mirror of https://github.com/python/cpython
c012c8ab7b
This implements the delayed reuse of mimalloc pages that contain Python objects in the free-threaded build. Allocations of the same size class are grouped in data structures called pages. These are different from operating system pages. For thread-safety, we want to ensure that memory used to store PyObjects remains valid as long as there may be concurrent lock-free readers; we want to delay using it for other size classes, in other heaps, or returning it to the operating system. When a mimalloc page becomes empty, instead of immediately freeing it, we tag it with a QSBR goal and insert it into a per-thread state linked list of pages to be freed. When mimalloc needs a fresh page, we process the queue and free any still empty pages that are now deemed safe to be freed. Pages waiting to be freed are still available for allocations of the same size class and allocating from a page prevent it from being freed. There is additional logic to handle abandoned pages when threads exit. |
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mimalloc | ||
mimalloc.h |