Re: [PATCH 4/5] aio: vmap ringbuffer

Zach Brown
2012-10-09T18:30:00Z

On Mon, Oct 08, 2012 at 11:39:19PM -0700, Kent Overstreet wrote:
> It simplifies a lot of stuff if the ringbuffer is contiguously mapped
> into kernel space, and we can delete a lot of code - in particular, this
> is useful for converting read_events() to cmpxchg.

1) I'm concerned that Our Favourite Database Benchmarkers will see an
effect of having more TLB pressure from that mapping. kmap_atomic()
should be cheaper. We'll need to measure the difference.

2) I'm not at all convinced that the current ring semantics are safe
with cmpxchg(), more in the next patch.

- z