GH-127010: Don't lazily track and untrack dicts (GH-127027)

5 files changed, 5 insertions, 51 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 029bdb2..7ffe2f5 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2340,10 +2340,6 @@ dummy_func(
             DEOPT_IF(ep->me_key != name);
             PyObject *old_value = ep->me_value;
             DEOPT_IF(old_value == NULL);
-            /* Ensure dict is GC tracked if it needs to be */
-            if (!_PyObject_GC_IS_TRACKED(dict) && _PyObject_GC_MAY_BE_TRACKED(PyStackRef_AsPyObjectBorrow(value))) {
-                _PyObject_GC_TRACK(dict);
-            }
             _PyDict_NotifyEvent(tstate->interp, PyDict_EVENT_MODIFIED, dict, name, PyStackRef_AsPyObjectBorrow(value));
             ep->me_value = PyStackRef_AsPyObjectSteal(value);
             // old_value should be DECREFed after GC track checking is done, if not, it could raise a segmentation fault,
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index e9c9ed2..976a342 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -2914,10 +2914,6 @@
                 UOP_STAT_INC(uopcode, miss);
                 JUMP_TO_JUMP_TARGET();
             }
-            /* Ensure dict is GC tracked if it needs to be */
-            if (!_PyObject_GC_IS_TRACKED(dict) && _PyObject_GC_MAY_BE_TRACKED(PyStackRef_AsPyObjectBorrow(value))) {
-                _PyObject_GC_TRACK(dict);
-            }
             _PyFrame_SetStackPointer(frame, stack_pointer);
             _PyDict_NotifyEvent(tstate->interp, PyDict_EVENT_MODIFIED, dict, name, PyStackRef_AsPyObjectBorrow(value));
             stack_pointer = _PyFrame_GetStackPointer(frame);
diff --git a/Python/gc.c b/Python/gc.c
index a774183..63adecf 100644
--- a/Python/gc.c
+++ b/Python/gc.c
@@ -5,7 +5,7 @@
 #include "Python.h"
 #include "pycore_ceval.h"         // _Py_set_eval_breaker_bit()
 #include "pycore_context.h"
-#include "pycore_dict.h"          // _PyDict_MaybeUntrack()
+#include "pycore_dict.h"          // _PyInlineValuesSize()
 #include "pycore_initconfig.h"
 #include "pycore_interp.h"        // PyInterpreterState.gc
 #include "pycore_object.h"
@@ -747,21 +747,6 @@ untrack_tuples(PyGC_Head *head)
     }
 }
 
-/* Try to untrack all currently tracked dictionaries */
-static void
-untrack_dicts(PyGC_Head *head)
-{
-    PyGC_Head *next, *gc = GC_NEXT(head);
-    while (gc != head) {
-        PyObject *op = FROM_GC(gc);
-        next = GC_NEXT(gc);
-        if (PyDict_CheckExact(op)) {
-            _PyDict_MaybeUntrack(op);
-        }
-        gc = next;
-    }
-}
-
 /* Return true if object has a pre-PEP 442 finalization method. */
 static int
 has_legacy_finalizer(PyObject *op)
@@ -1258,15 +1243,10 @@ handle_resurrected_objects(PyGC_Head *unreachable, PyGC_Head* still_unreachable,
     gc_list_merge(resurrected, old_generation);
 }
 
-
-#define UNTRACK_TUPLES 1
-#define UNTRACK_DICTS 2
-
 static void
 gc_collect_region(PyThreadState *tstate,
                   PyGC_Head *from,
                   PyGC_Head *to,
-                  int untrack,
                   struct gc_collection_stats *stats);
 
 static inline Py_ssize_t
@@ -1328,7 +1308,7 @@ gc_collect_young(PyThreadState *tstate,
 
