Hi, On Fri, Jan 8, 2016 at 5:42 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Thu, Jan 07, 2016 at 04:36:44PM -0800, Douglas Anderson wrote: >> This patch adds the DMA_ATTR_NOHUGEPAGE attribute to the DMA-mapping >> subsystem. >> >> This attribute can be used as a hint to the DMA-mapping subsystem that >> it's likely not worth it to try to allocation large pages behind the >> scenes. Large pages are likely to make an IOMMU TLB work more >> efficiently but may not be worth it. See the Documentation contained in >> this patch for more details about this attribute and when to use it. >> >> Note that the name of the hint (DMA_ATTR_NOHUGEPAGE) is based on the >> name MADV_NOHUGEPAGE, which has the same meaning. If we have expected >> users, we could also add MADV_HUGEPAGE which has the opposite meaning of >> this hint. > > A user of this features seems to be missing in the series. Please don't > add any clutter with unclear usage to the kernel unless there is a real > need which can be deonstrated in form of patches and numbers. In my cover letter I tried to address this. See <http://comments.gmane.org/gmane.linux.kernel/2121364>. I said: > Notably missing from this series is the fourth patch that adds teeth to > the second and third. You can find that out of tree at > <https://chromium-review.googlesource.com/#/c/320498/>. Unfortunately > the rk3288_vpu, which is what I'm working on, is out of tree. ...but today I realized that I also needed to do work to get Exynos's MFC codec using this patch and MFC _is_ upstream. ...so my next series will include the MFC patch. Hopefully that will help address your concerns. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
