Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> writes:
> Implementing perf related APIs to activate and terminate
> a trace session. More specifically dealing with the sink
> buffer's internal mechanic along with perf's API to start
> and stop interactions with the ring buffers.
A matter of preference, but I'd say that it would be easier to review
this part if you merged all the buffer related patches together.
> +static void etb_reset_buffer(struct coresight_device *csdev,
> + struct perf_output_handle *handle,
> + void *sink_config)
> +{
> + struct cs_buffers *buf = sink_config;
> + struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + if (buf) {
> + /*
> + * In snapshot mode ->data_size holds the new address of the
> + * ring buffer's head. The size itself is the whole address
> + * range since we want the latest information.
> + */
> + if (buf->snapshot)
> + handle->head = local_xchg(&buf->data_size,
> + buf->nr_pages << PAGE_SHIFT);
Does it make sense to do this in etb_update_buffer() instead?
> + perf_aux_output_end(handle, local_xchg(&buf->data_size, 0),
> + local_xchg(&buf->lost, 0));
The corresponding perf_aux_output_begin() is done in etm_event_add(),
I'd suggest that you do this in etm_event_del(),
unconditionally. Otherwise you're risking ending up with a refcount leak
and all sorts of horror.
Regards,
--
Alex
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