Rename functions and types

Author: colesbury

Include/internal/pycore_interp.h

@@ -35,7 +35,7 @@ extern "C" {
 #include "pycore_qsbr.h"          // struct _qsbr_state
 #include "pycore_tstate.h"        // _PyThreadStateImpl
 #include "pycore_tuple.h"         // struct _Py_tuple_state
-#include "pycore_uniqueid.h"      // struct _Py_type_id_pool
+#include "pycore_uniqueid.h"      // struct _Py_unique_id_pool
 #include "pycore_typeobject.h"    // struct types_state
 #include "pycore_unicodeobject.h" // struct _Py_unicode_state
 #include "pycore_warnings.h"      // struct _warnings_runtime_state
@@ -221,7 +221,7 @@ struct _is {
 #if defined(Py_GIL_DISABLED)
     struct _mimalloc_interp_state mimalloc;
     struct _brc_state brc;  // biased reference counting state
-    struct _Py_type_id_pool type_ids;
+    struct _Py_unique_id_pool unique_ids;  // object ids for per-thread refcounts
     PyMutex weakref_locks[NUM_WEAKREF_LIST_LOCKS];
 #endif
 

Include/internal/pycore_object.h

@@ -335,12 +335,12 @@ _Py_INCREF_TYPE(PyTypeObject *type)
     // Unsigned comparison so that `unique_id=-1`, which indicates that
     // per-thread refcounting has been disabled on this type, is handled by
     // the "else".
-    if ((size_t)ht->unique_id < (size_t)tstate->types.size) {
+    if ((size_t)ht->unique_id < (size_t)tstate->refcounts.size) {
 #  ifdef Py_REF_DEBUG
         _Py_INCREF_IncRefTotal();
 #  endif
         _Py_INCREF_STAT_INC();
-        tstate->types.refcounts[ht->unique_id]++;
+        tstate->refcounts.values[ht->unique_id]++;
     }
     else {
         // The slow path resizes the thread-local refcount array if necessary.
@@ -368,12 +368,12 @@ _Py_DECREF_TYPE(PyTypeObject *type)
     // Unsigned comparison so that `unique_id=-1`, which indicates that
     // per-thread refcounting has been disabled on this type, is handled by
     // the "else".
-    if ((size_t)ht->unique_id < (size_t)tstate->types.size) {
+    if ((size_t)ht->unique_id < (size_t)tstate->refcounts.size) {
 #  ifdef Py_REF_DEBUG
         _Py_DECREF_DecRefTotal();
 #  endif
         _Py_DECREF_STAT_INC();
-        tstate->types.refcounts[ht->unique_id]--;
+        tstate->refcounts.values[ht->unique_id]--;
     }
     else {
         // Directly decref the type if the type id is not assigned or if

Include/internal/pycore_tstate.h

@@ -32,15 +32,15 @@ typedef struct _PyThreadStateImpl {
     struct _Py_freelists freelists;
     struct _brc_thread_state brc;
     struct {
-        // The thread-local refcounts for heap type objects
-        Py_ssize_t *refcounts;
+        // The per-thread refcounts
+        Py_ssize_t *values;
 
         // Size of the refcounts array.
         Py_ssize_t size;
 
-        // If set, don't use thread-local refcounts
+        // If set, don't use per-thread refcounts
         int is_finalized;
-    } types;
+    } refcounts;
 #endif
 
 #if defined(Py_REF_DEBUG) && defined(Py_GIL_DISABLED)

