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SubjectRe: [PATCH v2 05/10] coresight: trbe: Drop duplicate TRUNCATE flags
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On 30/07/2021 05:47, Anshuman Khandual wrote:
>
>
> On 7/23/21 6:16 PM, Suzuki K Poulose wrote:
>> We mark the buffer as TRUNCATED when there is no space left
>> in the buffer. But we do it at different points.
>> __trbe_normal_offset()
>> and also, at all the callers of the above function via
>> compute_trbe_buffer_limit(), when the limit == base (i.e
>> offset = 0 as returned by the __trbe_normal_offset()).
>>
>> So, given that the callers already mark the buffer as TRUNCATED
>> drop the caller inside the __trbe_normal_offset().
>>
>> This is in preparation to moving the handling of TRUNCATED
>> into a central place.
>>
>> 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 | 7 +------
>> 1 file changed, 1 insertion(+), 6 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
>> index 446f080f8320..62e1a08f73ff 100644
>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>> @@ -253,13 +253,9 @@ static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
>> * trbe_base trbe_base + nr_pages
>> *
>> * Perf aux buffer does not have any space for the driver to write into.
>> - * Just communicate trace truncation event to the user space by marking
>> - * it with PERF_AUX_FLAG_TRUNCATED.
>> */
>> - if (!handle->size) {
>> - perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
>> + if (!handle->size)
>> return 0;
>> - }
>>
>> /* Compute the tail and wakeup indices now that we've aligned head */
>> tail = PERF_IDX2OFF(handle->head + handle->size, buf);
>> @@ -361,7 +357,6 @@ static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
>> return limit;
>>
>> trbe_pad_buf(handle, handle->size);
>> - perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
>> return 0;
>> }
>
> What about in trbe_handle_spurious() path which used to set the flag via
> compute_trbe_buffer_limit(), but would not any more after this change. I
> guess following additional change would be required to preserve the past
> behaviour.
>
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -685,6 +685,7 @@ static void trbe_handle_spurious(struct perf_output_handle *handle)
> buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
> if (buf->trbe_limit == buf->trbe_base) {
> trbe_drain_and_disable_local();
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
> return;
> }
> trbe_enable_hw(buf);
>

Agreed, I will add this.

Thanks
Suzuki

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