On 20/11/2020 02:54, Matthew Wilcox wrote: > On Fri, Nov 20, 2020 at 02:25:08AM +0000, Pavel Begunkov wrote: >> On 20/11/2020 02:22, Ming Lei wrote: >>> iov_iter_npages(bvec) still can be improved a bit by the following way: >> >> Yep, was doing exactly that, +a couple of other places that are in my way. > > Are you optimising the right thing here? Assuming you're looking at > the one in do_blockdev_direct_IO(), wouldn't we be better off figuring > out how to copy the bvecs directly from the iov_iter into the bio > rather than calling dio_bio_add_page() for each page? Ha, you got me, *add_page() was that "couple of others". It shows up much more, but iov_iter_npages() just looked simple enough to do first. -- Pavel Begunkov
