Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

gh-124218: Use per-thread reference counting for globals and builtins #125713

Merged
merged 3 commits into from
Oct 21, 2024
Merged

gh-124218: Use per-thread reference counting for globals and builtins #125713

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
568d6b9
gh-124218: Use per-thread reference counting for globals and builtins
colesbury Oct 15, 2024
17653fd
Changes from review:
colesbury Oct 21, 2024
50813b4
Fix shift of id on 32-bit platforms
colesbury Oct 21, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 33 additions & 0 deletions Include/internal/pycore_dict.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -229,6 +229,8 @@ static inline PyDictUnicodeEntry* DK_UNICODE_ENTRIES(PyDictKeysObject *dk) {
#define DICT_VERSION_INCREMENT (1 << (DICT_MAX_WATCHERS + DICT_WATCHED_MUTATION_BITS))
#define DICT_WATCHER_MASK ((1 << DICT_MAX_WATCHERS) - 1)
#define DICT_WATCHER_AND_MODIFICATION_MASK ((1 << (DICT_MAX_WATCHERS + DICT_WATCHED_MUTATION_BITS)) - 1)
#define DICT_UNIQUE_ID_SHIFT (DICT_MAX_WATCHERS + DICT_WATCHED_MUTATION_BITS)
mpage marked this conversation as resolved.
Show resolved Hide resolved
#define DICT_UNIQUE_ID_MAX (UINT64_MAX >> DICT_UNIQUE_ID_SHIFT)


PyAPI_FUNC(void)
Expand Down Expand Up @@ -307,8 +309,39 @@ _PyInlineValuesSize(PyTypeObject *tp)
int
_PyDict_DetachFromObject(PyDictObject *dict, PyObject *obj);

// Enables per-thread ref counting on this dict in the free threading build
extern void _PyDict_EnablePerThreadRefcounting(PyObject *op);

PyDictObject *_PyObject_MaterializeManagedDict_LockHeld(PyObject *);

#ifndef Py_GIL_DISABLED
# define _Py_INCREF_DICT Py_INCREF
Yhg1s marked this conversation as resolved.
Show resolved Hide resolved
# define _Py_DECREF_DICT Py_DECREF
#else
static inline Py_ssize_t
_PyDict_UniqueId(PyDictObject *mp)
{
// Offset by on so that _ma_watcher_tag=0 represents an unassigned id
colesbury marked this conversation as resolved.
Show resolved Hide resolved
return (Py_ssize_t)(mp->_ma_watcher_tag >> DICT_UNIQUE_ID_SHIFT) - 1;
}

static inline void
_Py_INCREF_DICT(PyObject *op)
{
assert(PyDict_Check(op));
Py_ssize_t id = _PyDict_UniqueId((PyDictObject *)op);
_Py_THREAD_INCREF_OBJECT(op, id);
}

static inline void
_Py_DECREF_DICT(PyObject *op)
{
assert(PyDict_Check(op));
Py_ssize_t id = _PyDict_UniqueId((PyDictObject *)op);
_Py_THREAD_DECREF_OBJECT(op, id);
}
#endif

#ifdef __cplusplus
}
#endif
Expand Down
14 changes: 14 additions & 0 deletions Objects/dictobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1636,6 +1636,20 @@ _PyDict_MaybeUntrack(PyObject *op)
_PyObject_GC_UNTRACK(op);
}

void
_PyDict_EnablePerThreadRefcounting(PyObject *op)
{
assert(PyDict_Check(op));
#ifdef Py_GIL_DISABLED
Py_ssize_t id = _PyObject_AssignUniqueId(op);

PyDictObject *mp = (PyDictObject *)op;
assert((mp->_ma_watcher_tag >> DICT_UNIQUE_ID_SHIFT) == 0);
// Plus 1 so that _ma_watcher_tag=0 represents an unassigned id
mp->_ma_watcher_tag += (id + 1) << DICT_UNIQUE_ID_SHIFT;
#endif
}

static inline int
is_unusable_slot(Py_ssize_t ix)
{
Expand Down
38 changes: 32 additions & 6 deletions Objects/funcobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@

