Messages in this thread | | | Subject | Re: [PATCH v2 14/17] coresight: trbe: Make sure we have enough space | From | Anshuman Khandual <> | Date | Wed, 22 Sep 2021 15:28:21 +0530 |
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On 9/21/21 7:11 PM, Suzuki K Poulose wrote: > The TRBE driver makes sure that there is enough space for a meaningful > run, otherwise pads the given space and restarts the offset calculation > once. But there is no guarantee that we may find space or hit "no space".
So what happens currently when it neither finds the required minimum buffer space for a meaningful run nor does it hit the "no space" scenario ?
> Make sure that we repeat the step until, either : > - We have the minimum space > OR > - There is NO space at all. > > 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> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight-trbe.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c > index 3373f4e2183b..02f9e00e2091 100644 > --- a/drivers/hwtracing/coresight/coresight-trbe.c > +++ b/drivers/hwtracing/coresight/coresight-trbe.c > @@ -451,10 +451,14 @@ static unsigned long trbe_normal_offset(struct perf_output_handle *handle) > * If the head is too close to the limit and we don't > * have space for a meaningful run, we rather pad it > * and start fresh. > + * > + * We might have to do this more than once to make sure > + * we have enough required space.
OR no space at all, as explained in the commit message. Hence this comment needs an update.
> */ > - if (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) { > + while (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) { > trbe_pad_buf(handle, limit - head); > limit = __trbe_normal_offset(handle); > + head = PERF_IDX2OFF(handle->head, buf);
Should the loop be bound with a retry limit as well ?
> } > return limit; > } >
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