Messages in this thread | | | Date | Tue, 12 Feb 2013 09:13:05 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH v2] lib/scatterlist: add simple page iterator |
| |
Hello,
On Tue, Feb 12, 2013 at 07:07:20PM +0200, Imre Deak wrote: > It's the one implemented by sg_miter_{start,stop} in scatterlist.c. It > also iterates through a scatterlist a page at a time, but it also kmaps > these pages. Since in our use case we don't need to map the pages we > needed a solution without this overhead.
I'm not against having non-mapping iterator but please consider that kmaps are no-ops on many configurations. It matters only for archs w/ high memory.
> where each entry on the sglist contained 16 consecutive pages. This > takes ~10% more time for the uninlined version to run. This is a rather > artificial test and I couldn't come up with something more real-life > using only the i915 driver's ioctl interface that would show a > significant change in speed. > > So at least for now I'm ok with just uninlining all the helpers.
Can we reimplement mapping iters using the new ones?
Thanks.
-- tejun
| |