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 5/8] perf auxtrace: Change to use SMP memory barriers Date: Wed, 2 Jun 2021 18:30:04 +0800 [thread overview] Message-ID: <20210602103007.184993-6-leo.yan@linaro.org> (raw) In-Reply-To: <20210602103007.184993-1-leo.yan@linaro.org> The kernel and the userspace tool can access the AUX ring buffer head and tail from different CPUs, thus SMP class of barriers are required on SMP system. This patch changes to use SMP barriers to replace mb() and rmb() barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- tools/perf/util/auxtrace.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h index a4fbb33b7245..42b7ef811bde 100644 --- a/tools/perf/util/auxtrace.h +++ b/tools/perf/util/auxtrace.h @@ -444,7 +444,7 @@ static inline u64 auxtrace_mmap__read_snapshot_head(struct auxtrace_mmap *mm) u64 head = READ_ONCE(pc->aux_head); /* Ensure all reads are done after we read the head */ - rmb(); + smp_rmb(); return head; } @@ -458,7 +458,7 @@ static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm) #endif /* Ensure all reads are done after we read the head */ - rmb(); + smp_rmb(); return head; } @@ -470,7 +470,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail) #endif /* Ensure all reads are done before we write the tail out */ - mb(); + smp_mb(); #if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT) pc->aux_tail = tail; #else -- 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 5/8] perf auxtrace: Change to use SMP memory barriers Date: Wed, 2 Jun 2021 18:30:04 +0800 [thread overview] Message-ID: <20210602103007.184993-6-leo.yan@linaro.org> (raw) In-Reply-To: <20210602103007.184993-1-leo.yan@linaro.org> The kernel and the userspace tool can access the AUX ring buffer head and tail from different CPUs, thus SMP class of barriers are required on SMP system. This patch changes to use SMP barriers to replace mb() and rmb() barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- tools/perf/util/auxtrace.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h index a4fbb33b7245..42b7ef811bde 100644 --- a/tools/perf/util/auxtrace.h +++ b/tools/perf/util/auxtrace.h @@ -444,7 +444,7 @@ static inline u64 auxtrace_mmap__read_snapshot_head(struct auxtrace_mmap *mm) u64 head = READ_ONCE(pc->aux_head); /* Ensure all reads are done after we read the head */ - rmb(); + smp_rmb(); return head; } @@ -458,7 +458,7 @@ static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm) #endif /* Ensure all reads are done after we read the head */ - rmb(); + smp_rmb(); return head; } @@ -470,7 +470,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail) #endif /* Ensure all reads are done before we write the tail out */ - mb(); + smp_mb(); #if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT) pc->aux_tail = tail; #else -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev 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 ` Leo Yan [this message] 2021-06-02 10:30 ` [PATCH v2 5/8] perf auxtrace: Change to use SMP memory barriers 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 ` [PATCH v2 7/8] perf auxtrace: Use WRITE_ONCE() for updating aux_tail Leo Yan 2021-06-02 10:30 ` 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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