diff --git a/hgext/chgserver.py b/hgext/chgserver.py
--- a/hgext/chgserver.py
+++ b/hgext/chgserver.py
@@ -60,6 +60,7 @@ from mercurial import (
     error,
     extensions,
     osutil,
+    server,
     util,
 )
 
@@ -635,7 +636,7 @@ def chgunixservice(ui, repo, opts):
     return commandserver.unixforkingservice(ui, repo=None, opts=opts, handler=h)
 
 def uisetup(ui):
-    commandserver._servicemap['chgunix'] = chgunixservice
+    server._cmdservicemap['chgunix'] = chgunixservice
 
     # CHGINTERNALMARK is temporarily set by chg client to detect if chg will
     # start another chg. drop it to avoid possible side effects.
diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -35,7 +35,6 @@ from . import (
     bundle2,
     changegroup,
     cmdutil,
-    commandserver,
     copies,
     dagparser,
     dagutil,
@@ -6299,7 +6298,7 @@ def serve(ui, repo, **opts):
         s.serve_forever()
 
     if opts["cmdserver"]:
-        service = commandserver.createservice(ui, repo, opts)
+        service = server.createcmdservice(ui, repo, opts)
     else:
         service = hgweb.createservice(ui, repo, opts)
     return server.runservice(opts, initfn=service.init, runfn=service.run)
diff --git a/mercurial/commandserver.py b/mercurial/commandserver.py
--- a/mercurial/commandserver.py
+++ b/mercurial/commandserver.py
@@ -529,15 +529,3 @@ class unixforkingservice(object):
             _serverequest(self.ui, self.repo, conn, h.createcmdserver)
         finally:
             gc.collect()  # trigger __del__ since worker process uses os._exit
-
-_servicemap = {
-    'pipe': pipeservice,
-    'unix': unixforkingservice,
-    }
-
-def createservice(ui, repo, opts):
-    mode = opts['cmdserver']
-    try:
-        return _servicemap[mode](ui, repo, opts)
-    except KeyError:
-        raise error.Abort(_('unknown mode %s') % mode)
diff --git a/mercurial/server.py b/mercurial/server.py
--- a/mercurial/server.py
+++ b/mercurial/server.py
@@ -15,6 +15,7 @@ import tempfile
 from .i18n import _
 
 from . import (
+    commandserver,
     error,
     util,
 )
@@ -105,3 +106,15 @@ def runservice(opts, parentfn=None, init
 
     if runfn:
         return runfn()
+
+_cmdservicemap = {
+    'pipe': commandserver.pipeservice,
+    'unix': commandserver.unixforkingservice,
+}
+
+def createcmdservice(ui, repo, opts):
+    mode = opts['cmdserver']
+    try:
+        return _cmdservicemap[mode](ui, repo, opts)
+    except KeyError:
+        raise error.Abort(_('unknown mode %s') % mode)