bpo-45953: Statically allocate the main interpreter (and initial thread state).#29883

ericsnowcurrently · 2021-12-01T19:30:32Z

Currently the main interpreter is allocated on the heap during runtime initialization. Here we are instead embedding it into _PyRuntimeState, which means it is statically allocated as part of the _PyRuntime global. The same goes for the initial thread state (of each interpreter, including the main one). Consequently there are fewer allocations during runtime/interpreter init, fewer possible failures, and better memory locality.

FYI, this also helps efforts to consolidate globals, which in turns helps work on subinterpreter isolation.

https://bugs.python.org/issue45953

markshannon · 2021-12-02T16:26:43Z

Python/ceval.c

-int
-_PyEval_InitState(struct_ceval_state*ceval)
+void
+_PyEval_InitState(struct_ceval_state*ceval, PyThread_type_lockpending_lock)


Would this be a good opportunity to remove this function?
The _pending_calls struct belongs on the interpreter state, not on the ceval as only the main interpreter can handle them.

There's enough going on in this PR that I'd rather not.

Modules/posixmodule.c

markshannon

A couple of tests have been inverted.

bedevere-bot · 2021-12-02T16:39:15Z

When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

…r is.

Include/cpython/pystate.h

Include/internal/pycore_interp.h

markshannon · 2022-01-10T18:06:41Z

Include/internal/pycore_interp.h

+ } _preallocated;
 };

+#define_PyInterpreterState_INIT \


This is only used once, please remove it.

FYI, I brought this back to avoid so much nesting and clutter in _PyRuntimeState_INIT.

Include/internal/pycore_runtime.h

markshannon · 2022-01-10T18:10:25Z

Include/internal/pycore_runtime.h

+ } _preallocated;
 } _PyRuntimeState;

 #define_PyRuntimeState_INIT \


Might as well remove this as well. It is also only used once.

Should _Py_global_objects_INIT also move? It's pretty big and likely to get much bigger.

Actually, _PyRuntimeState_INIT is used twice.

ericsnowcurrently · 2022-01-12T22:56:00Z

With basically all feedback addressed I plan on merging this soon, to unblock other changes I have waiting. If I missed something, I'd be glad to address it in a follow-up PR.

gvanrossum · 2022-01-12T23:06:39Z

Fine with me.

…

On Wed, Jan 12, 2022 at 2:56 PM Eric Snow ***@***.***> wrote: With basically all feedback addressed I plan on merging this soon, to unblock other changes I have waiting. If I missed something, I'd be glad to address it in a follow-up PR. — Reply to this email directly, view it on GitHub <#29883 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAWCWMXNEYDUC6YIRLTJAEDUVYBIXANCNFSM5JFJMYAA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

-- --Guido van Rossum (python.org/~guido)

As of CPython 3.11 (via python/cpython#29883) stdbool.h is now included in Python.h so do attempt to redefine bool/true/false.

ericsnowcurrently added 11 commits December 1, 2021 10:54

Return void from _PyEval_InitState().
5e6eda9

Fix a memory leak.
de12b98

Move thread-related interpreter state into a sub-struct.
035eff3

Factor out init_threadstate().
1569a53

Do not initialize a thread state if already initialized.
518e3f3

Avoid allocating the first thread state.
9995a84

Factor out init_interpreter().
f22d0da

Preallocate the main interpreter.
cf39d57

Add a note about expectations for init_interpreter().
b840213

Add a NEWS entry.
3bf69b0

Add _PyInterpreterState_Main().
4de466e

ericsnowcurrently requested a review from markshannon as a code owner December 1, 2021 19:30

the-knights-who-say-ni added the CLA signed label Dec 1, 2021

bedevere-bot added the awaiting core review label Dec 1, 2021

ericsnowcurrently mentioned this pull request Dec 1, 2021
Use member non-pointer declarations in Py*State structs instead of heap-allocated pointers. faster-cpython/ideas#79
Closed

markshannon reviewed Dec 2, 2021
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markshannon requested changes Dec 2, 2021
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bedevere-bot added the awaiting changes label Dec 2, 2021

ericsnowcurrently added 8 commits December 2, 2021 16:43

Fix a check for the main interpreter.
9bb32a6

Ensure no subinterpreters are created until after the main interprete…
385f298
…r is.

Make sure the interpreter is fully initialized.
354997f

Use PyMem_RawCalloc() to allocate thread states.
9bbf8a0

Make sure the thread state is fully initialized.
8d1cf35

Clear the preallocated states when "deleted".
188aed8

Statically initialize the "preallocated" states.
e0da483

Fix a typo.
46c7767

markshannon reviewed Jan 10, 2022
View reviewed changes

ericsnowcurrently added 5 commits January 10, 2022 13:55

Fold _PyThreadState_INIT into _PyInterpreterState_INIT.
5b34b42

Fold _PyInterpreterState_INIT into _PyRuntimeState_INIT.
837bfe6

Drop PyThreadState._preallocated.
ebefa35

tstate -> initial_thread.
eb7a080

Mirror the top-level structure in _preallocated.
1ef4a39

ericsnowcurrently requested a review from markshannon January 11, 2022 00:16

ericsnowcurrently added 13 commits January 11, 2022 09:41

Merge branch 'main' into preallocate-main
771e574

Clarify some comments.
b5c43f1

Fold in _PyRuntimeState._preallocated.
bfc3906

Make "initial" const.
9b25c8b

Fold in PyInterpreterState._preallocated.
e776c31

Move the initial thread to the bottom of PyInterpreterState.
c6bda1f

Split up _PyRuntimeState_INIT for less nesting and clutter.
8ab6261

Fix a comment.
ff8de28

Move the main interpreter to the bottom of _PyRuntimeState.
b28afb3

Clarify some comments.
0d30300

Add a comment for the _static field.
e193794

Move the comments about pre-allocated data down.
e9f1262

Fix a typo.
a6a6471

ericsnowcurrently merged commit ed57b36 into python:mainJan 12, 2022

bedevere-bot removed the awaiting change review label Jan 12, 2022

ericsnowcurrently deleted the preallocate-main branch January 12, 2022 23:28

tacaswell added a commit to tacaswell/typed_ast that referenced this pull request Jan 25, 2022
FIX: Account form stdbool.h being included in Python.h
9b849ca
As of CPython 3.11 (via python/cpython#29883) stdbool.h is now included in Python.h so do attempt to redefine bool/true/false.

tacaswell mentioned this pull request Jan 25, 2022
FIX: Account form stdbool.h being included in Python.h python/typed_ast#184
Merged

srittau pushed a commit to python/typed_ast that referenced this pull request Jan 25, 2022
FIX: Account form stdbool.h being included in Python.h (#184)
36110cf
As of CPython 3.11 (via python/cpython#29883) stdbool.h is now included in Python.h so do attempt to redefine bool/true/false.

ericsnowcurrently mentioned this pull request Nov 8, 2022
Statically allocate interpreter states as much as possible. #90111
Closed

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bpo-45953: Statically allocate the main interpreter (and initial thread state).#29883

bpo-45953: Statically allocate the main interpreter (and initial thread state). #29883

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ericsnowcurrently commented Jan 12, 2022

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gvanrossum commented Jan 12, 2022 via email

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ericsnowcurrently commented Dec 1, 2021•
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