syslet: add proper read barrier between user_tail and completion read

[fio.git] / arch / arch-x86_64.h

diff --git a/arch/arch-x86_64.h b/arch/arch-x86_64.h
index 4f75addc1be14fd35d46e9631a57b50978bb6023..979c3206185f87334488d60179ff9918e13642cf 100644 (file)
--- a/arch/arch-x86_64.h
+++ b/arch/arch-x86_64.h
@@ -29,7 +29,8 @@
 
 #define FIO_HAVE_SYSLET
 
-#define nop    __asm__ __volatile__("rep;nop": : :"memory")
+#define nop            __asm__ __volatile__("rep;nop": : :"memory")
+#define read_barrier() asm volatile("lfence":::"memory")
 
 static inline unsigned long fio_ffz(unsigned long bitmask)
 {