diff -r 72b1f300800f -r f4e28b781143 hgext3rd/evolve/utility.py
--- a/hgext3rd/evolve/utility.py	Thu Dec 21 03:07:14 2017 +0100
+++ b/hgext3rd/evolve/utility.py	Thu Dec 21 03:30:13 2017 +0100
@@ -43,4 +43,7 @@
         return False
     if not configbool('experimental', 'obshashrange.warm-cache', True):
         return False
+    maxrevs = repo.ui.configint('experimental', 'obshashrange.max-revs', None)
+    if maxrevs is not None and maxrevs < len(repo.unfiltered()):
+        return False
     return True