[Python-Dev] RE: Program very slow to finish

[M.-A. Lemburg]

Neil Schemenauer wrote:
> 
> Tim Peters wrote:
> > Can any Python-Dev'er make time to dig into the advisability of making
> > PyMalloc the default?  I only took time for this because I'm out sick today,
> > and was looking for something mindless to occupy my fevered thoughts; alas,
> > it paid off <wink>.  I recall there are still thread issues wrt PyMalloc,
> > and there *were* some reports that PyMalloc was slower on some platforms.
> 
> The problem is with extension modules.  We can make sure code in CVS
> always has the big lock held when calling PyMalloc.  We can't be sure
> that extension modules are safe.
> 
> The other, more serious problem is that many extension modules allocate
> memory with PyObject_New() and free it with free() or PyMem_DEL()
> instead of PyObject_Del() or PyObject_DEL().  If pymalloc is enabled
> then memory allocated by a PyObject_* function must be freed by a
> PyObject_* funciton.
> 
> mxDateTime is the first module I ran into that does this but there are
> many others I'm sure.  I think almost all of the C modules I have
> written do it.  The code in xxmodule.c used to do it as well.

What is considered the "right" approach for this ? Should Python
objects *always* be deallocated using one of PyObject_Del() and
PyObject_DEL() or is PyMem_DEL() usable as well ?

The reason I'm asking is that the mxDateTime objects I'm
deallocating are actually unreferenced objects on a
free list, so PyObject_Del() will probably bomb on them.

Also, what should be done with failing constructors ? I usually
use PyMem_DEL() to prevent the deallocator from being called but
still free the allocated memory. Is that the correct approach ?

-- 
Marc-Andre Lemburg
CEO eGenix.com Software GmbH
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