Upgrade mimalloc version from 2.1.2 to 2.5.2 #159111

Feature or enhancement

Upgrading to mimalloc to 3.x.x would need huge architecture changes, maybe we need to write a PEP for this.
But upgrading to latest 2.5.2 version would get following benefits.

1. Some CPython downstream changes are already applied to upstream.
   • microsoft/mimalloc@0c4041fa: custom heap and page tags
   • microsoft/mimalloc@d9aa19a7: sub-processes to isolate abandoned segments per interpreter
   • microsoft/mimalloc@855e3b25: visit all abandoned blocks per sub-process
   • microsoft/mimalloc@66052f13: MI_PRIM_THREAD_ID hook for a custom thread id
2. Handling abandoned segments have been improved.
   • microsoft/mimalloc@bdda13b8: track abandoned segments in per-arena bitmaps instead of a global list
   • microsoft/mimalloc@64edbc92, microsoft/mimalloc@9c96d05e: reclaim an abandoned segment when freeing into it (on by default)
   • microsoft/mimalloc@ee92b337: don't reclaim segments when freeing from a thread whose heap is already abandoned
   • microsoft/mimalloc@7774e800: don't visit full pages on a collection
3. Several memory leakage issues are fixed.
   • microsoft/mimalloc@d7a72c49: fix thread data leak
   • microsoft/mimalloc@96b69d7e: fix leak where OS-allocated abandoned segments were not always reclaimed
   • microsoft/mimalloc@635d626c: fix leak in abandoned block visiting
   • microsoft/mimalloc@acd6f6ce, microsoft/mimalloc@4e50cec3: fix purge expiry handling so arena memory is actually returned to the OS
4. Security fixes are applied.
   • microsoft/mimalloc@ef3867f5: guard against free list corruption in the double-free check
   • microsoft/mimalloc@25d6dcfc: check for overflow in claim_huge_pages
   • microsoft/mimalloc@4bc8b2f9: check size limits in mi_manage_os_memory / mi_reserve_os_memory
   • microsoft/mimalloc@66b93802, microsoft/mimalloc@204c6cbc — validate overlong environment values and strtol errors when reading MIMALLOC_* options

I 've applied changes in my local but we need to veify this on free-threading performance benchmark from Meta.

cc @mpage @itamaro @colesbury

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-159111: Update vendored mimalloc to v2.5.2 #159112