Re: [PATCH v6 3/3] iomap: add simple dio path for small direct I/O

[Joanne Koong]

On Thu, Jul 2, 2026 at 7:35 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> On Wed, Jul 01, 2026 at 12:35:24PM -0700, Joanne Koong wrote:
> > I think it ends up being pretty simple to get it integrated since
> > ->iomap_next already contains the logic to only begin the mapping at
> > the start and only finish the mapping when the iter has been fully
> > consumed, eg
>
> I wonder if this adds overhead that the simple path removed.

Ah I see now, the whole point of Fengnan's series is to k eep the
logic minimal...

Fengnan, I think you had mentioned earlier [1] that enabling
iomap_next brought the simple-read gain down from 10% to 7%? Thanks
for running those numbers. Would you be able to share the changes you
made to iomap_dio_rw to support iomap_next for those benchmarks you
ran?

Thanks,
Joanne

[1] https://lore.kernel.org/linux-fsdevel/e85e73bd-5fbe-4d11-89ba-7b42c237dd34@xxxxxxxxxxxxx/