diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
index 0fd22df..897869c 100644
--- a/arch/powerpc/configs/ppc64_defconfig
+++ b/arch/powerpc/configs/ppc64_defconfig
@@ -49,6 +49,7 @@
 CONFIG_CRASH_DUMP=y
 CONFIG_IRQ_ALL_CPUS=y
 CONFIG_MEMORY_HOTREMOVE=y
+CONFIG_KSM=y
 CONFIG_SCHED_SMT=y
 CONFIG_PCCARD=y
 CONFIG_ELECTRA_CF=y