Messages in this thread | | | Subject | Re: [PATCH 4/5] coresight: trbe: Move irq_work queue processing | From | Anshuman Khandual <> | Date | Thu, 15 Jul 2021 08:53:46 +0530 |
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On 7/12/21 5:08 PM, Suzuki K Poulose wrote: > The TRBE driver issues the irq_work_run() to ensure that > any pending disable event callback has been processed. But this > is done before we mark the AUX buffer as TRUNCATED, making > the call pointless. Move the call after the current handle > has been closed.
So there is a possibility that a disable event gets missed before the buffer is marked TRUNCATED ? But even then would not another disable event be triggered again subsequently ? Just trying to understand what is the actual problem because of the current placement of irq_work_run() ?
> > Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver") > Reported-by: Tamas Zsoldos <Tamas.Zsoldos@arm.com> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org> > Cc: Mike Leach <mike.leach@linaro.org> > Cc: Peter Zijlstra (Intel) <peterz@infradead.org> > Cc: Leo Yan <leo.yan@linaro.org> > Cc: Will Deacon <will@kernel.org> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight-trbe.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c > index ec38cf17b693..c0c264264427 100644 > --- a/drivers/hwtracing/coresight/coresight-trbe.c > +++ b/drivers/hwtracing/coresight/coresight-trbe.c > @@ -723,6 +723,14 @@ static void trbe_handle_overflow(struct perf_output_handle *handle) > perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW | > PERF_AUX_FLAG_TRUNCATED); > perf_aux_output_end(handle, size); > + > + /* > + * Ensure perf callbacks have completed. Since we > + * always TRUNCATE the buffer on IRQ, the event > + * is scheduled to be disabled. Make sure that happens > + * as soon as possible. > + */ > + irq_work_run(); > } > > static bool is_perf_trbe(struct perf_output_handle *handle) > @@ -777,12 +785,6 @@ 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: >
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