Re: [PATCH 3/7] iomap: optional zero range dirty folio processing

[Brian Foster <bfoster@redhat.com>]

On Tue, Jun 10, 2025 at 06:29:10AM -0700, Christoph Hellwig wrote:
> On Tue, Jun 10, 2025 at 08:21:06AM -0400, Brian Foster wrote:
> > Yes.. but I'm not totally sure wrt impact on the fbatch checks quite
> > yet. The next thing I wanted to look at is addressing the same unwritten
> > mapping vs. dirty folios issue in the seek data/hole path. It's been a
> > little while since I last investigated there (and that was also before
> > the whole granular advance approach was devised), but IIRC it would look
> > rather similar to what this is doing for zero range. That may or may
> > not justify just making the batch required for both operations and
> > potentially simplifying this logic further. I'll keep that in mind when
> > I get to it..
> 
> On thing that the batch would be extremely useful for is making
> iomap_file_unshare not totally suck by reading in all folios for a
> range (not just the dirty ones) similar to the filemap_read path
> instead of synchronously reading one block at a time.
> 

I can add it to the list to look into. On a quick look though any reason
we wouldn't want to just invoke readahead or something somewhere in that
loop, particularly if that is mainly a performance issue..?

Brian