dtrace: two buffers for ring and fill policies?

[Andriy Gapon]

I've just noticed that DTrace allocates two per-CPU principal buffers even when 
a bufpolicy of ring or fill is used.
I believe that the second buffer is never used in those cases.

This is the code:
                if (flags & DTRACEBUF_NOSWITCH)
                        continue;

                if ((buf->dtb_xamot = kmem_zalloc(size,
                    KM_NOSLEEP | KM_NORMALPRI)) == NULL)
                        goto err;

As far as I can see,  DTRACEBUF_NOSWITCH is not implied by DTRACEBUF_RING or 
DTRACEBUF_FILL.
Maybe it should be?

--
Andriy Gapon