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neal.norwitz
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Fix a few more memory leaks
Document more info about the benefits of configuring without pymalloc when running valgrind git-svn-id: http://svn.python.org/projects/python/trunk@41486 6015fed2-1504-0410-9fe1-9d1591cc4771
1 parent cb31e33 commit 467487e

4 files changed

Lines changed: 29 additions & 3 deletions

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‎Misc/README.valgrind‎

Lines changed: 15 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,19 @@ Misc/valgrind-python.supp. Second, you must do one of the following:
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* Uncomment the lines in Misc/valgrind-python.supp that
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suppress the warnings for PyObject_Free and PyObject_Realloc
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If you want to use Valgrind more effectively and catch even more
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memory leaks, you will need to configure python --without-pymalloc.
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PyMalloc allocates a few blocks in big chunks and most object
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allocations don't call malloc, they use chunks doled about by PyMalloc
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from the big blocks. This means Valgrind can't detect
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many allocations (and frees), except for those that are forwarded
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to the system malloc. Note: configuring python --without-pymalloc
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makes Python run much slower, especially when running under Valgrind.
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You may need to run the tests in batches under Valgrind to keep
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the memory usage down to allow the tests to complete. It seems to take
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about 5 times longer to run --without-pymalloc.
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Details:
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--------
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Python uses its own small-object allocation scheme on top of malloc,
@@ -21,7 +34,8 @@ Valgrind may show some unexpected results when PyMalloc is used.
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Starting with Python 2.3, PyMalloc is used by default. You can disable
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PyMalloc when configuring python by adding the --without-pymalloc option.
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If you disable PyMalloc, most of the information in this document and
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the supplied suppressions file will not be useful.
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the supplied suppressions file will not be useful. As discussed above,
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disabling PyMalloc can catch more problems.
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If you use valgrind on a default build of Python, you will see
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many errors like:

‎Python/ast.c‎

Lines changed: 10 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1054,8 +1054,12 @@ ast_for_listcomp(struct compiling *c, const node *n)
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return NULL;
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}
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1057-
if (asdl_seq_LEN(t) == 1)
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if (asdl_seq_LEN(t) == 1) {
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lc = comprehension(asdl_seq_GET(t, 0), expression, NULL);
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/* only free the sequence since we grabbed element 0 above */
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if (lc)
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asdl_seq_free(t); /* ok */
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}
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else
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lc = comprehension(Tuple(t, Store, LINENO(ch)), expression, NULL);
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@@ -1222,9 +1226,13 @@ ast_for_genexp(struct compiling *c, const node *n)
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return NULL;
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}
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1225-
if (asdl_seq_LEN(t) == 1)
1229+
if (asdl_seq_LEN(t) == 1) {
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ge = comprehension(asdl_seq_GET(t, 0), expression,
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NULL);
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/* only free the sequence since we grabbed element 0 above */
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if (ge)
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asdl_seq_free(t); /* ok */
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}
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else
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ge = comprehension(Tuple(t, Store, LINENO(ch)),
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expression, NULL);

‎Python/compile.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2384,7 +2384,10 @@ compiler_import_as(struct compiler *c, identifier name, identifier asname)
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dot = strchr(src, '.');
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attr = PyString_FromStringAndSize(src,
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dot ? dot - src : strlen(src));
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if (!attr)
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return -1;
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ADDOP_O(c, LOAD_ATTR, attr, names);
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Py_DECREF(attr);
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src = dot + 1;
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}
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}

‎Python/modsupport.c‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -82,6 +82,7 @@ Py_InitModule4(char *name, PyMethodDef *methods, char *doc,
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}
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Py_DECREF(v);
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}
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Py_DECREF(n);
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}
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if (doc != NULL) {
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v = PyString_FromString(doc);

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