diff --git a/libc/include/sys/shm.h b/libc/include/sys/shm.h
index fb6f20c..8ab3d9a 100644
--- a/libc/include/sys/shm.h
+++ b/libc/include/sys/shm.h
@@ -36,11 +36,12 @@
 #include <sys/cdefs.h>
 #include <sys/ipc.h>
 #include <sys/types.h>
+#include <unistd.h>
 
 #include <linux/shm.h>
 
 #define shmid_ds shmid64_ds
-#define SHMLBA 4096
+#define SHMLBA getpagesize()
 
 __BEGIN_DECLS