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?
