Make more things internal to this file. Remove
visit_finalizer_reachable since it's the same as visit_reachable.
Rename visit_reachable to visit_move. Objects can now have the GC type
flag set, reachable by tp_traverse and not be in a GC linked list. This
should make the collector more robust and easier to use by extension
module writers. Add memory management functions for container objects
(new, del, resize).
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index dcf0128..30b6839 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -8,7 +8,7 @@
Based on a post on the python-dev list. Ideas from Guido van Rossum,
Eric Tiedemann, and various others.
- http://www.arctrix.com/nas/python/gc.html
+ http://www.arctrix.com/nas/python/gc/
http://www.python.org/pipermail/python-dev/2000-March/003869.html
http://www.python.org/pipermail/python-dev/2000-March/004010.html
http://www.python.org/pipermail/python-dev/2000-March/004022.html
@@ -18,18 +18,21 @@
*/
-
#include "Python.h"
#ifdef WITH_CYCLE_GC
-/* magic gc_refs value */
-#define GC_MOVED -1
+/* Get an object's GC head */
+#define AS_GC(o) ((PyGC_Head *)(o)-1)
+
+/* Get the object given the GC head */
+#define FROM_GC(g) ((PyObject *)(((PyGC_Head *)g)+1))
+
/*** Global GC state ***/
/* linked lists of container objects */
-static PyGC_Head generation0 = {&generation0, &generation0, 0};
+PyGC_Head _PyGC_generation0 = {&_PyGC_generation0, &_PyGC_generation0, 0};
static PyGC_Head generation1 = {&generation1, &generation1, 0};
static PyGC_Head generation2 = {&generation2, &generation2, 0};
static int generation = 0; /* current generation being collected */
@@ -43,6 +46,9 @@
/* net new objects allocated since last collection */
static int allocated;
+/* true if we are currently running the collector */
+static int collecting;
+
/* set for debugging information */
#define DEBUG_STATS (1<<0) /* print collection statistics */
#define DEBUG_COLLECTABLE (1<<1) /* print collectable objects */
@@ -57,6 +63,9 @@
DEBUG_SAVEALL
static int debug;
+/* Special gc_refs value */
+#define GC_MOVED -123
+
/* list of uncollectable objects */
static PyObject *garbage;
@@ -86,10 +95,7 @@
{
node->gc_prev->gc_next = node->gc_next;
node->gc_next->gc_prev = node->gc_prev;
-#ifdef Py_DEBUG
- node->gc_prev = NULL;
- node->gc_next = NULL;
-#endif
+ node->gc_next = NULL; /* object is not currently tracked */
}
static void
@@ -137,13 +143,14 @@
/*** end of list stuff ***/
+
/* Set all gc_refs = ob_refcnt */
static void
update_refs(PyGC_Head *containers)
{
PyGC_Head *gc = containers->gc_next;
for (; gc != containers; gc=gc->gc_next) {
- gc->gc_refs = PyObject_FROM_GC(gc)->ob_refcnt;
+ gc->gc_refs = FROM_GC(gc)->ob_refcnt;
}
}
@@ -151,7 +158,9 @@
visit_decref(PyObject *op, void *data)
{
if (op && PyObject_IS_GC(op)) {
- PyObject_AS_GC(op)->gc_refs--;
+ PyGC_Head *gc = AS_GC(op);
+ if (gc->gc_next != NULL)
+ AS_GC(op)->gc_refs--;
}
