Re: [PATCH 08/15] tracing: Introduce names for ring buffers

[Steven Rostedt]

On Wed, 13 Dec 2023 01:35:16 +0100
Alexander Graf <graf@xxxxxxxxxx> wrote:

> > The trace_array is the structure that represents each tracing instance. And
> > it already has a name field. And if you can get the associated ring buffer
> > from that too.
> >
> > struct trace_array *tr;
> >
> >          tr->array_buffer.buffer
> >
> >          tr->name
> >
> > When you do: mkdir /sys/kernel/tracing/instance/foo
> >
> > You create a new trace_array instance where tr->name = "foo" and allocates
> > the buffer for it as well.  
> 
> The name in the ring buffer is pretty much just a copy of the trace 
> array name. I use it to reconstruct which buffer we're actually 
> referring to inside __ring_buffer_alloc().

No, I rather not tie the ring buffer to the trace_array.

> 
> I'm all ears for alternative suggestions. I suppose we could pass tr as 
> argument to ring_buffer_alloc() instead of the name?

I'll have to spend some time (that I don't currently have :-( ) on looking
at this more. I really don't like the copying of the name into the ring
buffer allocation, as it may be an unneeded burden to maintain, not to
mention the duplicate field.

-- Steve