Re: [PATCH 11/30] iomap: add the new iomap_iter model

On Thu, Aug 12, 2021 at 08:49:14AM +0200, Christoph Hellwig wrote:

On Wed, Aug 11, 2021 at 12:17:08PM -0700, Darrick J. Wong wrote:

quoted

quoted

iter.c is also my preference, but in the end I don't care too much.

Ok.  My plan for this is to change this patch to add the new iter code
to apply.c, and change patch 24 to remove iomap_apply.  I'll add a patch
on the end to rename apply.c to iter.c, which will avoid breaking the
history.

What history?  There is no shared code, so no shared history and.

The history of the gluecode that enables us to walk a bunch of extent
mappings.  In the beginning it was the _apply function, but now in our
spectre-weary world, you've switched it to a direct loop to reduce the
number of indirect calls in the hot path by 30-50%.

As you correctly point out, there's no /code/ shared by the two
implementations, but Dave and I would like to preserve the continuity
from one to the next.

quoted

I'll send the updated patches as replies to this series to avoid
spamming the list, since I also have a patchset of bugfixes to send out
and don't want to overwhelm everyone.

Just as a clear statement:  I think this dance is obsfucation and doesn't
help in any way.  But if that's what it takes..

I /would/ appreciate it if you'd rvb (or at least ack) patch 31 so I can
get the 5.15 iomap changes finalized next week.  Pretty please? :)

--D