From 41100833cdd8b1bef363b81a6482d74711c116ad Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Mon, 9 Aug 2021 19:14:02 +0800 Subject: perf/x86: Add compiler barrier after updating BTS Since BTS is coherent, simply add a compiler barrier to separate the BTS update and aux_head store. Signed-off-by: Leo Yan Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20210809111407.596077-5-leo.yan@linaro.org --- arch/x86/events/intel/bts.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c index 6320d2cfd9d3..974e917e65b2 100644 --- a/arch/x86/events/intel/bts.c +++ b/arch/x86/events/intel/bts.c @@ -209,6 +209,12 @@ static void bts_update(struct bts_ctx *bts) } else { local_set(&buf->data_size, head); } + + /* + * Since BTS is coherent, just add compiler barrier to ensure + * BTS updating is ordered against bts::handle::event. + */ + barrier(); } static int -- cgit v1.2.3