     PyGC_Head survivors;
     gc_list_init(&survivors);
-    gc_collect_region(tstate, young, &survivors, UNTRACK_TUPLES, stats);
+    gc_collect_region(tstate, young, &survivors, stats);
     Py_ssize_t survivor_count = 0;
     if (gcstate->visited_space) {
         /* objects in visited space have bit set, so we set it here */
@@ -1471,7 +1451,7 @@ gc_collect_increment(PyThreadState *tstate, struct gc_collection_stats *stats)
     gc_list_validate_space(&increment, gcstate->visited_space);
     PyGC_Head survivors;
     gc_list_init(&survivors);
-    gc_collect_region(tstate, &increment, &survivors, UNTRACK_TUPLES, stats);
+    gc_collect_region(tstate, &increment, &survivors, stats);
     gc_list_validate_space(&survivors, gcstate->visited_space);
     gc_list_merge(&survivors, visited);
     assert(gc_list_is_empty(&increment));
@@ -1504,7 +1484,6 @@ gc_collect_full(PyThreadState *tstate,
     gc_list_merge(pending, visited);
 
     gc_collect_region(tstate, visited, visited,
-                      UNTRACK_TUPLES | UNTRACK_DICTS,
                       stats);
     gcstate->young.count = 0;
     gcstate->old[0].count = 0;
@@ -1522,7 +1501,6 @@ static void
 gc_collect_region(PyThreadState *tstate,
                   PyGC_Head *from,
                   PyGC_Head *to,
-                  int untrack,
                   struct gc_collection_stats *stats)
 {
     PyGC_Head unreachable; /* non-problematic unreachable trash */
@@ -1536,12 +1514,7 @@ gc_collect_region(PyThreadState *tstate,
     gc_list_init(&unreachable);
     deduce_unreachable(from, &unreachable);
     validate_consistent_old_space(from);
-    if (untrack & UNTRACK_TUPLES) {
-        untrack_tuples(from);
-    }
-    if (untrack & UNTRACK_DICTS) {
-        untrack_dicts(from);
-    }
+    untrack_tuples(from);
     validate_consistent_old_space(to);
     if (from != to) {
         gc_list_merge(from, to);
diff --git a/Python/gc_free_threading.c b/Python/gc_free_threading.c
index 499ee51..a6e0022 100644
--- a/Python/gc_free_threading.c
+++ b/Python/gc_free_threading.c
@@ -3,7 +3,7 @@
 #include "pycore_brc.h"           // struct _brc_thread_state
 #include "pycore_ceval.h"         // _Py_set_eval_breaker_bit()
 #include "pycore_context.h"
-#include "pycore_dict.h"          // _PyDict_MaybeUntrack()
+#include "pycore_dict.h"          // _PyInlineValuesSize()
 #include "pycore_freelist.h"      // _PyObject_ClearFreeLists()
 #include "pycore_initconfig.h"
 #include "pycore_interp.h"        // PyInterpreterState.gc
@@ -493,13 +493,6 @@ update_refs(const mi_heap_t *heap, const mi_heap_area_t *area,
                 return true;
             }
         }
-        else if (PyDict_CheckExact(op)) {
-            _PyDict_MaybeUntrack(op);
-            if (!_PyObject_GC_IS_TRACKED(op)) {
-                gc_restore_refs(op);
-                return true;
-            }
-        }
     }
 
     // We repurpose ob_tid to compute "gc_refs", the number of external
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 4d89753..f3db2f9 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -7435,10 +7435,6 @@
                 DEOPT_IF(ep->me_key != name, STORE_ATTR);
                 PyObject *old_value = ep->me_value;
                 DEOPT_IF(old_value == NULL, STORE_ATTR);
-                /* Ensure dict is GC tracked if it needs to be */
-                if (!_PyObject_GC_IS_TRACKED(dict) && _PyObject_GC_MAY_BE_TRACKED(PyStackRef_AsPyObjectBorrow(value))) {
-                    _PyObject_GC_TRACK(dict);
-                }
                 _PyFrame_SetStackPointer(frame, stack_pointer);
                 _PyDict_NotifyEvent(tstate->interp, PyDict_EVENT_MODIFIED, dict, name, PyStackRef_AsPyObjectBorrow(value));
                 stack_pointer = _PyFrame_GetStackPointer(frame);