Merged revisions 76007 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r76007 | antoine.pitrou | 2009-11-01 12:58:22 +0100 (dim., 01 nov. 2009) | 3 lines

  Buffered I/O: optimize lock taking in the common non-contended case.
........

Modules/_io/bufferedio.c

@@ -260,9 +260,11 @@ typedef struct {
 
 #ifdef WITH_THREAD
 #define ENTER_BUFFERED(self) \
-    Py_BEGIN_ALLOW_THREADS \
-    PyThread_acquire_lock(self->lock, 1); \
-    Py_END_ALLOW_THREADS
+    if (!PyThread_acquire_lock(self->lock, 0)) { \
+        Py_BEGIN_ALLOW_THREADS \
+        PyThread_acquire_lock(self->lock, 1); \
+        Py_END_ALLOW_THREADS \
+    }
 
 #define LEAVE_BUFFERED(self) \
     PyThread_release_lock(self->lock);