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Allow to build Python without freelists #89685
Description
| BPO | 45522 |
|---|---|
| Nosy | @vstinner, @tiran, @markshannon, @miss-islington |
| PRs |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = 'https://github.com/tiran'
closed_at = None
created_at = <Date 2021-10-19.11:06:04.660>
labels = ['expert-C-API', 'type-feature', '3.11']
title = 'Allow to build Python without freelists'
updated_at = <Date 2022-01-17.13:14:15.976>
user = 'https://github.com/tiran'bugs.python.org fields:
activity = <Date 2022-01-17.13:14:15.976>
actor = 'vstinner'
assignee = 'christian.heimes'
closed = False
closed_date = None
closer = None
components = ['C API']
creation = <Date 2021-10-19.11:06:04.660>
creator = 'christian.heimes'
dependencies = []
files = []
hgrepos = []
issue_num = 45522
keywords = ['patch']
message_count = 6.0
messages = ['404289', '404599', '405207', '405293', '410614', '410778']
nosy_count = 4.0
nosy_names = ['vstinner', 'christian.heimes', 'Mark.Shannon', 'miss-islington']
pr_nums = ['29056', '29086']
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue45522'
versions = ['Python 3.11']
Activity
tiran commentedon Oct 19, 2021
Freelists are an optimization trick to avoid allocation and deallocation of commonly used structures. Currently Python has freelists for frame, tuple, float, list, dict, async generators, and context objects. Small ints are also cached.
For experimentation with alternative memory allocators such as mimalloc, I would like to introduce a way to disable freelists. Tuples's _Py_tuple_state struct has a conditional check on #if PyTuple_MAXSAVESIZE > 0. I propose to add same logic to all other structs.
miss-islington commentedon Oct 21, 2021
New changeset 9942f42 by Christian Heimes in branch 'main':
bpo-45522: Allow to disable freelists on build time (GH-29056)
9942f42
markshannon commentedon Oct 28, 2021
I think we should revert this. It just makes working with freelists more cumbersome. Having more configure options just makes it more likely that we will fail to test some configuration.
If you want to disable freelists in your experiments, feel free to do so, but it doesn't need to be in main, IMO.
tiran commentedon Oct 29, 2021
Which part of the patch is causing you extra work? Would you be fine if I only remove the configure option and leave the fixes for zero-length freelists (#define PyList_MAXFREELIST 0) in?
vstinner commentedon Jan 15, 2022
Can you please document the new configuration option in https://docs.python.org/dev/using/configure.html ?
When you write :option:`--without-freelists` in what's new in Python 3.11 to get a link ;-)
vstinner commentedon Jan 17, 2022
I reopen the issue to not forget to complete the doc.
erlend-aasland commentedon Jun 19, 2023
I checked the docs, and this option is now documented; marking the issue as resolved.