diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -161,3 +161,6 @@ coreconfigitem('worker', 'backgroundclos
 coreconfigitem('worker', 'backgroundcloseminfilecount',
     default=2048,
 )
+coreconfigitem('worker', 'backgroundclosethreadcount',
+    default=4,
+)
diff --git a/mercurial/vfs.py b/mercurial/vfs.py
--- a/mercurial/vfs.py
+++ b/mercurial/vfs.py
@@ -550,7 +550,7 @@ class backgroundfilecloser(object):
         # Windows defaults to a limit of 512 open files. A buffer of 128
         # should give us enough headway.
         maxqueue = ui.configint('worker', 'backgroundclosemaxqueue')
-        threadcount = ui.configint('worker', 'backgroundclosethreadcount', 4)
+        threadcount = ui.configint('worker', 'backgroundclosethreadcount')
 
         ui.debug('starting %d threads for background file closing\n' %
                  threadcount)