Include/internal/pycore_uniqueid.h

@@ -10,61 +10,58 @@ extern "C" {
 
 #ifdef Py_GIL_DISABLED
 
-// This contains code for allocating unique ids to heap type objects
-// and re-using those ids when the type is deallocated.
+// This contains code for allocating unique ids to objects for 
+// per-thread reference counting.
 //
-// The type ids are used to implement per-thread reference counts of
-// heap type objects to avoid contention on the reference count fields
-// of heap type objects. Static type objects are immortal, so contention
-// is not an issue for those types.
+// Per-thread reference counting is used along with deferred reference
+// counting to avoid scaling bottlenecks due to reference count contention.
 //
-// Type id of -1 is used to indicate a type doesn't use thread-local
-// refcounting. This value is used when a type object is finalized by the GC
-// and during interpreter shutdown to allow the type object to be
+// An id of -1 is used to indicate that an object doesn't use per-thread
+// refcounting. This value is used when the object is finalized by the GC
+// and during interpreter shutdown to allow the object to be
 // deallocated promptly when the object's refcount reaches zero.
 //
-// Each entry implicitly represents a type id based on it's offset in the
+// Each entry implicitly represents a unique id based on its offset in the
 // table. Non-allocated entries form a free-list via the 'next' pointer.
-// Allocated entries store the corresponding PyTypeObject.
-typedef union _Py_type_id_entry {
+// Allocated entries store the corresponding PyObject.
+typedef union _Py_unique_id_entry {
     // Points to the next free type id, when part of the freelist
-    union _Py_type_id_entry *next;
+    union _Py_unique_id_entry *next;
 
-    // Stores the type object when the id is assigned
-    PyHeapTypeObject *type;
-} _Py_type_id_entry;
+    // Stores the object when the id is assigned
+    PyObject *obj;
+} _Py_unique_id_entry;
 
-struct _Py_type_id_pool {
+struct _Py_unique_id_pool {
     PyMutex mutex;
 
-    // combined table of types with allocated type ids and unallocated
-    // type ids.
-    _Py_type_id_entry *table;
+    // combined table of object with allocated unique ids and unallocated ids.
+    _Py_unique_id_entry *table;
 
     // Next entry to allocate inside 'table' or NULL
-    _Py_type_id_entry *freelist;
+    _Py_unique_id_entry *freelist;
 
     // size of 'table'
     Py_ssize_t size;
 };
 
-// Assigns the next id from the pool of type ids.
-extern void _PyType_AssignId(PyHeapTypeObject *type);
+// Assigns the next id from the pool of ids.
+extern Py_ssize_t _PyObject_AssignUniqueId(PyObject *obj);
 
-// Releases the allocated type id back to the pool.
-extern void _PyType_ReleaseId(PyHeapTypeObject *type);
+// Releases the allocated id back to the pool.
+extern void _PyObject_ReleaseUniqueId(Py_ssize_t unique_id);
 
-// Merges the thread-local reference counts into the corresponding types.
-extern void _PyType_MergeThreadLocalRefcounts(_PyThreadStateImpl *tstate);
+// Merges the per-thread reference counts into the corresponding objects.
+extern void _PyObject_MergePerThreadRefcounts(_PyThreadStateImpl *tstate);
 
-// Like _PyType_MergeThreadLocalRefcounts, but also frees the thread-local
+// Like _PyObject_MergePerThreadRefcounts, but also frees the per-thread
 // array of refcounts.
-extern void _PyType_FinalizeThreadLocalRefcounts(_PyThreadStateImpl *tstate);
+extern void _PyObject_FinalizePerThreadRefcounts(_PyThreadStateImpl *tstate);
 
 // Frees the interpreter's pool of type ids.
-extern void _PyType_FinalizeIdPool(PyInterpreterState *interp);
+extern void _PyObject_FinalizeUniqueIdPool(PyInterpreterState *interp);
 
-// Increfs the type, resizing the thread-local refcount array if necessary.
+// Increfs the type, resizing the per-thread refcount array if necessary.
 PyAPI_FUNC(void) _PyType_IncrefSlow(PyHeapTypeObject *type);
 
 #endif   /* Py_GIL_DISABLED */

Objects/typeobject.c

@@ -3932,7 +3932,7 @@ type_new_alloc(type_new_ctx *ctx)
     et->ht_token = NULL;
 
