[PATCH v2 0/8] perf: Refine barriers for AUX ring buffer

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 0/8] perf: Refine barriers for AUX ring buffer
Date: Wed,  2 Jun 2021 18:29:59 +0800	[thread overview]
Message-ID: <20210602103007.184993-1-leo.yan@linaro.org> (raw)

Based on the discussion [1], this patch series is to refine the memory
barriers for AUX ring buffer.

Patches 01 ~ 04 to address the barriers usage in the kernel.  The first
patch is to make clear comment for how to use the barriers between the
data store and aux_head store, this asks the driver to make sure the
data is visible.  Patches 02 ~ 04 is to refine the drivers for barriers
after the data store.

Patches 05 ~ 07 is to fix and clean up the memory barries in perf tool
for AUX ring buffer.

Since the 64-bit value's atomicity is not promised on 32-bit perf, the
last patch is to report error and let perf to directly exit for this
case.

Have testes the patches on Arm64 Juno platform.

[1] https://lore.kernel.org/patchwork/patch/1431867/

Leo Yan (8):
  perf/ring_buffer: Add comment for barriers on AUX ring buffer
  coresight: tmc-etr: Add barrier after updating AUX ring buffer
  coresight: tmc-etf: Add comment for store ordering
  perf/x86: Add barrier after updating bts
  perf auxtrace: Change to use SMP memory barriers
  perf auxtrace: Drop legacy __sync functions
  perf auxtrace: Use WRITE_ONCE() for updating aux_tail
  perf record: Directly bail out for compat case

 arch/x86/events/intel/bts.c                   |  3 +++
 .../hwtracing/coresight/coresight-tmc-etf.c   |  6 +++++
 .../hwtracing/coresight/coresight-tmc-etr.c   |  8 ++++++
 kernel/events/ring_buffer.c                   |  9 +++++++
 tools/perf/builtin-record.c                   | 17 ++++++++++++
 tools/perf/util/auxtrace.h                    | 27 +++----------------
 6 files changed, 47 insertions(+), 23 deletions(-)

-- 
2.25.1

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