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From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v2 7/8] perf auxtrace: Use WRITE_ONCE() for updating aux_tail
Date: Wed,  2 Jun 2021 18:30:06 +0800	[thread overview]
Message-ID: <20210602103007.184993-8-leo.yan@linaro.org> (raw)
In-Reply-To: <20210602103007.184993-1-leo.yan@linaro.org>

Use WRITE_ONCE() for updating aux_tail, so can avoid unexpected memory
behaviour.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 tools/perf/util/auxtrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index e625bc76cdde..abc4282f5272 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -458,7 +458,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
 
 	/* Ensure all reads are done before we write the tail out */
 	smp_mb();
-	pc->aux_tail = tail;
+	WRITE_ONCE(pc->aux_tail, tail);
 }
 
 int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v2 7/8] perf auxtrace: Use WRITE_ONCE() for updating aux_tail
Date: Wed,  2 Jun 2021 18:30:06 +0800	[thread overview]
Message-ID: <20210602103007.184993-8-leo.yan@linaro.org> (raw)
In-Reply-To: <20210602103007.184993-1-leo.yan@linaro.org>

Use WRITE_ONCE() for updating aux_tail, so can avoid unexpected memory
behaviour.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 tools/perf/util/auxtrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index e625bc76cdde..abc4282f5272 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -458,7 +458,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
 
 	/* Ensure all reads are done before we write the tail out */
 	smp_mb();
-	pc->aux_tail = tail;
+	WRITE_ONCE(pc->aux_tail, tail);
 }
 
 int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
-- 
2.25.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-06-02 10:30 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-02 10:29 [PATCH v2 0/8] perf: Refine barriers for AUX ring buffer Leo Yan
2021-06-02 10:29 ` Leo Yan
2021-06-02 10:30 ` [PATCH v2 1/8] perf/ring_buffer: Add comment for barriers on " Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-07 15:27   ` Peter Zijlstra
2021-06-07 15:27     ` Peter Zijlstra
2021-06-02 10:30 ` [PATCH v2 2/8] coresight: tmc-etr: Add barrier after updating " Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-02 10:30 ` [PATCH v2 3/8] coresight: tmc-etf: Add comment for store ordering Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-02 10:30 ` [PATCH v2 4/8] perf/x86: Add barrier after updating bts Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-07 15:29   ` Peter Zijlstra
2021-06-07 15:29     ` Peter Zijlstra
2021-06-02 10:30 ` [PATCH v2 5/8] perf auxtrace: Change to use SMP memory barriers Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-07 10:02   ` Adrian Hunter
2021-06-07 10:02     ` Adrian Hunter
2021-06-07 15:29   ` Peter Zijlstra
2021-06-07 15:29     ` Peter Zijlstra
2021-06-08 16:45     ` Arnaldo Carvalho de Melo
2021-06-08 16:45       ` Arnaldo Carvalho de Melo
2021-06-02 10:30 ` [PATCH v2 6/8] perf auxtrace: Drop legacy __sync functions Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-02 10:47   ` Adrian Hunter
2021-06-02 10:47     ` Adrian Hunter
2021-06-02 11:16     ` Leo Yan
2021-06-02 11:16       ` Leo Yan
2021-06-02 11:21       ` Adrian Hunter
2021-06-02 11:21         ` Adrian Hunter
2021-06-02 13:01         ` Leo Yan
2021-06-02 13:01           ` Leo Yan
2021-06-02 10:30 ` Leo Yan [this message]
2021-06-02 10:30   ` [PATCH v2 7/8] perf auxtrace: Use WRITE_ONCE() for updating aux_tail Leo Yan
2021-06-07 10:03   ` Adrian Hunter
2021-06-07 10:03     ` Adrian Hunter
2021-06-07 15:31   ` Peter Zijlstra
2021-06-07 15:31     ` Peter Zijlstra
2021-06-08 17:04     ` Arnaldo Carvalho de Melo
2021-06-08 17:04       ` Arnaldo Carvalho de Melo
2021-06-09  0:21       ` Leo Yan
2021-06-09  0:21         ` Leo Yan
2021-06-02 10:30 ` [PATCH v2 8/8] perf record: Directly bail out for compat case Leo Yan
2021-06-02 10:30   ` Leo Yan
2021-06-02 11:18   ` Adrian Hunter
2021-06-02 11:18     ` Adrian Hunter
2021-06-02 12:38     ` Leo Yan
2021-06-02 12:38       ` Leo Yan
2021-06-07 10:23       ` Adrian Hunter
2021-06-07 10:23         ` Adrian Hunter
2021-06-07 15:09         ` Leo Yan
2021-06-07 15:09           ` Leo Yan
2021-06-09  8:23           ` Adrian Hunter
2021-06-09  8:23             ` Adrian Hunter
2021-06-09  8:57             ` Leo Yan
2021-06-09  8:57               ` Leo Yan

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