diff --git a/.hgtags b/.hgtags
index 2235619fe4cf95956f8e753e928fac17fccb49c1..0d83d5839e585ed0800efadb449f51708173ecba 100644
--- a/.hgtags
+++ b/.hgtags
@@ -674,3 +674,5 @@ b852350a2bc6d5f43006e2be53fb74d148290708 hs25.60-b19
 bd9221771f6e34e63b3b340ffcf9906ccf882dae jdk8u60-b19
 e01a710549a962cee94728271248a7d89fb56c49 hs25.60-b20
 3b6c97747ccc61d189bca64b4afa3ffc13680810 jdk8u60-b20
+4b6687a4f2fe84211b8b3b5afb34b5186afbddf6 hs25.60-b21
+e0d75c284bd1c09fd7d9ef09627d8a99b88d468d jdk8u60-b21
diff --git a/make/hotspot_version b/make/hotspot_version
index 691dd76efacdccc49fa8691a28b70acc3e5ef263..7972d0131d5600cd24be2b7c409c995936f8dae5 100644
--- a/make/hotspot_version
+++ b/make/hotspot_version
@@ -35,7 +35,7 @@ HOTSPOT_VM_COPYRIGHT=Copyright 2015
 
 HS_MAJOR_VER=25
 HS_MINOR_VER=60
-HS_BUILD_NUMBER=20
+HS_BUILD_NUMBER=21
 
 JDK_MAJOR_VER=1
 JDK_MINOR_VER=8
diff --git a/src/share/vm/memory/genMarkSweep.cpp b/src/share/vm/memory/genMarkSweep.cpp
index ee4afdc6d7742739dac73d6c497442d11a9fe55a..c5dc4947c282174134fbe98918de579b237c67bb 100644
--- a/src/share/vm/memory/genMarkSweep.cpp
+++ b/src/share/vm/memory/genMarkSweep.cpp
@@ -211,7 +211,7 @@ void GenMarkSweep::mark_sweep_phase1(int level,
                          false, // Younger gens are not roots.
                          true,  // activate StrongRootsScope
                          GenCollectedHeap::SO_None,
-                         GenCollectedHeap::StrongRootsOnly,
+                         ClassUnloading,
                          &follow_root_closure,
                          &follow_root_closure,
                          &follow_cld_closure);
diff --git a/src/share/vm/memory/heap.cpp b/src/share/vm/memory/heap.cpp
index 3b54600383ec4e75e37c27d1d30519810a866421..a0fb60346c2d8d5a36dbef6c504cfb7478017396 100644
--- a/src/share/vm/memory/heap.cpp
+++ b/src/share/vm/memory/heap.cpp
@@ -99,9 +99,7 @@ bool CodeHeap::reserve(size_t reserved_size, size_t committed_size,
   // Reserve and initialize space for _memory.
   size_t page_size = os::vm_page_size();
   if (os::can_execute_large_page_memory()) {
-    const size_t min_pages = 8;
-    page_size = MIN2(os::page_size_for_region_aligned(committed_size, min_pages),
-                     os::page_size_for_region_aligned(reserved_size, min_pages));
+    page_size = os::page_size_for_region_unaligned(reserved_size, 8);
   }
 
   const size_t granularity = os::vm_allocation_granularity();
diff --git a/src/share/vm/runtime/arguments.cpp b/src/share/vm/runtime/arguments.cpp
index 7a7fbe666ed81d398cf45a3759b3ab7b4b7dc2eb..0ca38f1e9948c2878c0280f8a12d9322f5c1a784 100644
--- a/src/share/vm/runtime/arguments.cpp
+++ b/src/share/vm/runtime/arguments.cpp
@@ -1372,6 +1372,12 @@ void Arguments::set_cms_and_parnew_gc_flags() {
   if (!FLAG_IS_DEFAULT(CMSParPromoteBlocksToClaim) || !FLAG_IS_DEFAULT(OldPLABWeight)) {
     CFLS_LAB::modify_initialization(OldPLABSize, OldPLABWeight);
   }
+
+  if (!ClassUnloading) {
+    FLAG_SET_CMDLINE(bool, CMSClassUnloadingEnabled, false);
+    FLAG_SET_CMDLINE(bool, ExplicitGCInvokesConcurrentAndUnloadsClasses, false);
+  }
+
   if (PrintGCDetails && Verbose) {
     tty->print_cr("MarkStackSize: %uk  MarkStackSizeMax: %uk",
       (unsigned int) (MarkStackSize / K), (uint) (MarkStackSizeMax / K));