Messages in this thread | | | Date | Tue, 9 Oct 2012 11:29:49 -0700 | From | Zach Brown <> | Subject | Re: [PATCH 4/5] aio: vmap ringbuffer |
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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
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