diff --git a/compiler-rt/lib/scudo/standalone/allocator_config.h b/compiler-rt/lib/scudo/standalone/allocator_config.h
--- a/compiler-rt/lib/scudo/standalone/allocator_config.h
+++ b/compiler-rt/lib/scudo/standalone/allocator_config.h
@@ -44,10 +44,10 @@
                                /*MaySupportMemoryTagging=*/true>
       Primary;
 #else
-  // 512KB regions
-  typedef SizeClassAllocator32<SizeClassMap, 19U> Primary;
+  // 256KB regions
+  typedef SizeClassAllocator32<SizeClassMap, 18U> Primary;
 #endif
-  typedef MapAllocator<MapAllocatorCache<>> Secondary;
+  typedef MapAllocator<MapAllocatorCache<32U, 1UL << 21>> Secondary;
   template <class A>
   using TSDRegistryT = TSDRegistrySharedT<A, 2U>; // Shared, max 2 TSDs.
 };