singletons
between all subinterpreters.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index bc87fb2..be9301f 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3,6 +3,7 @@
/* XXX The functional organization of this file is terrible */
#include "Python.h"
+#include "pycore_pystate.h" /* _Py_IsMainInterpreter() */
#include "longintrepr.h"
#include <float.h>
@@ -15,12 +16,8 @@
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ec0275e3422a36e3]*/
-#ifndef NSMALLPOSINTS
-#define NSMALLPOSINTS 257
-#endif
-#ifndef NSMALLNEGINTS
-#define NSMALLNEGINTS 5
-#endif
+#define NSMALLPOSINTS _PY_NSMALLPOSINTS
+#define NSMALLNEGINTS _PY_NSMALLNEGINTS
_Py_IDENTIFIER(little);
_Py_IDENTIFIER(big);
@@ -35,13 +32,6 @@
PyObject *_PyLong_One = NULL;
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
-/* Small integers are preallocated in this array so that they
- can be shared.
- The integers that are preallocated are those in the range
- -NSMALLNEGINTS (inclusive) to NSMALLPOSINTS (not inclusive).
-*/
-static PyLongObject* small_ints[NSMALLNEGINTS + NSMALLPOSINTS] = {0};
-
#define IS_SMALL_INT(ival) (-NSMALLNEGINTS <= (ival) && (ival) < NSMALLPOSINTS)
#define IS_SMALL_UINT(ival) ((ival) < NSMALLPOSINTS)
@@ -53,7 +43,8 @@
get_small_int(sdigit ival)
{
assert(IS_SMALL_INT(ival));
- PyObject *v = (PyObject*)small_ints[ival + NSMALLNEGINTS];
+ PyThreadState *tstate = _PyThreadState_GET();
+ PyObject *v = (PyObject*)tstate->interp->small_ints[ival + NSMALLNEGINTS];
Py_INCREF(v);
#ifdef COUNT_ALLOCS
if (ival >= 0)
@@ -5782,7 +5773,7 @@
}
int
-_PyLong_Init(void)
+_PyLong_Init(PyThreadState *tstate)
{
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i=0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
@@ -5797,37 +5788,43 @@
Py_SIZE(v) = size;
v->ob_digit[0] = (digit)abs(ival);
- small_ints[i] = v;
+ tstate->interp->small_ints[i] = v;
}
#endif
- _PyLong_Zero = PyLong_FromLong(0);
- if (_PyLong_Zero == NULL) {
- return 0;
- }
- _PyLong_One = PyLong_FromLong(1);
- if (_PyLong_One == NULL) {
- return 0;
- }
-
- /* initialize int_info */
- if (Int_InfoType.tp_name == NULL) {
- if (PyStructSequence_InitType2(&Int_InfoType, &int_info_desc) < 0) {
+ if (_Py_IsMainInterpreter(tstate)) {
+ _PyLong_Zero = PyLong_FromLong(0);
+ if (_PyLong_Zero == NULL) {
return 0;
}
+
+ _PyLong_One = PyLong_FromLong(1);
+ if (_PyLong_One == NULL) {
+ return 0;
+ }
+
+ /* initialize int_info */
+ if (Int_InfoType.tp_name == NULL) {
+ if (PyStructSequence_InitType2(&Int_InfoType, &int_info_desc) < 0) {
+ return 0;
+ }
+ }
}
return 1;
}
void
-_PyLong_Fini(void)
+_PyLong_Fini(PyThreadState *tstate)
{
- Py_CLEAR(_PyLong_One);
- Py_CLEAR(_PyLong_Zero);
+ if (_Py_IsMainInterpreter(tstate)) {
+ Py_CLEAR(_PyLong_One);
+ Py_CLEAR(_PyLong_Zero);
+ }
+
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i = 0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
- Py_CLEAR(small_ints[i]);
+ Py_CLEAR(tstate->interp->small_ints[i]);
}
#endif
}