Name arenas allocated by `mmap` in `_PyMem_ArenaAlloc` for debugging

[SpecLad]

Feature or enhancement

Proposal:

In Linux 5.17 a new feature was added, PR_SET_VMA_ANON_NAME, which lets you give names to anonymous virtual memory ranges. These names are shown in /proc/<pid>/maps, which can help with debugging.

The pymalloc allocator uses mmap to allocate arenas. It should use PR_SET_VMA_ANON_NAME to give names to the memory ranges containing arenas, e.g. "Python: arena".

Some examples of this done for other languages are in Glibc and Go.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-141770: Annotate anonymous mmap usage if "-X dev" is used #142079

[picnixz]

Please discuss this on https://discuss.python.org/ first. We support older kernels and rewriting this might need a concrete proposal to estimate how this would be achieved. In addition, it's only for Linux so portability is an issue.

EDIT: ok I looked at the issue and it's maybe not that hard. No need for a discuss thread though.

[picnixz]

Urhg... It's funny but... I cannot test this because I don't have a recent enough Linux kernel :D

[corona10]

Working and verifying in my local environment.
This feature should be enabled by kernel config itself too.
https://bugzilla.redhat.com/show_bug.cgi?id=2302746

[encukou]

Should this be exposed to users, with something like mmap.mmap(..., name=...)?