diff --git a/Source/bmalloc/ChangeLog b/Source/bmalloc/ChangeLog
index 0fac1aa..541539f 100644
--- a/Source/bmalloc/ChangeLog
+++ b/Source/bmalloc/ChangeLog
@@ -1,3 +1,21 @@
+2019-07-12  Keith Miller  <keith_miller@apple.com>
+
+        Increase JSValue cage size on iOS and reduce the max slide
+        https://bugs.webkit.org/show_bug.cgi?id=199765
+
+        Reviewed by Saam Barati.
+
+        Since the WebContent jetsam limit has changed we sometimes run out
+        of JSValue cage VA space causing us to run out of memory for
+        arrays. This change makes the JSValue cage a more reasonable upper
+        limit for what should be possible without jetsamming.
+
+        The worst case memory mapping with this configuration is has not
+        changed from before. Under both configurations we could map 36GB
+        with a temporary mapping of 38GB (to align the VA to 2GB).
+
+        * bmalloc/Gigacage.h:
+
 2019-07-03  Keith Miller  <keith_miller@apple.com>
 
         PACCage should first cage leaving PAC bits intact then authenticate
diff --git a/Source/bmalloc/bmalloc/Gigacage.h b/Source/bmalloc/bmalloc/Gigacage.h
index a37d0ba..c730493 100644
--- a/Source/bmalloc/bmalloc/Gigacage.h
+++ b/Source/bmalloc/bmalloc/Gigacage.h
@@ -68,9 +68,9 @@
 
 #if BCPU(ARM64)
 constexpr size_t primitiveGigacageSize = 2 * bmalloc::Sizes::GB;
-constexpr size_t jsValueGigacageSize = 1 * bmalloc::Sizes::GB;
+constexpr size_t jsValueGigacageSize = 2 * bmalloc::Sizes::GB;
 constexpr size_t gigacageBasePtrsSize = 16 * bmalloc::Sizes::kB;
-constexpr size_t maximumCageSizeReductionForSlide = bmalloc::Sizes::GB / 2;
+constexpr size_t maximumCageSizeReductionForSlide = bmalloc::Sizes::GB / 4;
 #define GIGACAGE_ALLOCATION_CAN_FAIL 1
 #else
 constexpr size_t primitiveGigacageSize = 32 * bmalloc::Sizes::GB;