diff --git a/libc/kernel/common/linux/android_pmem.h b/libc/kernel/common/linux/android_pmem.h
index bdf3abae6..be0b34221 100644
--- a/libc/kernel/common/linux/android_pmem.h
+++ b/libc/kernel/common/linux/android_pmem.h
@@ -23,6 +23,7 @@
 #define PMEM_CONNECT _IOW(PMEM_IOCTL_MAGIC, 6, unsigned int)
 
 #define PMEM_GET_TOTAL_SIZE _IOW(PMEM_IOCTL_MAGIC, 7, unsigned int)
+#define PMEM_CACHE_FLUSH _IOW(PMEM_IOCTL_MAGIC, 8, unsigned int)
 
 struct android_pmem_platform_data
 {