diff options
| -rw-r--r-- | Modules/gcmodule.c | 241 |
1 files changed, 148 insertions, 93 deletions
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 @@ static int threshold2 = 10; /* generation1 collections before collecting 2 */ /* 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 @@ static int allocated; DEBUG_SAVEALL static int debug; +/* Special gc_refs value */ +#define GC_MOVED -123 + /* list of uncollectable objects */ static PyObject *garbage; @@ -86,10 +95,7 @@ gc_list_remove(PyGC_Head *node) { 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 @@ gc_list_size(PyGC_Head *list) /*** 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 @@ static int 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 @@ subtract_refs(PyGC_Head *containers) 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 @@ move_roots(PyGC_Head *containers, PyGC_Head *roots) } 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 @@ move_root_reachable(PyGC_Head *reachable) 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 @@ move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers) 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 @@ move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers) } } - -/* 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 @@ move_finalizer_reachable(PyGC_Head *finalizers) 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 @@ handle_finalizers(PyGC_Head *finalizers, PyGC_Head *old) } 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 @@ delete_garbage(PyGC_Head *unreachable, PyGC_Head *old) 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 @@ collect(PyGC_Head *young, PyGC_Head *old) "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 @@ collect(PyGC_Head *young, PyGC_Head *old) 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 @@ collect(PyGC_Head *young, PyGC_Head *old) 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 @@ collect_generations(void) 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 @@ collect_generations(void) 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 @@ collect_generations(void) 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 @@ gc_collect(PyObject *self, PyObject *args) 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 @@ gc_referents_for(PyObject *objs, PyGC_Head *list, PyObject *resultlist) 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 @@ static PyObject * 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 @@ append_objects(PyObject *py_list, PyGC_Head *gc_list) { 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 @@ gc_get_objects(PyObject *self, PyObject *args) 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 @@ initgc(void) 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 +} + |