Re: [RFC PATCH v2] implement orangefs_readahead

[Mike Marshall <hubcap@omnibond.com>]

Hi David...

I got your netfs-lib branch as of Apr 15.

I added my orangefs_readahead on top of it and ran through
xfstests. I failed generic 75, 112, 127, & 263, which I
don't usually fail.

I took off my orangefs_readahead patch and ran xfstests with
your untouched netfs-lib branch. No regressions.

I git-reset back to 5.12.0-rc4 (I think your netfs-lib branch is based
on a linus-tree-of-the-day?) and ran xfstests... no regressions.

So... I think all your stuff is working well from my perspective
and that I need to figure out why my orangefs_readahead patch
is causing the regressions I listed. My readahead implementation (via your
readahead_expand) is really fast, but it is bare-bones... I'm probably
leaving out some important stuff... I see other filesystem's
readahead implementations doing stuff like avoiding doing readahead
on pages that have yet to be written back for example.

The top two commits at https://github.com/hubcapsc/linux/tree/readahead_v3
is the current state of my readahead implementation.

Please do add
Tested-by: Mike Marshall <hubcap@omnibond.com>

-Mike

On Tue, Apr 13, 2021 at 11:08 AM David Howells <dhowells@redhat.com> wrote:
>
> Mike Marshall <hubcap@omnibond.com> wrote:
>
> > Hi David... I've been gone on a motorcycle adventure,
> > sorry for the delay... here's my public branch...
> >
> > https://github.com/hubcapsc/linux/tree/readahead_v3
>
> That seems to have all of my fscache-iter branch in it.  I thought you'd said
> you'd dropped them because they were causing problems.
>
> Anyway, I've distilled the basic netfs lib patches, including the readahead
> expansion patch and ITER_XARRAY patch here:
>
>         https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=netfs-lib
>
> if that's of use to you?
>
> If you're using any of these patches, would it be possible to get a Tested-by
> for them that I can add?
>
> David
>