Charles-François Natali added the comment: > Julian Taylor added the comment: > > it defaulted to 128kb ten years ago, its a dynamic threshold since ages.
Indeed, and that's what encouraged switching the allocator to use mmap. The problem with dynamic mmap threshold is that since the Python allocator uses fixed-size arenas, basically malloc always ends up allocating from the heap (brk). Which means that given that we don't use a - compacting - garbage collector, after a while the heap would end up quite fragmented, or never shrink: for example let's say you allocate 1GB - on the heap - and then you free them, but a single object is allocated at the top of the heap, you heap never shrinks back. This has bitten people (and myself a couple times at work). Now, I see several options: - revert to using malloc, but this will re-introduce the original problem - build some form of hysteresis in the arena allocation - somewhat orthogonally, I'd be interested to see if we couldn't increase the arena size ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue26601> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
