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[3.15] gh-159111: Update vendored mimalloc to v2.5.2 (gh-159112) - #160178
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…159112) * Update vendored mimalloc to v2.5.2 Upgrade mimalloc from v2.1.2 to v2.5.2 as-is from upstream. v2.1.2: https://github.com/microsoft/mimalloc/releases/tag/v2.1.2 v2.5.2: https://github.com/microsoft/mimalloc/releases/tag/v2.5.2 * Re-apply CPython-specific changes to mimalloc v2.5.2 Most of the previous downstream changes were upstreamed in mimalloc v2.1.3 - v2.1.7 (heap tags, _mi_heap_init/_mi_tld_init, MI_PRIM_THREAD_ID, sub-processes, heap walk optimizations, platform fixes) and are dropped. Remaining CPython-specific changes, all marked with a "CPython" comment: - QSBR delayed page freeing for free-threaded builds (pythongh-115103, pythongh-145615): mi_page_t/mi_heap_t fields and _PyMem_mi_* hooks in page.c, heap.c and segment.c. - debug_offset: preserve the first bytes of a PyObject (ob_tid, refcount fields) when filling freed or uninitialized memory in debug builds (pythongh-115491). - Atomic mi_block_t.next loads/stores to avoid TSAN reports (pythongh-129748). - Relax the owning thread assertion in _mi_free_delayed_block for free-threaded builds, since the GC traverses heaps of other threads. - Call _mi_heap_delayed_free_partial() in mi_heap_visit_blocks() (pythongh-112532). - Only count reclaimed pages up to MI_MEDIUM_OBJ_SIZE_MAX as a "right page" in mi_segment_reclaim (pythongh-115103). - Rename the weak _ZSt15get_new_handlerv symbol and disable the mi_is_in_heap_region debug warning. - Zero-initialize _mi_page_empty instead of a positional initializer. * Update the free-threaded build to mimalloc v2.5.2 changes mimalloc v2.1.4 replaced the list of abandoned segments with per-arena bitmaps and introduced sub-processes (mi_subproc_t) to keep abandoned segments of separate interpreters apart. Use them instead of the CPython-specific mi_abandoned_pool_t: - Each interpreter owns a mi_subproc_t created in init_interpreter(). - tstate_mimalloc_bind() sets tld->segments.subproc and uses the upstream _mi_heap_init() signature. - The GC and sys.getallocatedblocks() visit abandoned segments with _PyMem_mi_visit_abandoned_blocks(), the upstream cursor API without the mi_option_visit_abandoned requirement, while STW. * Update NEWS.d * fix MSAN * fix TSAN * fix test_cext * Disable THP * Address code review * Address code review * Address code review * nit * Address code review * Address code review (cherry picked from commit aff7a2e) Co-authored-by: Donghee Na <donghee.na@python.org>
corona10
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a team,
AA-Turner,
FFY00,
ZeroIntensity,
emmatyping,
ericsnowcurrently and
erlend-aasland
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October 22, 2026 04:19
Documentation build overview
160 files changed ·
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…_ on Emscripten (from pythonGH-159039)
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@DinoV Need the approval before merge :) (dup) |
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