Hi Ming,
Thanks.
I have tested kernel '5.4.0-rc6+', which includes 07173c3ec276.
But the virtio is still be filled with single page by page.
Ming Lei <ming.lei@xxxxxxxxxx> 于2020年3月12日周四 下午8:34写道：
>
> On Thu, Mar 12, 2020 at 07:13:28PM +0800, Feng Li wrote:
> > Hi experts,
> >
> > May I ask a question about block layer?
> > When running fio in guest os, I find a 256k IO is split into the page
> > by page in bio, saved in bvecs.
> > And virtio-blk just put the bio_vec one by one in the available
> > descriptor table.
> >
> > So if my backend device does not support iovector
> > opertion(preadv/pwritev), then IO is issued to a low layer page by
> > page.
> > My question is: why doesn't the bio save multi-pages in one bio_vec?
>
> We start multipage bvec since v5.1, especially since 07173c3ec276
> ("block: enable multipage bvecs").
>
> Thanks,
> Ming
>
