- date
2015/3/6
Linux glibc often hesitates to return memory to the OS. The mechanism is well explained in the issue tracker discussions. As such, CPython 3.3 changed to use :cmmap to allocate arenas: https://hg.python.org/cpython/rev/f8a697bc3ca8/ and https://hg.python.org/cpython/rev/e7aa72e6aad4/. The enhancement was later back-ported to 2.7: https://hg.python.org/cpython/rev/4e43e5b3f7fc/.
Alternatively, to resolve the wild glibc, one can use another memory allocator. Guys at ESN tried tcmalloc and found it is useful. For debugging memory issues tcmalloc looks like a good tool, as it offers quite nice heap analyzer.