On Tue, Nov 6, 2018 at 8:35 PM Johannes Thumshirn <jthumshirn@xxxxxxx> wrote: > > On 05/11/2018 13:01, Ming Lei wrote: > > If you mean the real huge page, this patch shouldn't have made a difference > > because bio_vec->bv_offset is in [0, PAGE_SIZE), and iSer sets virt > > boundary as 4K - 1. > > > > However, things will change after multipage bvec is introduced. > > > Hi Ming, > > I've received a blktrace from our customer showing the issue [1]. > > In this example trace they've submitted (contiguous) 64K I/Os and > without this patch, they're seeing a lot of splits as indicated by the > trace. > > With the patch applied the I/O is directly issued to the LLDD without > the splits. > > [1] http://beta.suse.com/private/jthumshirn/blktrace.txt blktrace won't help on this issue because .bv_offset isn't recorded. This patch makes sense on >4KB PAGE_SIZE. If your issue happens on ARCH with 4K PAGE_SIZE, maybe you should root cause why it makes a difference on iSer. And it is highly possible there is bug somewhere. As I mentioned, the description of huge page part in the commit log is misleading, and it has to be fixed. Otherwise, the patch itself is fine: Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks Ming Lei
