Re: [PATCH v3 10/15] iomap: add bias for async read requests

Christoph Hellwig
2025-09-22T18:33:56Z

On Thu, Sep 18, 2025 at 03:30:18PM -0700, Darrick J. Wong wrote:
> > + iomap_start_folio_read(folio, 1);
>
> I wonder, could you achieve the same effect by elevating
> read_bytes_pending by the number of bytes that we think we have to read,
> and subtracting from it as the completions come in or we decide that no
> read is necessary?

Weren't we going to look into something like that anyway to stop
the read code from building bios larger than the map to support the
extN boundary conditions? I'm trying to find the details of that,
IIRC willy suggested it. Because once we touch this area for
non-trivial changes it might be a good idea to get that done, or at
least do the prep work.