return 0;
}
@@ -163,8 +172,8 @@
traverseproc traverse;
PyGC_Head *gc = containers->gc_next;
for (; gc != containers; gc=gc->gc_next) {
- traverse = PyObject_FROM_GC(gc)->ob_type->tp_traverse;
- (void) traverse(PyObject_FROM_GC(gc),
+ traverse = FROM_GC(gc)->ob_type->tp_traverse;
+ (void) traverse(FROM_GC(gc),
(visitproc)visit_decref,
NULL);
}
@@ -188,13 +197,13 @@
}
static int
-visit_reachable(PyObject *op, PyGC_Head *roots)
+visit_move(PyObject *op, PyGC_Head *tolist)
{
if (PyObject_IS_GC(op)) {
- PyGC_Head *gc = PyObject_AS_GC(op);
- if (gc && gc->gc_refs != GC_MOVED) {
+ PyGC_Head *gc = AS_GC(op);
+ if (gc->gc_next != NULL && gc->gc_refs != GC_MOVED) {
gc_list_remove(gc);
- gc_list_append(gc, roots);
+ gc_list_append(gc, tolist);
gc->gc_refs = GC_MOVED;
}
}
@@ -209,15 +218,15 @@
PyGC_Head *gc = reachable->gc_next;
for (; gc != reachable; gc=gc->gc_next) {
/* careful, reachable list is growing here */
- PyObject *op = PyObject_FROM_GC(gc);
+ PyObject *op = FROM_GC(gc);
traverse = op->ob_type->tp_traverse;
(void) traverse(op,
- (visitproc)visit_reachable,
+ (visitproc)visit_move,
(void *)reachable);
}
}
-/* move all objects with finalizers (instances with __del__) */
+/* Move all objects with finalizers (instances with __del__) */
static void
move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers)
{
@@ -230,7 +239,7 @@
Py_FatalError("PyGC: can't initialize __del__ string");
}
for (; gc != unreachable; gc=next) {
- PyObject *op = PyObject_FROM_GC(gc);
+ PyObject *op = FROM_GC(gc);
next = gc->gc_next;
if (PyInstance_Check(op) && PyObject_HasAttr(op, delstr)) {
gc_list_remove(gc);
@@ -239,22 +248,6 @@
}
}
-
-/* called by tp_traverse */
-static int
-visit_finalizer_reachable(PyObject *op, PyGC_Head *finalizers)
-{
- if (PyObject_IS_GC(op)) {
- PyGC_Head *gc = PyObject_AS_GC(op);
- if (gc && gc->gc_refs != GC_MOVED) {
- gc_list_remove(gc);
- gc_list_append(gc, finalizers);
- gc->gc_refs = GC_MOVED;
- }
- }
- return 0;
-}
-
/* Move objects referenced from roots to roots */
static void
move_finalizer_reachable(PyGC_Head *finalizers)
@@ -263,9 +256,9 @@
PyGC_Head *gc = finalizers->gc_next;
for (; gc != finalizers; gc=gc->gc_next) {
/* careful, finalizers list is growing here */
- traverse = PyObject_FROM_GC(gc)->ob_type->tp_traverse;
- (void) traverse(PyObject_FROM_GC(gc),
- (visitproc)visit_finalizer_reachable,
+ traverse = FROM_GC(gc)->ob_type->tp_traverse;
+ (void) traverse(FROM_GC(gc),
+ (visitproc)visit_move,
(void *)finalizers);
}
}
@@ -306,7 +299,7 @@
}
for (gc = finalizers->gc_next; gc != finalizers;
gc = finalizers->gc_next) {
- PyObject *op = PyObject_FROM_GC(gc);
+ PyObject *op = FROM_GC(gc);
if ((debug & DEBUG_SAVEALL) || PyInstance_Check(op)) {
/* If SAVEALL is not set then just append
* instances to the list of garbage. We assume
@@ -330,7 +323,7 @@
while (unreachable->gc_next != unreachable) {
PyGC_Head *gc = unreachable->gc_next;
