Skip to content

gh-110481: Implement biased reference counting #110764

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

Merged
corona10 merged 8 commits into from
Oct 30, 2023
Merged

gh-110481: Implement biased reference counting #110764

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
94bfbde
Remove trailing commas in _PyObject_HEAD_INIT and _PyVarObject_HEAD_INIT
colesbury Oct 4, 2023
b1cb396
Implement biased reference counting
colesbury Sep 13, 2023
425d570
Add blurb
colesbury Oct 12, 2023
8c68c78
Changes from review:
colesbury Oct 19, 2023
86892d9
Fix compile errors from rebasing on main
colesbury Oct 19, 2023
3c85ca1
Fix typo
colesbury Oct 20, 2023
c6c6ec6
Add missing guards
colesbury Oct 20, 2023
ac2c957
Add TODOs for missing Py_DECREF specializations
colesbury Oct 24, 2023
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
Next Next commit
Remove trailing commas in _PyObject_HEAD_INIT and _PyVarObject_HEAD_INIT 
Removing the trailing comma allows the macros to be used in more places,
which means fewer `#ifdef Py_NOGIL` checks.

Note that the public API macros `PyObject_HEAD_INIT` and
`PyVarObject_HEAD_INIT` are not changed.
  • Loading branch information
@colesbury @corona10
colesbury authored and corona10 committed Oct 30, 2023
commit 94bfbdee82c421656db8e75250e7d8605e79fa36
2 changes: 1 addition & 1 deletion Include/internal/pycore_long.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -317,7 +317,7 @@ _PyLong_FlipSign(PyLongObject *op) {

#define _PyLong_DIGIT_INIT(val) \
{ \
.ob_base = _PyObject_HEAD_INIT(&PyLong_Type) \
.ob_base = _PyObject_HEAD_INIT(&PyLong_Type), \
.long_value = { \
.lv_tag = TAG_FROM_SIGN_AND_SIZE( \
(val) == 0 ? 0 : ((val) < 0 ? -1 : 1), \
Expand Down
6 changes: 3 additions & 3 deletions Include/internal/pycore_object.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -58,12 +58,12 @@ PyAPI_FUNC(int) _PyObject_IsFreed(PyObject *);
{ \
.ob_refcnt = _Py_IMMORTAL_REFCNT, \
.ob_type = (type) \
},
}

@markshannon markshannon Oct 23, 2023

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Loosing the trailing comma is definitely better style, but is bound to break some third party code.
I think you need to leave the comma.

@colesbury colesbury Oct 23, 2023

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is in an internal-only header (Include/internal/pycore_object.h), not used by third party code.

There's a similarly named public macro used by third party code that is not changed.

#define _PyVarObject_HEAD_INIT(type, size) \
{ \
.ob_base = _PyObject_HEAD_INIT(type) \
.ob_base = _PyObject_HEAD_INIT(type), \
.ob_size = size \
},
}
Comment thread
corona10 marked this conversation as resolved.

extern void _Py_NO_RETURN _Py_FatalRefcountErrorFunc(
const char *func,
Expand Down
14 changes: 7 additions & 7 deletions Include/internal/pycore_runtime_init.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -129,13 +129,13 @@ extern PyTypeObject _PyExc_MemoryError;
.latin1 = _Py_str_latin1_INIT, \
}, \
.tuple_empty = { \
.ob_base = _PyVarObject_HEAD_INIT(&PyTuple_Type, 0) \
.ob_base = _PyVarObject_HEAD_INIT(&PyTuple_Type, 0), \
}, \
.hamt_bitmap_node_empty = { \
.ob_base = _PyVarObject_HEAD_INIT(&_PyHamt_BitmapNode_Type, 0) \
.ob_base = _PyVarObject_HEAD_INIT(&_PyHamt_BitmapNode_Type, 0), \
}, \
.context_token_missing = { \
.ob_base = _PyObject_HEAD_INIT(&_PyContextTokenMissing_Type) \
.ob_base = _PyObject_HEAD_INIT(&_PyContextTokenMissing_Type), \
}, \
}, \
}, \
Expand Down Expand Up @@ -172,11 +172,11 @@ extern PyTypeObject _PyExc_MemoryError;
.singletons = { \
._not_used = 1, \
.hamt_empty = { \
.ob_base = _PyObject_HEAD_INIT(&_PyHamt_Type) \
.ob_base = _PyObject_HEAD_INIT(&_PyHamt_Type), \
.h_root = (PyHamtNode*)&_Py_SINGLETON(hamt_bitmap_node_empty), \
}, \
.last_resort_memory_error = { \
_PyObject_HEAD_INIT(&_PyExc_MemoryError) \
_PyObject_HEAD_INIT(&_PyExc_MemoryError), \
.args = (PyObject*)&_Py_SINGLETON(tuple_empty) \
}, \
}, \
Expand Down Expand Up @@ -206,7 +206,7 @@ extern PyTypeObject _PyExc_MemoryError;

#define _PyBytes_SIMPLE_INIT(CH, LEN) \
{ \
_PyVarObject_HEAD_INIT(&PyBytes_Type, (LEN)) \
_PyVarObject_HEAD_INIT(&PyBytes_Type, (LEN)), \
.ob_shash = -1, \
.ob_sval = { (CH) }, \
}
Expand All @@ -217,7 +217,7 @@ extern PyTypeObject _PyExc_MemoryError;

