2018-07-24 12:09 GMT+02:00 Bartosz Golaszewski <b...@bgdev.pl>: > 2018-07-23 21:51 GMT+02:00 Thomas Jollans <t...@tjol.eu>: >> On 23/07/18 20:02, Bartosz Golaszewski wrote: >>> Hi! >> >> Hey! >> >>> A user recently reported a memory leak in python bindings (C extension >>> module) to a C library[1] I wrote. I've been trying to fix it since >>> but so far without success. Since I'm probably dealing with a space >>> leak rather than actual memory leak, valgrind didn't help much even >>> when using malloc as allocator. I'm now trying to use >>> PYTHONMALLOCSTATS but need some help on how to interpret the output >>> emitted it's enabled. >> >> Oh dear. >> >>> >>> [snip] >>> >>> The number of pools in arena 53 continuously grows. Its size column >>> says: 432. I couldn't find any documentation on what it means but I >>> assume it's an allocation of 432 bytes. [...] >> >> I had a quick look at the code (because what else does one do for fun); >> I don't understand much, but what I can tell you is that >> (a) yes, that is an allocation size in bytes, and >> (b) as you can see, it uses intervals of 8. This means that pool 53 >> is used for allocations of 424 < nbytes <= 432 bytes. Maybe your >> breakpoint needs tweaking. >> (c) Try breaking on _PyObject_Malloc or pymalloc_alloc. I think they're >> called by both PyMem_Malloc and PyObject_Malloc. >> >> int _PyObject_DebugMallocStats(FILE *out) >> >> https://github.com/python/cpython/blob/b18f8bc1a77193c372d79afa79b284028a2842d7/Objects/obmalloc.c#L2435 >> >> static int pymalloc_alloc(void *ctx, void **ptr_p, size_t nbytes) >> >> https://github.com/python/cpython/blob/b18f8bc1a77193c372d79afa79b284028a2842d7/Objects/obmalloc.c#L1327 >> >> >> Have fun debugging! >> >> -- Thomas >> >>
[snip!] > > I don't see any other allocation of this size. Can this be some bug in > the interpreter? > > Bart Ok so this is strange: I can fix the leak if I explicitly call PyObject_Free() on the leaking object which is created by "calling" its type. Is this normal? Shouldn't Py_DECREF() be enough? The relevant dealloc callback is called from Py_DECREF() but the object's memory is not freed. Bart -- https://mail.python.org/mailman/listinfo/python-list
