diff -r 3ff40811aeed -r 896cf79a19a7 Include/ceval.h
--- a/Include/ceval.h	Thu Aug 25 15:01:15 2011 +0200
+++ b/Include/ceval.h	Mon Aug 29 10:44:10 2011 +0200
@@ -184,6 +184,12 @@
 #define Py_END_ALLOW_THREADS    PyEval_RestoreThread(_save); \
                  }
 
+/* two internal functions that can be overridden by 3rd-party modules
+   that want to take more precise control over the GIL */
+typedef void (*_PyEval_GIL_func)(PyThreadState *);
+PyAPI_DATA(_PyEval_GIL_func) _PyEval_TakeGIL;
+PyAPI_DATA(_PyEval_GIL_func) _PyEval_DropGIL;
+
 #else /* !WITH_THREAD */
 
 #define Py_BEGIN_ALLOW_THREADS {
diff -r 3ff40811aeed -r 896cf79a19a7 Python/ceval.c
--- a/Python/ceval.c	Thu Aug 25 15:01:15 2011 +0200
+++ b/Python/ceval.c	Mon Aug 29 10:44:10 2011 +0200
@@ -294,6 +294,9 @@
 
 #include "ceval_gil.h"
 
+_PyEval_GIL_func _PyEval_TakeGIL = take_gil;
+_PyEval_GIL_func _PyEval_DropGIL = drop_gil;
+
 int
 PyEval_ThreadsInitialized(void)
 {
@@ -306,7 +309,7 @@
     if (gil_created())
         return;
     create_gil();
-    take_gil(PyThreadState_GET());
+    _PyEval_TakeGIL(PyThreadState_GET());
     main_thread = PyThread_get_thread_ident();
     if (!pending_lock)
         pending_lock = PyThread_allocate_lock();
@@ -327,7 +330,7 @@
     PyThreadState *tstate = PyThreadState_GET();
     if (tstate == NULL)
         Py_FatalError("PyEval_AcquireLock: current thread state is NULL");
-    take_gil(tstate);
+    _PyEval_TakeGIL(tstate);
 }
 
 void
@@ -337,7 +340,7 @@
        We therefore avoid PyThreadState_GET() which dumps a fatal error
        in debug mode.
     */
-    drop_gil((PyThreadState*)_Py_atomic_load_relaxed(
+    _PyEval_DropGIL((PyThreadState*)_Py_atomic_load_relaxed(
         &_PyThreadState_Current));
 }
 
@@ -348,7 +351,7 @@
         Py_FatalError("PyEval_AcquireThread: NULL new thread state");
     /* Check someone has called PyEval_InitThreads() to create the lock */
     assert(gil_created());
-    take_gil(tstate);
+    _PyEval_TakeGIL(tstate);
     if (PyThreadState_Swap(tstate) != NULL)
         Py_FatalError(
             "PyEval_AcquireThread: non-NULL old thread state");
@@ -361,7 +364,7 @@
         Py_FatalError("PyEval_ReleaseThread: NULL thread state");
     if (PyThreadState_Swap(NULL) != tstate)
         Py_FatalError("PyEval_ReleaseThread: wrong thread state");
-    drop_gil(tstate);
+    _PyEval_DropGIL(tstate);
 }
 
 /* This function is called from PyOS_AfterFork to ensure that newly
@@ -379,7 +382,7 @@
         return;
     recreate_gil();
     pending_lock = PyThread_allocate_lock();
-    take_gil(tstate);
+    _PyEval_TakeGIL(tstate);
     main_thread = PyThread_get_thread_ident();
 
     /* Update the threading module with the new state.
@@ -426,7 +429,7 @@
         Py_FatalError("PyEval_SaveThread: NULL tstate");
 #ifdef WITH_THREAD
     if (gil_created())
-        drop_gil(tstate);
+        _PyEval_DropGIL(tstate);
 #endif
     return tstate;
 }
@@ -439,10 +442,10 @@
 #ifdef WITH_THREAD
     if (gil_created()) {
         int err = errno;
-        take_gil(tstate);
+        _PyEval_TakeGIL(tstate);
         /* _Py_Finalizing is protected by the GIL */
         if (_Py_Finalizing && tstate != _Py_Finalizing) {
-            drop_gil(tstate);
+            _PyEval_DropGIL(tstate);
             PyThread_exit_thread();
             assert(0);  /* unreachable */
         }
@@ -1258,11 +1261,11 @@
                 /* Give another thread a chance */
                 if (PyThreadState_Swap(NULL) != tstate)
                     Py_FatalError("ceval: tstate mix-up");
-                drop_gil(tstate);
+                _PyEval_DropGIL(tstate);
 
                 /* Other threads may run now */
 
-                take_gil(tstate);
+                _PyEval_TakeGIL(tstate);
                 if (PyThreadState_Swap(tstate) != NULL)
                     Py_FatalError("ceval: orphan tstate");
             }