linux-kernel - Re: [PATCH 02/16] mm: introduce leaf entry type and use to simplify leaf entry logic

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Message-ID: <aQus_MNi2gFyY_pL@gourry-fedora-PF4VCD3F>
Date: Wed, 5 Nov 2025 15:01:00 -0500
From: Gregory Price <gourry@...rry.net>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: Matthew Wilcox <willy@...radead.org>,
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Subject: Re: [PATCH 02/16] mm: introduce leaf entry type and use to simplify
 leaf entry logic

On Wed, Nov 05, 2025 at 07:52:36PM +0000, Lorenzo Stoakes wrote:
> On Wed, Nov 05, 2025 at 02:25:34PM -0500, Gregory Price wrote:
> > On Wed, Nov 05, 2025 at 07:06:11PM +0000, Matthew Wilcox wrote:
> I thought about doing this but it doesn't really work as the type is
> _abstracted_ from the architecture-specific value, _and_ we use what is
> currently the swp_type field to identify what this is.
> 
> So we would lose the architecture-specific information that any 'hardware leaf'
> entry would require and not be able to reliably identify it without losing bits.
> 
> Trying to preserve the value _and_ correctly identify it as a present entry
> would be difficult.
> 
> And I _really_ didn't want to go on a deep dive through all the architectures to
> see if we could encode it differently to allow for this.
> 
> Rather I think it's better to differentiate between s/w + h/w leaf entries.
>

Reasonable - names are hard, but just about anything will be better than swp_entry.

SWE / sw_entry seems perfectly reasonable.

~Gregory