Re: [PATCH v4 00/12] Change readahead API

[Matthew Wilcox]

On Tue, Feb 04, 2020 at 04:32:27PM +0100, David Sterba wrote:
> On Sat, Feb 01, 2020 at 07:12:28AM -0800, Matthew Wilcox wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
> > 
> > I would particularly value feedback on this from the gfs2 and ocfs2
> > maintainers.  They have non-trivial changes, and a review on patch 5
> > would be greatly appreciated.
> > 
> > This series adds a readahead address_space operation to eventually
> > replace the readpages operation.  The key difference is that
> > pages are added to the page cache as they are allocated (and
> > then looked up by the filesystem) instead of passing them on a
> > list to the readpages operation and having the filesystem add
> > them to the page cache.  It's a net reduction in code for each
> > implementation, more efficient than walking a list, and solves
> > the direct-write vs buffered-read problem reported by yu kuai at
> > https://lore.kernel.org/linux-fsdevel/20200116063601.39201-1-yukuai3@xxxxxxxxxx/
> > 
> > v4:
> >  - Rebase on current Linus (a62aa6f7f50a ("Merge tag 'gfs2-for-5.6'"))
> 
> I've tried to test the patchset but haven't got very far, it crashes at boot
> ritht after VFS mounts the root. The patches are from mailinglist, applied on
> current master, bug I saw the same crash with the git branch in your
> repo (probably v1).

Yeah, I wasn't able to test at the time due to what turned out to be
the hpet bug in Linus' tree.  Now that's fixed, I've found & fixed a
couple more bugs.  There'll be a v5 once I fix the remaining problem
(looks like a missing page unlock somewhere).