Hi Christian, could you explain how you came up with the 256 entry limit ? It appears to be rather low and somehow arbitrary. I understand that some limit is required, but since these objects get created a lot (e.g. for bound methods), setting the limit too low will significantly slow down the interpreter. BTW: What does pybench have to say to this patch ? To get an idea of how many objects are typically part of the free list, I'd suggest running an application such as Zope for a while and then check the maximum numfree value. Thanks, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Feb 06 2008)

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Python/Zope Consulting and Support ... http://www.egenix.com/ mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! :::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 On 2008-02-06 13:44, christian.heimes wrote:

Author: christian.heimes Date: Wed Feb 6 13:44:34 2008 New Revision: 60614

Modified: python/trunk/Misc/NEWS python/trunk/Objects/classobject.c python/trunk/Objects/methodobject.c Log: Limit free list of method and builtin function objects to 256 entries each.

Modified: python/trunk/Misc/NEWS ============================================================================== --- python/trunk/Misc/NEWS (original) +++ python/trunk/Misc/NEWS Wed Feb 6 13:44:34 2008 @@ -12,6 +12,9 @@ Core and builtins -----------------

+- Limit free list of method and builtin function objects to 256 entries + each. + - Patch #1953: Added ``sys._compact_freelists()`` and the C API functions ``PyInt_CompactFreeList`` and ``PyFloat_CompactFreeList`` to compact the internal free lists of pre-allocted ints and floats.

Modified: python/trunk/Objects/classobject.c ============================================================================== --- python/trunk/Objects/classobject.c (original) +++ python/trunk/Objects/classobject.c Wed Feb 6 13:44:34 2008 @@ -4,10 +4,16 @@ #include "Python.h" #include "structmember.h"

+/* Free list for method objects to safe malloc/free overhead + * The im_self element is used to chain the elements. + */ +static PyMethodObject *free_list; +static int numfree = 0; +#define MAXFREELIST 256 + #define TP_DESCR_GET(t) \ (PyType_HasFeature(t, Py_TPFLAGS_HAVE_CLASS) ? (t)->tp_descr_get : NULL)

- /* Forward */ static PyObject *class_lookup(PyClassObject *, PyObject *, PyClassObject **); @@ -2193,8 +2199,6 @@ In case (b), im_self is NULL */

-static PyMethodObject *free_list; - PyObject * PyMethod_New(PyObject *func, PyObject *self, PyObject *klass) { @@ -2207,6 +2211,7 @@ if (im != NULL) { free_list = (PyMethodObject *)(im->im_self); PyObject_INIT(im, &PyMethod_Type); + numfree--; } else { im = PyObject_GC_New(PyMethodObject, &PyMethod_Type); @@ -2332,8 +2337,14 @@ Py_DECREF(im->im_func); Py_XDECREF(im->im_self); Py_XDECREF(im->im_class); - im->im_self = (PyObject *)free_list; - free_list = im; + if (numfree < MAXFREELIST) { + im->im_self = (PyObject *)free_list; + free_list = im; + numfree++; + } + else { + PyObject_GC_Del(im); + } }

static int @@ -2620,5 +2631,7 @@ PyMethodObject *im = free_list; free_list = (PyMethodObject *)(im->im_self); PyObject_GC_Del(im); + numfree--; } + assert(numfree == 0); }

Modified: python/trunk/Objects/methodobject.c ============================================================================== --- python/trunk/Objects/methodobject.c (original) +++ python/trunk/Objects/methodobject.c Wed Feb 6 13:44:34 2008 @@ -4,7 +4,12 @@ #include "Python.h" #include "structmember.h"

+/* Free list for method objects to safe malloc/free overhead + * The m_self element is used to chain the objects. + */ static PyCFunctionObject *free_list = NULL; +static int numfree = 0; +#define MAXFREELIST 256

PyObject * PyCFunction_NewEx(PyMethodDef *ml, PyObject *self, PyObject *module) @@ -14,6 +19,7 @@ if (op != NULL) { free_list = (PyCFunctionObject *)(op->m_self); PyObject_INIT(op, &PyCFunction_Type); + numfree--; } else { op = PyObject_GC_New(PyCFunctionObject, &PyCFunction_Type); @@ -125,8 +131,14 @@ _PyObject_GC_UNTRACK(m); Py_XDECREF(m->m_self); Py_XDECREF(m->m_module); - m->m_self = (PyObject *)free_list; - free_list = m; + if (numfree < MAXFREELIST) { + m->m_self = (PyObject *)free_list; + free_list = m; + numfree++; + } + else { + PyObject_GC_Del(m); + } }

static PyObject * @@ -346,14 +358,16 @@ PyCFunctionObject *v = free_list; free_list = (PyCFunctionObject *)(v->m_self); PyObject_GC_Del(v); + numfree--; } + assert(numfree == 0); }

/* PyCFunction_New() is now just a macro that calls PyCFunction_NewEx(), but it's part of the API so we need to keep a function around that existing C extensions can call. */ - + #undef PyCFunction_New PyAPI_FUNC(PyObject *) PyCFunction_New(PyMethodDef *, PyObject *);

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