diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -403,9 +403,21 @@
         self._delayed = False
         self._delaybuf = None
         self._divert = False
-        self.filteredrevs = frozenset()
+        self._filteredrevs = frozenset()
+        self._filteredrevs_hashcache = {}
         self._copiesstorage = opener.options.get(b'copies-storage')
 
+    @property
+    def filteredrevs(self):
+        return self._filteredrevs
+
+    @filteredrevs.setter
+    def filteredrevs(self, val):
+        # Ensure all updates go through this function
+        assert isinstance(val, frozenset)
+        self._filteredrevs = val
+        self._filteredrevs_hashcache = {}
+
     def delayupdate(self, tr):
         """delay visibility of index updates to other readers"""
 
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -364,13 +364,15 @@
     cl = repo.changelog
     if not cl.filteredrevs:
         return None
-    key = None
-    revs = sorted(r for r in cl.filteredrevs if r <= maxrev)
-    if revs:
-        s = hashutil.sha1()
-        for rev in revs:
-            s.update(b'%d;' % rev)
-        key = s.digest()
+    key = cl._filteredrevs_hashcache.get(maxrev)
+    if not key:
+        revs = sorted(r for r in cl.filteredrevs if r <= maxrev)
+        if revs:
+            s = hashutil.sha1()
+            for rev in revs:
+                s.update(b'%d;' % rev)
+            key = s.digest()
+            cl._filteredrevs_hashcache[maxrev] = key
     return key