diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index 5e4974d40e..f2d2425f53 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -227,6 +227,7 @@ const (
 	// --------------  ---------  ----------  ----------  -----------
 	//       */64-bit         48        64MB           1    4M (32MB)
 	// windows/64-bit         48         4MB          64    1M  (8MB)
+	//      ios/arm64         33         4MB           1  2048  (8KB)
 	//       */32-bit         32         4MB           1  1024  (4KB)
 	//     */mips(le)         31         4MB           1   512  (2KB)
 
@@ -247,7 +248,7 @@ const (
 	// logHeapArenaBytes is log_2 of heapArenaBytes. For clarity,
 	// prefer using heapArenaBytes where possible (we need the
 	// constant to compute some other constants).
-	logHeapArenaBytes = (6+20)*(_64bit*(1-sys.GoosWindows)*(1-sys.GoarchWasm)) + (2+20)*(_64bit*sys.GoosWindows) + (2+20)*(1-_64bit) + (2+20)*sys.GoarchWasm
+	logHeapArenaBytes = (6+20)*(_64bit*(1-sys.GoosWindows)*(1-sys.GoarchWasm)*(1-sys.GoosIos*sys.GoarchArm64)) + (2+20)*(_64bit*sys.GoosWindows) + (2+20)*(1-_64bit) + (2+20)*sys.GoarchWasm + (2+20)*sys.GoosIos*sys.GoarchArm64
 
 	// heapArenaBitmapBytes is the size of each heap arena's bitmap.
 	heapArenaBitmapBytes = heapArenaBytes / (sys.PtrSize * 8 / 2)