#include "Python.h"
#include "pycore_ceval.h" // _PyEval_BuiltinsFromGlobals()
#include "pycore_dict.h" // _Py_INCREF_DICT()
#include "pycore_long.h" // _PyLong_GetOne()
#include "pycore_modsupport.h" // _PyArg_NoKeywords()
#include "pycore_object.h" // _PyObject_GC_UNTRACK()
Expand Down Expand Up @@ -112,8 +113,15 @@ _PyFunction_FromConstructor(PyFrameConstructor *constr)
Py_XDECREF(module);
return NULL;
}
op->func_globals = Py_NewRef(constr->fc_globals);
op->func_builtins = Py_NewRef(constr->fc_builtins);
_Py_INCREF_DICT(constr->fc_globals);
op->func_globals = constr->fc_globals;
if (PyDict_Check(constr->fc_builtins)) {
_Py_INCREF_DICT(constr->fc_builtins);
}
else {
Py_INCREF(constr->fc_builtins);
}
op->func_builtins = constr->fc_builtins;
op->func_name = Py_NewRef(constr->fc_name);
op->func_qualname = Py_NewRef(constr->fc_qualname);
_Py_INCREF_CODE((PyCodeObject *)constr->fc_code);
Expand Down Expand Up @@ -143,7 +151,7 @@ PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname
{
assert(globals != NULL);
assert(PyDict_Check(globals));
Py_INCREF(globals);
_Py_INCREF_DICT(globals);

PyThreadState *tstate = _PyThreadState_GET();

Expand Down Expand Up @@ -184,7 +192,12 @@ PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname
if (builtins == NULL) {
goto error;
}
Py_INCREF(builtins);
if (PyDict_Check(builtins)) {
_Py_INCREF_DICT(builtins);
}
else {
Py_INCREF(builtins);
}

PyFunctionObject *op = PyObject_GC_New(PyFunctionObject, &PyFunction_Type);
if (op == NULL) {
Expand Down Expand Up @@ -1057,8 +1070,21 @@ func_clear(PyObject *self)
{
PyFunctionObject *op = _PyFunction_CAST(self);
func_clear_version(_PyInterpreterState_GET(), op);
Py_CLEAR(op->func_globals);
Py_CLEAR(op->func_builtins);
PyObject *globals = op->func_globals;
op->func_globals = NULL;
if (globals != NULL) {
_Py_DECREF_DICT(globals);
}
PyObject *builtins = op->func_builtins;
op->func_builtins = NULL;
if (builtins != NULL) {
if (PyDict_Check(builtins)) {
_Py_DECREF_DICT(builtins);
}
else {
Py_DECREF(builtins);
}
}
Py_CLEAR(op->func_module);
Py_CLEAR(op->func_defaults);
Py_CLEAR(op->func_kwdefaults);
Expand Down
3 changes: 2 additions & 1 deletion Objects/moduleobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@

#include "Python.h"
#include "pycore_call.h" // _PyObject_CallNoArgs()
#include "pycore_dict.h" // _PyDict_EnablePerThreadRefcounting()
#include "pycore_fileutils.h" // _Py_wgetcwd
#include "pycore_interp.h" // PyInterpreterState.importlib
#include "pycore_long.h" // _PyLong_GetOne()
Expand Down Expand Up @@ -105,7 +106,7 @@ new_module_notrack(PyTypeObject *mt)
static void
track_module(PyModuleObject *m)
{
_PyObject_SetDeferredRefcount(m->md_dict);
_PyDict_EnablePerThreadRefcounting(m->md_dict);
PyObject_GC_Track(m->md_dict);

_PyObject_SetDeferredRefcount((PyObject *)m);
Expand Down
13 changes: 12 additions & 1 deletion Python/uniqueid.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#include "Python.h"

#include "pycore_dict.h" // DICT_UNIQUE_ID_MAX
#include "pycore_lock.h" // PyMutex_LockFlags()
#include "pycore_pystate.h" // _PyThreadState_GET()
#include "pycore_object.h" // _Py_IncRefTotal
Expand Down Expand Up @@ -90,10 +91,15 @@ _PyObject_AssignUniqueId(PyObject *obj)
}

_Py_unique_id_entry *entry = pool->freelist;
Py_ssize_t unique_id = (entry - pool->table);
if ((uint64_t)unique_id >= DICT_UNIQUE_ID_MAX) {
Yhg1s marked this conversation as resolved.
Show resolved Hide resolved
UNLOCK_POOL(pool);
return -1;
}

pool->freelist = entry->next;
entry->obj = obj;
_PyObject_SetDeferredRefcount(obj);
Py_ssize_t unique_id = (entry - pool->table);
UNLOCK_POOL(pool);
return unique_id;
}
Expand Down Expand Up @@ -128,6 +134,11 @@ clear_unique_id(PyObject *obj)
id = co->_co_unique_id;
co->_co_unique_id = -1;
}
else if (PyDict_Check(obj)) {
PyDictObject *mp = (PyDictObject *)obj;
id = _PyDict_UniqueId(mp);
mp->_ma_watcher_tag &= ~(UINT64_MAX << DICT_UNIQUE_ID_SHIFT);
}
return id;
}

Expand Down
Loading