bpo-40521: Make slice cache per-interpreter (GH-20637)
Each interpreter now has its own slice cache:
* Move slice cache into PyInterpreterState.
* Add tstate parameter to _PySlice_Fini().
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index c0eed00..70054ef 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -187,6 +187,10 @@
#endif
struct _Py_tuple_state tuple;
struct _Py_float_state float_state;
+
+ /* Using a cache is very effective since typically only a single slice is
+ created and then deleted again. */
+ PySliceObject *slice_cache;
};
/* Used by _PyImport_Cleanup() */
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
index 2643abc..bba9bd9 100644
--- a/Include/internal/pycore_pylifecycle.h
+++ b/Include/internal/pycore_pylifecycle.h
@@ -65,7 +65,7 @@
extern void _PySet_Fini(void);
extern void _PyBytes_Fini(void);
extern void _PyFloat_Fini(PyThreadState *tstate);
-extern void _PySlice_Fini(void);
+extern void _PySlice_Fini(PyThreadState *tstate);
extern void _PyAsyncGen_Fini(void);
extern void PyOS_FiniInterrupts(void);
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst b/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
index 016f116..74c7a49 100644
--- a/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
@@ -1,2 +1,3 @@
-Tuple free lists, empty tuple singleton, and float free list are no longer
-shared by all interpreters: each interpreter now its own free lists.
+The tuple free lists, the empty tuple singleton, the float free list, and the
+slice cache are no longer shared by all interpreters: each interpreter now has
+its own free lists and caches.
diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c
index 391711f..f97a570 100644
--- a/Objects/sliceobject.c
+++ b/Objects/sliceobject.c
@@ -15,7 +15,7 @@
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
-#include "pycore_object.h"
+#include "pycore_object.h" // _PyObject_GC_TRACK()
#include "structmember.h" // PyMemberDef
static PyObject *
@@ -95,16 +95,13 @@
/* Slice object implementation */
-/* Using a cache is very effective since typically only a single slice is
- * created and then deleted again
- */
-static PySliceObject *slice_cache = NULL;
-void _PySlice_Fini(void)
+void _PySlice_Fini(PyThreadState *tstate)
{
- PySliceObject *obj = slice_cache;
+ PyInterpreterState *interp = tstate->interp;
+ PySliceObject *obj = interp->slice_cache;
if (obj != NULL) {
- slice_cache = NULL;
+ interp->slice_cache = NULL;
PyObject_GC_Del(obj);
}
}
@@ -116,10 +113,11 @@
PyObject *
PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
{
+ PyInterpreterState *interp = _PyInterpreterState_GET();
PySliceObject *obj;
- if (slice_cache != NULL) {
- obj = slice_cache;
- slice_cache = NULL;
+ if (interp->slice_cache != NULL) {
+ obj = interp->slice_cache;
+ interp->slice_cache = NULL;
_Py_NewReference((PyObject *)obj);
} else {
obj = PyObject_GC_New(PySliceObject, &PySlice_Type);
@@ -324,14 +322,17 @@
static void
slice_dealloc(PySliceObject *r)
{
+ PyInterpreterState *interp = _PyInterpreterState_GET();
_PyObject_GC_UNTRACK(r);
Py_DECREF(r->step);
Py_DECREF(r->start);
Py_DECREF(r->stop);
- if (slice_cache == NULL)
- slice_cache = r;
- else
+ if (interp->slice_cache == NULL) {
+ interp->slice_cache = r;
+ }
+ else {
PyObject_GC_Del(r);
+ }
}
static PyObject *
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 716303c..ee9d698 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -1265,9 +1265,9 @@
if (is_main_interp) {
_PyDict_Fini();
- _PySlice_Fini();
}
+ _PySlice_Fini(tstate);
_PyWarnings_Fini(tstate->interp);
if (is_main_interp) {