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gh-112532: Use separate mimalloc heaps for GC objects (gh-113263)

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* gh-112532: Use separate mimalloc heaps for GC objects

In `--disable-gil` builds, we now use four separate heaps in
anticipation of using mimalloc to find GC objects when the GIL is
disabled. To support this, we also make a few changes to mimalloc:

* `mi_heap_t` and `mi_tld_t` initialization is split from allocation.
  This allows us to have a `mi_tld_t` per-`PyThreadState`, which is
  important to keep interpreter isolation, since the same OS thread may
  run in multiple interpreters (using different PyThreadStates.)

* Heap abandoning (mi_heap_collect_ex) can now be called from a
  different thread than the one that created the heap. This is necessary
  because we may clear and delete the containing PyThreadStates from a
  different thread during finalization and after fork().

* Use enum instead of defines and guard mimalloc includes.

* The enum typedef will be convenient for future PRs that use the type.
* Guarding the mimalloc includes allows us to unconditionally include
  pycore_mimalloc.h from other header files that rely on things like
  `struct _mimalloc_thread_state`.

* Only define _mimalloc_thread_state in Py_GIL_DISABLED builds
This commit is contained in:
Sam Gross 2023-12-26 11:53:20 -05:00 • committed by GitHub
parent 8f5b998706
commit acf3bcc886
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9 changed files with 163 additions and 25 deletions
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24
Objects/mimalloc/init.c
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@ -297,24 +297,20 @@ static bool _mi_heap_init(void) {
mi_thread_data_t* td = mi_thread_data_zalloc();
if (td == NULL) return false;
mi_tld_t* tld = &td->tld;
mi_heap_t* heap = &td->heap;
_mi_tld_init(&td->tld, &td->heap);
_mi_heap_init_ex(&td->heap, &td->tld, _mi_arena_id_none());
_mi_heap_set_default_direct(&td->heap);
}
return false;
}
void _mi_tld_init(mi_tld_t* tld, mi_heap_t* bheap) {
_mi_memcpy_aligned(tld, &tld_empty, sizeof(*tld));
_mi_memcpy_aligned(heap, &_mi_heap_empty, sizeof(*heap));
heap->thread_id = _mi_thread_id();
_mi_random_init(&heap->random);
heap->cookie = _mi_heap_random_next(heap) | 1;
heap->keys[0] = _mi_heap_random_next(heap);
heap->keys[1] = _mi_heap_random_next(heap);
heap->tld = tld;
tld->heap_backing = heap;
tld->heaps = heap;
tld->segments.stats = &tld->stats;
tld->segments.os = &tld->os;
tld->os.stats = &tld->stats;
_mi_heap_set_default_direct(heap);
}
return false;
tld->heap_backing = bheap;
tld->heaps = bheap;
}
// Free the thread local default heap (called from `mi_thread_done`)