#define _PyUnicode_ASCII_BASE_INIT(LITERAL, ASCII) \
{ \
.ob_base = _PyObject_HEAD_INIT(&PyUnicode_Type) \
.ob_base = _PyObject_HEAD_INIT(&PyUnicode_Type), \
.length = sizeof(LITERAL) - 1, \
.hash = -1, \
.state = { \
Expand Down
10 changes: 2 additions & 8 deletions Objects/object.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1926,10 +1926,7 @@ PyTypeObject _PyNone_Type = {
none_new, /*tp_new */
};

PyObject _Py_NoneStruct = {
{ _Py_IMMORTAL_REFCNT },
&_PyNone_Type
};
PyObject _Py_NoneStruct = _PyObject_HEAD_INIT(&_PyNone_Type);

/* NotImplemented is an object that can be used to signal that an
operation is not implemented for the given type combination. */
Expand Down Expand Up @@ -2028,10 +2025,7 @@ PyTypeObject _PyNotImplemented_Type = {
notimplemented_new, /*tp_new */
};

PyObject _Py_NotImplementedStruct = {
{ _Py_IMMORTAL_REFCNT },
&_PyNotImplemented_Type
};
PyObject _Py_NotImplementedStruct = _PyObject_HEAD_INIT(&_PyNotImplemented_Type);


PyStatus
Expand Down
5 changes: 1 addition & 4 deletions Objects/setobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2394,7 +2394,4 @@ static PyTypeObject _PySetDummy_Type = {
Py_TPFLAGS_DEFAULT, /*tp_flags */
};

static PyObject _dummy_struct = {
{ _Py_IMMORTAL_REFCNT },
&_PySetDummy_Type
};
static PyObject _dummy_struct = _PyObject_HEAD_INIT(&_PySetDummy_Type);
5 changes: 1 addition & 4 deletions Objects/sliceobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -98,10 +98,7 @@ PyTypeObject PyEllipsis_Type = {
ellipsis_new, /* tp_new */
};

PyObject _Py_EllipsisObject = {
{ _Py_IMMORTAL_REFCNT },
&PyEllipsis_Type
};
PyObject _Py_EllipsisObject = _PyObject_HEAD_INIT(&PyEllipsis_Type);


/* Slice object implementation */
Expand Down
12 changes: 2 additions & 10 deletions Python/instrumentation.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,17 +19,9 @@
/* Uncomment this to dump debugging output when assertions fail */
// #define INSTRUMENT_DEBUG 1

PyObject _PyInstrumentation_DISABLE =
{
.ob_refcnt = _Py_IMMORTAL_REFCNT,
.ob_type = &PyBaseObject_Type
};
PyObject _PyInstrumentation_DISABLE = _PyObject_HEAD_INIT(&PyBaseObject_Type);

PyObject _PyInstrumentation_MISSING =
{
.ob_refcnt = _Py_IMMORTAL_REFCNT,
.ob_type = &PyBaseObject_Type
};
PyObject _PyInstrumentation_MISSING = _PyObject_HEAD_INIT(&PyBaseObject_Type);

static const int8_t EVENT_FOR_OPCODE[256] = {
[RETURN_CONST] = PY_MONITORING_EVENT_PY_RETURN,
Expand Down
2 changes: 1 addition & 1 deletion Python/specialize.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2525,7 +2525,7 @@ static const PyBytesObject no_location = {
};

const struct _PyCode_DEF(8) _Py_InitCleanup = {
_PyVarObject_HEAD_INIT(&PyCode_Type, 3)
_PyVarObject_HEAD_INIT(&PyCode_Type, 3),
.co_consts = (PyObject *)&_Py_SINGLETON(tuple_empty),
.co_names = (PyObject *)&_Py_SINGLETON(tuple_empty),
.co_exceptiontable = (PyObject *)&_Py_SINGLETON(bytes_empty),
Expand Down
9 changes: 3 additions & 6 deletions Tools/build/deepfreeze.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,7 @@ def __init__(self, file: TextIO) -> None:
self.inits: list[str] = []
self.identifiers, self.strings = self.get_identifiers_and_strings()
self.write('#include "Python.h"')
self.write('#include "internal/pycore_object.h"')
self.write('#include "internal/pycore_gc.h"')
self.write('#include "internal/pycore_code.h"')
self.write('#include "internal/pycore_frame.h"')
Expand Down Expand Up @@ -154,14 +155,10 @@ def block(self, prefix: str, suffix: str = "") -> None:
self.write("}" + suffix)

def object_head(self, typename: str) -> None:
with self.block(".ob_base =", ","):
self.write(f".ob_refcnt = _Py_IMMORTAL_REFCNT,")
self.write(f".ob_type = &{typename},")
self.write(f".ob_base = _PyObject_HEAD_INIT(&{typename}),")

def object_var_head(self, typename: str, size: int) -> None:
with self.block(".ob_base =", ","):
self.object_head(typename)
self.write(f".ob_size = {size},")
self.write(f".ob_base = _PyVarObject_HEAD_INIT(&{typename}, {size}),")

def field(self, obj: object, name: str) -> None:
self.write(f".{name} = {getattr(obj, name)},")
Expand Down