- PyObject *op = PyObject_FROM_GC(gc);
+ PyObject *op = FROM_GC(gc);
if (debug & DEBUG_SAVEALL) {
PyList_Append(garbage, op);
}
@@ -366,7 +359,7 @@
"gc: collecting generation %d...\n"
"gc: objects in each generation: %ld %ld %ld\n",
generation,
- gc_list_size(&generation0),
+ gc_list_size(&_PyGC_generation0),
gc_list_size(&generation1),
gc_list_size(&generation2));
}
@@ -407,7 +400,7 @@
gc = gc->gc_next) {
m++;
if (debug & DEBUG_COLLECTABLE) {
- debug_cycle("collectable", PyObject_FROM_GC(gc));
+ debug_cycle("collectable", FROM_GC(gc));
}
}
/* call tp_clear on objects in the collectable set. This will cause
@@ -421,7 +414,7 @@
gc = gc->gc_next) {
n++;
if (debug & DEBUG_UNCOLLECTABLE) {
- debug_cycle("uncollectable", PyObject_FROM_GC(gc));
+ debug_cycle("uncollectable", FROM_GC(gc));
}
}
if (debug & DEBUG_STATS) {
@@ -461,7 +454,7 @@
if (collections1 > threshold2) {
generation = 2;
- gc_list_merge(&generation0, &generation2);
+ gc_list_merge(&_PyGC_generation0, &generation2);
gc_list_merge(&generation1, &generation2);
if (generation2.gc_next != &generation2) {
n = collect(&generation2, &generation2);
@@ -471,7 +464,7 @@
else if (collections0 > threshold1) {
generation = 1;
collections1++;
- gc_list_merge(&generation0, &generation1);
+ gc_list_merge(&_PyGC_generation0, &generation1);
if (generation1.gc_next != &generation1) {
n = collect(&generation1, &generation2);
}
@@ -480,52 +473,13 @@
else {
generation = 0;
collections0++;
- if (generation0.gc_next != &generation0) {
- n = collect(&generation0, &generation1);
+ if (_PyGC_generation0.gc_next != &_PyGC_generation0) {
+ n = collect(&_PyGC_generation0, &generation1);
}
}
return n;
}
-void
-_PyGC_Insert(PyObject *op)
-{
- /* collection lock since collecting may cause allocations */
- static int collecting = 0;
-
-#ifdef Py_DEBUG
- if (!PyObject_IS_GC(op)) {
- abort();
- }
-#endif
- if (allocated > threshold0 &&
- enabled &&
- threshold0 &&
- !collecting &&
- !PyErr_Occurred()) {
- collecting++;
- collect_generations();
- collecting--;
- }
- allocated++;
- gc_list_append(PyObject_AS_GC(op), &generation0);
-}
-
-void
-_PyGC_Remove(PyObject *op)
-{
- PyGC_Head *g = PyObject_AS_GC(op);
-#ifdef Py_DEBUG
- if (!PyObject_IS_GC(op)) {
- abort();
- }
-#endif
- gc_list_remove(g);
- if (allocated > 0) {
- allocated--;
- }
-}
-
static char gc_enable__doc__[] =
"enable() -> None\n"
"\n"
@@ -595,7 +549,7 @@
return NULL;
generation = 2;
- gc_list_merge(&generation0, &generation2);
+ gc_list_merge(&_PyGC_generation0, &generation2);
gc_list_merge(&generation1, &generation2);
n = collect(&generation2, &generation2);
@@ -693,7 +647,7 @@
PyObject *obj;
traverseproc traverse;
for (gc = list->gc_next; gc != list; gc = gc->gc_next) {
- obj = PyObject_FROM_GC(gc);
+ obj = FROM_GC(gc);
traverse = obj->ob_type->tp_traverse;
if (obj == objs || obj == resultlist)
continue;
@@ -713,7 +667,7 @@
gc_get_referents(PyObject *self, PyObject *args)
