[PATCH v4 04/11] perf/x86: Add barrier after updating bts

[Leo Yan]

Add barrier wmb() to separate the AUX data store and aux_head store.

Signed-off-by: Leo Yan <leo.yan at linaro.org>
---
 arch/x86/events/intel/bts.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index 6320d2cfd9d3..4a015d160bc5 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -209,6 +209,9 @@ static void bts_update(struct bts_ctx *bts)
 	} else {
 		local_set(&buf->data_size, head);
 	}
+
+	/* The WMB separates data store and aux_head store matches. */
+	wmb();
 }
 
 static int
-- 
2.25.1