Messages in this thread Patch in this message |  | | From | Suzuki K Poulose <> | Subject | [PATCH v2 09/10] coresight: trbe: End the AUX handle on truncation | Date | Fri, 23 Jul 2021 13:46:10 +0100 |
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When we detect that there isn't enough space left to start a meaningful session, we disable the TRBE, marking the buffer as TRUNCATED. But we delay the notification to the perf layer by perf_aux_output_end() until the event is scheduled out. This will cause significant black outs in the trace. Now that the CoreSight PMU layer can handle a closed "AUX" handle properly, we can close the handle as soon as we detect the case, allowing the userspace to collect and re-enable the event.
Also, while in the IRQ handler, move the irq_work_run() after we have updated the handle, to make sure the "TRUNCATED" flag causes the event to be disabled as soon as possible.
Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Leach <mike.leach@linaro.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight-trbe.c | 25 ++++++++++++-------- 1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 6d6aad171c72..e7567727e8fc 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -134,6 +134,7 @@ static void trbe_stop_and_truncate_event(struct perf_output_handle *handle) trbe_drain_and_disable_local(); perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED | PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW); + perf_aux_output_end(handle, 0); *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL; } @@ -699,7 +700,7 @@ static void trbe_handle_spurious(struct perf_output_handle *handle) isb(); } -static void trbe_handle_overflow(struct perf_output_handle *handle) +static int trbe_handle_overflow(struct perf_output_handle *handle) { struct perf_event *event = handle->event; struct trbe_buf *buf = etm_perf_sink_config(handle); @@ -728,10 +729,10 @@ static void trbe_handle_overflow(struct perf_output_handle *handle) */ trbe_drain_and_disable_local(); *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL; - return; + return -EINVAL; } - __arm_trbe_enable(buf, handle); + return __arm_trbe_enable(buf, handle); } static bool is_perf_trbe(struct perf_output_handle *handle) @@ -762,6 +763,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) struct perf_output_handle *handle = *handle_ptr; enum trbe_fault_action act; u64 status; + bool truncated = false; /* Reads to TRBSR_EL1 is fine when TRBE is active */ status = read_sysreg_s(SYS_TRBSR_EL1); @@ -786,24 +788,27 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) if (!is_perf_trbe(handle)) return IRQ_NONE; - /* - * Ensure perf callbacks have completed, which may disable - * the trace buffer in response to a TRUNCATION flag. - */ - irq_work_run(); - act = trbe_get_fault_act(status); switch (act) { case TRBE_FAULT_ACT_WRAP: - trbe_handle_overflow(handle); + truncated = !!trbe_handle_overflow(handle); break; case TRBE_FAULT_ACT_SPURIOUS: trbe_handle_spurious(handle); break; case TRBE_FAULT_ACT_FATAL: trbe_stop_and_truncate_event(handle); + truncated = true; break; } + + /* + * If the buffer was truncated, ensure perf callbacks + * have completed, which will disable the event. + */ + if (truncated) + irq_work_run(); + return IRQ_HANDLED; } -- 2.24.1
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