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Date: Thu, 16 Apr 2026 07:33:03 +0200
From: Christoph Hellwig <hch@lst.de>
To: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jeff Layton <jlayton@kernel.org>, lsf-pc@lists.linux-foundation.org,
	linux-fsdevel@vger.kernel.org,
	Christian Brauner <brauner@kernel.org>,
	Christoph Hellwig <hch@lst.de>, Jan Kara <jack@suse.cz>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-m68k <linux-m68k@vger.kernel.org>,
	linux-sh <linux-sh@vger.kernel.org>
Subject: Re: [LSF/MM/BPF TOPIC] Should we make inode->i_ino a u64?
Message-ID: <20260416053303.GA15238@lst.de>
References: <08f8444c7237566ffb4ba8c9eb0ab4b4a5f14440.camel@kernel.org> <1b340c4e635dcab3bed8c52d6381b4c341c0741a.camel@physik.fu-berlin.de>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Wed, Apr 15, 2026 at 11:11:32AM +0200, John Paul Adrian Glaubitz wrote:
> So, this went just over Phoronix [1] and as someone who is still invested
> in 32-bit architectures, I'm only notified about the performance impact on
> these systems now as the pull request has already been sent to Linus.

What performance impact do you see?  When using modern file systems
reducing the memory usage should eventually improve performance, although
this change will require additional file system changes to get there.
btrfs already has a series out, and I'm working on the XFS conversion
to remove the duplicate 64-bit inode information.

Either way 7.0 will reduce the inode size already, as the shrinking
mutex/rw_semaphore (and for the XFS inode semaphore) cuts a lot of space,
which even on 32-bit by far overshadows the increased size of i_ino.

I'm also not sure what personal notification you expect?  This has been
discussion in-and-out on linux-fsdevel.