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gh-142048: Fix lost allocations on thread cleanup - #142233

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kumaraditya303 merged 2 commits into
python:mainfrom
kevmo314:fix-lost-allocations
Dec 10, 2025
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gh-142048: Fix lost allocations on thread cleanup#142233
kumaraditya303 merged 2 commits into
python:mainfrom
kevmo314:fix-lost-allocations

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@kevmo314

@kevmo314kevmo314 commented Dec 3, 2025•
edited by bedevere-app Bot
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Fixes some lost allocation counts in the local allocation counters when threads are cleaned up.

@bedevere-appbedevere-appBot mentioned this pull request Dec 3, 2025
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kevmo314
kevmo314 commented Dec 3, 2025
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Comment threadPython/pystate.c
// Flush the thread's local GC allocation count to the global count
// before the thread state is cleared, otherwise the count is lost.
_PyThreadStateImpl *tstate_impl = (_PyThreadStateImpl *)tstate;
_Py_atomic_add_int(&tstate->interp->gc.young.count,

@kevmo314kevmo314Dec 3, 2025

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Since this is less common perhaps it's ok to allow the global GC count to go negative here? The compare-and-exchange loop is more accurate though, I can update to use that if preferred.

@colesburycolesburyDec 4, 2025

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Yeah, I think going negative here is fine

@colesbury
colesbury self-requested a review December 4, 2025 21:54
@kumaraditya303kumaraditya303 added needs backport to 3.13 bugs and security fixes needs backport to 3.14 bugs and security fixes labels Dec 10, 2025
@kumaraditya303
kumaraditya303 enabled auto-merge (squash) December 10, 2025 07:04
@kumaraditya303
kumaraditya303 merged commit 49b1fb4 into python:mainDec 10, 2025
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miss-islington-appBot commented Dec 10, 2025

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Thanks @kevmo314 for the PR, and @kumaraditya303 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14.
🐍🍒⛏🤖

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Dec 10, 2025
@kevmo314@miss-islington
pythongh-142048: Fix lost gc allocations count on thread cleanup (pyt…
ff4212e
…honGH-142233)
(cherry picked from commit 49b1fb4)
Co-authored-by: Kevin Wang <kevmo314@gmail.com>
@miss-islington-app

miss-islington-appBot commented Dec 10, 2025

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Sorry, @kevmo314 and @kumaraditya303, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 49b1fb43f65290dadeb83ed6f7c0c74995fda7a1 3.13

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bedevere-appBot commented Dec 10, 2025

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GH-142504 is a backport of this pull request to the 3.14 branch.

@bedevere-appbedevere-appBot removed the needs backport to 3.14 bugs and security fixes label Dec 10, 2025
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bedevere-appBot commented Dec 10, 2025

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GH-142506 is a backport of this pull request to the 3.13 branch.

@bedevere-appbedevere-appBot removed the needs backport to 3.13 bugs and security fixes label Dec 10, 2025
kumaraditya303 pushed a commit to kumaraditya303/cpython that referenced this pull request Dec 10, 2025
@kevmo314@kumaraditya303
[3.13]pythongh-142048: Fix lost gc allocations count on thread clean…
3900e86
…up (pythonGH-142233)
(cherry picked from commit 49b1fb4)
Co-authored-by: Kevin Wang <kevmo314@gmail.com>
kumaraditya303 pushed a commit that referenced this pull request Dec 10, 2025
@miss-islington@kevmo314
[3.14]gh-142048: Fix lost gc allocations count on thread cleanup (GH…
0114178
…-142233) (#142504)
gh-142048: Fix lost gc allocations count on thread cleanup (GH-142233)
(cherry picked from commit 49b1fb4)
Co-authored-by: Kevin Wang <kevmo314@gmail.com>
kumaraditya303 pushed a commit to kumaraditya303/cpython that referenced this pull request Dec 10, 2025
@kevmo314@kumaraditya303
[3.13]pythongh-142048: Fix lost gc allocations count on thread clean…
decf93d
…up (pythonGH-142233)
(cherry picked from commit 49b1fb4)
Co-authored-by: Kevin Wang <kevmo314@gmail.com>
kumaraditya303 added a commit that referenced this pull request Dec 11, 2025
@kumaraditya303@kevmo314
[3.13]gh-142048: Fix lost gc allocations count on thread cleanup (GH… (
fda856f
#142506)
[3.13] gh-142048: Fix lost gc allocations count on thread cleanup (GH-142233)
(cherry picked from commit 49b1fb4)
Co-authored-by: Kevin Wang <kevmo314@gmail.com>
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@colesburycolesburycolesbury approved these changes
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