Re: [PATCH v2] f2fs: another way to set large folio by remembering inode number

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Apr 15, 2026 at 10:02:26PM +0000, Jaegeuk Kim wrote:
> On 04/15, Matthew Wilcox wrote:
> > On Wed, Apr 15, 2026 at 04:44:04PM +0000, Jaegeuk Kim wrote:
> > > On 04/14, Christoph Hellwig wrote:
> > > > Please add the relevant mailing lists when adding new user interfaces.
> > > > 
> > > > And I'm not sure hacks working around the proper large folio
> > > > implementation are something that should be merged upstream.
> > > 
> > > Cc'ed linux-api and linux-fsdevel onto the patch thread with a proposal that
> > > I'm not sure it's acceptable or not. 
> > 
> > You haven't sent a proposal.  This is a reply to a reply to a reply of a
> > patch.  There's no justification for why f2fs is so special that it
> > needs this.  What the hell is going on?  You know this is not the way to
> > get code merged into Linux.
> 
> I added two ideas in that email. Have you even tried to understand?

You want to establish "user.fadvise" as an extended attribute containing
a bitmask.  The sole bit defined in that attribute means "use large
folios", but you also have to change the file mode and set the IMMUTABLE
bit for it to actually do anything.

Meanwhile, you can't actually persist any of the fadvise(2) advice
flags, so the xattr name doesn't even make sense.  Maybe you meant to
call it "user.madvise" since the closest thing I can think of is
MADV_HUGEPAGE?

I've understood enough.  YUCK.

--D