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	Fri, 22 May 2026 12:55:59 +0000
Date: Fri, 22 May 2026 13:55:59 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Theodore Tso <tytso@mit.edu>, Christoph Hellwig <hch@infradead.org>,
	linux-kernel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	Akilesh Kailash <akailash@google.com>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-api@vger.kernel.org, Christian Brauner <christian@brauner.io>
Subject: Re: [PATCH v2] f2fs: another way to set large folio by remembering
 inode number
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On Fri, May 22, 2026 at 03:59:45AM +0000, Jaegeuk Kim wrote:
> On 05/21, Matthew Wilcox wrote:
> > On Thu, May 21, 2026 at 11:57:48AM -0400, Theodore Tso wrote:
> > > So let me get this straight.  This is a magic xattr interface which is
> > > not even persisted in the file system, but instead sets a 32-bit
> > > bitmask in the struct inode which disappears once the inode gets
> > > flushed from the inode stack.  And it uses a generic xattr name,
> > > "user.fadvise".
> > > 
> > > There's no way in *hell* any other file system is likely to adopt such
> > > a broken interface, so why didn't you just use an ioctl to set this
> > > magic f2fs-specific flag?
> > 
> > I mean, yes, this API is horrendous.  But it's just another example of
> > f2fs thinking it's somehow special and not just enabling large folios
> > like other filesystems do.  This hurts everyone, not just people who use
> > f2fs.
> 
> >From the production viewpoint, I raised a concern on setting large folio by
> default, since that exhausts lots of high-order pages, which were needed for
> essential system services and critical apps.

Random fears or actual data?