diff --git a/include/sys/sysmacros.h b/include/sys/sysmacros.h
index c56d7e12a620..4838ab3be3a5 100644
--- a/include/sys/sysmacros.h
+++ b/include/sys/sysmacros.h
@@ -78,6 +78,7 @@
 #define proc_pageout			NULL
 #define curproc				current
 #define max_ncpus			num_possible_cpus()
+#define boot_ncpus			num_online_cpus()
 #define CPU_SEQID			smp_processor_id()
 #define _NOTE(x)
 #define is_system_labeled()		0