[Python-Dev] Activating pymalloc

[Guido van Rossum]

> I wonder whether it's actually a good idea for PyMem_New (etc) to
> keep on calling malloc/free even when pymalloc is enabled.  Anyone
> think they know a reason (other than theoretical purity <wink>) for
> why pymalloc only targets the PyObject family?  If Michael is right,
> the current distinction is indeed guaranteed to break just about
> every extension written for 1.5.2.  It's also plain irritating that
> if you have, e.g., a gazillion tiny lists, only the list headers
> will enjoy pymalloc's speed & memory savings (the guts still get
> allocated via PyMem_XXX).

Well, then you would have to provide yet another set of macros that
don't require the GIL, for use by extensions that need to allocate
memory while not holding the GIL.  Of course, you could say, "then
just use malloc/free", but the intention of pymem.h was that it would
*also* be possible to provide a malloc/free substitute that *was*
thread-safe -- unlike pymalloc.  I don't know how realistic that is --
the only candidate would be GNU malloc but that would just replace the
malloc/realloc/free entry points so wouldn't need any of the
pymem.h-approved hackery.

--Guido van Rossum (home page: http://www.python.org/~guido/)