Re: [PATCH V2 19/30] coresight: etb10: implementing the setup_aux() API

From: Alexander Shishkin
Date: Mon Oct 19 2015 - 09:45:56 EST


Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> writes:

> Adding an ETB10 specific auxiliary area setup operation to be
> used by the perf framework when events are initialised.
>
> Part of this operation involves modeling the mmap'ed area based
> on the specific ways a sink buffer gathers information.

It really doesn't seem to be ETB10 specific at all. When you add more
sinks, you'll probably end up copying this code every time.

Furthermore,

> +static void *etb_setup_aux(struct coresight_device *csdev, int cpu,
> + void **pages, int nr_pages, bool overwrite)
> +{
> + int node, pg;
> + struct cs_buffers *buf;
> +
> + if (cpu == -1)
> + cpu = smp_processor_id();
> + node = cpu_to_node(cpu);
> +
> + buf = kzalloc_node(offsetof(struct cs_buffers, addr[nr_pages]),
> + GFP_KERNEL, node);
> + if (!buf)
> + return NULL;
> +
> + buf->snapshot = overwrite;
> + buf->nr_pages = nr_pages;
> +
> + /* Record information about buffers */
> + for (pg = 0; pg < buf->nr_pages; pg++)
> + buf->addr[pg] = pages[pg];
> +
> + return buf;
> +}
> +

this one is so generic that I'm tempted to move this into perf's
ring_buffer code, because by the looks of it we'll need it pretty much
in every setup_aux().

Regards,
--
Alex
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