 #ifdef Py_GIL_DISABLED
-    _PyType_AssignId(et);
+    et->unique_id = _PyObject_AssignUniqueId((PyObject *)et);
 #endif
 
     return type;
@@ -5026,7 +5026,7 @@ PyType_FromMetaclass(
 
 #ifdef Py_GIL_DISABLED
     // Assign a type id to enable thread-local refcounting
-    _PyType_AssignId(res);
+    res->unique_id = _PyObject_AssignUniqueId((PyObject *)res);
 #endif
 
     /* Ready the type (which includes inheritance).
@@ -6080,7 +6080,7 @@ type_dealloc(PyObject *self)
     Py_XDECREF(et->ht_module);
     PyMem_Free(et->_ht_tpname);
 #ifdef Py_GIL_DISABLED
-    _PyType_ReleaseId(et);
+    _PyObject_ReleaseUniqueId(et->unique_id);
 #endif
     et->ht_token = NULL;
     Py_TYPE(type)->tp_free((PyObject *)type);

Python/gc_free_threading.c

@@ -217,12 +217,12 @@ disable_deferred_refcounting(PyObject *op)
         merge_refcount(op, 0);
     }
 
-    // Heap types also use thread-local refcounting -- disable it here.
+    // Heap types also use per-thread refcounting -- disable it here.
     if (PyType_Check(op)) {
-        // Disable thread-local refcounting for heap types
-        PyTypeObject *type = (PyTypeObject *)op;
-        if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
-            _PyType_ReleaseId((PyHeapTypeObject *)op);
+        if (PyType_HasFeature((PyTypeObject *)op, Py_TPFLAGS_HEAPTYPE)) {
+            PyHeapTypeObject *ht = (PyHeapTypeObject *)op;
+            _PyObject_ReleaseUniqueId(ht->unique_id);
+            ht->unique_id = -1;
         }
     }
 
@@ -1221,7 +1221,7 @@ gc_collect_internal(PyInterpreterState *interp, struct collection_state *state,
         _PyThreadStateImpl *tstate = (_PyThreadStateImpl *)p;
 
         // merge per-thread refcount for types into the type's actual refcount
-        _PyType_MergeThreadLocalRefcounts(tstate);
+        _PyObject_MergePerThreadRefcounts(tstate);
 
         // merge refcounts for all queued objects
         merge_queued_objects(tstate, state);

Python/pylifecycle.c

@@ -1834,7 +1834,7 @@ finalize_interp_types(PyInterpreterState *interp)
 
     _PyTypes_Fini(interp);
 #ifdef Py_GIL_DISABLED
-    _PyType_FinalizeIdPool(interp);
+    _PyObject_FinalizeUniqueIdPool(interp);
 #endif
 
     _PyCode_Fini(interp);

Python/pystate.c

@@ -1745,7 +1745,7 @@ PyThreadState_Clear(PyThreadState *tstate)
 
     // Merge our thread-local refcounts into the type's own refcount and
     // free our local refcount array.
-    _PyType_FinalizeThreadLocalRefcounts((_PyThreadStateImpl *)tstate);
+    _PyObject_FinalizePerThreadRefcounts((_PyThreadStateImpl *)tstate);
 
     // Remove ourself from the biased reference counting table of threads.
     _Py_brc_remove_thread(tstate);
@@ -1805,7 +1805,7 @@ tstate_delete_common(PyThreadState *tstate, int release_gil)
     _PyThreadStateImpl *tstate_impl = (_PyThreadStateImpl *)tstate;
     tstate->interp->object_state.reftotal += tstate_impl->reftotal;
     tstate_impl->reftotal = 0;
-    assert(tstate_impl->types.refcounts == NULL);
+    assert(tstate_impl->refcounts.values == NULL);
 #endif
 
     HEAD_UNLOCK(runtime);