{
PyObject *result = PyList_New(0);
- if (!(gc_referents_for(args, &generation0, result) &&
+ if (!(gc_referents_for(args, &_PyGC_generation0, result) &&
gc_referents_for(args, &generation1, result) &&
gc_referents_for(args, &generation2, result))) {
Py_DECREF(result);
@@ -735,7 +689,7 @@
{
PyGC_Head *gc;
for (gc = gc_list->gc_next; gc != gc_list; gc = gc->gc_next) {
- PyObject *op = PyObject_FROM_GC(gc);
+ PyObject *op = FROM_GC(gc);
if (op != py_list) {
Py_INCREF(op);
PyList_Append(py_list, op);
@@ -751,7 +705,7 @@
if (!PyArg_ParseTuple(args, ":get_objects")) /* check no args */
return NULL;
result = PyList_New(0);
- append_objects(result, &generation0);
+ append_objects(result, &_PyGC_generation0);
append_objects(result, &generation1);
append_objects(result, &generation2);
return result;
@@ -820,4 +774,105 @@
PyInt_FromLong(DEBUG_LEAK));
}
+/* for debugging */
+void _PyGC_Dump(PyGC_Head *g)
+{
+ _PyObject_Dump(FROM_GC(g));
+}
+
#endif /* WITH_CYCLE_GC */
+
+/* extension modules might be compiled with GC support so these
+ functions must always be available */
+
+void
+_PyObject_GC_Track(PyObject *op)
+{
+ _PyObject_GC_TRACK(op);
+}
+
+void
+_PyObject_GC_UnTrack(PyObject *op)
+{
+ _PyObject_GC_UNTRACK(op);
+}
+
+PyObject *
+_PyObject_GC_Malloc(PyTypeObject *tp, int size)
+{
+ PyObject *op;
+#ifdef WITH_CYCLE_GC
+ PyGC_Head *g = PyObject_MALLOC(_PyObject_VAR_SIZE(tp, size) +
+ sizeof(PyGC_Head));
+ if (g == NULL)
+ return (PyObject *)PyErr_NoMemory();
+ g->gc_next = NULL;
+ allocated++;
+ if (allocated > threshold0 &&
+ enabled &&
+ threshold0 &&
+ !collecting &&
+ !PyErr_Occurred()) {
+ collecting = 1;
+ collect_generations();
+ collecting = 0;
+ }
+ op = FROM_GC(g);
+#else
+ op = PyObject_MALLOC(_PyObject_VAR_SIZE(tp, size));
+ if (op == NULL)
+ return (PyObject *)PyErr_NoMemory();
+
+#endif
+ return op;
+}
+
+PyObject *
+_PyObject_GC_New(PyTypeObject *tp)
+{
+ PyObject *op = _PyObject_GC_Malloc(tp, 0);
+ return PyObject_INIT(op, tp);
+}
+
+PyVarObject *
+_PyObject_GC_NewVar(PyTypeObject *tp, int size)
+{
+ PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(tp, size);
+ return PyObject_INIT_VAR(op, tp, size);
+}
+
+PyVarObject *
+_PyObject_GC_Resize(PyVarObject *op, int size)
+{
+#ifdef WITH_CYCLE_GC
+ PyGC_Head *g = AS_GC(op);
+ g = PyObject_REALLOC(g, _PyObject_VAR_SIZE(op->ob_type, size) +
+ sizeof(PyGC_Head));
+ if (g == NULL)
+ return (PyVarObject *)PyErr_NoMemory();
+ op = (PyVarObject *) FROM_GC(g);
+#else
+ op = PyObject_REALLOC(op, _PyObject_VAR_SIZE(op->ob_type, size));
+ if (op == NULL)
+ return (PyVarObject *)PyErr_NoMemory();
+#endif
+ op->ob_size = size;
+ return op;
+}
+
+void
+_PyObject_GC_Del(PyObject *op)
+{
+#ifdef WITH_CYCLE_GC
+ PyGC_Head *g = AS_GC(op);
+ if (g->gc_next != NULL)
+ gc_list_remove(g);
+ if (allocated > 0) {
+ allocated--;
+ }
+ PyObject_FREE(g);
+#else
+ PyObject_FREE(op);
+#endif
+}
+